Дисертації з теми "Mécanisme de transcription"
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Tremblay, Jacques. "Mécanisme d'action de PTX1, un facteur de transcription à homéodomaine." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq43040.pdf.
Flajollet, Sébastien. "Etude du mécanisme d'activation de la transcription en réponse aux rétinoïdes." Lille 2, 2006. http://www.theses.fr/2006LIL2S041.
The Retinoic Acid Receptor (RAR) is a ligand activated transcription factor which modulates the expression of retinoic acid-target genes. These genes are implied in fundamental biological processes such as cellular homeostasis, embryogenesis, growth and reproduction. RAR recruits a plethora of coregulators with multiple functions in response to retinoids. These multiprotein complexes are key structural components in the complex and controlled transcription mechanism. Many of them participate in remodeling of chromatin, while otehrs are implied transcription complex formation. This underlines the importance of these coactivators in transcriptional activation. Yet their contribution to RAR-mediated transactivation remains poorly studied. This PhD thesis focused on the recruitment of three coactivator complexes : P160, mediator and SWI/SNF complex. These proteins are implied in distinct steps of the RAR-mediated process. I investigated this question by assessing the respective role of these coactivators by using molecular and cellular biology approaches in the P19 embryonal carcinoma cell line, an appropriate developmental system to study the role of RARs. Results of knock-down of SRC1 and med1 by RNA interference have demonstrated distinct roles of these coactivator complexes in retinoid-induced biological responses. This allowed us to propose a model summarizing complex formation during transcription initiation at the RARBeta2 promoter, a prototypical retinoic acid-regulated gene. Finally the study of the interaction between the ATP-dependent chromatin remodeling SWI-SNF complex and RAR identified us an additional step in the regulation of transcription by retinoids. Characterization of the role of each coactivators provide important information to better understand this complex regulation of RA-induced transcription
Tupin, Audrey. "Inhibiteurs de la transcription bactérienne : étude du mécanisme d'action de la lipiarmycine et dépendance au facteur de transcription σ". Thesis, Montpellier 1, 2010. http://www.theses.fr/2010MON13512/document.
The growing number of antibiotic-resistant bacteria added to the problem caused by persistent cells stress the need for developing new antibiotics and for understanding their mechanism of action. RNA polymerase is the main enzyme of the transcription process and is an interesting target for antibiotics. In this study we focus on a particular inhibitor of RNA polymerase : lipiarmycin. It is a macrocyclic inhibitor of transcription inhibiting Gram + bacteria that is developed in phase III clinical trials for treatment of Clostridium difficile infections. The objective of this work was to determine the mechanism of action of lipiarmycin and the mechanism confering resistance against the molecule. We first define more precisely its binding site on RNA polymerase and then used genetic and biochemical approaches to determine its mechanism of action and the effect of some specific mutations on transcription. Our experiments reveal a new mechanism of t ranscription inhibitor action
Moumen, Abdeladim. "Etude du mécanisme de la recombinaison homologue chez les rétrovirus." Paris 11, 2002. http://www.theses.fr/2002PA112133.
Homologous recombination is one of the main factors generating genetic variability in retrovirus. Recombination results from a transfer, by the reverse transcriptase, of the DNA synthesis from a genomic RNA (donor RNA) to the other one (acceptor RNA) presents within the virion. In order to dissect the molecular mechanism of this phenomenon, we have developed a reconstituted in vitro system, which allowed us to study recombination on any retroviral sequence of interest. One third of the genome has been investigated and most regions analysed yielded a high degree of recombination. We have identified, for the first time, that recombination efficiency of a given sequence was dependent on its folding and namely on the presence of a stable hairpin. This hairpin structure was required to be present in the acceptor RNA. Furthermore, we have shown that the strand transfer reaction is an intramolecular process where the acceptor RNA is complexed to the nascent DNA before the transfer. Based on these results, we have proposed a model of recombination in which the acceptor RNA, by its hairpin structure, hybridises to the nascent DNA before the switch occurs. This hybridisation both allows the acceptor RNA to be in close proximity with the nascent DNA and disrupts the process of reverse transcription ongoing on the donor RNA, thereby leading to a displacement of the donor RNA from the polemerase active site and its replacement by the acceptor RNA. It is well known that the folding of the RNA is involved in several biological processes, we have now demonstrated that it is also involved in the process, which generates genetic variability in retrovirus: homologous recombination
Debaize, Lydie. "Nouveau mécanisme d’activation d’un oncogène impliquant RUNX1 et FUBP1 dans les leucémies aiguës lymphoblastiques." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1B016/document.
Hematopoiesis is initiated from hematopoietic stem cells and results in the continuous and controlled production of mature blood cells. RUNX1 (Runt-related transcription factor 1) encodes a transcription factor playing a key role in hematopoiesis. Abnormal functions of this protein are implicated in blood cancer, notably in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Moreover, its transcriptional activity is controlled by the recruitment of cofactors. To unravel the mechanisms behind the regulation of RUNX1 transcriptional activity, we performed RUNX1 specific immunoprecipitation experiments followed by mass spectrometry and identified the Far Upstream Element Binding Protein 1 (FUBP1) as a potential cofactor of RUNX1. FUBP1 is a multifunctional regulator involved in diverse cellular processes. FUBP1 has recently been described to be essential for expansion and self-renewal of hematopoietic stem cells and to function as a potential cancer driver gene in lymphoblastic leukemia. We have shown, with a proximity ligation assay that we have optimized in non-adherent cells, that FUBP1 is a new cofactor of RUNX1 and that these two proteins can be part of the same regulatory complex in human pre-B lymphoblasts. By chromatin immunoprecipitation combined with sequencing, we have localized common chromatin regions bound by RUNX1 and FUBP1. We have identified the oncogene c-KIT as a common target gene, and characterized two regulatory regions bound by both RUNX1, FUBP1 and active histone marks, within the first c-KIT intron: one at +700 bp and the other on an enhancer at +30 kb. Moreover, we have determined RUNX1 and FUBP1 binding sites essential for the enhancer activation. Finally, we have demonstrated that RUNX1 and FUBP1 overexpression in a pre-B cell line increases the expression of c-KIT both at mRNA and protein levels, exacerbates one of the c-KIT downstream pathways, promotes cell proliferation in vitro and in vivo and renders cells more resistant to a c-KIT inhibitor. In conclusion, we have demonstrated that FUBP1 is a new cofactor of RUNX1 and that they activate the transcription of the c-KIT oncogene by binding on a common enhancer, thus promoting cell proliferation. Therefore, since FUBP1 and RUNX1 are overexpressed in some types of leukemia, alterations in this regulation may contribute to the onset or maintenance of leukemias. These new findings open new perspectives on understanding the control of RUNX1 transcriptional activity, and on leukemias related to RUNX1, FUBP1 or c-KIT deregulations
Auriol, Jérôme. "Etude fonctionnelle du facteur de transcription/réparation TFIIH : rôles dans le mécanisme de réparation de l'ADN par excision de nucléotides." Université Louis Pasteur (Strasbourg) (1971-2008), 2002. http://www.theses.fr/2002STR13178.
TFIIH is a multiprotein complex involved in transcription of class II and class I genes, and in nucleotide excision repair (NER). The cellular importance of this complex is illustrated by genetic disorders associated with mutations in two subunits of TFIIH, the XPB and XPD helicases. Those helicases are essentials for transcriptional and DNA repair mechanisms. During my PhD studies, we became interested in the function of TFIIH in NER. We studied the molecular consequences of an XPB mutation which change the last 40 C-terminal amino acids. Mutation disrupts TFIIH activity both in transcription and in repair. This mutant allowed us to identify an XPB phosphorylation site required for the cellular functions of TFIIH. Moreover, we isolated a complex containing TFIIH, RNA polymerase I and two repair proteins XPG and CSB. This complex is involved in ribosomal RNA synthesis. We show that mutations within the CSB protein destabilized the complex. This is also true for mutations within XPB and XPD, arguing for the biological significance of this complex. Finally, in order to study the regulation of TFIIH expression, we study the organisation of murine gene coding for p62 subunit as well as its promoter
Caillier, Bertrand. "Mécanisme de régulation de la transcription de l'UGT1A3 au foie et effet de variants génétiques." Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24528/24528.pdf.
Savare, Jean. "Mécanisme d'action du facteur de transcription SoxNeuro chez la drosophile : partenariat et modifications post-traductionnelles." Montpellier 1, 2005. http://www.theses.fr/2005MON13504.
Thénot, Sandrine. "Mécanisme d'activation de la transcription par les récepteurs aux oestrogènes : étude du cofacteur transcriptionnel hTIF1alpha." Montpellier 1, 2000. http://www.theses.fr/2000MON1T008.
Teyssier, Catherine. "Mécanisme de l'interférence transcriptionnelle entre le récepteur des oestrogènes et les facteurs AP-1." Montpellier 1, 2000. http://www.theses.fr/2000MON1T007.
Chambeyron, Severine. "Caractérisation des transcrits et du mécanisme d'initiation de la transcription inverse du facteur I chez Drosophila Melanogaster." Montpellier 2, 2002. http://www.theses.fr/2002MON20044.
Carascossa, Sophie. "Mécanisme d'action de deux cofacteurs transcriptionnels, SHP et RIP140 : rôle dans la signalisation androgénique." Montpellier 1, 2005. http://www.theses.fr/2005MON1T017.
Bruck, Nathalie. "Phosphorylation des récepteurs nucléaires de l'acide rétinoïque : Mécanisme et conséquences sur la transcription des gènes cibles." Université Louis Pasteur (Strasbourg) (1971-2008), 2008. http://www.theses.fr/2008STR13134.
Mercier, Alexandre. "Découverte d'un nouveau mécanisme homéostatique régissant l'utilisation du fer chez la levure à fission." Thèse, Université de Sherbrooke, 2010. http://savoirs.usherbrooke.ca/handle/11143/4302.
Nivon, Mathieu. "L'autophagie dépendante du facteur de transcription NFκB : un mécanisme de réponse à l'hyperthermie et à l'agrégation protéique". Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00926473.
Nivon, Mathieu. "L’autophagie dépendante du facteur de transcription NFκB : un mécanisme de réponse à l’hyperthermie et à l’agrégation protéique". Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10166/document.
The heat shock response is a widely described defense mechanism during which the preferential expression of heat shock proteins (Hsps) helps the cell to recover from thermal damages such as protein denaturation/aggregation. We have previously reported that NFκB transcription factor is activated during the recovery period after heat shock. Thus, we aimed to analyze the consequences of NFκB activation during heat shock recovery, by comparing the heat shock response of NFκB competent and incompetent cells. We demonstrated that NFκB plays a major and crucial role during the heat shock response by activating autophagy, which increases the survival of heat-treated cells. Indeed, we observed that autophagy is not activated during heat shock recovery leading to an increased level of necrotic cell death in NFκB incompetent cells. Moreover, when autophagy is artificially induced in these cells, the heat shock cytotoxicity is turned back to normal. We showed that the key regulators of autophagy (mTOR complex, and class III PI3Kinase complex) are not regulated by NFκB after heat shock. In contrast, we observed that aberrantly folded/aggregated proteins accumulation is a prime event in the activation of NFκB -mediated autophagy. Moreover, NFκB -depleted cells accumulate higher levels of protein aggregates induced by either heat shock treatment or mutated form of HspB5, indicating that the protein quality control process seem to be altered in these cells. This alteration could be caused by a defect in BAG3-HspB8 complex formation in NFκB -depleted cells. We demonstrated that heat shock treatment induces a NFB-dependent overexpression of the bag3 and hspb8 genes. Moreover, the accumulation of BAG3-HspB8 complex in heat shocked NFκB -competent cells is inhibited by NFκB depletion. Our findings how / prove / highlight revealed that NFκB -induced autophagy during heat shock recovery is an additional response to protein denaturation/aggregation induced by heat shock. This process depends on the BAG3-HspB8 complex formation and increases cell survival, probably through clearance of aggregated proteins
Tollenaere, Armelle. "Étude de la balance transcriptionnelle du rétrovirus HTLV-1 : identification d'un nouveau mécanisme de répression de la transcription antisens du rétrovirus HTLV-1 par la transcription sens Hijacking of the O-GlcNAcZYME complex by the HTLV-1 Tax oncoprotein facilitates viral transcription." Thesis, Sorbonne Paris Cité, 2019. https://wo.app.u-paris.fr/cgi-bin/WebObjects/TheseWeb.woa/wa/show?t=2091&f=16975.
HTLV-1 retrovirus infects mainly T CD4 lymphocytes and is the causative agent of Adult T cell Leukemia and an inflammatory pathology targeting the central nervous system named Tropical spastic paraparesis. The oncogenic properties of this virus lay in the expression of two oncoproteins, Tax and HBZ. Tax and all viral products except for HBZ are produced from the sense promoter of the virus located in the 5'LTR (Long Terminal Repeat). HTLV-1 antisense transcription leads to the synthesis of two transcripts one spliced, sHBZ, the other one unspliced, usHBZ. These two RNAs once translated give birth to two HBZ protein in which only a few amino acid differ in N-terminal extremity of the proteins. Tax and HBZ induce T lymphocytes proliferation, genomic abnormalities, lymphocytes immortalisation, ... Yet in leukemic cells, most of the time, Tax expression is lost, often by epigenetic repression of the 5'LTR. Thus even if Tax and HBZ actively take part in leukemic clones emergence, HTLV-1 transcriptional balance is deregulated in favor of HBZ at the final stage of transformation. In order to better comprehend how HTLV-1 leads to the development of leukemia, it is essential to understand how HTLV-1 transcriptional balance is regulated in the first steps of HTLV-1 infection. Whereas HBZ inhibitory effect on sense transcription is well described, little is known on the effect of sense transcription on HBZ expression. In this study, it has been shown that sHBZ promoter is less active in HTLV-1 infected lymphocytes with an active sense transcription. To confirm this observation, two pharmacological inhibitors of sense transcription have been caracterized and used to analyze the effect of a change in sense transcription level on sHBZ and usHBZ production. The inhibition of sense transcription is shown to inhibit usHBZ expression and enhance sHBZ transcription. The two antisense transcripts thus exhibit opposite patterns regarding sense transcription. To better define how this repression on sHBZ production is established and how the two promoters in the 3'LTR are regulated, a new model has been built. Jurkat T cells are stably transfected with a plasmid allowing the expression of sense transcripts under the control of the CMV promoter or a plasmid without sense transcription. These models will allow a precise characterization of sHBZ and usHBZ promoter and the deciphering of the inhibition initiated by sense transcription on sHBZ expression
Sauvé, Simon. "Détermination du mécanisme de discrimination entre l'ADN spécifique et non-spécifique par les facteurs de transcription B/HLH/LZ." Thèse, Université de Sherbrooke, 2006. http://savoirs.usherbrooke.ca/handle/11143/4228.
Veschambre, Philippe. "Mécanisme d'action du transactivateur viral Tat sur l'initiation de la transcription du promoteur HIV-1 : rôle de l'interaction de Tat avec les facteurs généraux de transcription TBP et TFIIB." Lyon 1, 1995. http://www.theses.fr/1995LYO1T290.
Ioannoni, Raphaël. "Élucidation du rôle et du mécanisme d’action de la protéine Cuf2 lors de la méiose chez la levure Schizosaccharomyces pombe." Thèse, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/9542.
Chamboredon, Sandrine. "La répression des gènes cibles directs sparc et collagène alpha2(I) par l'oncoprotéine v-Jun au cours de la transformation : un nouveau mécanisme qui implique les facteurs de transcription ubiquitaires SP1et Sp3." Lyon, École normale supérieure (sciences), 2004. http://www.theses.fr/2004ENSL0277.
Raffalli, Chloé. "Les allergies cutanées aux fragrances : mécanisme d'action et rôle du facteur de transcription Nrf2. Du modèle 2D au modèle 3D." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS045/document.
Allergic contact dermatitis (ACD) represents a severe health problem. It is a dendritic cells (DCs) mediated skin disease caused by repeated exposure to an allergenic compound. ACD cases of fragrances in general population is estimated from 1.7 % to 4.1%. Contact sensitizers are compounds termed haptens and they will form a conjugate with epidermis and dermis proteins. Example is cinnamaldehyde (CinA), a molecule found in cinnamon. Linalool and limonene are terpenes found in lavender and oranges. In contact with the air, they will autoxidize to form highly allergenic compounds: allylic hydroperoxides. The first aim of this thesis was to study the mechanism of action of those terpenes and their respective allylic hydroperoxides on THP-1 cell-line, described as a surrogate of DCs. The transcription factor Nrf2 is playing a major role in oxidative stress and was also investigated.Consumers of cosmetic products are exposed to low quantities of allergenic compounds, but several times a day or a week. We wanted to study repeated exposure of low concentration of haptens on the skin.KCs also play a key role in ACD: they are the first cells that will encounter the allergenic compound in the skin. The second aim of this thesis was to study the impact of repeated exposure of low concentrations of CinA on those KCs and more particularly on the epidermis differenciation, using a 3D organotypic culture of skin
Roy, Gauthier. "Étude d'un système d'acquisition du cuivre chez Bordetella pertussis : nouveau mécanisme de régulation post-transcriptionnelle et caractérisation fonctionnelle préliminaire." Electronic Thesis or Diss., Université de Lille (2022-....), 2022. http://www.theses.fr/2022ULILS058.
Several transition metals are essential micronutrients for most living beings, including bacteria. In addition, they play important roles at the host-pathogen interface: the host tends to restrict bacterial access to iron, manganese and zinc, while intoxicating invading microorganisms with copper or zinc during phagocytosis. Bacteria have therefore acquired various homeostasis mechanisms in order to adapt to those conditions. Whereas iron, zinc or manganese import systems have been extensively characterized, very little is known for copper, for which studies have mostly focused on defense mechanisms. Besides, while several post-transcriptional regulation mechanisms are known for other metals, only transcriptional regulators have been identified in response to copper.Previous work performed in the laboratory on copper homeostasis in the human-restricted pathogen Bordetella pertussis, responsible for the whooping cough disease, has shown that this bacterium has shed most of its defense mechanisms against excess copper. On the other hand, we have identified a three-gene operon called bp2923-bfrG-bp2921, in which the last two genes are down-regulated by copper excess. bfrG is notably predicted to encode a TonB-dependent transporter, a protein family well-known for metal import across the outer membrane in Gram-negative bacteria, and bp2921 has a characterized homolog encoding a siderophore reductase, which hints at a system involved in copper acquisition. We have shown that the protein encoded by the first gene, a member of the DUF2946 protein family, represents a new type of upstream Open Reading Frame (uORF) involved in post-transcriptional regulation of the downstream genes. In the absence of copper, the entire operon is transcribed and translated. Perception of copper by the nascent bp2923-coded protein via its conserved CXXC motif triggers Rho-dependent transcription termination between the first and second genes by relieving translation arrest on a conserved C-terminal RAPP motif. Homologs of bp2923 are widespread in bacterial genomes, where they head operons predicted to participate in copper importation or utilization. We have thus identified a new mode of genetic regulation by a transition metal and identified a regulatory function for a member of an uncharacterized family of bacterial proteins that we have named CruR, for Copper responsive upstream Regulator. Additional work on this system has shed a light on the complexity of bacterial regulation, as our operon is regulated not only by copper, but is also overexpressed upon virulence modulation or in stationary growth phase.We have also initiated the characterization of the function of this operon. BfrG has been shown to specifically bind copper in vitro, and phenotypic analyses have shown a crucial role for the operon when B. pertussis is placed in low-oxygen conditions. Among the cuproproteins produced by B. pertussis are several cytochrome oxidases in the respiratory chain, which suggests that BfrG and Bp2921 could play a role in delivering copper for their assembly. Combined with results on the regulation, this suggests a possible role for copper and our operon in bacterial persistence in the respiratory tract during infection. Many aspects of this system remain to be further investigated
Jacques, Cécile. "Etude du rôle et du mécanisme d'action des facteurs de transcription glial cell deficient/glial cells missing au cours du développement." Université Louis Pasteur (Strasbourg) (1971-2008), 2007. https://publication-theses.unistra.fr/public/theses_doctorat/2007/JACQUES_Cecile_2007.pdf.
Gcm-Gcm2 transcription factors are known for their role in glial and plasmatocytes differentiation in Drosophila embryo. During my PhD, I have shown that gcm-gcm2 genes are required for terminal differentiation of a subpopulation of tendon cells. Thereafter, we showed that the chicken c-GCM1 orthologue is required during embryogenesis for the differentiation of spinal cord neural precursors into neurons. We have also shown that gcm genes are expressed and required in post-embryonic neural brain lineages of Drosophila. All these studies show that the specific role of Gcm transcription factors depends on the cellular context in which they are expressed. A two hybrid screen enabled me to identify the cofactor dpias and its study has allowed me to show the implication of Gcm in larval hematopoiesis
Ayach, Maya. "Interaction hôte-pathogène : mécanisme d’inhibition de la synthèse protéique humaine par la protéine circumsporozoïte de Plasmodium falciparum, agent du paludisme." Strasbourg, 2011. http://www.theses.fr/2011STRA6100.
During my PhD, I was concerned by the study of the host-parasite interaction and its consequences on protein synthesis in human and Plasmodium falciparum (parasite responsible of the malaria) respectively. I have developed two major aspects : (i) The study of the aminoacylation reaction of transfer RNA and thus by comparison of human and parasite systems and (ii) the understanding of the mechanism of inhibition of protein synthesis in human by the Circumsporozoite protein of the parasite, a transmembrane protein which is secreted during the parasite infection of host hepatocytes. The plasmodial cytosolic tyrosyl-tRNA synthetase is a classical synthetase concerning its structural organization. It possesses two functional domains, catalytic domain and tRNA binding one. The kinetic characteristics of the aminocylation reaction (Km, Kcat and plateau) were determined. I have clearly shown that plasmodial TyrRS animoacylates both transcripts of plasmodial and human tRNATyr with the same efficiency. On the other hand, only a small fraction of modified human tRNATyr was aminoacylated by the parasite enzyme. These results indicate that crossaminoacylation reactions between the parasite and human are possible, but their efficiency varies from one system to another. Concerning the apicoplastic TyrRS, this enzyme, at the opposite of the cytosolic one, it presents two insertions. These insertions are characteristic of some parasite proteins and are called LCR (Low Complexity Region). The presence of such sequences in the apicoplastic TyrRS but also in other parasite proteins makes their expression in heterologous systems a difficult obstacle in the study of the parasite. During my PhD work, I did participate to the collaboration of a new hypothese concerning the function and the role of these insertions in the production of soluble proteins. These LCRs play a key role in the co-translational folding of the parasite proteins. Finally, the big part of my work concerns the study of consequence of the host-parasite interactions on protein synthesis in human liver cells during the hepatic stage of the infection. During this stage, the parasite is covered by a transmembrane protein called the Circumsporozoite protein (CSP). Previous study in 1997 showed that CSP is secreted by the parasite, and co-localizes with endoplasmique reticulum where it does probably inhibit host translation. I have demonstrated by using rabbit reticulocytes lysate, that CSP inhibits efficiently translation and that by inhibiting the formation of pre-initiation complex 48 S. This inhibition involves a direct interaction between the CSP and the small ribosomal particle 40 S. This work shows for the first time that parasites, like some virus, could affect directly host protein synthesis. My work is part of large project concerning the study of hepatic stage of the infection; in this manuscript I will discuss the role and the consequences of such translation inhibition on the parasite life cycle
Wang, Qiannan. "Investigation du mécanisme fonctionnel des gènes AtRING1 et AtZRF1 dans la régulation de la croissance et du développement chez les plantes." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAJ129/document.
In plants as in animals, the Polycomb Group (PcG) proteins play key roles in diverse developmental processes by repressing the expression of genes. These proteins work in multi-protein complexes, among them the best characterized ones are Polycomb Repressive Complex 1 (PRC1) and PRC2. Although PRC2 was extensively studied in Arabidopsis, it is only recently that components of PRC1 were identified in plants and their function mechanism remains largely elusive. My thesis work focused on the characterization of AtRING1A, one of the PRC1 core subunits, and of AtZRF1, a protein proposed as a reader of the histone H2A-monoubiquitin (H2Aub1) downstream to the PRC1 function. My results show that a total loss-of-function of AtRING1A, by CRISPR/Cas9 gene editing, leads to partial embryonic lethal and callus-formation of seedlings in Arabidopsis. Several mutations within the RAWUL domain at the C-terminus of AtRING1A are better tolerated and induce several defects in plant vegetative growth, flowering time, floral organ formation and seed production. My molecular data indicate a role of the RAWUL domain in H2Aub1 deposition in vivo and suppression of several key developmental genes. Our characterization of loss-of-function of AtZRF1 provides important detailed information about its function in the regulation of cell division and cell differentiation
Malenfant, Francis. "La régulation de l’expression génique peut passer par un mécanisme de terminaison prémature de la transcription dépendant de la RNase III chez Saccharomyces cerevisiae." Mémoire, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/11078.
Abstract : Gene expression is a highly regulated coordination of processes with the objective of producing functional proteins from the DNA code of the cell. To control the amount of proteins produced, cells use messenger RNAs as an intermediate to permit genomic information to move across the cell. To assure the quality of this signal and to control the level of gene expression, many RNA degradation mechanisms coordinate together according to their own specificities. Scientific literature has demonstrated long ago the existing interactions between RNA synthesis and RNA degradation pathways and how they closely work together to achieve viable gene expression regulation. One of those mechanisms induces transcription termination in the 3’ untranscribed region of coding genes initiated with a RNA cleavage from a ribonuclease III. In this master thesis, we show that a similar RNase III dependent mechanism can induce premature transcription termination inside the coding sequence. This mechanism seems promotor and terminator independent and depends mostly on the sequence coding for a stem-loop structure in the mRNA. Different sequences can induce a stem-loop structure recognizable by RNase III. However, there are some functional differences between stem-loop structures and not all of them can induce premature transcription termination. Since this mechanism must not happen every time and somehow must be inducible to permit gene expression when needed, this could possibly lead to a new gene regulation model.
Bidon, Baptiste. "Mediator and NER factors in transcription initiation." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAJ093/document.
The synthesis of messenger RNA is a highly regulated process. During transcription initiation, a large number of proteins are recruited to gene promoter, including the RNA polymerase II, general transcription factors, co-activators, chromatin remodellers and the Mediator complex. Some DNA repair factors from the NER pathway are also recruited. Using cells derived from patients bearing mutations in either MED12 gene or XPC gene, we studied the roles of such proteins in transcription. MED12 patients are mostly characterised by intellectual disability and developmental delay. We showed that MED12 is implicated in the transcription regulation of immediate early genes like JUN, known for its role in neurological development and neuronal plasticity. JUN expression is markedly altered by MED12 mutations. We also showed that the position of the mutation influences this alteration, bringing possible explanation for inter-patients symptom variability. Meanwhile, XPC patients are mostly characterized by photosensitivity. We showed that XPC protein, which engages one of the NER pathways, is implicated in chromatin post-translational modification. Together with E2F1, it helps the recruitment of GCN5 acetyl-transferase to promoter of a certain set of genes. On the promoter, GCN5 notably cooperates with TFIIH to modify the chromatin environment during transcription initiation. In addition to help the comprehension of the transcription mechanisms, these results bring knew insight into the aetiology of mutations associated diseases
Vieu, Erwann. "Dissection du mécanisme de terminaison-antiterminaison au niveau du terminateur tR1 du phage lambda : application à l'étude des complexes ARN-protéine in vivo." Orléans, 2004. http://www.theses.fr/2004ORLE2075.
Najjar, Imen. "Etude du mécanisme d'activation de STAT1 et analyse des rôles spécifiques de ses isoformes alpha et beta dans les lymphocytes B transformés par l'EBV." Paris 7, 2007. http://www.theses.fr/2007PA077136.
STAT1 is a transcription factor that is essential to immunity against pathogens including viruses and to tumour suppression. However, paradoxically, the Epstein-Barr virus (EBV) which is associated with several types of tumours, is responsible for the constitutive activation of STAT1. One of the aims of our work was to elucidate the molecular mechanism of this activation in B cell Unes. We found that the EBV, through the activation of the NFKB pathway, is responsible for the constitutive activation of STAT1 by inducing the secretion of interferons. We further studied the specific roles of the a and the p isoforms of STAT1 in these cells. This allowed us to demonstrate that the a isoform is involved in apoptosis induction and cell cycle arrest in B cells. Interestingly the biologic action of the β isoform was found to differ according to the expression of the α isoform: when overexpressed, STAT1ß was a 'dominant negative' of STAT1α, but when expressed separately, it exhibited properties analogous to those of STAT1α. Both isoforms appeared to have different mechanisms of action, as, following treatment with a cytotoxic agent such as fludarabine, the a isoform induced the phosphorylation and nuclear translocation of p53, while the ß isoform was much less efficient in inducing the phosphorylation of p53 and prevented its nuclear translocation. Finally, in the course of these studies, we identified a novel function of STAT1 i. E. Its involvement in the intracellular trafficking of IgG, pointing to a so far unsuspected function of STAT1 in immunity. Further research in this area will be devoted to the understanding of the individual function of the two isoforms of STAT1 in tumour suppression, apoptosis and immune surveillance, the cell Systems at hand will also allow to determine whether these isoforms have different targets and to identify them
Nasser, Amin. "Un mécanisme de régulation génétique permettant la synthèse de deux isoformes de la ferrédoxine : NADP oxydoréductase, à partir d'un seul gène, chez la cyanobactérie Synechocystis sp. PCC 6803." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00834306.
Welterlin-Pelpel, Karine. "Etude de nouvelles voies de régulation positive de la myogénèse : rôles de C-MOS et des CKI sur les facteurs myogéniques MYOD et MRF4." Paris 5, 1999. http://www.theses.fr/1999PA05S010.
Virolle, Thierry. "Caractérisation des séquences régulatrices du transcrit α3A de la laminine-5 : mise en évidence d'un mécanisme de répression "cellule-spécifique" des gènes". Nice, 2000. http://www.theses.fr/2000NICE5452.
Livolsi, Antonia. "Caractérisation d'un mécanisme d'activation alternatif du facteur de transcription NF-kB utilisant la phosphorylation sur tyrosine de la sous-unité inhibitrice IkB-α". Nice, 2001. http://www.theses.fr/2001NICE5613.
NF-kB transcription factor is involved in the regulation of several genes essential for immune, inflammatory, proliferative and apoptic responses. NF-kB is sequestered in the cytosol by the inhibitory subunit IkB. Following simulation, IKB is phosphorylated on two N-terminal serines then degraded by the 26S proteasome, allowing NF-kB nuclear translocation. In this work, we revealed an alternative mechanism of NF-kB activation in T lymphocytes, using tyrosine phosphorylation of IkB-α induce association of NF-kB/IkB complexes. We showed that Lck t and ZAP-70 tyrosine kinases are involved in the phosphorylation of tyrosines 42 and 305 of IkB-α and NF-kB activation by pervanadate (an inhibitor of tyrosine phosphatases). By contrast to serine phosphorylation, tyrosine phosphorylation of IkB-α does not lead to its degradation. Interaction of phosphorylated IkB-α with SH2 domain-containing proteins may participate to the dissociation of NF-kB/ IkB-α complexes. We showed that reoxygenation or H2O2 stimulation of Jurkat cells induce tyrosine phosphorylation of IkB-α. This reaction is also observed in the case of ischemia/reperfusion of the liver and the heart or X-rays irradiation of astrocytes, suggesting that ROIs are involved in this new pathway of NF-kB activation. Engagement of surface receptors such as TNF-R1 in bone marrow macrophages or NGF-R in neurons also induces the pTyr-dependent pathways. In conclusion, we contributed to the characterization of the molecular mechanisms that control NF-kB activity, whose dysregulation is associated to diverse pathologies (chronic inflammation, cancers, and neurodegenerative diseases). Understanding these mechanisms will allow in fine to design specific inhibitors to improve the treatment of these diseases
Delaunay, Jérôme. "Contribution à l'analyse d'un mécanisme de répression traductionnelle conservé entre le xénope et la drosophile : identification et caractérisation du facteur protéique Bru3 de liaison à l'élément EDEN." Montpellier 1, 2004. http://www.theses.fr/2004MON1T001.
Joyeux, Raffenot Annick. "Effet antioestrogénique de l'acide rétinoi͏̈que dans les cellules de cancer mammaire ER-positives : étude du mécanisme moléculaire." Montpellier 2, 1996. http://www.theses.fr/1996MON20182.
Lecine, Patrick. "Contrôle transcriptionnel du gène CD25/IL-2R(alpha) humain : mécanisme biphasique impliquant les familles de facteurs de transcription Rel/NF-kB, SRF, Stat et Ets." Aix-Marseille 2, 1996. http://www.theses.fr/1996AIX22083.
Sena, Sandra. "Mécanisme de différenciation du muscle lisse vasculaire : role de la β-catenine et des facteurs de transcription lef-tcf dans la régulation transcriptionnelle du gène humain de la chaine lourde de myosine du muscle lisse". Bordeaux 2, 2003. http://www.theses.fr/2003BOR21073.
Differentiated smooth muscle cell (SMC) is a key component of the arterial wall. The smooth muscle myosin heavy chain (sm-MHC) is a contractile protein expressed in differentiated SMC. Beta-catenin is a cytosolic protein involved in cell-cell interactions and in the cell-ECM interactions by participating to the Integrin-Linked Kinase pathway. We studied the role of β-catenin and LEF-TCF factors in the transcriptional regulation of he human sm-MHC expression. Overexpression of β-catenin stimulates the sm-MHC promoter. On the other hand, the LEF-TCF factors inhibit of the sm-MHC activity. Beta-catenin cooperate with the GATA-6 factor to positively regulate the sm-MHC promoter activity. The sm-MHC promoter is regulated by a β-catenin-dependant, LEF/TCF-independant mechanism. On the other hand, a β-catenin-dependent, LEF/TCF-dependent mechanism inhibits the sm-MHC expression. Cooperation between β-catenin and GATA-6 could explain the β-catenin-dependant, LEF/TCF-independant mechanism
Vetter, Guillaume. "Caractérisation du mécanisme de transport nucléo-cytoplasmique de la protéine P25 et mise en évidence d'interactions entre les protéines de mouvement du virus des nervures jaunes et nécrotiques de la betterave." Université Louis Pasteur (Strasbourg) (1971-2008), 2003. http://www.theses.fr/2003STR13051.
Beet necrotic yellow vein virus (BNYVV) is responsible for rhizomania disease of sugar beet. Its genome is composed of 4 or 5 plus-sense RNAs. The results described in this thesis concern (1) the nucleo-cytoplasmic transport of the protein P25 coded by BNYVV RNA 3 and its influence on symptomatology, and (2) the subcellular localization and the interactions among the three viral proteins implicated in cell-to-cell movement of the virus. Previous studies showed that P25 is responsible for the typical symptoms of rhizomania. By means of laser scanning confocal microscopy, I have shown that P25 fused to GFP localizes to both the cytoplasm and the nucleus of infected cells. Both a nuclear localization signal (NLS) and a nuclear export signal (NEMS) were detected on P25. The transport of P25 from the cytoplasm to the nucleus involved a direct interaction between the NLS and importin-a. Nuclear export required the NEMS sequence and occured by the Exportin1 pathway. Mutagenesis of potential phosphorylation sites on P25 indicated that its nuclear-cytoplasmic trafficking was regulated by protein kinases. A correlative study of leaf symptoms and the subcellular localization of wild-type and mutant P25's expressed in the context of a viral infection showed that nuclear import-deficient P25 mutants did not induce the leaf symptoms associated with P25 expression. Finally, one-hybrid experiments revealed that P25 can activate transcription of reporter genes in yeast. Taken together, these results suggest that P25, which contains a Zn-finger motif and a C-terminal acidic domain, could modulate transcription of cellular genes, and this could explain the characteristic symptoms of rhizomania. In the second part of my thesis, I have used electron microscopy to show that the BNYVV movement proteins TGBp1 and TGBp2 co-localize at plasmodesmata of BNYVV-infected cells. The existence of interactions between the two proteins was confirmed by farwestern and co-immunoprecipitation experiments
VIEU, Erwann. "DISSECTION DU MÉCANISME DE TERMINAISON/ANTITERMINAISON AU NIVEAU DU TERMINATEUR TRI DU PHAGE LAMBDA : APPLICATION A L'ÉTUDE DES COMPLEXES ARN-PROTÉINE IN VIVO." Phd thesis, Université d'Orléans, 2004. http://tel.archives-ouvertes.fr/tel-00009769.
Saillant, Vincent. "Comprendre le mécanisme du système senseur d’hème des bactéries pathogènes, une cible antibiotique innovante A novel Enterococcus faecalis heme transport regulator (FhtR) is a heme sensor in the gastrointestinal tract." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASB023.
Heme, a porphyrin containing an iron atom, is an essential cofactor of several bacterial functions. Heme is also toxic because of the reactivity of the iron generating reactive oxygen species. One of the main mechanisms of heme detoxification, in Gram-positive bacteria, relies on the expression of a heme efflux ABC transporter, HrtBA. The regulation of this transporter has been investigated in two opportunistic pathogens, Enterococcus faecalis and Staphylococcus aureus, two bacteria responsible for multiresistant nosocomial infections. In E. faecalis, a new TetR family regulator, FhtR, has been identified and characterized. The FhtR dependent transcriptional inhibition of hrtBA is lifted by its binding to heme. FhtR controls the intracellular heme pools as showed par the activity of the endogenous heme dependent catalase, KatA. FhtR is thus a master regulator of heme intracellular homeostasis in E. faecalis. In a mouse model of intestinal transit, HrtBA is expressed, demonstrating the relevance of this system in the gastrointestinal tract where E. faecalis is a commensal resident. In S. aureus, hrtBA transcription is controled by the two-component system, HssRS. The study of the mechanism of the membrane heme sensor HssS showed that the intracytoplasmic of the histidine kinase was responsible of the binding and heme signal transduction for HrtBA expression. Alltogether, these results demonstrate that while HrtBA is conserved among Gram positive bacteria, the regulating mechanisms leading to its expression are varied. This suggests that the host heme response is dependent of the bacteria lifestyle and underlies the importance of this cofactor in the host-pathogen relationship. Inhibiting heme effux by HrtBA or the heme sensing mechanisms could lead to new antibiotic strategies
Praly, Elise. "Etude du mécanisme d'action des facteurs de remodelage de la chromatine, à l'échelle de la molécule unique." Phd thesis, Université Paris-Diderot - Paris VII, 2009. http://tel.archives-ouvertes.fr/tel-00397683.
Nous utilisons ici un dispositif de pinces magnétiques pour sonder l'action de différents facteurs de remodelage (RSC, yISW1a et CHD1) sur une molécule d'ADN nue. Nous montrons que ces complexes ont des comportements différents vis-à-vis de ce substrat : en l'absence d'ATP, yISW1a et CHD1 s'accrochent à l'ADN de manière coopérative et réduisent son extension bout-à-bout. En présence d'ATP, RSC est capable de former de larges boucles d'ADN, sous-enroulées, dont la taille dépend de la force et de la concentration en ATP. Nous souhaitons maintenant sonder l'action de ces facteurs sur un substrat nucléosomal. Dans ce but, nous avons mis au point un protocole efficace pour préparer un substrat mono-nucléosomal, manipulable en pinces magnétiques, et nous avons défini une procédure pour s'assurer de la présence du nucléosome. Ce substrat de choix va nous servir de base pour l'étude de l'action des facteurs de remodelage de la chromatine.
Ramalanjaona, Nick. "Etude du rôle de la protéine NCp7 dans le mécanisme d'hybridation de la séquence PBS lors du second saut de brin de la transcription inverse de VIH-1." Strasbourg 1, 2007. http://www.theses.fr/2007STR13160.
The NCp7 protein is a potential target for an anti-HIV therapy since it is involved in numerous stages of the viral cycle, and its sequence is highly conserved. By combining fluorescence spectroscopy and RMN techniques, we showed that NCp7 modifies the conformation of the PBS loop and destabilizes the upper extremity of the stem. Therefore, NCp7 activates the PBS annealing by stimulating the formation of “kissing complexes”, while in absence of protein, the protruding extremity constitutes the main nucleation site. The modifications of PBS loop inferred by NCp7 also allow homodimers of PBS, which probably play a role in the genetic variability of the virus. The spectroscopic properties of the 8-vinyl-déoxyadenosine, a fluorescent analogue of the adenine, were studied. By its properties, this probe seems superior to the 2-AP
Yassine, May. "Analyse de l'intérêt pronostique du profil moléculaire dépendant de la sortiline nucléaire dans le cancer de poumon." Electronic Thesis or Diss., Limoges, 2023. http://www.theses.fr/2023LIMO0099.
Sortilin, a glycoprotein of the Vps10 family, is widely recognized for its key role in protein sorting. However, its dual role in oncology, as either tumor promoter or tumor suppressor, has given rise to much debate. In non-small cell lung cancer (NSCLC), and more specifically in adenocarcinoma (LUAD), an inverse correlation was observed between sortilin expression and tumor growth, as well as tumor grade. Identified as a novel membrane inhibitor, sortilin promises to remodel EGFR trafficking. It provides a promising pathway for limiting proliferative signaling and counteracting resistance to EGFR inhibitors, especially in LUAD with EGFR mutations. This perspective suggests its major involvement in moderating tumor aggressiveness. In the absence of data concerning the nuclear localization and role of sortilin at this level, our team has highlighted its colocalization with EGFR in the nucleus. Furthermore, sortilin interacted with chromatin and competed with EGFR at the transcription initiation sites (TSS) of EGFR-targeted genes. This points to a potential influence of sortilin on gene transcription, notably through its involvement in the recruitment of RNA polymerase II. In the present study, we show that sortilin plays a much more prominent nuclear role than previously recognized, adding to its known role as a tumor suppressor like. Our transcriptomic analyses, carried out in LUAD lines, revealed that sortilin down-regulates a large set of genes involved in oncogenic pathways, in addition to EGFR target genes. This role appears to be intrinsically linked to the regulation of DNA repair, transcription and chromatin organization orchestrated by sortilin. Sortilin would also associate with key proteins involved in these mechanisms at the nuclear level. These results challenge the traditional view of sortilin, which extends beyond the simple framework of protein sorting. Its highlight its varied functions in various tumors. Moreover, sortilin is emerging as a therapeutic target of interest for developing innovative strategies against LUAD
Debierre-Grockiego, Françoise. "Étude des mécanismes d'action de la dexaméthasone sur les cellules de la lignée éosinophile : rôle dans la prolifération, la différentiation et l'apoptose." Amiens, 1999. http://www.theses.fr/1999AMIED004.
El-Asmar, Bassam. "Mécanisme d'action de l'IL-1 dans la régulation de l'expression du gène Nur77 au niveau des celllules de Leydig chez la souris." Master's thesis, Université Laval, 2008. http://hdl.handle.net/20.500.11794/20366.
Abes, Rachida. "Vecteurs peptidiques pour la délivrance d'oligonucléotides : conception, mécanisme d'internalisation cellulaire et applications à la régulation de l'épissage." Thesis, Montpellier 1, 2010. http://www.theses.fr/2010MON13513.
The use of antisense oligonucleotides PMO or PNA to correct splicing errors by steric- block represents a new promising therapeutic strategy. These ONs lead to the treatment of diseases such as β-thalassemia, Duchenne muscular dystrophy (DMD) or cancers. However their functional success requires efficient delivery. Cationic cell penetrating peptides (CPPs) are characterized by their ability to be internalized in eukaryotic cells. However their efficiency in promoting cytoplasmic and nuclear delivery of ON has been hampered by endocytic sequestration and subsequent degradation of internalized material in endocytic vesicles, which is responsible for the degradation of internalized material. We have contributed to the study of intracellular trafficking and activity (using splicing correction assay) of several families of CPPs capable of delivering effective analogs ON at nontoxic doses and in the absence of agents endosomolytic. Our mechanistic studies indicate that these constructs (covalent or noncovalent) CPP-ON are internalized through clathrin, that segregation in endosomes remains a limitation and that there is good correlation between biological activity and their ability to destabilize endosomal membranes
Fawal, Mohamad-Ali. "The role of mRNA metaboism in NPM-ALK-mediated oncogenesis." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/633/.
Anaplastic Large Cell Lymphomas (ALCLs) are characterized by the expression of a fusion protein (XALK), in which the N-terminal partner (in most cases the nuclephosmin NPM) is fused to the cytoplasmic portion of ALK (Anaplastic Lymphoma Kinase) containing a tyrosine kinase domain. The constitutive expression of this oncogenic tyrosine kinase causes activation of many signalling pathways responsible for malignant transformation of the cells that express it. Following the discovery that the RNA binding protein AUF1 to is a partner of NPM-ALK, we hypothesized that besides its effect on transcription, NPM-ALK may also regulate gene expression at the post-transcriptional level. In fact, AUF1belongs to the AUBP family that controls the stability and translation of many RNAs containing in their 3' non-coding region a region rich adenine and uridine (ARE). The majority of these mRNAs encode proteins involved in controlling cell proliferation, apoptosis, stress and immune response. Therefore, following its interaction with NPM-ALK, AUF1 activity could be modified resulting in deregulation of the expression of its RNA targets. Using a combination of biochemical approaches, we have shown that AUF1 is hyperphosphorylated in murine NIH3T3 cells stably expressing the NPM-ALK translocation and this hyperphosphorylation is correlated with an increased stability of a number of ARE containing RNAs (e. G. C-myc, cyclin D1, A1, B2. . . ). Using cell imaging experiments, we showed that AUF1, HuR (another AUBP) and NPM-ALK (or other fusion X-ALK proteins) were concentrated in cytoplasmic granules, which we called AG for ALK granules. We analyzed by video microscopy the relationship between AG and other cytoplasmic granules, the processing bodies (PBs) and stress granules (SGs), which play a role in sorting, storage or degradation of mRNA. Finally, we identified the protein and ribonucleic (mRNA and miRNA) of AG. All our results show that AGs contribute to the control of RNA metabolism in the cells and could play a major role in NPM-ALK mediated oncogenicity
Fenouil, Romain. "Etude des mécanismes de la régulation transcriptionnelle et développement d'outils bioinformatiques pour le traitement des données de séquençage haut débit." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4089.
Mechanisms underlying the regulation of genetic expression are crucial for cell maintenance and adaptation to environment (differentiation, development...). Molecular approaches reveal a great diversity of factors involved in this process (TFs, epigenetics, nucleosomes) and several layers of regulation (transcription initiation, elongation, splicing, maturation) which contribute to the observed transcriptome complexity. During my thesis, we studied the mechanisms of transcription regulation in mammals during lymphocyte differentiation. Briefly, we described the recruitment of GTFs and the transcriptional activity occurring on promoters and enhancers. We also reveal that CpG islands (CGIs) are major regulator elements in mammals, which contribute to nucleosome depletion in a transcription-independent manner on a significant amount of promoters. Together with our collaborators, we also studied the mechanisms of transcription elongation, alternative splicing, or the complex combinatorial patterns of PTMs that can be set on the CTD of RNA Polymerase II and on histone tails. In the context of transition from pre-genomic studies to genome-wide experiments, an important part of my work consisted in the development of bioinformatics tools for the processing and analysis of experimental datasets from ChIP-on-chip, and HTS technologies (ChIP-Seq, MNase-Seq, RNA-Seq)
Reguillon, Isabelle. "Les mécanismes de la transcription chez les eucaryotes." Bordeaux 2, 1994. http://www.theses.fr/1994BOR2P049.