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Eisbacher, Michael School of Medical Science UNSW. "The regulation of megakaryocyte-specific genes by Fli-1 and GATA-1." Awarded by:University of New South Wales. School of Medical Science, 2003. http://handle.unsw.edu.au/1959.4/19171.
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The successive activation of tissue-specific genes during cellular differentiation is orchestrated by the formation of transcriptional complexes consisting of cellspecific and ubiquitous transcription factors. Understanding the molecular events associated with normal megakaryocyte (Mk) differentiation is an issue of central importance to haematology. The aims of this study were therefore to: (i) define the transcription factors responsible for regulating the expression of Mkspecific genes such as Glycoprotein IX, (ii) identify the protein partners of such important Mk-regulatory transcription factors and (iii) examine the mechanisms utilised by these factors to regulate gene expression. First, the regulatory elements in the GPIX promoter required for basal and inducible expression were examined in megakaryoblastic Dami cells stimulated to undergo differentiation. The resulting data suggested that an Ets site in the GPIX promoter binding the Ets-family member Fli-1 was crucial in regulating both constitutive and inducible GPIX expression. Second, a two-hybrid screen of a K-562 cDNA library was used to identify transcription factors that interacted with Fli-1 and were potential regulators of Mk development. Results of this screen identified a novel protein-protein interaction with GATA-1, a previously well-characterised zinc finger transcription factor also implicated in erythroid and Mk development. Mapping of the domains required for the interaction show that the zinc fingers of GATA-1 interact with the Ets domain of Fli-1. The biological significance of the Fli-1/GATA-1 interaction was demonstrated in transient transfection assays, which resulted in synergistic activation of Mkspecific promoters. Analysis of Fli-1 and GATA-1 expression in a series of erythroleukaemic and megakaryoblastic cell lines demonstrated that the Fli- 1/GATA-1 combination correlates with a Mk-phenotype. Moreover, expression of Fli-1 in K-562 cells (a line rich in GATA-1 but normally lacking Fli-1) induces endogenous GPIX expression. Quantitative mobility shift assays reveal that Fli- 1 and GATA-1 exhibit cooperative DNA-binding in which the binding of GATA-1 to DNA is increased approximately 26 fold in the presence of Fli-1. This data provides a mechanism for the observed transcriptional synergy. In conclusion, this work suggests that Fli-1 and GATA-1 work together through protein-protein interaction and cooperative DNA-binding to activate the expression of genes associated with the terminal differentiation of Mks.
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Barbeau, Benoit. "Caractérisation des promoteurs des gènes fli-1 murin et humain." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0007/NQ32578.pdf.
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PEREIRA, RUI. "Etude des proprietes transformantes de fli-1 et spi-1/pu. 1 dans les erythroblastes primaires." Paris 11, 2001. http://www.theses.fr/2001PA112021.
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Les proteines ets sont souvent impliquees dans des processus oncogeniques chez l'homme et l'animal. Les erythroleucemies induites chez la souris par le virus de friend est un modele classique d'un processus leucemogene multi-etape caracterise par differentes alterations moleculaires dont la surexpression de genes de la famille ets, spi-1 et fli-1. Spi-1 est specifiquement surexprime dans les erythroleucemies causees par le virus sffv. Chez la souris nouveau-nee, c'est fli-1 qui est surexprime par mutagenese insertionelle dans les erythroleucemies induites par le f-mulv. Par l'utilisation d'un systeme heterologue d'erythroblastes primaires, nous avons analyse et compare les consequences de l'expression forcee des proteines spi-1 et fli-1 sur le controle de la survie, la proliferation et la differenciation des erythroblastes primaires, afin de mieux apprecier leur contribution dans les erythroleucemies de friend. Nous avons montre l'existence d'une cooperation entre spi-1 et le recepteur a l'erythropoietine active anormalement (epor/gp55), amenant a une inhibition de la differenciation erythroide et a la conversion de la reponse normale a l'erythropoietine (differenciation) en une reponse proliferative. Par contre, l'expression de fli-1 est, a elle seule, suffisante pour inhiber le processus normal de differenciation des erythroblastes primaires et induire la survie accrue et la proliferation de ces cellules. Pour aborder les mecanismes d'actions de fli-1 et spi-1 dans la transformation erythroblastique, differents mutants de fli-1 ont ete construits et compares a la proteine fli-1 sauvage pour leur capacite a transformer les erythroblastes. Les resultats obtenus montrent que l'integrite du domaine ets de fli-1 est requise pour que celle-ci transforme les erythroblastes. D'autre part, l'echange du domaine ets de fli-1 par celui de ets-1 conserve les proprietes transformantes de fli-1 ; par contre l'echange par celui de spi-1 genere une proteine non transformante. Ces resultats indiquent que fli-1 et spi-1 transforment les erythroblastes par des mecanismes moleculaires distincts. Nos resultats indiquent aussi que la difference d'activite in vivo entre fli-1 et spi-1 pourrait resulter de la deregulation de genes cibles differents ou/et de leur interaction en trans avec des proteines distinctes.
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Kayali, Samer. "Spi-1,Fli-1et miR-17-92 contribuent au même réseau oncogénique impliqué dans le contrôle de la prolifération dans l’érythroleucémie de Friend." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10100.
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Plus de 90% des érythroleucémies induites par le virus de Friend sont associées à l'activation récurrente de l’un ou l’autre des facteurs de transcription ETS Spi-1 ou Fli-1, ou du cluster miR-17-92. La contribution de ces trois oncogènes à la prolifération des clones érythroleucémiques correspondant a déjà été indépendamment démontrée. De plus, il a été montré dans l’équipe que Spi-1 active de façon directe l’expression de Fli-1 et que les deux facteurs activent des gènes cibles communs. Dans cette thèse, j’ai montré que Spi-1 et Fli-1 activent l’expression du cluster miR-17-92 en se liant sur un motif ETS conservé dans le promoteur de ce cluster. J’ai montré que la réexpression de miR-17 et miR-20a est suffisante pour contrebalancer partiellement la baisse de la prolifération et la survie cellulaire induite par l’inhibition de l’expression de Fli-1. De plus, j’ai identifié Hbp1 comme une cible de ces miARNs dans les cellules érythroleucémiques. Ces résultats montrent que les trois oncogènes activés de façon récurrente par le virus de Friend constituent un seul réseau oncogénique contrôlant la prolifération. Ces résultats suggèrent également un rôle potentiel de réseaux ETS-miR-17-92 dans d’autres contextes normaux ou pathologiquesClonal erythroleudemia developing in susceptible mice infected by Friend virus complex are associated with higly recurrent orviral insertinons at one of three loci called Spi-1, Fli-1 or Fli-3, leading to deregulated expression of oncogenic Spi-1 or Fli-1 transcription factors or miR-17-92 miRNA cluster, respectively. Deregulated expression of each of these here ocongenes has been independently shown to contribute to cell profileration of erythroleukemic clones. Previous studies showed close relationship between Spi-1 and Fli-1, which belong te the seame ETS family, Spi-1 activating fli-1 gene and both Spi-1 and Fli-1 activating multiple common target genes involved in ribosome biogenesis. In this tehesis, we habe also demonstrated that physiological re-expression of exogenous miR-17 and MiR-20a are able to partially rescue proliferation arrest induced by Fli-1 knock down and we identified Hbp1 as a tarteg of these miRNAs in erythroleukemia cell line.These results establish that three of the most recurrently activated oncogenes in Friend erythroleukemia are arctually involved in the same oncogenic network controlling proliferation . The putative contribution of similar ETS-MiR-17-92 network in other normal or hyper
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Johnson, Lacey Nicole St George Clinical School UNSW. "Molecular regulation of Megakaryopoiesis: the role of Fli-1 and IFI16." Awarded by:University of New South Wales. St George Clinical School, 2006. http://handle.unsw.edu.au/1959.4/26819.
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Megakaryocytes (Mks) are unique bone marrow cells, which produce platelets. Dysregulated Mk development can lead to abnormal platelet number and the production of functionally defective platelets, causing bleeding, thrombotic events, and leukaemia. Understanding the molecular mechanisms driving megakaryopoiesis may yield insights into the molecular genetics and cellular pathophysiology of a diversity of disorders. The primary aim of this thesis was to gain insight into the molecular events required for normal Mk development. As transcription factors and cytokines play a central role in driving Mk development, both of these processes were investigated. Fli-1 and GATA-1 are key transcription factors regulating Mk-gene expression, alone and co-operatively. To understand the mechanism of transcriptional synergy exerted by Fli-1 and GATA-1, in vitro assays were carried out investigating the interactions between Fli-1, GATA-1 and DNA that mediate synergy. A novel mechanism of synergy was identified, where Fli-1 DNA binding is not required, although an interaction between Fli-1 and GATA-1, and GATA-1 DNA binding is required. Importantly, the results demonstrate that Fli-1 DNA binding is not essential for promoting Mk-gene expression in primary murine bone marrow cells. Thrombopoietin (TPO) is the primary cytokine responsible for Mk and platelet development. Identifying novel TPO gene-targets may provide invaluable information to aid the understanding of the complex and unique processes required for Mk development. Using microarray technology, IFI16 was identified as a TPO-responsive gene that has not previously been studied in the Mk lineage. This work demonstrated that IFI16 is expressed in CD34+ HSC-derived Mks, and that the Jak/STAT pathway is essential for the activation of IFI16 by both TPO and IFN-??. Of biological significance, IFI16 was found to regulate both the proliferation and differentiation of primary Mks, suggesting that IFI16 may control the balance between these two essential processes. In conclusion, the data in this thesis presents a novel mechanism through which Fli-1 and GATA-1 regulate the synergistic activation of Mk genes. The identification and functional characterisation of a novel TPO-inducible gene, IFI16, involved in regulating the proliferation and differentiation of Mks is also described. These findings have implications for several congenital and malignant conditions affecting Mk and platelet development, and possibly a mechanism for IFN-induced thrombocytopaenia.
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Chan, David Wai 1968. "The role of EWS/FLI-1 fusion gene in Ewing's sarcoma." Monash University, Institute of Reproduction and Development, 2001. http://arrow.monash.edu.au/hdl/1959.1/8307.
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Lebigot, Ingrid. "Recherche des gènes dérégulés dans les érythroblastes transformés par FLI-1." Paris 11, 2003. http://www.theses.fr/2003PA11TO40.
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Ano, Sabine. "Etude du facteur de transcription FLI-1 dans la transformation érythroblastique." Paris 7, 2004. http://www.theses.fr/2004PA077200.
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Mateo, Lozano Silvia. "Sarcoma de Ewing: nuevas aproximaciones terapéuticas y búsqueda de dianas biológicas del oncogén EWS/FLI-1." Doctoral thesis, Universitat Autònoma de Barcelona, 2007. http://hdl.handle.net/10803/3571.
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La familia de tumores del sarcoma de Ewing (ESFT) incluye un grupo heterogéneo de neoplasias caracterizadas por la presencia de células redondas de pequeño tamaño con mínima evidencia morfológica de diferenciación. ESFT es el segundo tumor óseo más frecuente, afectando fundamentalmente a niños y adolescentes. A pesar del uso de terapias agresivas combinando quimioterapia, radioterapia y cirugía, la supervivencia de pacientes con metástasis es aproximadamente del 30%, mientras que en ausencia de enfermedad metastásica alcanza valores del 70 %. Debido a esto, son necesarias nuevas aproximaciones terapéuticas dirigidas a reducir la morbilidad relacionada con el tratamiento y a mejorar el índice de supervivencia. Afortunadamente, los ESFT presentan una diana molecular perfecta que resulta de la translocación cromosómica t(11;22)(q24;q12), que ocurre en aproximadamente un 95% de los casos, e involucra al gen EWS y a un miembro de la familia de factores de transcripción ETS, fundamentalmente FLI-1 o ERG. La translocación más común genera la formación de la oncoproteína de fusión EWS/FLI-1 que actúa como factor de transcripción y regula de forma aberrante la expresión de genes diana, favoreciendo el proceso tumorigénico. De esta forma la inactivación de la proteína de fusión EWS/FLI-1 se convierte en una estrategia atractiva, no sólo debido su papel fundamental en la tumorigénesis de ESFT, sino también por su especificidad en células transformadas. En este estudio se evaluaron diferentes estrategias dirigidas a reducir los niveles expresión de EWS/FLI-1 in vitro e in vivo. La primera estrategia utilizada para inhibir los niveles de expresión de la proteína de fusión EWS/FLI-1 se basó en el uso de la rapamicina, un antifúngico e inmunosupresor con propiedades anticancerígenas. La rapamicina inhibió la vía de señalización de mTOR/p70s6K y la proliferación de células de ESFT. Estos resultados sugirieron el uso de esta droga como agente citostático en el tratamiento de este tipo de tumores. La segunda aproximación terapéutica se basó en la inhibición simultánea de EWS/FLI-1 a nivel transcripcional y post-transcripcional. El tratamiento combinado de oligonucleótidos antisentido y rapamicina resultó en un incremento en la muerte de células de ESFT, a través de un proceso que involucra la restauración de la vía de señalización pro-apoptótica del TGF?1/TGF?-RII. In vivo, la administración del tratamiento combinado causó un retraso en el crecimiento de los tumores. Estos datos aportan la base para una mayor exploración del potencial del tratamiento combinado como una nueva estrategia en el tratamiento de este tipo de tumores. Los análisis moleculares mostraron que ESFT presentan alteraciones en proteínas reguladoras del ciclo celular, incluyendo la sobreexpresión de proteínas quinasas ciclina-dependientes (CDK2) y la pérdida o baja expresión de sus inhibidores. Basándonos en ésto, la tercera estrategia se basó en la reversión de alguna de estas alteraciones, mediante el uso de la roscovitina, un potente inhibidor de la actividad quinasa de las CDKs. El tratamiento con roscovitina resultó en un incremento de los niveles de apoptosis en células de ESFT in vitro e in vivo, por un mecanismo dependiente de la activación de caspasas. Estos resultados sugieren que la roscovitina puede ser un agente terapéutico efectivo en el tratamiento de ESFT, sola o en combinación con otras drogas potencialmente sinérgicas. Con el objetivo de identificar y evaluar nuevas proteínas que interactúan con EWS/FLI-1 y contribuir de esta forma a la comprensión de los mecanismos de transformación, identificamos como una diana transcripcional directa de EWS/FLI-1 a la caveolina-1, proteína involucrada en gran variedad de procesos celulares, tales como endocitosis, homeostasis del colesterol, transducción de señales y tumorigénesis. Los resultados de este trabajo mostraron que caveolina-1 juega un papel determinante en la tumorigénesis de células de ESFT y su inhibición podría permitir el desarrollo de nuevas estrategias terapéuticas moleculares dirigidas a mejorar el tratamiento de los pacientes de ESFT.
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Cohet, Nathalie. "Mécanismes de répression de la transcription par l'oncoprotéine FLI-1 dans les érythroleucémies." Lyon 1, 2005. http://www.theses.fr/2005LYO10137.
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Le proto-oncogène FLI-1 est impliqué de manière récurrente dans les érythroleucémies induites par le virus de Friend chez la souris. Sa surexpression constitutive, suite à l'insertion du provirus, participe au blocage de la différenciation érythrocytaire. Ayant montré que FLI-1 est capable de réprimer la transcription des gènes de globine β, l'objectif de ma thèse a été d'éclaircir son mode d'action dans ce contexte. Nos résultats ont d'abord révélé que l'activité répresseur de FLI-1 passait par des interactions protéine-protéine avec des facteurs activateurs de la différenciation érythrocytaire. Ainsi un antagonisme fonctionnel a été mis en évidence entre FLI-1 et le facteur EKLF. Puis, des études par immunoprécipitation de chromatine directement sur le locus des gènes de globine β ont montré que FLI-1 était recruté sur les séquences régulatrices de globine β et qu'il pouvait aussi interférer avec l'activité du facteur de transcription NF-E2 en empêchant son recrutement sur l'ADN
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Giraud, Guillaume. "Mise en évidence de gènes cibles directs communs à FLI-1 et à SPI-1/PU.1 dans les érythroleucémies de Friend." Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00707722.
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Les facteurs de transcription FLI-1 et SPI-1/PU.1 appartiennent à la famille ETS et reconnaissent le même motif sur l'ADN GGAA. Leur activation est observée de manière récurrente dans les érythroleucémies murines induites par le virus de Friend. Ces observations suggèrent un rôle crucial de ces deux facteurs dans la transformation de la lignée érythrocytaire potentiellement par la dérégulation de gènes cibles communs. Mon travail de thèse a consisté à tester la contribution de ces deux facteurs au phénotype des cellules érythroleucémiques et à rechercher les gènes cibles directs communs.Nous avons pu montrer que FLI-1 et SPI-1/PU.1 ont des contributions additives au phénotype des cellules érythroleucémiques surexprimant les deux facteurs. Par une approche transcriptomique, nous avons identifié une grande proportion de gènes cibles directs communs à FLI-1 et à SPI-1/PU.1 impliqués dans différentes étapes de la biogenèse des ribosomes. La déplétion de ces facteurs induit une réduction de la biogenèse des ribosomes qui n'induit pas de stress ribosomique stabilisant p53. Néanmoins, nous avons mis en évidence une contribution spécifique de RPL11, un médiateur essentiel du stress ribosomique, à la différenciation des cellules érythroleucémiques induites par l'absence de ces facteurs.Nous avons mené en parallèle l'inventaire par ChIP-Seq des sites de recrutement de FLI-1 et de SPI-1/PU.1 sur le génome entier de 3 lignées érythroleucémiques indépendantes. Cette stratégie nous a permis de montrer que les régions de recrutement communes sont la conséquence de la proximité de consensus spécifiques et distincts et du recrutement de FLI-1 et de SPI-1/PU.1 sur leur propre consensus.
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Juban, Gaëtan. "Etude du rôle et du mode d'action du proto-oncogène fli-1 dans les érythroleucémies de Friend." Phd thesis, Université Claude Bernard - Lyon I, 2008. http://tel.archives-ouvertes.fr/tel-00347366.
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FLI-1 est un facteur de transcription de la famille ETS dont le gène activé dans les érythroleucémies murines induites par le virus F-MuLV. Le gène fli-1 est également activé par le facteur SPI-1 / PU.1, un autre facteur ETS dont le gène est lui-même activé dans les érythroleucémies induites par le virus SFFV. Mon travail de thèse visait à définir la contribution de FLI-1 dans les érythroleucémies induites par SPI-1 / PU.1. Par déplétion inductible de FLI-1, j'ai montré qu'il contribue effectivement à la prolifération et au blocage de la différenciation de cellules érythroleucémiques surexprimant
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Juban, Gaëtan. "Étude du rôle et du mode d'action du proto-oncogène fli-1 dans les érythroleucémies de Friend." Lyon 1, 2008. http://tel.archives-ouvertes.fr/docs/00/34/73/66/PDF/TheseGaetanJuban.pdf.
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FLI-1 est un facteur de transcription de la famille ETS dont le gène activé dans les érythroleucémies murines induites par le virus F-MuLV. Le gène fli-1 est également activé par le facteur SPI-1 / PU. 1, un autre facteur ETS dont le gène est lui-même activé dans les érythroleucémies induites par le virus SFFV. Mon travail de thèse visait à définir la contribution de FLI-1 dans les érythroleucémies induites par SPI-1 / PU. 1. Par déplétion inductible de FLI-1, j'ai montré qu'il contribue effectivement à la prolifération et au blocage de la différenciation de cellules érythroleucémiques surexprFLI-1 is an ETS family transcription factor which gene is activated in murine FMuLV-induced erythroleukemias. Fli-1 gene is also activated by SPI-1 / PU. 1, another ETS transcription factor, which gene is activated in murine SFFV-induced erythrloleukemias. My thesis work aimed to define the FLI-1 contribution in SPI-1-induced erythroleukemias. By an unducible fli-1 knock-down, I showed that it contributes effectively to the proliferation and differentiation inhibition of spi-1 overexpressing erythroleukemic cells. A candidate gene approach and globals transcriptomes analysis, showed the FLI-1 implication in synthesis inhibition of P27KIP1 cyclin kinase inhibitor, direct transcriptionnal activation of several genes controlling rRNA synthesis and maturation, and repression of several erythrocytic genes and btg2 antiproliferative gene
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DAUPHINOT, LUCE. "Recherche de genes cibles de la proteine de fusion ews-fli-1 impliquee dans les tumeurs d'ewing." Paris 7, 2001. http://www.theses.fr/2001PA077073.
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La tumeur d'ewing est une tumeur osseuse indifferenciee de l'enfant et de l'adulte jeune, caracterisee par des remaniements chromosomiques specifiques impliquant le gene ews et un gene de la famille des facteurs de transcription ets. Dans 85% des cas, la translocation t(11 ; 22) cree un gene de fusion entre les regions 5 du gene ews et 3 du gene fli-1. Ce gene code pour un facteur de transcription ews-fli-1 aberrant possedant le domaine transactivateur de ews fusionne au domaine ets de liaison a l'adn de fli-1. Ews-fli-1 est capable de lier l'adn sur des sequences similaires a fli-1 et avec une affinite identique, mais active la transcription de genes rapporteurs places sous le controle de sequences ets bien plus efficacement que fli-1. Ews-fli-1 est egalement capable de transformer les cellules nih3t3, et cette activite necessite la presence du domaine transactivateur de ews et du domaine ets de fli-1. Ces observations suggerent que l'activite transformante de ews-fli-1 passe par la deregulation de genes cibles specifiques. L'identification de ces genes cibles represente une etape fondamentale pour la comprehension des mecanismes d'oncogenese de la tumeur d'ewing. Dans cette optique, differentes strategies ont ete developpees au cours de mon travail de these : i) projet visant a realiser un modele cellulaire, ii) etude de genes candidats, iii) etude des regulateurs du cycle cellulaire, iv) criblage differentiel de membranes spottees a haute densite d'adnc. L'ensemble de ce travail a permis d'identifier le cki p57 k i p 2 comme un gene reprime par ews-fli-1, ainsi que plusieurs autres genes cibles dont le role dans la tumorigenese d'ewing reste a preciser. Parmi ces genes, le recepteur membranaire fcrn induit par ews-fli-1 se presente comme un bon candidat pour la therapie. Des experiences complementaires devraient permettre de caracteriser les mecanismes moleculaires par lesquels ews-fli-1 regule l'expression de ces genes, et induit la transformation cellulaire.
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Buet, Dorothée. "Régulation transcriptionnelle de l'hématopoïèse par l'activité tyrosine kinase de BCR-ABL : exemples des gènes Cxr4 et Fli-1." Paris 7, 2006. http://www.theses.fr/2006PA077038.
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L'oncoprotéine de fusion p210BCR-ABL possède une activité tyrosine kinase constitutive activant de nombreuse: voies de signalisation cellulaires conduisant à un phénotype malin. L'objectif de cette thèse a été d'analyser les mécanismes moléculaires par lesquels p210B R"ABL induit, d'une part, des anomalies d'adhésion des cellules humaines leucémiques avec leur microenvironnement et d'autre part, des anomalies de l'érythropoïèse. Nos travaux ont d'abord porté sur l'effet de p210 CR~ABL sur la fonction du récepteur CXCR4, impliqué dans l'adhésion des cellules hématopoïétiques. Nous avons mis en évidence une diminution fonctionnelle de CXCR4 par deux mécanismes distincts, liés au niveau d'expression de p210BCR-ABL, l'un régulant la signalisation à partir de CXCR4, l'autre diminuant la transcription du gène Cxcr4. Le second aspec a porté sur l'étude des effets de p210BCR-ABL sur la balance entre la différenciation erythrocytaire et mégacaryocytaire (MK) qui partagent un progéniteur commun (E/MK). Nos travaux ont montré que p210-ABL favorise la différenciation erythrocytaire au détriment de la différenciation MK et que cette différenciation erythrocytaire s'accompagne d'une régulation négative de la transcription de FLI-1, un facteur de transcription MK. Cette observation nous a conduit à réaliser des expériences d'inhibition de FLI-1 par ARN interférence dans des cellules primaires CD34+. Les résultats indiquent que FLI-1 joue un rôle majeur dans l'engagement de la différenciation du progéniteur bipotent E/MK vers la lignée MK. En conclusion, ce travail a montré qu'en plus des effets au niveau post-transcriptionnel, l'activité kinase d'un oncogène comme p210BCR-ABL pouvait moduler le phénotype d'une cellule en régulant la transcription de certains gènes clésThe expression of p210BCR-ABL, a fusion protein responsible for the development of chronic myelogenous leukemia, leads to a malignant phenotype with reduced growth factor requirement, résistance to apoptosis and altered adhesion properties, caused by its high constitutive tyrosine kinase activity activating multiple biochemical pathways. The aim of this thesis was to study the effect of p210BCR-ABL on transcription during hematopoiesis, particularly during two special aspects of the pathology: loss of adhesion to bone marrow stroma and and the anormal erythroid differentiation. First, we have studied the interactions between p210BCR-ABL and the CXCR4 receptor function, to better understand the loss of adhesion of hematopoietic progenitors to bone marrow stroma. We showed that two mechanisms could regulate CXCR4 function, depending on p210BCR-ABL expression level, one associated with diminution of Cxcr4 transcription. P210BCR-ABL can also modify the erythroid differentiation. Knowing that a close developmental relationship exists between the erythroid and the megakaryocytic (MK) differentiation, the second part of my work consisted in the study of p210BCR-ABL effects on these two lineages programming. We showed a major expansion of the erythroid lineage occurring at the expense of the MK differentiation in presence of p210BCR-ABL, associated with a diminution of the MK transcription factor FLI-1 transcription. Then we wanted to better understand the role of the regulation of FLI-1 expression during the commitment of the bipotent E/MK progenitor, in normal conditions. We showed, by RNA interference, that the FLI-1 expression level regulates the commitment in primary human CD34+cells
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Wang, Min. "Importance of insulin-like growth factor-1 receptor and EWS/FLI-1 fusion protein in growth and survival of two different types of neuroectodermal tumor cells /." Stockholm, 1998. http://diss.kib.ki.se/1998/91-628-3293-X/.
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DERAMAUDT, BERTRAND. "Role des proto-oncogenes fli-1 et erg dans l'expression du gene de l'heme oxygenase-1 humaine, caracterisation et etude de leurs sites de fixation a l'adn." Université Louis Pasteur (Strasbourg) (1971-2008), 2001. http://www.theses.fr/2001STR13089.
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L'heme oxygenase-1 (ho1) est une enzyme degradant l'heme en biliverdine, fer et monoxyde de carbone. On observe une surexpression de ho-1 dans de nombreuses pathologies. La regulation du gene ho-1 est encore mal connue, du fait des nombreux transactivateurs susceptibles de moduler son expression. Le promoteur du gene ho-1 presente de nombreux sites de liaison de differents facteurs de transcription dont certains pourraient etre reconnus par des membres de la famille des genes ets. Cette famille de genes code pour des facteurs de transcription se liant a l'adn sur des sequences caracterisees par un motif cur gga(a/t) et sont notamment impliques dans la regulation de genes intervenant dans l'angiogenese. De nombreuses etudes ont montre l'expression du gene ho-1 durant la cicatrisation, l'inflammation ou la croissance des muscles lisses, mais le role direct du gene ho-1 dans l'angiogenese est peu documente. Pour ce faire, nous avons utilise un modele d'angiogenese in vitro et montre que des cellules endotheliales transformees de maniere stable et surexprimant le gene humain ho-1, croissent plus vite et forment un reseau plus fourni que des cellules non transformees. Des essais ovocytaires nous ont permis de mettre en evidence une regulation negative du gene ho-1 entre les nucleotides-1163 et -1004 et la levee de cette inhibition par les proteines fli-1, erg et ets-1 au travers d'une region comprise entre les nucleotides -1412 et -1322. En utilisant une methode de selection et d'amplification d'oligonucleotides de sequences aleatoires un motif consensus de liaison a l'adn pour erg et fli-1 a ete determine et s'avere etre pratiquement identique pour ces deux proteines : aaccggaary. Les proteines erg et fli-1 n'ayant pas de reelle difference d'affinite et de sequence vis-a-vis de leur motif de liaison a l'adn, leur difference d'action pourrait s'expliquer par l'intervention de partenaires proteiques modulant leur affinite et leur activite.
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Elhamess, Hind. "Etude in vivo du rôle de nanosphères recouvertes de chitosan dans le ciblage de l'oncogène EWS/Fli-1 par des oligonucléotides." Paris 11, 2009. http://www.theses.fr/2009PA11T048.
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BOUAKHAM, DERAMAUDT THERESE. "Etude des partenaires de deux membres de la famille des proteines ets, fli-1 et erg, et etude de l'inhibition de l'expression de l'heme oxygenase-1 par la dexamethasone." Université Louis Pasteur (Strasbourg) (1971-2008), 2001. http://www.theses.fr/2001STR13051.
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Fli-1 et erg sont deux membres homologues de la famille des genes ets apparentes au protooncogene c-ets-1. Ces genes codent pour des facteurs de transcription impliques dans des processus biologiques tels que la proliferation, l'hematopoiese et la transformation cellulaire. La premiere partie de notre etude a consiste a identifier de nouveaux partenaires proteiques de fli-1 et erg, qui leur conferent des specificites de reconnaissance vis-a-vis de sequences cibles ou modifient leurs proprietes d'effecteurs transcriptionnels. Le systeme du double-hybride a ete utilise pour cribler une banque d'adnc de xenope avec les proteines fli-1 et erg comme appats. 12 partenaires specifiques pour fli-1 et 1 pour erg (hsp90) ont ete identifies. Ces 12 partenaires de fli-1 incluent 3 facteurs nucleaires impliques dans le processus de maturation de l'arn (u1c, jktbp, alf-c1), 3 facteurs impliques dans le developpement (soxd, xvent-2, xvent-2b), 3 facteurs impliques, entre autres, dans l'hematopoiese (haf, sap18, nudc), un inhibiteur des cyclines kinases (xic-1), une proteine impliquee dans la transduction du signal (sh3bgrl) et une proteine impliquee dans le processus de modification post-traductionnelle sumo-1. Des essais de coprecipitation in vitro montrent que fli-1 et erg interagissent specifiquement avec u1c, xvent-2 et xvent-2b. Des essais de transfection et d'analyse de complexe adn/proteine confirment le recrutement possible de xvent-2 et xvent-2b sur un motif de fixation des facteurs ets. Des essais de coexpression dans les embryons de xenope montrent que l'expression de bmp-4 est induite par fli-1 et reprimee par cette derniere a forte dose. La deuxieme partie de notre etude montre que la repression par les glucocorticoides de
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Sarrazin, Sandrine. "Étude de l'implication du proto-oncogène FLI-1 dans les leucémies de Friend et de la régulation traductionnelle et post-traductionnelle de son expression." Lyon 1, 2001. http://www.theses.fr/2001LYO10016.
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L'objectif essentiel de mon travail de thèse était d'explorer les multiples niveaux de régulation de l'expression du proto-oncogène Fli-1 initialement décrit pour son activation récurrente dans les érythroleucémies induites par le virus de Friend F-MuLV chez la souris. Conformément à cet objectif, les résultats obtenus ont permis de mettre en évidence trois nouveaux mécanismes impliqués respectivement dans la régulation de l'expression du gène Fli-1 au niveau transcriptionnel, traductionnel et post-traductionnel. Au niveau transcriptionnel, nos travaux ont permis de montrer l'existence d'un nouveau promoteur du gène Fli-1 régulé positivement par le facteur de transcription SPI-1 dans les lignée érythroleucémiques induites par le virus SFFV. La surexpression de protéines FLI-1 qui en résulte contribue elle-même au blocage de la différenciation de ces lignées érythroleucémiques SFFV. Au niveau traductionnel, nous avons démontré l'existence d'un mécanisme original permettant la régulation, à la fois positive et négative, de la synthèse de deux isoformes de protéines FLI-1 à partir d'un même ARNm Fli-1. Ce mécanisme pourrait constituer une stratégie remarquablement bien adaptée permettant d'éviter les effets délétères d'une production trop élevée de protéines FLI-1 tout en permettant son ajustement aux besoins de la cellule. Au niveau post-traductionnel, nous avons pu démontrer que les protéines FLI-1 peuvent être clivées par la caspase 3 au moins in vitro. Le facteur FLI-1 étant probablement impliqué dans le maintien de la survie, sa protéolyse pourrait être un moyen de réguler cette activité. Ces résultats soulignent la complexité des mécanismes de contrôle de l'expression du proto-oncogène Fli-1. Compte tenu des effets délétères et multiples engendrés par l'inactivation complète du gène Fli-1, ce travail fournit la base de l'exploration des multiples fonctions du gène par des inactivations sélectives des différentes séquences régulant son expression.
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Prieur, Alexandre. "Recherche de gènes cibles directs de EWS/Fli-1dans les cellules d'Ewing : étude du rôle de l'IGFBP-3 et de DKK-1 dans l'oncogénèse des tumeurs d'Ewing." Paris 11, 2005. http://www.theses.fr/2005PA11T006.
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Caron, Sandrine. "Etude de régulations transcriptionnelles et traductionnelles induites par la thrombopoi͏̈étine dans la cellule mégacaryocytaire." Paris 7, 2003. http://www.theses.fr/2003PA077140.
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Cohen, Sarah. "Le Sarcome d'Ewing et ses transcrits de fusion : de l'étude fonctionnelle de protéines historiquement impliquées à la découverte de nouvelles entittés clinico-biologiques." Paris 7, 2014. http://www.theses.fr/2014PA077087.
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Le sarcome d'Ewing, tumeur osseuse à petites cellules rondes de l'adolescent et de l'adulte jeune, est caractérisé par une translocation chromosomique récurrente t(11 ;22) (q24 ;q12) dans laquelle le gène EWS est fusionné au gène FLI1, codant pour un membre de la famille de facteurs de transcription ETS. EWS est membre de la famille de protéines FET dont font également partie FUS et TAF15. La protéine de fusion EWS-FLI1 contient la partie N-terminale de EWS et le domaine C-terminal de liaison à l'ADN du facteur de transcription FLI1. J'ai travaillé selon deux axes de recherche. Le premier, plus fondamental, a consisté en l'étude des fonctions « normales » des protéines de la famille FET. J'ai pu montrer qu'elles ont un rôle dans la prolifération ainsi que dans la régulation de l'expression génique. J'ai identifié trois transcrits (CDK6, CTGF et CYR61) dont l'expression est inversement régulée par les protéines FET et EWS-FLI1. Ceci nous permet de faire l'hypothèse d'un effet dominant négatif d'EWS-FLI1 sur la fonction normale des protéines FET. Ces trois transcrits impliqueraient la voie de signalisation Hippo-YAP/TAZ dans la biologie du sarcome d'Ewing. Le second axe, plus translationnel, a consisté en l'étude des tumeurs « Ewing-like », tumeurs au phénotype Ewing mais sans transcrit de fusion retrouvé. Par RNA-seq, nous avons mis en évidence un nouveau transcrit de fusion non-FET/non-ETS, BCOR-CCNB3, présent dans 4% des tumeurs Ewing¬like. Nous avons montré que ces tumeurs ont une biologie distincte de celle du sarcome d'Ewing. J'ai enfin réalisé la description clinico-biologique exhaustive de ces patients et proposé de premières recommandations thérapeutiquesEwing sarcoma, a small round cell bone tumor of the adolescent and young adult, is characterized by a recurrent chromosomal translocation t(11 ;22) (q24 ;q12) in which EWS is fused to FLI1, coding for a member of the ETS family of transcription factors. EWS is a member of the FET family of proteins which also comprises FUS and TAF15. The fusion protein EWS-FLI1 consists of the N-terminal part of EWS and the C-terminal DNA-binding domain of FLI1 transcription factor. I pursued two main projects. The first, more fundamental, consisted in the study of the normal functions of the FET family of proteins. I was able to show that they have a role in proliferation as well as in regulation of gene expression. I identified three transcripts (CDK6, CTGF and CYR61) whose expression is conversely regulated by the FET proteins and EWS-FLI1. This leads to the hypothesis of EWS-FLI1 exerting a dominant negative effect on the FET proteins normal functions. Those three transcripts might involve the Hippo-YAP/TAZ signaling pathway in the biology of Ewing sarcoma. The second project, more translational, consisted in the study of «Ewing-like» tumors, that have an Ewing phenotype but lack a canonical fusion transcript. Through RNA-seq, we identified a new non¬FET/non-ETS fusion transcript, BCOR-CCNB3, found in 4% of Ewing-like tumors. We have demonstrated that the biology of BCOR-CCNB3 positive tumors is distinct from that of Ewing sarcoma. I then carried out a thorough clinical and pathological description of these patients, and formulated preliminary treatment recommendations
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Saultier, Paul. "Pathologies plaquettaires constitutionnelles associées aux défauts des facteurs de transcription FLI1, ETV6 et GATA1." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0262.
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Les thrombopénies constitutionnelles (TC) sont des maladies encore incomplètement caractérisées. Ce travail de thèse concerne les TC liées à 10 variants des gènes codant les facteurs de transcription FLI1, ETV6 et GATA1, dont 9 n’avaient jamais été décrits. Ces pathologies ont été étudiés à partir de patients recruté dans un réseau national (Centre de Référence des Pathologies Plaquettaires CRPP) et un réseau international (BRIDGE consortium).Nous montrons qu’il existe un déficit sévère en granules denses dans les plaquettes des patients porteurs de variants FLI1 du fait d’un probable défaut de biogénèse. Ce travail, et d’autres études publiées récemment, ont permis de définir la TC liée aux variants ETV6 en tant que nouveau syndrome de prédisposition aux hémopathies malignes. Les variants FLI1 s’associent à une diminution d’activité transcriptionnelle et d’accumulation nucléaire de la protéine et à des anomalies de la différenciation mégacaryocytaire. Les variants ETV6 s’associent à un défaut d’activité répressive et les mégacaryocytes dérivés des patients montrent un excès de prolifération et un défaut marqué de formation des proplaquettes. Les plaquettes de patients porteurs de variants GATA1 ont montré une expression anormale de la protéine MYH10, ce qui suggère un défaut de répression du gène MYH10 au cours de la mégacaryopoïèse. Une analyse in silico de données de ChIP-seq a ainsi montré l’existence d’une fixation de GATA1 dans le promoteur et dans un intron de MYH10 dans le mégacaryocyte.Ce projet a permis d'apporter des connaissances sur les causes génétiques, le phénotype, le diagnostic, le pronostic et les mécanismes physiopathologiques des TCConstitutional thrombocytopenia (CT) is a group of diseases incompletely characterized. This thesis focused on CTs due to 10 variants in genes encoding the transcription factors FLI1, ETV6 and GATA1, of which 9 had never been described. These diseases were studied in French and European patients recruited using national (French national reference center for inherited platelet disorders CRPP) and international (BRIDGE consortium) networks.We showed that the platelets of patients carrying FLI1 variants harbored a severe dense granule defect probably due a biogenesis defect. Our work, associated with data published by other groups, has defined ETV6-related CT as a new hematological malignancy predisposition syndrome. FLI1 variants are associated with a decreased transcriptional activity, a decreased nuclear accumulation of the protein and abnormal megakaryocyte differentiation. ETV6 variants led to a decreased repressive activity and the megakaryocytes derived from patients showed increased proliferation and a marked defect in proplatelet formation. The platelets of GATA1 variant carriers showed aberrant expression of MYH10 protein suggesting a defective silencing of MYH10 gene during megakaryopoiesis. Consistently, in silico analysis of ChIP-seq data showed that GATA1 binds the promoter and an intronic region of the MYH10 in megakaryocytes.This project has provided insights into genetic causes, phenotype, diagnosis, prognosis and pathophysiological mechanisms of CTs
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Domanowsky, Lukas [Verfasser]. "Expressionsmuster von FLI-1, IGFBP3, TOPK und BCL9L in der solid pseudopapillären Pankreasneoplasie, dem duktalen Adenokarzinom des Pankreas und der Intraduktalen papillär-muzinösen Neoplasie des Pankreas im Vergleich zu Normalgewebe des Pankreas / Lukas Domanowsky." Kiel : Universitätsbibliothek Kiel, 2019. http://d-nb.info/1184879656/34.
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Guillon, Noëlle. "Recherche de gènes cibles directs de EWS-FLI-1 dans les cellules d'Ewing : Description de cibles microsatellites et étude du rôle de la cible Sec 14L2 dans des mécanismes de sensibilité à l'alpha tocophérol succinate." Paris 11, 2008. http://www.theses.fr/2008PA11T092.
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Franzetti, Georges-Alain. "EWS-FLI1 dans le Sarcome d'Ewing : rôle des miARN et conséquences de l'hétérogénéité de l'expression de EWS-FLI1 sur la dissémination métastatique." Paris 7, 2014. http://www.theses.fr/2014PA077156.
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Le sarcome d'Ewing, seconde tumeur de l'os chez les adolescents et les jeunes adultes, est une tumeur très agressive et métastatique. Dans 85 % des cas, cette tumeur est caractérisée par la translocation chromosomique t(11;22)(q24:q12) aboutissant à une protéine de fusion, EWS-FLI1, décrite comme un facteur de transcription aberrant modulant l'expression de gènes cibles spécifiques. Histologiquement, la tumeur d'Ewing est caractérisée par le marqueur membranaire CD99. Par des études in vitro et in vivo, nous avons montré que l'inhibition de EWS-FLI1 entraine une perte de l'expression membranaire de CD99, mais seulement une faible diminution du transcrit de CD99, suggérant ainsi une régulation post-transcriptionnelle. Mon travail de thèse a permis d'identifier le miR-30a-5p comme régulateur de l'expression de CD99, permettant ainsi de faire le lien entre deux marqueurs du sarcome d'Ewing, EWS-FLI1 et CD99. Ensuite, le second axe de mes travaux de thèse s'est porté sur l'analyse du profil protéomique, obtenu par 2D-DIGE, dépendant de EWS-FLI1. Ces travaux ont permis de montrer que EWS-FLI1 module l'expression de protéines du cytosquelette d'actine. De façon inattendue, c'est la perte de l'oncogène EWS-FLI1 qui va permettre à la cellule d'acquérir un phénotype migratoire et invasif. De plus, la perte de l'expression de EWS-FLI1 va augmenter la dissémination et la colonisation métastatique au niveau du poumon chez la souris. Ces résultats paradoxaux nous ont permis de proposer un nouveau modèle de dissémination métastatique basé sur l'hétérogénéité de l'expression de EWS-FLI1, permettant de passer d'un état prolifératif EWS-FLI1élevé à un état invasif EWS-FLI1basEwing sarcoma, the second most frequent bone tumor among teenagers and young adults, constitute a highly aggressive and metastatic tumor. In 85% of cases, Ewing tumor is characterized by th expression of the fusion protein EWS-FLI1, resulting to the chromosomal translocation t(11;22)(q24:q12) and described as an aberrant transcription factor modulating the expression of specific target genes. Histologically, Ewing tumor is characterized by the membrane marker CD99 By in vitro and in vivo studies, we have shown that EWS-FLI1 inhibition induces a dramatic decreas of CD99 membrane expression, whereas only a slight decrease of CD99 mRNA expression i observed, suggesting a post-transcriptional regulation. My thesis work allowed to identify the miR 30a-5p as a regulator of CD99 expression, making the link between two Ewing sarcoma markers EWS-FLI1 and CD99. Then, the second axis of my thesis was focused on the proteomic profil EWS-FLI1-dependant, obtained by 2D-DIGE. This work demonstrated that EWS-FLI1 modulate the expression of actin cytoskeleton proteins. Unexpectedly, the loss of EWS-FLI1 ôncogene allow the cell to acquire the phenotype of migration and invasion. Moreover, the loss of EWS-FL1 expression increases also the dissemination and the metastatic colonization to mice lungs. Thes paradoxical results enabled us to propose a new model of Ewing sarcoma metastatic dissemination based on EWS-FLI1 heterogeneity, switching between an EWS-FLI1high proliferative state and EWS FLI1low invasive state
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Bittencourt, Danielle. "Coupling between gene expression steps in mammalian cells : role of transcriptional coregulators and physio-pathological impact." Paris 7, 2008. http://www.theses.fr/2008PA077124.
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J'ai étudié la régulation de l'expression génique en réponse à une hormone stéroïde, l'estradiol, pour trois gènes modèles en prenant en compte fensernbte des étapes impliquées, J'ai pu montrer que l’épissage co-transcriptionnelle est plus efficace dans le cas de la cyctîne 01 par rapport à pS2 et potentialise la production de l’ARNrn de la cycline D1. Ce travail montre que, in vivo, la coordination entre la transcription et l’épissage est nécessaire à la production efficace d’ ARNm en réponse à un stimulus transcriptionnel. Afin de déterminer les acteurs moléculaires responsables du couplage entre là transcription et l’épissage, j’ai réalisé un crible basé sur l'Inhibition de l'expression de plusieurs corégulateurs transcriptionnels par la technique de siRNA, En effet plusieurs corégulateurs transcriptionnels, qui sont des protéines recrutées sur le promoteur de leurs gènes cibles et qui modulent leur transcription, peuvent aussi affecter leur épissage. J'ai identifié le coregulateur transcriptionel EWS en tant que régulateur de l'expression du gène de la cycllne D1. De façon intéressante, EWS est altéré dans les sarcomes d’Ewing où une translocation chromosomique résulte en la fusion du gène EWS avec le gène codant le facteur de transcription Fli-1. J'ai montré que EWS favorise l'élongation tandis que EWS-Fli l’inhibe ce qui aboutit à la production d'un variant d’épîssage oncogénique de la cycline D1 dans les sarcomes d'Ewing. De plus, j'ai montré que le corégulateur transcriptionnel p68 contrôle le devenir et régule l’export des ARNm de c-fos. Ce résultat est important car il étend la fonction jusqu’ici connue des corégulateurs dans la régulation de l'expression géniqueIn order to investigate the biological significance of coupling between the different steps of the gene expression process in vivo, I studied the regulation of gene expression in response to a steroid hormone, estradiol, for three gene models by taking into account all the steps involved, I showed that the efficiency of co-transcriptional splicing was higher in the of cyclin D1 when compared to pS2 and potentiated the cyclin D1 mRNA production rate, This work shows that, in vivo, efficient coupling between transcription and splicing is necessary for efficient mRNA production in response to a transcriptional stimulus, In order to investigate the molecular actors of coupling between transcription and splicing, I conducted a siRNA-based approach to downregulate the expression of several transcriptional coregulators, I firstly identified the EWS transcriptional coregulator as a regulator of cyclin D1 expression, interestingly, EWS is altered in Ewing sarcomas where a chromosomal translocation results in the fusion of the EWS gene with the Fl-1 gene encoding a transcription factor, EWS-FB. Remarkably EWS favors transcription elongation whereas EWS-Fli inhibits elongation thus favoring the production of an oncogenic cyclin D1 splice variant in Ewing sarcomas; In addition, I showed that the p68 transcriptional coregulator and splicing factor controls the fate and regulates the export of c-fos mRNAs. This result is important because it expands the known functions of coregulators in gene expression regulation
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Mendonça, Monique Culturato Padilha 1986. "Expressão do fator de crescimento endotelial vascular (VEGF) e seus receptores Flt-1 e Flk-1 após envenenamento pela aranha Phoneutria nigriventer em ratos = Expression of vascular endothelial growth factor (VEGF) and its receptors Flt-1 and Flk-1 after envenoming by Phoneutria nigriventer spider in rats." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/310754.
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Orientador: Maria Alice da Cruz HoflingDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
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Resumo: O fator de crescimento endotelial vascular (VEGF), o principal regulador da angiogênese e da permeabilidade vascular, foi recentemente reconhecido como neurotrófico, neurogênico e neuroprotetor, sendo, portanto, regulado positivamente em muitos processos neuropatológicos. Neste modelo experimental de quebra da barreira hematoencefálica (BHE) pelo veneno da aranha Phoneutria nigriventer (PNV), a expressão do VEGF e seus receptores tirosina-quinase, Flt-1 e Flk-1 e de seus RNAs mensageiros foi investigada no hipocampo e cerebelo de ratos Wistar (Rattus norvegicus) por imunohistoquímica (IHQ), western blotting (WB) e reação em cadeia da polimerase em tempo real (qPCR). Paralelamente, a integridade da BHE foi avaliada através da expressão das proteínas da via paracelular, Ocludina e ?-catenina, e da principal proteína da membrana basal, a Laminina, que estão presentes no endotélio na interface sangue-cérebro. O estudo foi realizado em ratos de 14 dias (neonatos) e de 8-10 semanas (adultos jovens) para avaliar diferenças em função da idade na funcionalidade da BHE e na possível mediação dos efeitos neurotóxicos do PNV pelo VEGF. A via escolhida para administração de PNV (1,7 mg/kg em 0,5ml de salina 0,9%) foi intraperitoneal, devido sua administração mais favorável nos animais neonatos. Os tempos de 2, 5 e 24 horas após a administração de PNV visaram investigar a expressão das proteínas, RNAs mensageiros e uma possível mediação pelo VEGF na fase aguda do envenenamento. A administração do PNV provocou sinais imediatos de intoxicação nos animais, os quais foram mais severos e imediatos nos neonatos do que nos adultos. No hipocampo, os dados do WB mostraram aumento da expressão de VEGF, Flt-1 e Flk-1 e respectivos RNAs mensageiros, que foram concomitantes com o desenvolvimento de edema perivascular e diminuição da expressão da Ocludina, ?-catenina e Laminina. Os dados da IHQ mostraram que a imunorreatividade de VEGF ocorreu nos corpos dos neurônios piramidais e dendritos nos subcampos CA1, CA2, CA3 e giro denteado do hipocampo, em contraste com a marcação nuclear de Flt-1 e Flk-1. O PNV aumentou visivelmente a imunomarcação das três proteínas. No cerebelo, os dados do WB e IHQ mostraram que o PNV induziu aumento na expressão dos componentes do sistema VEGF/Flt-1/Flk-1. Células presentes na camada granular e molecular que não mostraram marcação nos animais controles passaram a ser positivas nos animais xviii envenenados, principalmente as células de Purkinje. Os animais adultos apresentaram aumentos mais proeminentes no sistema VEGF/Flt-1/Flk-1 do cerebelo do que os recémnascidos; nestes, o PNV induziu diminuição na expressão da Ocludina, ?-catenina e Laminina, enquanto nos adultos a diminuição ocorreu apenas na Ocludina e ?-catenina. O veneno da aranha P. nigriventer contem peptídeos neurotóxicos que causam excitabilidade na neurotransmissão nervosa por modificarem a fisiologia dos canais de sódio, potássio e cálcio. Uma vez que a dinâmica das alterações descritas diferiu entre regiões cerebrais e entre animais neonatos e adultos jovens, sugerimos particularidades regionais e de funcionalidade, tanto da BHE, como dos neurônios imunorreativos em resposta ao PNV. Estes resultados são os primeiros a demonstrar alterações do sistema VEGF/Flt-1/Flk-1 no hipocampo e cerebelo que cursam com sinais neuroexcitotóxicos dos animais que foram tratados com o veneno
Abstract: Vascular endothelial growth factor (VEGF), a major regulator of developmental angiogenesis and vascular permeability, was recently recognized as neurotrophic, neurogenic and neuroprotector, hence being upregulated in many neuropathological processes. In this experimental model of blood brain barrier (BBB) breakdown by the Phoneutria nigriventer spider venom (PNV), the expression of VEGF and its receptor tyrosine kinases, Flt-1 and Flk-1 and their mRNAs was investigated in the hippocampus and cerebellum of Wistar rats (Rattus norvegicus) by immunohistochemistry (IHC), western blotting (WB) and real time polymerase chain reaction (qPCR). Simultaneously, the BBB integrity was assessed through expression of paracellular pathway proteins, ?- catenin and Occludin, and the main basement membrane protein, Laminin, which are present in the endothelium blood-brain interface. The study was performed in rats by 14 days (neonates) and 8-10 weeks (young adults) to assess differences related to age in the BBB functionality and the possible mediation of the PNV neurotoxic effects by VEGF. The via chosen for PNV administration (1.7 mg/kg in 0.5 ml of 0.9% saline) was intraperitoneally, due to more favorable application in neonate animals. The times of 2, 5 and 24 hours after PNV administration aimed to investigate the expression of proteins, mRNAs, and possible mediation by VEGF in acute envenomation. The PNV administration provoked immediate signs of intoxication in animals, which were more severe and immediate in neonates than in adults. In hippocampus, the WB data showed increased expression of VEGF, Flt-1 and Flk-1 and their mRNAs, which were concomitant with the development of perivascular edema, and decreased expression of Occludin, ?-catenin and Laminin. IHC data show that VEGF immunoreactivity occurred in the bodies and dendrites of pyramidal neurons in the subfield CA1, CA2, CA3 and dentate gyrus of the hippocampus, in contrast with nuclear staining of Flt-1 and Flk-1. The PNV visibly increased immunostaining of the three proteins. In cerebellum, the WB data and IHC showed that the PNV induced an increase in the expression of VEGF/Flt-1/Flk-1 system components. Cells in the granular and molecular layer showed no marking in the control animals became positive in animals envenomed, especially Purkinje cells. Adult animals showed increases more prominent in the VEGF/Flt-1/Flk-1 system of the cerebellum than xx neonates; in these animals, the PNV induced decrease in expression of Occludin, ?-catenin and Laminin, while in adults the decrease occurred only in Occludin and ?-catenin. The venom of the spider P. nigriventer contains peptides that cause excitability in the nervous neurotransmission by modifying the physiology of sodium, potassium and calcium channels. Since the dynamics of the changes described differed between brain regions and among neonates and young adult animals, we suggest regional specificities and functionality of BHE and immunoreactive neurons in response to PNV. These results are the first to demonstrate changes in the hippocampus and cerebellum VEGF/Flt-1/Flk-1 system that courses with neuroexcitotoxic signs of animals that were treated with venom
Mestrado
Farmacologia
Mestra em Farmacologia
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Niboucha, Razika. "Mise en évidence de l'anisotropie d'un substrat par analyse de fonctions de distribution radiales (cas de l'Au sur (100)FLi)." Thèse, Université du Québec à Trois-Rivières, 1997. http://depot-e.uqtr.ca/4806/1/000638639.pdf.
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Schramek, Chris. "Expression and mutational analysis of Flt-1." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0020/MQ58080.pdf.
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McRae, Lisa Angharad. "Flk-1 signalling during ES cell differentiation." Thesis, University of Bath, 2007. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512262.
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Flk-1 (Foetal liver kinase-1), a receptor tyrosine kinase, and its ligand VEGF (vascular endothelial growth factor) are essential for vasculogenesis and haemopoiesis in the early embryo. Flk-1 is expressed initially on the haemangioblast, the common precursor of haemopoietic and endothelial cells, and on subsequent committed endothelial lineages. Flk-1 expression is maintained on adult endothelial cells and mediates angiogenesis, making it an important pharmaceutical target in the pathology of many human diseases including cancer and rheumatoid arthritis. Though involvement of Flk-1 in disease has lead to its extensive study in adult humans little is known about the signals it mediates during development. Using ES cells as a model of development, the aim of this investigation was to identify signals mediated through Flk-1 during early development and to characterise their relative importance in the formation of the haemopoietic, endothelial and cardiomyocyte lineages. Activation of the MAPK and PLC signalling pathways were demonstrated following VEGF treatment of Flk-1-expressing embryoid bodyderived cells, though surprisingly activation of Flk-1 did not appear to mediate activation of the PI3K signalling pathway. Use of an embryoid body-based endothelial sprouting assay demonstrated a requirement for Flk-1 in both endothelial specification and angiogenic expansion. However, this activity was not mediated through either the MAPK or PI3K pathways. The finding that the PI3K pathway is not activated following VEGF stimulation nor required for early vasculogenesis/angiogenesis is surprising given its important role in both homeostatic and pathological angiogenesis in the adult. Previous work had suggested a role for Flk-1 in cardiac differentiation. Investigation of cardiomyocyte differentiation using Flk-1 null ES cells demonstrated a delay in formation of beating cardiomyocytes suggesting that Flk-1 may be involved in, but not required for cardiomyocyte specification. Finally, Flk-1-Tet-on ES cell lines were generated to facilitate investigation of the temporal importance of Flk-1 signalling during different developmental processes. Due to unforeseen difficulties in the maintenance of Flk-1 expression upon ES cell differentiation the full potential of this system was not realised in this study.
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Pallarés, Quixal Judit. "Expresión de los factores angiogénicos VEGF y bFGF, y de los receptores FLK/ KDR y Flt-1 en la neoplasia intraepitelial prostática." Doctoral thesis, Universitat Autònoma de Barcelona, 2004. http://hdl.handle.net/10803/4226.
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El proceso de angiogénesis es necesario para el crecimiento de los tumores por encima de los 2-3mm y para el desarrollo de metástasis a distancia. El Factor de Crecimiento vascular endotelial (VEGF) es el factor angiogénico más potente conocido. Puede actuar de forma sinérgica junto al Factor de crecimiento fibroblástico básico (bFGF) en algunos modelos tumorales. VEGF ejerce sus funciones principalmente en las células endoteliales a través de dos receptores con acción tirosín quinasa FLK/ KDR (VEGFR2) y Flt-1( VEGFR2).
En el cáncer prostático se ha demostrado un aumento de la densidad vascular o angiogénesis en el carcinoma respecto al tejido normal, correlacionándose con otros marcadores pronósticos del cáncer prostático ya conocidos. Nuestro estudio ha demostrado un incremento de la densidad vascular y de la expresión de los factores angiogénicos VEGF y bFGF, y de los receptores FLK/ KDR y Flt-1 en la lesión precursora del cáncer de prostático, la neoplasia intraepitelial de alto grado (PINAG). Además, el aumento de la angiogénesis se ha correlacionado con los adenocarninomas prostáticos de alto grado de Gleason y estadios avanzados (pT3).
El aumento de la angiogénesis y la expresión de los factores angiogénicos y de sus receptores en la neoplasia intraepitelial de alto grado, apoya un papel de esta lesión como precursora en el cáncer prostático, y plantea su posible aplicación en biopsia por aguja en la próstata como marcador pronóstico adicional del adenocarcinoma prostático.
The process of angiogenesis is necessary for tumor growth beyond 2-3mm and for the development of metastasis. Vascular endothelial growth factor (VEGF) is the most potent angiogenic factor so far detected, and can function synergistically with Basic Fibroblastic growth factor (bFGF) inducing angiogenesis. VEGF acts upon binding to two tyrosine kinase receptors FLK/ KDR (VEGFR2) and Flt-1 (VEGFR2).
In prostate cancer the study of angiogenesis has revealed an increase in the microvessels density in the carcinoma compared to normal prostatic glands, and its has been correlated with pathological stage. Our results demostrated an increase in the vessels density and in the expression of the angiogenic factors VEGF and bFGF, and the receptors FLK/ KDR and Flt-1 in the prostatic intraepithelial neoplasia. Interestingly, angiogenesis also correlated with tumor grade and pathological stage (pT3).
The increased angiogenesis and expression of the angiogenic factors and their receptors in the prostatic intraepithelial neoplasia, support a premalignant role for this lesion, and suggest their application in prostatic core-biopsies as an additional prognostic factor in prostatic cancer.
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Elvert, Gerd. "Untersuchungen zur transkriptionellen Regulierung des VEGF-Rezeptors 2 (Flk-1)." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963193163.
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Kappas, Nicholas Chris Bautch Victoria L. "Analysis of the VEGFr1 (Flt-1) isoforms in vascular development." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2006. http://dc.lib.unc.edu/u?/etd,601.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2006.Title from electronic title page (viewed Oct. 10, 2007). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Biology." Discipline: Biology; Department/School: Biology.
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Vetteth, Sandeep. "Central Role for Marinobufagenin in the Pathogenesis of Uremic Cardiomyopathy." University of Toledo Health Science Campus / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=mco1229552226.
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Roche, Rebecca I. "Role of RNA Processing Factors in the Expression of Flt-1 and its Secreted Variant, sFlt-1." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/29632.
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Vascular endothelial growth factor (VEGF) is an endothelial cell mitogen involved in angiogenesis, the formation of new blood vessels. sFlt-1, a secreted form of the signal-transducing VEGF receptor Flt-1, can inhibit cellular responses to VEGF both in vitro and in vivo. sFlt-1 is generated by alternative pre-mRNA processing; removal of Flt-1 intron 13 by splicing produces the mRNA for transmembrane Flt-1, whereas cleavage/polyadenylation within this intron, preserving the exon 13/intron 13 junction, yields sFlt-1 mRNA. Despite the likely importance of sFlt-1 in VEGF signaling, little is known about the regulation of its expression.
Previous studies using an Flt-1 minigene (pFIN13) revealed that intronic cleavage/polyadenylation signals can affect Flt-1 expression, and, conversely, that 3' intronic splice signals can affect sFlt-1 expression. The goal of present work was to test the hypothesis that splicing and cleavage/polyadenylation factors compete functionally on Flt-1 transcripts, by 1) assessing the influence of exon 13/14 splicing determinants on expression of Flt-1 RNA processing variants in a transfected cell model system; 2) determining the effects of altering the relative abundance of proteins principally involved in splicing or cleavage/polyadenylation; and 3) characterizing a previously-unknown splice variant, predicted to encode a novel sFlt-1 protein isoform, in cells overexpressing the spliceosomal RNA binding protein U2AF65.
When the upstream exon in pFIN13 was decreased from 2135 to 309 bp, the sFlt-1:Flt-1 mRNA ratio decreased 8.9-fold and an aberrant 5'UTR/exon 14 splice decreased 60-fold, indicating that "exon definition" is a key parameter of successful Flt-1 RNA processing. Mutation of 5' or 3' intronic splice signals had little effect on Long sFlt-1:Total sFlt-1 mRNA ratio, suggesting that splicing and cleavage/polyadenylation factors may not compete physically for Flt-1 transcripts. Although co-transfection with RNA processing factor cDNAs did not generally produce the predicted pattern of effects on sFlt-1:Flt-1 mRNA ratio, a cryptic exon within intron 13 was revealed in cells overexpressing U2AF65. sFlt-1 protein apparently can be encoded by mRNAs either cleaved/polyadenylated within intron 13 or, surprisingly, by splicing of the cryptic exon "13b." Thus, the cellular decision to produce sFlt-1 or Flt-1 from a nascent RNA can no longer be viewed as a simple choice between cleavage/polyadenylation and splicing.Ph. D.
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Arantes, Ricardo Vinicius Nunes. "Estudo da angiogênese e da expressão temporal do VEGF e dos seus receptores VEGFR-1/Flt-1 e VEGFR-2/Flk-1 durante o reparo ósseo alveolar normal e com uso terapêutico de um antiinflamatório não esteroidal seletivo para COX-2 em ratos." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/25/25149/tde-12062012-151744/.
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Objetivo: Avaliar o efeito do Meloxicam sobre a expressão do VEGF e de seus receptores durante o reparo alveolar pós-exodontia em ratos. Material e Método: Foi realizada a exodontia do incisivo superior direito em 180 ratos Wistar, machos, com 60 dias de idade, subdivididos em dois grupos: 1) Grupo controle (n=90): os animais receberam injeção intraperitoneal de 0,1 ml de solução 0.9% NaCl diariamente, durante 7 dias; e 2) Grupo experimental (n=90): os animais receberam injeção diária de 3mg/kg de massa corporal de Meloxicam em solução 0.9%NaCl, durante 7 dias. Após 3, 7, 10, 14, 21 e 30 dias, os alvéolos foram coletados, fixados em formol a 10% em tampão fosfato, radiografados e processados histologicamente. Para o PCR-RT, as peças foram colocadas em Trizol® e armazenadas a -80ºC e para o Western blotting armazenado a -80ºC. Cortes histológicos semi-seriados (250m de intervalo entre os cortes) de todo o alvéolo no sentido transversal foram obtidos e corados pela hematoxilina e eosina. Avaliou-se nesses cortes pelo método morfométrico de volumetria de pontos a densidade de volume de tecido ósseo (%TO), tecido conjuntivo (%TC), coágulo sanguíneo (%Coa) e vaso sanguíneo (%VS). Os dados obtidos foram submetidos ao teste t para comparação entre os grupos por período e a ANOVA seguido do teste de Tukey para comparação entre períodos dentro de cada grupo, adotando nível de significância de p<0,05. Resultados: A análise radiográfica mostrou ocorrência com o transcorrer do tempo alterações no contorno da cortical óssea e redução no tamanho do alvéolo, além de um pequeno aumento na radiodensidade na região central do alvéolo. Morfologicamente, o grupo experimental exibiu em todos os períodos analisados, um atraso no processo de reparo em relação ao controle, exibindo maior quantidade de coágulo sanguíneo com lenta substituição por tecido conjuntivo e menor reabsorção da cortiça óssea alveolar e da formação/remodelação óssea. Na análise morfométrica a %TO no grupo controle foi de 0.817, 0.255, 0.368, 0.409 e 0.453 vezes maior em relação ao grupo experimental nos períodos de 3, 7, 10, 14 e 21 dias, respectivamente. Quanto a %Coa, os valores no grupo controle foram 0,097, 0,611, 1,189 e 1.497 vezes menor em relação ao grupo experimental nos períodos de 7, 10, 14 e 21 dias,respectivamente. A %VS no grupo controle apresentou 0,328 e 0,439 vezes maiores em relação ao grupo experimental nos períodos de 10 e 14 dias, respectivamente. A %TC não apresentou diferença estatística entre os grupos. As imunomarcações para VEGF e VEGFR-1 foram observadas em osteoblastos e osteócitos na cortical alveolar, e em fibroblastos no interior do alvéolo, com diferença estatisticamente significante apenas para VEGFR-1, onde a imunomarcação no grupo controle foi 0,544; 0,325 e 0,325 vezes maior em relação ao grupo experimental nos períodos de 3, 7 e 10 dias, respectivamente. As análises do PCR-RT para VEGF no grupo controle foi 1,274 vezes maior no período de 10 dias em relação ao grupo experimental. Na expressão de RNAm para VEGFR-1, o grupo controle foi 1,431; 0,951 e 0,845 vezes maior nos períodos de 3, 10 e 30 dias, respectivamente, em relação ao grupo experimental e VEGFR-2 no grupo controle de 4,649 e 0,790 vezes maior nos períodos de 3 e 7 dias, respectivamente. A expressão protéica do VEGF no grupo controle foi 0,365; 1,056; 2,187 e 0,350 vezes maior nos períodos de 3; 7; 10 e 14 dias em relação ao grupo experimental. Conclusões: Com base nos resultados obtidos foi possível concluir que o uso do antiinflamatório Meloxicam, administrado diariamente por 7 dias, altera a expressão do RNAm e das proteínas do VEGF e de seus receptores VEGFR, além de atrasar o processo de reparo e de remodelação óssea alveolar pós-exodontia.Objective: To evaluate the effect of Meloxicam on the expression of VEGF and its receptors during the post-extraction alveolar healing in rats. Material and Methods: The extraction of the right upper incisor was made in 180 male Wistar rats, aged 60 days old. The sample was divided in: 1) Control group (n=90) - the rats received intraperitoneal injection of 0.1 ml of 0.9% NaCl daily for 7 days, and 2) experimental group (n=90) - the rats received intraperitoneally 3mg/kg body weight of Meloxicam in 0.9% NaCl solution daily for 7 days. At 3, 7, 10, 14, 21 and 30 days later, the alveolar samples were collected, fixed in 10% formaldehyde in phosphate buffer, radiographed and histologically processed. For RT-PCR, the samples were placed in Trizol and stored at -80° and for Western blotting stored at -80°. Transversal semi-serial histological sections (with 250 um interval) of the whole alveolus were obtained and stained with hematoxylin and eosin. In these sections the volume density of bone tissue (% TO), connetive tissue (% CT), blood clot (Coa%) and blood vessel (% VS) was evaluated by point counting volumetry morphometric method. The obtained data were compared between groups for period by \"t\" test and between periods within each group by ANOVA and Tukey test, with a p<0.05 significance level. Results: a) The radiographic analysis showed changes in the contour of the cortical alveolar bone , reduction in size of the alveolus, and a small increase in radiodensity in their central region ; b) Morphologically the experimental group showed, in all periods, a delay in the repair process as compared to control, displaying greater amount of blood clot with slow replacement by connective tissue and lower cortical alveolar bone resorption and bone formation / remodeling c) In morphometric analysis the %TO in the control group were 0.817, 0.255, 0.368, 0.409 and 0.453 times higher than the experimental group during periods of 3, 7, 10, 14 and 21 days , respectively. The %Coa, the values in the control group were 0,097, 0,611, 1,189 and 1.497 times lower than in the experimental group on days 7, 10, 14 and 21 days respectively. The %VS in the control group showed 0.328 and 0.439 times higher than in the experimental group on days 10 and 14 days respectively. The% CT showed no statistical difference between groups. d) The imumunostaining for VEGF and VEGFR-1 were observed in osteoblasts and osteocytes in the cortical alveolar, and fibroblasts within the alveolus, which was statistically significant only for VEGFR-1, where the immunostaining in the control group was 0,544; 0,325 and 0,325 times higher than the experimental group during periods of 3, 7 and 10 days respectively e) The RT-PCR analysis for VEGF in the control group was 1.274 times higher within 10 days compared to the experimental group. In the expression of mRNA for VEGFR-1, the control group was 1,431; 0,951 and 0,845times higher in periods of 3, 10 and 30 days, respectively, compared to the experimental group and VEGFR-2 was 4.64 and 0.79 times higher in periods of 3 and 7 days, respectively, and f) The protein expression of VEGF in the control group was 0,365; 1,056; 2,187 and 0,350 times higher in periods of 3, 7, 10, 14 and 21 days compared to the experimental group. Conclusions: Based on the present results it was concluded that the use of Meloxicam, antiinflammatory administered daily for 7 days, alters the expression of mRNA and protein of VEGF and its receptors VEGFR, and slows the process of repair and remodeling post extraction alveolar
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Zaitseva, Yulia. "Rôle du dépôt et du substrat lors de la mise en évidence de l'anisotropie d'un plan de clivage (cas de l'Au et de l'Al sur (100)FLi) et de l'Al sur (100)FK)." Thèse, Université du Québec à Trois-Rivières, 1998. http://depot-e.uqtr.ca/4831/1/000642366.pdf.
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Bhimani, Munsif Ali. "Detecting mediators of the Flk-1 signalling pathway by mRNA differential display." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0001/MQ40799.pdf.
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Roche, Rebecca I. "Role of the Intron 13 Polypyrimidine Tract in Soluble Flt-1 Expression." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/32843.
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Angiogenesis is the formation of new blood vessels from existing vasculature. Vascular Endothelial Growth Factor (VEGF), a known angiogenic protein, stimulates endothelial cell proliferation and migration via interactions with its receptors, KDR and Flt-1. A secreted form of Flt-1 (sFlt-1), derived from alternatively-spliced RNA, can inhibit actions of VEGF in vivo. It has been suggested that alterations in sFlt-1 expression could significantly change the angiogenic VEGF activity. This project focuses on characterizing intronic elements that regulate Flt-1 mRNA splicing. A "wild-type" construct (pFIN13), containing the first 13 exons, intron 13 and exons 14-30 of mouse Flt-1, was shown to produce both forms of Flt-1 mRNA after transfection into HEK293 cells. To gauge the strength of the native splicing signals in intron 13 of Flt-1, a series of point mutations were made in the polypyrimidine tract using pFIN13. After transient transfection, the levels of Flt-1 and sFlt-1 protein and mRNA were compared using quantitative PCR, RNA hybridization analysis, and protein immunoblotting. Results from quantitative PCR showed that purine substitutions were associated with 120 to 350 fold decreases in Flt-1 mRNA (normalized against neor), consistent with less efficient splicing. These large decreases in Flt-1 mRNA were accompanied by increases in sFlt-1 mRNA. Modest (20 to 100%) increases in Flt-1 mRNA, reflecting improved splicing, resulted from increasing the uridine complement in the polypyrimidine tract. These results suggest that the wild-type polypyrimidine tract is of intermediate strength and may be a regulatory locus for modulating Flt-1: sFlt-1 ratios.Master of Science
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CURTO, R. A. "AVALIAÇÃO DE MÉTODOS DE ESTIMAÇÃO DE ALTURA E DE ESTRATIFICAÇÃO VERTICAL EM UMA FLORESTA ESTACIONAL SEMIDECIDUAL." Universidade Federal do Espírito Santo, 2011. http://repositorio.ufes.br/handle/10/4956.
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Previous issue date: 2011-02-04CURTO, Rafaella De Angeli. Avaliação de métodos de estimação de altura e de estratificação vertical em uma Floresta Estacional Semidecidual. 2011. Dissertação (Mestrado em Ciências Florestais) - Universidade Federal do Espírito Santo, Alegre-ES. Orientador: Prof. Dr. Gilson Fernandes da Silva. Coorientador: Prof. Dr. José Eduardo Macedo Pezzopane. Este estudo teve como objetivo avaliar métodos de estimação de altura total de árvores e métodos de estratificação vertical em uma floresta nativa. O presente estudo foi realizado em um fragmento de 52 ha de Floresta Estacional Semidecidual, conhecido como Floresta do Rosal, localizado no município de GuaçuíES. Para tanto, empregou-se o método de amostragem de área fixa, 2sendo distribuído um total de 16 parcelas de 600 m de forma sistemática no campo, totalizando uma área amostrada de 0,96 ha. Foi realizada uma análise descritiva dos dados de altura total de árvores e para avaliar a precisão na obtenção dessa variável foram propostos cinco métodos de estimação: Hipsômetro Vertex; Clinômetro digital; estimação com auxílio de uma régua de 15 metros; e estimações visuais com e sem treinamento; em três classes de altura: Classe 1 (15,00-17,99 m); Classe 2 (18,00-20,99 m) e; Classe 3 (>21,00 m), totalizando 15 tratamentos. Para comparar os tratamentos, foram mensurados 211 indivíduos, 124 em terreno plano e 87 em terreno inclinado, sendo a altura total desses, obtida por meio de escalada. Os dados de altura total foram comparados pelo teste t, a 5% de probabilidade, sendo realizadas também análises gráficas de resíduos e estatísticas complementares. Foram avaliados também a velocidade de execução dos métodos, além dos fatores:número de operadores, custo, robustez, facilidade de observação e compacidade. Para a avaliação da estratificação vertical, foram utilizados quatro diferentes métodos, sendo eles: Método 1 - Souza (1990); Método 2 - Souza et al. (2003); Método 3 - IUFRO; e Método 4 - Calegário et al. (1994). Além disso, foram avaliadas a composição florística, diversidade, estrutura horizontal e diamétrica da floresta em estudo. Com relação aos métodos de estimação de altura, o método de estimativa sem treinamento apresentou o pior desempenho quanto à precisão, para as duas condições de terreno avaliadas e o melhor desempenho foi para a estimativa com treinamento, sendo que a declividade afetou a estimativa da altura. Houve tendência em subestimar a altura com o aumento das classes, já o método de estimativa sem treinamento subestimou em todas as classes. Houve diferença quanto ao tempo médio para a estimação da altura entre os métodos e quanto ao efeito da classe, ressalvando algumas exceções. Foram amostrados 1596 indivíduos com DAP maior ou igual a 5 cm, totalizando 246 espécies. As famílias mais representativas em número de espécies foram: Fabaceae, Lauraceae, Myrtaceae e Rubiaceae. O índice de diversidade de Shannon-Weaver (H encontrado na amostragem alcança um valor expressivo. As espécies mais importantes da comunidade, tomando-se como base o IVI%, são: Mabea fistulifera, Siparuna guianensis, Pseudopiptadenia contorta, Apuleia leiocarpa e Myrcia fallax. A estrutura diamétrica do fragmento florestal estudado apresenta ertido, comum às florestas inequiâneas. Dentre os métodos de estratificação vertical, o método 1 não permitiu análise detalhada sobre o comportamento das espécies no estrato II, por apresentar tendências fortes em concentrar um maior número de indivíduos no referido estrato, já o método 2, permitiu um maior detalhamento dos estratos. O método 3, minimizou o problema encontrado no método 1, porém a mudança da altura dominante da amostragem pode mudar toda a discussão, demosntrando fragilidade no método. O método 4 não trouxe bons resultados para a estratificação da floresta em estudo, pois dividiu a floresta em apenas dois estratos de altura. Palavras-chave: floresta estacional semidecidual, estimação de altura, estratificação vertical.
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SILVA, R. G. "DINÂMICA TEMPORAL DE ÍNDICES DE VEGETAÇÃO E SUA CORRELAÇÃO COM A PRECIPITAÇÃO." Universidade Federal do Espírito Santo, 2016. http://repositorio.ufes.br/handle/10/7687.
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Previous issue date: 2016-02-26SILVA, Rosane Gomes da. Dinâmica temporal de índices de vegetação e sua correlação com a precipitação. 2016. Dissertação (Mestrado em ciências florestais) - Universidade Federal do Espírito Santo, Jerônimo Monteiro-ES. Orientador: Prof. Dr. Alexandre Rosa dos Santos. As florestas são áreas de grande relevância ambiental, pois seu ecossistema possibilita a manutenção de diversas espécies da fauna e contribui para a qualidade do solo e dos recursos hídricos. As variações climáticas constituem um dos principais agentes de alterações na dinâmica da vegetação, influenciando na distribuição, estrutura e função da vegetação, o que sugere uma desvaloração da mesma sob a forma de bens e serviços, estendendo os impactos à sócio-econômicos e de ecossistemas. Neste contexto, tornam-se cada vez mais importantes pesquisas que estudem a dinâmica de comportamento da vegetação e sua relação com o clima. O objetivo desta pesquisa foi analisar a tendência de comportamento da vegetação em bioma de mata atlântica, por meio de índices de vegetação do sensor MODIS, e sua correlação com a variabilidade dos dados mensais de precipitação do satélite TRMM. A pesquisa foi desenvolvida tendo como área de estudo o Parque Nacional do Caparaó e a parte da sua zona de amortecimento no estado do Espírito Santo. Foram utilizados dados de NDVI e EVI do sensor MODIS, produto MOD13Q1, do período de 2001 a 2014, totalizando 322 imagens e dados mensais de precipitação do satélite TRMM, do mesmo período, totalizando 168 imagens. As análises das tendências interanuais das séries temporais de Índices de vegetação foram realizadas por meio das metodologias de linearidade, correlação linear, tendência linear, tendência monotônica de Mann Kendall, tendência mediana de Theil-Sen e análise dos perfis temporais. Foi verificada a tendência sazonal por meio da análise de tendência sazonal (STA) e da transformada de ondaletas inversa de Haar. Por meio de técnicas de modelagem linear, expressas pelo R e R² calculados, foi estudada a correlação entre os dados de precipitação e índices de vegetação. Com a geração dos perfis temporais dos IV, observou-se que houve uma diminuição no vigor vegetativo, em especial nas áreas em que a vegetação apresenta-se mais vigorosa. Esse resultado foi de encontro às tendências interanuais estudadas, que indicaram decréscimo nos valores de IV tanto para a tendência monotônica de Mann Kendall como para a Tendência mediana, sendo um comportamento não linear de acordo com as metodologias de correlação linear, linearidade e tendência linear. De acordo com a Análise de Tendência sazonal puderam ser identificados dois ciclos sazonais na área de estudo, um ciclo anual e um ciclo semi-anual. Esse resultado foi o mesmo encontrado por meio da transformada de ondaleta para o EVI. Para o NDVI e a precipitação não foi observado padrão de comportamento sazonal pela transformada de ondaleta. Quanto à correlação dos índices de vegetação com a precipitação, foram encontrados valores de correlação que chegaram a 0,7 para o R e 0,6 para o R². No entanto, na maior parte da área, principalmente considerando o PARNA Caparaó, esses valores foram muito baixos. Dessa forma, outros fatores podem ter influenciado nas alterações de comportamento da dinâmica da vegetação no período considerado.
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Ajlouni, Burouj Kayed. "Polymorphisms in the Flt1 gene and their relation to expression of the secreted Flt1 variant." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/29426.
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Vascular endothelial growth factor (VEGF) is a potent angiogenic agent. VEGF activates its biologic responses through two cell-surface receptors, Flt1 and Flk1. In addition to the transmembrane form of Flt1, the Flt1 gene also encodes a secreted, truncated form of the receptor (sFlt1) translated from an mRNA in which a portion of intron 13 is preserved. sFlt1 retains high affinity for VEGF and thereby inhibits its
angiogenic activity. Intron 13 contains important cis elements involved in sFlt1 mRNA formation. Here, we test the hypothesis that polymorphisms in the human Flt1 gene, particularly SNPs at sites suspected to contain splicing or cleavage-polyadenylation
signals, influence Flt1 pre-mRNA processing and rates of Flt1 and sFlt1 expression. The NCBI SNP database contained 23 SNPs in the region of interest, one each in exons 13 and 14. An independent human SNP screen confirmed several of the reported SNPs. The web-based ESEfinder software predicted that the exon 13/14 SNPs had reduced potential for recruitment of splicing components. To test effects of exonic SNPs
on Flt1 pre-mRNA processing, wild type and mutant Flt1 minigene plasmids were transfected into NIH/3T3 cells. Both exonic SNPs were associated with ~40% decreases in Flt1:sFlt1 mRNA ratios determined by real-time PCR. To facilitate
exploration of ESEs in regulated RNA splicing, a PERL computer program, â EXONerator,â was written to silence predicted ESEs without altering polypeptide sequence. These results support the notion that small changes in exon composition can
have significant effects on splicing activity and underscore the utility of software tools for hypothesis generation.Ph. D.
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Binagui-Casas, Anahi Liliana. "Analysis of the role of Flk-1 during mouse haematopoietic stem cell development." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31134.
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In the mouse embryo, the first definitive haematopoietic stem cells (HSCs), capable of repopulating adult irradiated mice, emerge at mid-gestation by embryonic day E11. At this stage, the aorta-gonad-mesonephros (AGM) region is able to initiate and expand HSCs. Recently, it has been shown that the development of HSC in the AGM region results from the maturation of haematopoietic precursors called pre-HSCs. Mounting evidence points at an endothelial origin for these cells, the haematogenic endothelium. Analysis of VEGFs mutants, a critical pathway for endothelial developement, suggested that it also plays a role during early haematopoiesis. The main receptor of the pathway, FLK-1 (also known as VEGRR2 or KDR), is expressed in early hematopoietic and endothelial cells in the mouse embryo. Knock-out mutants for Flk-1 showed a decrease of endothelial and intra-embryonic haematopoietic progenitors. Although Flk-1 has been identified as an essential gene for HSC emergence, its exact point of action in HSC development remains unknown. In this thesis, I investigated the role of FLK-1 signalling in haematopoietic development and defined precise stages and cell types during HSC emergence in which FLK-1 is critically involved. by using a reporter line and antibody staining, I demonstrated that FLK-1 is expressed in the pre-HSCs/HSC lineage. Germ-line Flk-1 knockout results in embryonic lethality at around E9.0, before HSC emergence, mainly due to defects in vasculogenesis. Since arterial specification precedes HSC formation, it has never been elucidated whether the haematopoietic defects found in the knockouts are a secondary effect of the loss of vasculature or it FLK-1 is directly involved in haematopoietic specification. Therefore, to determine the role of the receptor in HSC development, I used a conditional inducible mutagenesis approach that allowed the deletion of Flk-1 precisely when pre-HSCs mature into HSCs at E10.5 and E11.5. My data showed that Flk-1 deletion at these stages affects both endothelial and haematopoietic progenitors, as well as HSCs. This suggests that the VEGF pathway is not only essential in early stages of haematopoietic development, as previously demonstrated, but it may be also involved in the maturation of pre HSC into HSCs at later stages.
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Niwa, Akira. "Orderly hematopoietic development of induced pluripotent stem cells via Flk-1(+) hemoangiogenic progenitors." Kyoto University, 2011. http://hdl.handle.net/2433/135380.
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Manemann, Barbara. "VEGF und Flt-1 als Prognosefaktoren bei neoadjuvant behandelten, lokal fortgeschrittenen nicht-kleinzelligen Lungentumoren." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969834942.
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Levin, Anette, and Anja Pielström. "Förslag till detaljplan : Svankila 1:84 m. fl. Melleruds kommun." Thesis, University West, Department of Technology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-708.
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Ishiguro, Naoki, Motoaki Kawasumi, Hiroshi Kitoh, and Karolina A. Siwicka. "Spatial and temporal distribution of growth factors receptors in the callus: Implications for improvement of distraction osteogenesis." Nagoya University School of Medicine, 2011. http://hdl.handle.net/2237/15354.
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Husse, Sorina Ines. "Die Wertigkeit des sFlt-1/PlGF-Quotienten als Prädiktionsmarker bei Schwangeren mit erhöhtem Präeklampsierisiko." Doctoral thesis, Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-160542.
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Einleitung: Die Dysbalance proangiogener (Placental Growth Factor = PlGF) und antiangiogener Faktoren (soluble fms-like tyrosine kinase 1 = sFlt-1) gilt heute als pathophysiologische Grundlage bei der Entstehung einer Präeklampsie (PE), eines HELLP-Syndroms (Haemolysis, Elevated Liver enzymes, Low Platelets) oder einer intrauterinen Wachstumsretardierung (IUGR). Der sFlt1/PlGF-Quotient, ein sensitiver und robuster diagnostischer Marker, ist bereits Wochen vor der Krankheitsmanifestation erhöht. Ziel dieser Studie war es, die Wertigkeit des sFlt1/PlGFQuotienten als prädiktiven Faktor bei Risikopatientinnen zu untersuchen. Patienten und Methode: In diese prospektive Studie wurden 68 Patientinnen mit einer Einlingsschwangerschaft und mindestens einem Risikofaktor für das Auftreten einer PE, eines HELLP-Syndrom oder einer IUGR im Schwangerschaftsverlauf eingeschlossen. Die Patientinnen wurden je nach Verlauf der Schwangerschaft in eine Gruppe mit Symptomen (Fallgruppe) und eine Gruppe ohne Symptome (Kontrollgruppe) für eine der oben genannten Erkrankungen unterteilt. Der sFlt1/PlGF-Quotient wurde bei der Aufnahme in die Studie und im weiteren Schwangerschaftsverlauf bestimmt. Ergebnisse: Eine PE, ein HELLP-Syndrom oder eine IUGR trat bei 41 % der Risikopatientinnen auf… Der absolute Wert des sFlt-1/PlGF-Quotienten war nur bei der Gruppe mit Symptomen auf ≥ 85 erhöht und zeigte sich in der 25 + 0-31 + 0 SSW (p = 0,005) und ab der 35 + 0 SSW (p = 0,044) als prädiktiver Faktor für eine PE, ein HELLP-Syndrom oder eine IUGR. Ab 7–10 Wochen vor der Entbindung war, in der Fallgruppe stärker als in der Kontrollgruppe, ein Anstieg des sFlt1/PlGFQuotienten zu beobachten. Dieser war 0–2 Wochen vor der Entbindung bei beiden Gruppen (Kontrollgruppe (MW ± SA 66,9 ± 134) vs. Fallgruppe (MW ± SA 393,3 ± 147,4, p = 0,021) am ,stärksten und zeigte sich ebenfalls als prädiktiver Faktor für eine der genannten Schwangerschaftserkrankungen (p = 0,025). Schlussfolgerung: Bei Risikoschwangeren kann der sFlt1/ PlGF-Quotient für die Einschätzung des individuellen Risikos für eine PE, ein HELLP-Syndrom oder eine IUGR im Schwangerschaftsverlauf genutzt werden. Wiederholte Messungen des Quotienten versprechen eine risikoangepasste Betreuung dieser PatientinnenBackground: A dysbalance of proangiogenic [placental growth factor (PlGF)] and antiangiogenic [soluble fms-like tyrosine kinase 1 (sFlt-1)] proteins is known to cause the symptoms of preeclampsia (PE), HELLP syndrome (hemolysis, elevated liver enzymes, low platelets) or intrauterine growth restriction (IUGR). An increased sFlt-1/ PlGF ratio ≥ 85 is considered a reliable diagnostic marker. Altered sFlt1 and PlGF concentrations can be detected several weeks prior to the onset of clinical symptoms. In this study we analysed the role of the sFlt1/PlGF ratio as a predictive marker for preeclampsia in a high-risk patient group. Patients and materials: We prospectively included 68 singleton pregnancies with at least one risk factor for PE, HELLP syndrome or IUGR. During the study the patients were divided into one group with symptoms (patient group) and one group without symptoms (control group) for the above-mentioned diseases. The sFlt1/PlGF ratios were measured on admission and during the course of pregnancy. Results: During pregnancy 41 % of patients developed PE, HELLP syndrome or IUGR. An increase of the absolute value of the sFlt1/PlGF ratio ≥ 85 was only observed in the patient group and was found to be a predictive factor for PE, HELLP syndrome or IUGR at 25 + 0 to 31 + 0 weeks of gestation (p = 0.005) and after 35 + 0 weeks of gestation (p = 0.044). Alterations of the sFlt1/PlGF ratio were observed in all patients but were higher in the patient group from 7–10 weeks prior to delivery and with the highest peak 0–2 weeks prior to delivery. Compared to the control group (mean ± SD 66.9 ± 134) absolute values of sFlt1/PlGF ratio were signifi cantly (p = 0.021) increased 0–2 weeks prior to delivery in the patient group (mean ± SD 393.3 ± 147.4). An increase of the sFlt1/PlGF ratio ≥ 85 0–2 weeks before delivery has shown to be predictive for one of the mentioned diseases (p = 0.025).Conclusions: In high-risk patients the sFlt1/PlGF ratio can be used for an individual risk assessment with regard to PE, HELLP syndrome or IUGR. Serial measurements permit a risk-adapted prenatal care of these patients