Littérature scientifique sur le sujet « Proteins maturation »

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Articles de revues sur le sujet "Proteins maturation"

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Hellen, Christopher U. T., et Eckard Wimmer. « Maturation of poliovirus capsid proteins ». Virology 187, no 2 (avril 1992) : 391–97. http://dx.doi.org/10.1016/0042-6822(92)90440-z.

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Garoff, Henrik, Roger Hewson et Dirk-Jan E. Opstelten. « Virus Maturation by Budding ». Microbiology and Molecular Biology Reviews 62, no 4 (1 décembre 1998) : 1171–90. http://dx.doi.org/10.1128/mmbr.62.4.1171-1190.1998.

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SUMMARY Enveloped viruses mature by budding at cellular membranes. It has been generally thought that this process is driven by interactions between the viral transmembrane proteins and the internal virion components (core, capsid, or nucleocapsid). This model was particularly applicable to alphaviruses, which require both spike proteins and a nucleocapsid for budding. However, genetic studies have clearly shown that the retrovirus core protein, i.e., the Gag protein, is able to form enveloped particles by itself. Also, budding of negative-strand RNA viruses (rhabdoviruses, orthomyxoviruses, and paramyxoviruses) seems to be accomplished mainly by internal components, most probably the matrix protein, since the spike proteins are not absolutely required for budding of these viruses either. In contrast, budding of coronavirus particles can occur in the absence of the nucleocapsid and appears to require two membrane proteins only. Biochemical and structural data suggest that the proteins, which play a key role in budding, drive this process by forming a three-dimensional (cage-like) protein lattice at the surface of or within the membrane. Similarly, recent electron microscopic studies revealed that the alphavirus spike proteins are also engaged in extensive lateral interactions, forming a dense protein shell at the outer surface of the viral envelope. On the basis of these data, we propose that the budding of enveloped viruses in general is governed by lateral interactions between peripheral or integral membrane proteins. This new concept also provides answers to the question of how viral and cellular membrane proteins are sorted during budding. In addition, it has implications for the mechanism by which the virion is uncoated during virus entry.
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Remington, S. James. « Fluorescent proteins : maturation, photochemistry and photophysics ». Current Opinion in Structural Biology 16, no 6 (décembre 2006) : 714–21. http://dx.doi.org/10.1016/j.sbi.2006.10.001.

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Matthews, Glenn. « Introduction : Proteolytic maturation of secretory proteins ». Seminars in Cell & ; Developmental Biology 9, no 1 (février 1998) : 1–2. http://dx.doi.org/10.1006/scdb.1997.0193.

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Sumi, Mamta P., et Arnab Ghosh. « Hsp90 in Human Diseases : Molecular Mechanisms to Therapeutic Approaches ». Cells 11, no 6 (12 mars 2022) : 976. http://dx.doi.org/10.3390/cells11060976.

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The maturation of hemeprotein dictates that they incorporate heme and become active, but knowledge of this essential cellular process remains incomplete. Studies on chaperon Hsp90 has revealed that it drives functional heme maturation of inducible nitric oxide synthase (iNOS), soluble guanylate cyclase (sGC) hemoglobin (Hb) and myoglobin (Mb) along with other proteins including GAPDH, while globin heme maturations also need an active sGC. In all these cases, Hsp90 interacts with the heme-free or apo-protein and then drives the heme maturation by an ATP dependent process before dissociating from the heme-replete proteins, suggesting that it is a key player in such heme-insertion processes. As the studies on globin maturation also need an active sGC, it connects the globin maturation to the NO-sGC (Nitric oxide-sGC) signal pathway, thereby constituting a novel NO-sGC-Globin axis. Since many aggressive cancer cells make Hbβ/Mb to survive, the dependence of the globin maturation of cancer cells places the NO-sGC signal pathway in a new light for therapeutic intervention. Given the ATPase function of Hsp90 in heme-maturation of client hemeproteins, Hsp90 inhibitors often cause serious side effects and this can encourage the alternate use of sGC activators/stimulators in combination with specific Hsp90 inhibitors for better therapeutic intervention.
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Gross, I. « Regulation of fetal lung maturation ». American Journal of Physiology-Lung Cellular and Molecular Physiology 259, no 6 (1 décembre 1990) : L337—L344. http://dx.doi.org/10.1152/ajplung.1990.259.6.l337.

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The recent identification of the genes for the surfactant proteins has greatly facilitated the study of the regulation of fetal lung alveolar epithelial cell development at the molecular level. In general, expression of the genes for the surfactant proteins is enhanced by the same hormones that stimulate phospholipid synthesis. There are, however, some notable differences that indicate that the genes for the different components of surfactant are independently regulated. Species differences in the response of the surfactant proteins to hormones such as glucocorticoids and adenosine 3',5'-cyclic monophosphate have also been demonstrated. This review focuses on current knowledge of the hormonal regulation of the surfactant proteins against a background of previous studies of lung development.
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Davis, Brandi N., Aaron C. Hilyard, Giorgio Lagna et Akiko Hata. « SMAD proteins control DROSHA-mediated microRNA maturation ». Nature 454, no 7200 (11 juin 2008) : 56–61. http://dx.doi.org/10.1038/nature07086.

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PAGES, Jean Marie, et Claude LAZDUNSKI. « Maturation of Exported Proteins in Escherichia coli ». European Journal of Biochemistry 124, no 3 (3 mars 2005) : 561–66. http://dx.doi.org/10.1111/j.1432-1033.1982.tb06630.x.

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Long, Courtney L., William L. Berry, Ying Zhao, Xiao-Hong Sun et Mary Beth Humphrey. « E proteins regulate osteoclast maturation and survival ». Journal of Bone and Mineral Research 27, no 12 (19 novembre 2012) : 2476–89. http://dx.doi.org/10.1002/jbmr.1707.

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Abaturov, A. E., et V. L. Babуch. « MiRNA biogenesis. Part 1. Maturation of pre-miRNA. Maturation of canonical miRNAs ». CHILD`S HEALTH 16, no 2 (13 mai 2021) : 200–207. http://dx.doi.org/10.22141/2224-0551.16.2.2021.229886.

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The scientific review presents the biogenesis of ­miRNAs. To write the article, information was searched using databases Scopus, Web of Science, MedLine, PubMed, Google Scholar, EMBASE, Global Health, The Cochrane Library, CyberLeninka. The article presents a brief description of the RNA sequence encoding miRNAs. It is emphasized that microRNAs, depending on the location of the sequence encoding them in the genome, are divided into two major groups: canonical and non-canonical miRNAs. It has been found that a single locus of a sequence encoding a miRNA can generate a series of non-coding mature transcripts. It is noted that there are canonical and non-canonical (alternative) ways of maturation of pri-miRNAs. The canonical path of maturation of miRNAs results from the functioning of DROSHA and DICER proteins. Intranuclear processing of pri-miRNA by the DROSHA protein is revealed, which leads to the formation of pre-miRNAs transported from the cell nucleus to the cytoplasm, where under the influence of the DICER protein they are converted into duplex microRNAs. Duplex miRNAs are recruited by Argonaute (AGO) proteins, on which they are spun, and as a result one of the two strands of RNA becomes mature miRNA. Non-canonical primary miRNA transcripts can be subjected to DROSHA-, DGCR8-independent, and DICER-independent processing. The dysfunction of microprocessor proteins and nuclear export of pre-miRNAs is accompanied by the development of some human diseases. Thus, in the biogenesis of miRNAs, there are canonical and non-canonical (alternative) ways of maturation of pri-miRNAs. The canonical path of maturation of primary micro­RNA transcripts is due to the functioning of ­DROSHA and DICER proteins. The non-canonical path of maturation of pre-miRNAs is performed by DROSHA-, DGCR8-independent, and DICER-independent processing. The dysfunction of various mechanisms of the canonical path of maturation of pre-miRNA is associated with the development of some human diseases.
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Thèses sur le sujet "Proteins maturation"

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Gilker, Eva Adeline Gilker. « INTERACTIONS AND LOCALIZATION OF PROTEIN PHOSPHATASES, YWHA PROTEINS AND CELL CYCLE CONTROL PROTEINS IN MEIOSIS ». Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent1532699317257539.

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Yarbrough, Daniel Kenneth. « Structural and mutational analysis of chromophore maturation in long wavelength fluorescent proteins / ». view abstract or download file of text, 2004. http://wwwlib.umi.com/cr/uoregon/fullcit?p3120630.

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Thesis (Ph. D.)--University of Oregon, 2004.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 142-152). Also available for download via the World Wide Web; free to University of Oregon users.
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Meissner, Christina Sylvia. « Influence of HCMV proteins pUL71 and pUL77 on viral maturation ». Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2011. http://dx.doi.org/10.18452/16414.

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Die Bildung infektiöser Viruspartikel des humanen Zytomegalievirus (HCMV) ist ein mehr-stufiger Prozess. Sie beginnt mit der Verpackung der DNA in die Kapside im Kern, gefolgt von weiterer Reifung während des Transports durch das Zytoplasma und der abschließenden Freisetzung aus der Zelle. Im Zuge dieser Arbeit wurden zwei Proteine, die Einfluss auf die ebengenannten Prozesse haben, analysiert. Der erste Teil der Arbeit befasst sich mit der funktionellen Charakterisierung des HCMV Pro-teins pUL77. Es ist bekannt, dass das homologe Protein pUL25 in alpha-Herpesvirinae essentiell für die DNA-Verpackung ist. Zunächst konnte das Protein als Kapsid-assoziiertes strukturelles Protein identifiziert werden. Es wurden Interaktionen von pUL77 mit DNA-Verpackungs- und Kapsidproteinen gezeigt. Weiterhin wurde die DNA-Bindungsfähigkeit von pUL77 in verschiedenen „in vitro“-Experimenten untersucht. Zusammengefasst weisen unsere Ergebnisse auf eine Funktion von HCMV pUL77 bei der DNA-Verpackung hin. Im zweiten Teil der Arbeit wurde das HCMV Protein pUL71 charakterisiert, das in allen Herpesviren konserviert vorkommt, dessen Funktion jedoch nicht charakterisiert ist. Zunächst wurde das Protein als strukturelles Tegumentprotein mit “earlylate“ Expressionskinetik klassifiziert. Weiterhin wurden die subzelluläre Lokalisation sowie virale und zelluläre Interaktionspartner untersucht. Die Ergebnisse weisen auf eine Funktion von HCMV pUL71 bei der Reifung und beim Transport der Virionen im Zytoplasma hin. „In silico“-Vorhersagen zeigten ein „Leuzin Zipper“-Motiv in pUL71, das als mögliche Oligomerisationsdomäne dienen könnte. Mutationen wurden in dieses Motiv eingebracht und die resultierenden Proteine auf ihre Oligomerisationsfähigkeit mit „in vitro“-Methoden und in rekombinanten Viren untersucht. Zusammenfassend konnten wir zeigen, dass das „Leuzin Zipper“-Motiv wichtig für die Funktion von pUL71 ist und diese mit einer unbeeinträchtigten Oligomerisation des Proteins zusammen hängt.
The morphogenesis of Human cytomegalovirus (HCMV) virions starts with the capsid assem-bly and DNA insertion in the nucleus followed by maturation during transport through the cytoplasm prior to release of virus progeny. In this study we are functionally characterising two proteins that are involved in those steps. The function of essential HCMV protein pUL77 is characterised in the first part of the study. HCMV pUL77 was shown to be a structural protein associated with capsids. Furthermore, our experiments demonstrated that HCMV pUL77 interacts with DNA packaging motor compo-nents and capsid proteins. The ability of HCMV pUL77 to bind double-stranded DNA was studied in “in vitro” assays designed for this study. The homologue α-Herpesvirinae protein pUL25 is described to be involved in processes connected with DNA packaging. Data ob-tained in this study demonstrates that HCMV pUL77 might serve a similar function. In the second part of the study HCMV pUL71, conserved throughout the Herpesvirus family but to date unclassified, was functionally characterised. HCMV pUL71 was defined a struc-tural tegument protein with early-late expression kinetics. We studied the sub-cellular local-isation and interactions of pUL71 with a subset of cellular and viral proteins. Thereby we could show that HCMV pUL71 function might be connected with processes of viral egress. By in silico analyses we identified a leucine zipper motif in pUL71 that might serve as a puta-tive oligomerisation domain. In order to investigate the function of the leucine zipper motif, we performed in vitro assays and investigated the alterations of the motif in the viral context. Taken together we can conclude that (i) an intact leucine zipper motif is crucial for the func-tion of pUL71 and (ii) this function is dependent upon undisturbed oligomerisation of the pro-tein.
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Atherton, Ruth Elizabeth. « Catalytic activity and maturation of the metalloprotease-disintegrin protein, MDC9 / ». Access full-text from WCMC, 1999. http://proquest.umi.com/pqdweb?did=733095101&sid=8&Fmt=2&clientId=8424&RQT=309&VName=PQD.

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Cotta, Doné Stefania. « Nephrin - intracellular trafficking and podocyte maturation / ». Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-411-2/.

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Tominaga, Taiga. « Structural studies on cyano group biosynthesis by [NiFe] hydrogenase maturation proteins ». 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/180637.

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Popescu, Costin-Ioan. « Maturation and processing of endogenous and viral proteins in the endoplasmic reticulum ». Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422667.

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Hodson, D. J. « The RNA-binding proteins TIS11b and TIS11d regulate lymphocyte development and maturation ». Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.604134.

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Over-expression studies in cultured B cells showed that both TIS11b and TIS11d were able to block plasma cell differentiation in vitro. This action was specific as class switch recombination was not affected. TIS11b conditional knockout mice showed normal lymphocyte development and maturation and a normal humoral immune response. TIS11b conditional knockout mice lacked marginal zone B cells and had reduced numbers of peritoneal B1 cells. However they mounted a normal humoral response to immunisation with NP-KLH, with normal affinity maturation and a normal memory response. Single knockouts were inter-crossed to create double knockout (dKO) mice. Unexpectedly, close to 100% of dKO mice developed T-lymphoblastic leukaemia from three months of age. Pre-leukaemic mice showed arrested B cell development at the pro-B stage and significantly perturbed thymic development. This included the aberrant passage of thymocytes through the β-selection checkpoint in the absence of expression of a functional T cell receptor β chain. A genome-wide approach to identify deregulated TIS11b/d targets in pre-leukaemic mice showed elevated expression of the oncogenic transcription factor Notch1. Bioinformatic analysis revealed potentials binding sites for TIS11b and TIS11d within a highly conserved region of the Notch1 3’UTR. The ability of TIS11b and TIS11d to interact and suppress expression of Notch1 was demonstrated by electromobility shift assay (EMSA) and luciferase reporter assays. Furthermore, development and proliferation of T-ALL was Notch1 dependent, both in vivo and in vitro.
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Lyall, Natalie. « The role of RAB2 in the maturation of macrophage phagosomes containing Candida albicans ». Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=238253.

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Phagosome maturation is a dynamic process involving the engulfment and degradation of pathogens by phagocytic cells. However, several pathogens have employed mechanisms that facilitate their survival and escape from the phagosome. The fungal pathogen, Candida albicans, is capable of switching from yeast to hyphal form to facilitate its pathogenicity and escape from the phagosome. Rab GTPases are key regulators in phagosome maturation by mediating interactions with the endocytic pathway and leading to biogenesis of the phagolysosome. The temporal localisation dynamics of Rab2 on maturing phagosomes containing live C. albicans was investigated. Live-cell imaging revealed green fluorescent protein (GFP)-tagged Rab2 was recruited to C. albicans-containing phagosomes. Rab2 appeared on phagosomes within 2 min following complete engulfment of C. albicans. Rab2 persisted transiently on macrophage phagosomes and this correlated with the length of C. albicans hyphae at the time of uptake, suggesting C. albicans morphology modulates Rab2 localisation dynamics. Expression of dominant negative or dominant active Rab2 did not affect macrophage migration, the rate of engulfment or phagosome acidification during the early stages of phagosome maturation. Furthermore, altered expression of Rab2 did not interfere with C. albicans ability to escape from and kill macrophages, suggesting Rab2 is not involved in the outcome of the host-pathogen interaction. However, altered expression of Rab2 reduced the acquisition of the late-stage phagosome maturation markers, cathepsin B and LAMP1, suggesting Rab2 impacts upon phagosome-lysosome fusion. Finally, the uptake of other particles by macrophages revealed Rab2 recruitment, as well as localisation dynamics on phagosomes, may be cargo-dependent. Through the use of live-cell imaging, real-time dynamics of phagosome biogenesis in live cells was examined, offering unique insight at the host-pathogen interface.
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Nangola, Sawitree. « The interference of human immunodeficiency virus assembly and maturation by ankyrin repeat proteins ». Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112044.

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Le but de ce travail est de découvrir des nouvelles protéines suceptibles d'interférer avec le cycle vital du virus HIV. De par leur repliement, les protéines à motifs ankyrines peuvent constituer une ossature protéique trés bien adaptée à cet objectif. Plusieurs interacteurs spécifiques de la protéine MA-CA du HIV ont été sélectionnées par exposition sur phage à partir d'une bibliothèque de variants d'ankyrines. Trois protéines isolées ont été produites à partir de clones ayant une forte activité de liaison. Le meilleur interacteur protéique (1D4) interagit avec un épitope situié sur le domaine CA. La constante de dissociation entre 1D4 et la protéine HACA a été déterminée par Calorimétrie de Titrage Isotherme (ou ITC) et est égale à 0,45M. La protéine 1D4 n'a pas d'effet détectable sur la maturation virale suivie par une technique ELISA de dosage de la Protease du HIV. En revanche, cette protéine interfere avec l'assemblage viral dans des cellules supT1 qui exprime de façon stable la protéine 1D4 sous forme myristoylée. Ce resultat ouvre une perspective d'appoche pour interferer avec le cycle vital du HIV
Presently, the standard regimen for antiretroviral treatment is highly active antiretroviral therapy (HAART). However, this strategy inherits the well-known side effects and is prone to promote the HIV drug-resistant strains. As a consequence, gene therapy has been introduced as an alternative approach. In this study, we aimed to discover the novel protein-based agents for intervening viral replication by gene targeting procedure. Regarding the efficient folding dynamic in cytoplasm, ankyrin repeat protein was considered to be a candidate scaffold. Several engineered ankyrin binders specific to HIV MA-CA domain were successfully retrieved from the ankyrin-displayed phage library. Three positive clones with high binding activity by ELISA were selected for further analyzing their binding property in soluble form. The best binder, 1D4, recognized its epitope located on CA domain as shown by Western immunobloting and ELISA. The affinity of 1D4 against H6MA-CA was 0.45 μM with one to two moles of target molecule determined by isothermal titration calorimetry (ITC). Although 1D4 exhibited no effect on viral maturation as verified by an ELISA based HIV protease assay technique, it disturbed the viral assembly process in Sup-T1 cells which stably expressed the myristoylated 1D4. This finding has provided a concrete prospect for HIV life cycle interruption by stem cell gene therapy in the future
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Livres sur le sujet "Proteins maturation"

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Workshop on Applied Molecular Evolution and the Maturation of the Immune Response (1989 Santa Fe, N.M.). Molecular evolution on rugged landscapes : Proteins, RNA, and the immune system : the proceedings of the Workshop on Applied Molecular Evolution and the Maturation of the Immune Response, held March, 1989 in Santa Fe, New Mexico. Sous la direction de Perelson Alan S. 1947- et Kauffman Stuart A. Redwood City, Calif : Addison-Wesley Pub. Co., 1991.

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McEwen, Robert Kenneth. Characterisation of the maturation and secretion of the acid extracellular proteinase of Yarrowia Lipolytica. Birmingham : University of Birmingham, 1996.

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VanSlyke, Judy K. Proteolytic maturation of vaccinia virus structural proteins. 1992.

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Growth and Maturation Factors (Growth & Maturation Factors). John Wiley & Sons, 1985.

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Whitehead, Stephen S. Proteolytic maturation of Vaccinia virus structural proteins : Enzyme and substrate analysis. 1994.

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Lee, Peiyu. Proteolytic maturation of vaccinia virus virion-associated proteins : Analysis of substrate determinants. 1993.

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Murphey, James Micheal. Soluble protein characteristics of Gewurztraminer and White Riesling grapes and wine during maturation. 1988.

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Biochemical, technological and structural changes in wheat proteins during grain maturation : Final technical report. Warsaw : Dept. of Biochemistry, Institute of Plant Biology, University of Agriculture, 1988.

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Leung, Doris G. Other Proven and Putative Autoimmune Disorders of the Peripheral Nervous System. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199937837.003.0098.

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Myasthenia gravis is in most cases an autoimmune disorder of the neuromuscular junction in which antibodies are directed at nicotinic acetylcholine receptors or other synaptic proteins, such as the MusK protein that is involved in the formation of the formation and maturation of the motor endplate. Less commonly, myasthenia gravis can result from antibodies directed to presynaptic calcium channels as a side effect of paraneoplastic antibodies (Lambert-Eaton syndrome) or from a developmental paucity of acetylcholine receptors in the neonatal form of the disease. Treatment is usually a combination of aceetylcoholinesterase inhibitors such as pyridostigmine to prolong the life of acetylcholine released at the neuromuscular junction and/or drugs such as corticosteroids aimed at reducing inflammation.
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Nikravan, Sara, et Frederick Mihm. Pathophysiology and management of functional endocrine tumours in the critically ill. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0264.

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Thyroid hormones act on most tissues via nuclear T3 receptors. Thyroid hormones stimulate oxygen consumption and heat production, influence cell growth and maturation (central nervous system, bone), and modulate metabolism (carbohydrates, lipids, proteins, drugs). Treatment for presumed thyroid disease frequently has to be initiated before the results of diagnostic tests are available. Treatment of hyperthyroidism should result in the reduction of serum thyroid hormone levels and their action on peripheral tissues with concurrent treatment of the precipitating event. In severe hypothyroidism the choice of thyroid hormone (thyroxine or tri-iodothyronine), optimal dosing, and the route of administration remain controversial
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Chapitres de livres sur le sujet "Proteins maturation"

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Cooper, Trevor G. « Epididymal Proteins and Sperm Maturation ». Dans Spermatogenesis — Fertilization — Contraception, 285–318. Berlin, Heidelberg : Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-662-02815-5_12.

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Cooper, Trevor G. « Epididymal Secretion and Resorption of Proteins ». Dans The Epididymis, Sperm Maturation and Fertilisation, 200–230. Berlin, Heidelberg : Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-71471-9_15.

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Fung, Jia Jun, Karla Blöcher-Juárez et Anton Khmelinskii. « High-Throughput Analysis of Protein Turnover with Tandem Fluorescent Protein Timers ». Dans Methods in Molecular Biology, 85–100. New York, NY : Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-1732-8_6.

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AbstractTandem fluorescent protein timers (tFTs) are versatile reporters of protein dynamics. A tFT consists of two fluorescent proteins with different maturation kinetics and provides a ratiometric readout of protein age, which can be exploited to follow intracellular trafficking, inheritance and turnover of tFT-tagged proteins. Here, we detail a protocol for high-throughput analysis of protein turnover with tFTs in yeast using fluorescence measurements of ordered colony arrays. We describe guidelines on optimization of experimental design with regard to the layout of colony arrays, growth conditions, and instrument choice. Combined with semi-automated genetic crossing using synthetic genetic array (SGA) methodology and high-throughput protein tagging with SWAp-Tag (SWAT) libraries, this approach can be used to compare protein turnover across the proteome and to identify regulators of protein turnover genome-wide.
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Sripathy, K. V., et Steven P. C. Groot. « Seed Development and Maturation ». Dans Seed Science and Technology, 17–38. Singapore : Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-5888-5_2.

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AbstractIn plants, a fascinating set of post-fertilization events result in the development of a dispersal unit known as a seed. During the maturation phase, seeds accumulate storage reserves and acquire desiccation tolerance, followed by an increase in seed vigour during maturation drying. Physiological (or mass) maturity may be attributed to the stage of seed maturation when maximum seed dry matter accumulation has occurred, marking the end of the seed-filling phase. The stage of maturity at harvest is one of the most important factors that can influence the quality of seeds. Recent studies established that seed vigour and longevity continue to increase even after physiological maturity, signifying the importance of the late maturation phase for maximizing seed quality. Among the plant hormones, abscisic acid (ABA) has been studied extensively for its role during seed development and maturation. Apart from ABA, gibberellic acid (GA), cytokinin and auxin also play a critical role during the development of seeds. Desiccation tolerance in seeds begins much before the attainment of physiological maturity. Acquisition of desiccation tolerance is associated with embryo accumulation of oligosaccharides of the raffinose family, low molecular weight antioxidants, late embryogenesis abundant proteins and heat shock proteins coupled with structural changes at the cellular level. To obtain seeds of maximum quality (in terms of germination, vigour and longevity), harvesting needs to be performed at or slightly after harvest maturity a period at which seed moisture content stabilizes with environmental factors. In this chapter, an attempt has been made to present the current understanding of seed development and maturation concentrating on various aspects viz. phases of seed development, the role of plant hormones, other factors affecting seed development, concepts of seed maturity, and its relevance to seed quality, maturity indices in crop plants and acquisition of desiccation tolerance in seeds.
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Ghosh, Arnab, et Dennis J. Stuehr. « Hsp90 and Its Role in Heme-Maturation of Client Proteins : Implications for Human Diseases ». Dans Heat Shock Proteins, 251–68. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-23158-3_12.

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Cuasnicú, Patricia S., Débora J. Cohen, Diego A. Ellerman, Dolores Busso, Vanina G. Da Ros et Mauro M. Morgenfeld. « Changes in Specific Sperm Proteins During Epididymal Maturation ». Dans The Epididymis : From Molecules to Clinical Practice, 389–403. Boston, MA : Springer US, 2002. http://dx.doi.org/10.1007/978-1-4615-0679-9_22.

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Robinson, Colin, Ian W. Brock, Laurence Hazell et Andrew Hulford. « Transport and Maturation of Cytosolically Synthesised Thylakoid Proteins ». Dans Research in Photosynthesis, 141–47. Dordrecht : Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-009-0383-8_31.

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Narayan, Mahesh. « The Case of Oxidative Folding of Ribonuclease A : Factors Impacting Fold Maturation of ER-Processed Proteins ». Dans Folding of Disulfide Proteins, 23–42. New York, NY : Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-7273-6_2.

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Adiga, P. R., et C. V. Ramana Murty. « Vitamin Carrier Proteins During Embryonic Development in Birds and Mammals ». Dans Ciba Foundation Symposium 98 - Molecular Biology of Egg Maturation, 111–36. Chichester, UK : John Wiley & Sons, Ltd, 2008. http://dx.doi.org/10.1002/9780470720790.ch8.

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Kante, A., J. M. Berrez et N. Latruffe. « Synthesis and Maturation of D-β-Hydroxybutyrate Dehydrogenase (BDH) from Mitochondrial Inner Membrane ». Dans Dynamics of Membrane Proteins and Cellular Energetics, 231–50. Berlin, Heidelberg : Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-73905-7_16.

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Actes de conférences sur le sujet "Proteins maturation"

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Jackson, C. W., N. K. Hutson et S. A. Steward. « CHANGES IN PROTEIN SYNTHESIS PROFILES OF MEGAKARYOCYTES (MK) DURING MATURATION ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643545.

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Several key differentiation events occur within the recognizable MK compartment; however, little is known about the macromolecular changes responsible for these events. In this study, protein synthesis profiles of morphologically immature and mature guinea pig MK populations have been analyzed by twodimensional gel electrophoresis after in vivo labeling with 35S-methionine. MK were enriched by a bovine plasma aggregation enrichment procedure (Blood 69:173, 1987) and then fractionated into immature and mature populations based on differences in their respective buoyant densities (Brit. J. Haematol. 64:33, 1986). With this protocol, immature and mature MK populations were obtained in which MK constituted 95% of the cell mass. Ninety percent of the MK in the immature population had basophilic, immature morphology while ≥90% of those in the mature population had acidophilic, mature staining characteristics after Wright's staining. Protease inhibitors were used throughout the isolation procedure. The cells were solubilized and proteins subjected to two-dimensional electrophoresis according to O'Farrell (J. Biol. Chem. 250:4007, 1975). To examine basic proteins, proteins were electrophoresed in the first dimension under nonequilibrium conditions in a pH gradient as described by O'Farrell et al. (Cell 12:1133, 1977). Analyses of fluorograms revealed both qualitative and quantitative differences in synthesis profiles between these two MK populations. Among acidic proteins whose synthesis was readily detected in immature but not mature MK were ones whose MW and pi were respectively: 120K, 6.4; 7OK, 5.9; 70K, 6.9; 65K, 6.8; 55K, 6.2; 55K, 6.0; 53K, 5.8; 53K, 6.5; 52K, 6.7; 50K, 6.8; 41K, 5.5 and 33K, 6.7. Acidic and neutral proteins prominently synthesized in mature but not immature MK were found at MW and PI of: 110K, 5.7; 110K, 5.8 and 80K, 7.2. Basic proteins prominently synthesized in immature but not mature MK were found at MWs of: 110K; 70K; 52K; 48K; 39K and 18K. Basic proteins actively synthesized by mature but not immature MK had MWs of: 83K; 43K and 17K. These findings demonstrate that differences in protein synthesis patterns can be readily detected between immature and mature MK and provide baseline data with which to explore the role of these proteins in MK differentiation
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Schick, B. P., C. J. Walsh et T. Jenkins-West. « CHANGES IN PROTEOGLYCAN AND SULFATED PROTEIN SYNTHESIS DURING MEGAKARYOCYTE MATURATION IN VIVO ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644620.

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We investigated changes in sulfated proteoglycan (PG) and sulfated protein synthesis during megakaryocyte (MK) maturation in vivo by characterizing the (35S)-labeled molecules in MKs and platelets (PLTs) obtained daily from 3 hr to 5 days after injection of guinea pigs with (35S)sulfate. Radioactivity in macromolecules was maximal in MKs 3 hr and in PLTs 3 days after the injection. The cells were solubilized in 8M urea/50mM Tris/0.2% Triton X-100/0.1M NaCl, and PGs and sulfoproteins were separated by DEAE-Sephacel chromatography. PGs (65% of cell 35s) were eluted as two fractions, one (PG-1, 87%) with 4M Gdn HC1 and another (PG-2, 13%) with 4M Gdn HCl/2% TX-100. The Kav of PLT PG-1 on Sepharose CL-6B shifted gradually from 0.18 to 0.10 from 1-5 days after (35S) injection, and the smaller and larger PG-1 species were resolved on SDS-PAGE by fluorography. The size of PG-1 molecules was a function of glycosaminoglycan (GAG) chain length. The appearance of the different size PG-1 molecules in PLTs was accounted for by their disappearance from MKs over the same time period. Thus the size of the PG-1 synthesized by MKs decreased with MK maturation. The (35S)-PG-2 appeared in PLTs only 2-3 days after (35S) injection, had Kav 0.07 on CL-6B, but had GAGs of the same average size as those of PG-1. The hydrophobic character of PG-2 suggests that it might be the membrane PG. PG-1 and PG-2 were separated by SDS-PAGE and identified by fluorography. The core proteins of PG-1 and PG-2 were obtained by chondroitinase digestion and identified by SDS-PAGE and fluorography. The GAGs of PG-1 and PG-2 were almost entirely chondroitin-6-sulfate. The average size of PG-1 was 200,000 and its GAGs about 45,000.The sulfated proteins (20-25% of total cell 35S) eluted in the wash-through of the DEAE-Sephacel column and with 0.23M NaCl. Their isoelectric points were 4.0-6.5. They eluted as a small peak near the V0 and a major broad peak from Kav 0.3-0.6 on CL-6B columns, and could be identified as at least 8 distinct bands on SDS-PAGE by fluorography. Digestion with NaOH/NaBH4, Pronase or papain released small (35S)-labeled fragments, and the (35S) appeared to be associated with oligosaccharides. The sulfoproteins appeared in PLTs primarily 2-4 days after (35S) injection, and different proteins were labeled at different time points.
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Ilina, E. L., A. S. Kiryushkin, E. D. Guseva et K. N. Demchenko. « Methodological approaches to agrobacterium-mediated transformation of buckwheat (Fagopyrum esculentum Moench) ». Dans 2nd International Scientific Conference "Plants and Microbes : the Future of Biotechnology". PLAMIC2020 Organizing committee, 2020. http://dx.doi.org/10.28983/plamic2020.106.

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The method of Agrobacterium rhizogenes-mediated transformation of buckwheat has been established; composite plants have been obtained. The distribution of the cellular response to auxin by reporter proteins with different maturation times coincides.
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Renkl, A. C., J. Wussler, T. Ahrens, K. Thoma, C. Bernardi, J. C. Simon et J. M. Weiss. « OPN INDUCES DENDRITIC CELL (DC) ACTIVATION AND POLARIZES THEIR MATURATION TOWARDS A DC1 PHENOTYPE ». Dans 3rd International Conference on Osteopontin and SIBLING (Small Integrin-Binding Ligand, N-linked Glycoprotein) Proteins, 2002. TheScientificWorld Ltd, 2002. http://dx.doi.org/10.1100/tsw.2002.312.

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Cramer, Elisabeth M., F. John, William Vainchenker et Janine Breton-Gorius. « PRODUCTION AND LOCALISATION OF ALPHA-GRANULE PROTEINS IN MATURING MEGAKARYOCYTES : AN OVERVIEW ON ULTRA-STRUCTURAL ASPECTS OF MEGAKARYOCYTE MATURATION ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642952.

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In order to study the production of α- granule proteins in maturing megakaryocytes, we used immunocytochemical techniques performed on cultured and enriched bone marrow megakaryocytes. Cultures were prepared from bone marrow CFU-MK with the methylcellulose and plasma clot techniques. Preparation of bone marrow megakaryocytes was carried out from human or pig rib marrow separated on percoll gradient and counterflow centrifugation. Megakaryocyte preparations were 90$ pure and represented 85$ of those in the whole marrow. Activation was prevented with prostacyclin and prefixation with low concentration glutaraldehyde. A panel of monoclonal and polyclonal antibodies, against different platelet membrane glycoproteins and against cytoplasmic antigens (such as von Willebrand Factor (vWF), fibrinogen (Fg) and thrombospondin (TSP)) was used and observed by immunofluorescence or by immunogold in electron microscopy.The first megakaryocytic precursors, promegakaryoblasts (PMKB) identifiable by these antibodies were found at day 5 of culture. They had the size of lymphocytes, were labelled for GP lib, Ilia, and Ilb-IIIa complex but not for GPIb which appeared later. Platelet peroxidase was also present, otherwise these cells were devoid of α- granules and only a few of them exhibited a diffuse pattern for vWF immunolabelling. One day later membrane GPIb and diffuse cytoplasmic labelling for vWF were detected in the majority of PMKB. At day 9 of culture, this pattern of labelling for vWF became more intense and granular. The same pattern was observed for TSP and platelet factor 4. Immunoelectron microscopy showed that in immature megakaryocytes isolated from human bone marrow, labelling for vWF and TSP was observed in vesicles located in the Golgi region; in addition numerous small granules less than 0.1pm in diameter, round or elongated in shape, were labelled for these antigens. In mature human megakaryocytes, the labelling for these cytoplasmic antigens was restricted to the platelet α- granules in a distribution pattern similar to that of platelet α- granules. However, the labelling for Fg was consistently less intense in the granules of immature and mature megakaryocytes than in platelets.Because in platelets α- granule immunolabelling for vWF is associated with tubular structures which are specially prominent in porcine species, we studied vWF and tubular structures in pig megakaryocytes. Standard and immunoelectron microscopy revealed the simultaneous appearance of both in the small vesicles located in the Golgi area in the small immature α- granules and later in the mature α- granules. In mature megakaryocytes, labelling for vWF was intense and restricted to the α- granules. It was distributed eccentrically as in porcine blood platelets. Gold particles were often eccentrically located at one pole of the α- granule either labelling only its periphery or outlining one side of an elongated granule. Standard electron microscopy showed that tubular structures were very numerous in the mature α-granules, regularly spaced, arranged in parallel and usually located at one side of the granule. On the other hand platelets from pigs with homozygous von Willebrand disease were found to be completely devoid of both tubular structures and immunolabelling for vWF suggesting that the tubules represent the vWF itself.In acute megakaryoblastic leukemia, several phenotypes of PMKB were found in different patients, which corresponded to the stages of maturation of cultured megakaryocytes from CFU-MK.In conclusion, immunolabelling methods combined with megakaryocyte enrichment techniques are useful tools to study the origin of megakaryocyte (and platelet) granular proteins.
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Moore, John J., Robert M. Moore, Deepak Kumar, Joseph M. Mansour, Brian M. Mercer, Elizabeth Yohannes, Jillian Novak et Mark Chance. « Differential Expression of Fibulin Family Proteins in Mechanically Strong vs. Weak Fetal Membrane Fragments ». Dans ASME 2007 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2007. http://dx.doi.org/10.1115/sbc2007-175332.

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Untimely rupture of the fetal membranes (FM), the amnion and choriodecidua, which normally surround and protect the fetus prior to delivery, is a major cause of preterm birth and results in significant infant mortality and morbidity. The physiological mechanism which normally leads the FM to weaken and fail prior to birth is not known. Conventional thinking that FM rupture is precipitated by the stress of uterine contractions during labor fails to explain the 10% of term deliveries and 40% of preterm deliveries in which FM rupture is the sentinel event, preceding any uterine contractions. Recent studies from several laboratories indicate that the FM undergo a genetically-programmed, biochemically-mediated, maturation process, near term, which is characterized by collagen remodeling and apoptosis. In human FM, in contrast to rat membranes, these changes are limited to the region of the FM overlying the cervix [1]. In a series of publications, our group has demonstrated that human FM have a zone of physical weakness (decreased force to rupture and work to rupture relative to the other areas of the same FM) overlying the cervical opening of the uterus. We further demonstrate that this same zone is characterized by specific markers of increased collagen remodeling and apoptosis [1–3]. These regional characteristics develop prior to the onset of contractions of labor and persist until delivery. Furthermore, the rupture tear line of the FM intersects this weak zone and thus the rupture process is hypothesized to initiate in this weak zone [3]. In order to investigate how differences in the biochemical composition of the extra-cellular matrix of the weak and the strong zones of FM reflect their different biomechanical properties, we utilized a proteomics approach to identify differences in the abundance of specific proteins in weak and strong FM fragments. Initial 2-DIGE screening resolved differences in Fibulin 5 protein expression. This prompted further analysis of additional members of the Fibulin protein family.
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Colman, R. W., A. Gewirtz, D. L. Wang, M. M. Huh, B. P. Schick, P. K. Schick et C. L. Shapiro. « BIOSYNTHESIS AND EXPRESSION OF FACTOR V IN MAGAKARYOCYTES ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642955.

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Coagulation factor V (FV), is a single chain, multifunctional glycoprotein of Mr 350,000 which interacts with a variety of hemostatic proteins such as factor Xa, prothrombin, thrombin and protein C, on the surface of platelets and vascular endothelial cells. FV serves as both a cofactor and substrate in the generation of thrombin and plays a critical regulatory role in both physiologic hemostasis and pathologic thrombosis. The biosynthesis of FV and its subsequent expression are therefore expected to be precisely controlled and may differ in the three sites of synthesis - hepatocytes, endothelial cells, and megakaryocytes (MK). We have previously demonstrated that each guinea pig MK contains 500 times as much FV as in a platelet, as quantified by a competitive enzyme-linked-immunosorbent assay and expresses FV by cytoimmunofluorescence. De novo biosynthesis was demonstrated by incorporation of S-methionine into FV purified on a immunoaffinity column. The purified MK protein exhibited both FV coagulant activity and antigenicity. However, MK FV was more slowly activated by thrombin, more stable in the absence of Ca and exhibited a slightly higher M of 380,000 compared to plasma FV. Similar studies have documented biosynthesis in human MK. In addition, all morphologically recognizable MK enriched by elutriation from human bone marrow contained FV as documented by both monospecific polyclonal and monoclonal antibodies (MAb) to FV. All these cells bound FV since a murine MAb reacting with the light chain of FV (B38) labeled all cells. In contrast, 68% of cells synthesized FV since B10, a MAb to the activation peptide recognizing FV but not FVa, labeled this fraction. To determine whether immature nonnorphologically recognizable MK expressed FV, we identified these cells with an antiserum to human platelet glycoproteins and then probed them with B38. Seventy percent (70%) of such small cells expressed FV. In contrast, no small cells in MK colonies cloned in FV deficient medium expressed FV while only 40% of such colonies contained cells which expressed FV.To further probe the regulation of FV in MK we attempted to correlate the synthesis of FV as probed by MAb B10 with geometric mean cell diameter, stage and ploidy. No significant correlation of FV with any of these indicators of MK maturation. In contrast, preliminary studies suggest that low doses of tetradecanoyl phorbol acetate augment both the number of MK containing FV and the level of FV expressed by individual cells. Thus, FV synthesis may be regulated independent of size, stage, or ploidy and protein kinase C may play a role.To further define the molecular nature of FV in MK we found that purified FV was converted from a monomer to high Mr multimers by an enzyme derived from MK. These multimers resulting from covalent crosslinking since they were stable to SDS, 100° C and reducing agents. The responsible enzyme appeared to be MK FXIIIa since it required C, was inhibited by agents which react with the active site thiol group and was blocked by pseudoamine donor substrates such as putrescine. In addition, FXIIIa was directly demonstrated in guinea pig MK by a specific activity stain. Other investigators have established that FV became irreversibly associated with platelet cytoskeletons after exposure to thrombin. tested whether FXIIIa might mediate this association by performing ligand blotting of platelet membrane proteins using 125I-FV(FV*). Only actin of all the membrane proteins was detected by radioautography. The binding of FV* to the cytoskeleton was dependent in the presence of Ca and FXIIIa. In purified systems crosslinked complexes containing FV* or radiolabeled actin were detected in separate experiments. In whole platelets, the formation of the heteropolymer, after thrombin stimulation, was inhibited by antibodies to FXIII a chain, FV activation peptide (B10) or actin. Endogenous platelet FV was also dependent on FXIII for incorporation into the platelet cytoskeleton after thrombin stimulation. When thrombin-treated FV was crosslinked to actin only the activation peptide (150 kDa) was crosslinked. The light chain or heavy chain of FVa were not involved. Thus FXIIIa play an important role in the binding of FV in platelets to the cytoskeleton during activation and secretion.Further studies of FV in megakaryocytes are necessary to define the regulation of biosynthesis and the control of expression which dictate its critical role in hemostasis and thrombosis.
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Batista, Michael, Hadi T. Nia, Karen Cox, Christine Ortiz, Alan J. Grodzinsky, Dick Heinegård et Lin Han. « Effects of Chondroadherin on Cartilage Nanostructure and Biomechanics via Murine Model ». Dans ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14516.

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While small leucine rich proteins/proteoglycans (SLRPs) are present in very low concentrations in the extracellular matrix (ECM), they have been shown to be critical determinants of the proper ECM assembly and function in connective tissues [1] including bone [2], cornea [3], and cartilage [4]. However, their direct and indirect roles in matrix biomechanics and the potential for osteoarthritis-related dysfunction of cartilage remain unclear. With the advent of new high resolution nanotechnological tools, the direct quantification of cartilage biomechanical properties using murine models can provide important insights into how secondary ECM molecules, such as SLRPs, affect the function and pathology of cartilage [5]. Previous nanoindentation studies of murine cartilage have assessed the effects of maturation and osteoarthritis-like degradation of cartilage on its biomechanical properties [6, 7]. Recently, murine models have received increased attention because of the availability of specific gene-knockout and gene alteration technologies [8]. For example, chondroadherin (CHAD) is a non-collagenous small leucine-rich proteoglycan (SLRP) with α-helix and β-sheet secondary structure, spatially localized in the territorial matrix (MW = 38 kDa) [9]. In articular cartilage, CHAD is distributed non-uniformly with depth [10], and binds to type II collagen and the α2β1 integrin and is hypothesized to function in the communication between chondrocytes and their surrounding matrix, as well as in the regulation of collagen fibril assembly [11, 12] (Fig. 1). The objective of the present study is to explore the role of CHAD and its depletion on the structure and nanomechanical properties of both superficial and middle/deep zone cartilage. The current methods thereby enabled depth-dependent analysis of cartilage nanostructure and dynamic energy-dissipative mechanisms.
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Tuan, Rocky S. « Functional Analysis of Bone-Biomaterial Interface ». Dans ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-2675.

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Abstract Proper function and long-term stability of orthopaedic implants depend on the intimate association between bone cells and the implant biomaterial, a process known as osseointegration. Understanding the processes responsible for the establishment and maintenance of a functional bone-biomaterial interface and how these processes may be enhanced is crucial to the rational design and optimization of prosthetic devices. We have utilized cellular, molecular, and high-resolution imaging approaches to analyze the mechanistic basis of bone-biomaterial interactions. Specifically, we have characterized the initial adhesion of osteoblasts in terms of kinetics and relationship to the surface topography and chemistry of the biomaterials, particularly the cobalt-chrome and titanium alloys commonly used to fabricate orthopaedic prostheses. Results from these studies indicate that the long-term performance of osteoblasts adherent to biomaterials is crucially dependent on the characteristics of the initial adhesion step. Furthermore, osteoactive factors such as members of the transforming growth factor-β superfamily, including TGF-β1 and BMP-2, significantly enhance osteoblast cell adhesion. The molecular components responsible for the adhesion process include extracellular matrix proteins (e.g. fibronectin and collagen type I) and their cognate membrane receptors, the integrins. Our recent studies reveal that specific downstream, intracellular signaling events are also activated as a result of osteoblast adhesion, and that these signaling events are coupled to signal transduction mechanisms mediating growth factor activity. These events in combination regulate the continued expression and maintenance of the osteoblastic phenotype of the adherent cells, resulting in matrix maturation and mineralization, hallmarks of the bony tissue. Our current efforts focus on defining the target molecular pathways responsible for bone cell functioning on biomaterials, and the identification of critical biological and material parameters to optimize long-term osteoblast function and interaction with orthopaedically relevant biomaterials. The information gathered from these studies should provide a rational basis for the design of optimal implant biomaterials. (Supported in part by the NIH and the Annenberg Foundation)
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Zaslona, Zbigniew, Carlos H. Serezani, Katsuhide Okunishi, David M. Aronoff et Marc Peters-Golden. « Prostaglandin E2 Restrains Macrophage Maturation Via E Prostanoid Receptor 2/Protein Kinase A Signaling ». Dans American Thoracic Society 2012 International Conference, May 18-23, 2012 • San Francisco, California. American Thoracic Society, 2012. http://dx.doi.org/10.1164/ajrccm-conference.2012.185.1_meetingabstracts.a1384.

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Rapports d'organisations sur le sujet "Proteins maturation"

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Theg, Steven. Targeting Maturation and Quality Control of Photosynthetic Membrane Proteins. Office of Scientific and Technical Information (OSTI), juin 2018. http://dx.doi.org/10.2172/1457570.

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Galili, Gad, et Alan Bennett. Role of Molecular Chaperone in Wheat Storage Protein Assembly. United States Department of Agriculture, avril 1995. http://dx.doi.org/10.32747/1995.7604926.bard.

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Following sequestration into the ER, wheat gliadins assemble into complexes that initiate the formation of protein bodies. In the present work we have characterized the DNA sequence and regulation of expression of a plant BiP and also studied its interaction with wheat storage proteins as well as its role in the maturation of these storage proteins. In the Israeli lab, immunoprecipitation studies were made using anti BiP and anti storage proteins sera, both in wheat and in transgenic tobacco plants expressing a wheat gliadin storage proteins. In both cases, we could show that BiP interacts with the gliadin storage proteins. In addition, we could show that BiP also played an important role in the initial assembly of the gliadins. In the American lab, the complexity, structure and properties of tomato BiP was characterized at the molecular and biochemical levels. In addition, tomato BiP was also overexpressed in bacteria and the overexpressed protein was found to be active. The cooperative findings of the Israeli and American labs clearly improves our understanding of the structure and expression of a plant BiP as well as its role in the maturation of storage proteins in plants seeds. In addition, it will serve as a foundation for future studies of the mechanisms of BiP function in in vitro studies using purified storage proteins and purified recombinant active BiP.
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Schuster, Gadi, et David Stern. Integrated Studies of Chloroplast Ribonucleases. United States Department of Agriculture, septembre 2011. http://dx.doi.org/10.32747/2011.7697125.bard.

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Gene regulation at the RNA level encompasses multiple mechanisms in prokaryotes and eukaryotes, including splicing, editing, endo- and exonucleolytic cleavage, and various phenomena related to small or interfering RNAs. Ribonucleases are key players in nearly all of these post-transcriptional mechanisms, as the catalytic agents. This proposal continued BARD-funded research into ribonuclease activities in the chloroplast, where RNase mutation or deficiency can cause metabolic defects and is often associated with plant chlorosis, embryo or seedling lethality, and/or failure to tolerate nutrient stress. The first objective of this proposal was to examined a series of point mutations in the PNPase enzyme of Arabidopsis both in vivo and in vitro. This goal is related to structure-function analysis of an enzyme whose importance in many cellular processes in prokaryotes and eukaryotes has only begun to be uncovered. PNPase substrates are mostly generated by endonucleolytic cleavages for which the catalytic enzymes remain poorly described. The second objective of the proposal was to examine two candidate enzymes, RNase E and RNase J. RNase E is well-described in bacteria but its function in plants was still unknown. We hypothesized it catalyzes endonucleolytic cleavages in both RNA maturation and decay. RNase J was recently discovered in bacteria but like RNase E, its function in plants had yet to be explored. The results of this work are described in the scientific manuscripts attached to this report. We have completed the first objective of characterizing in detail TILLING mutants of PNPase Arabidopsis plants and in parallel introducing the same amino acids changes in the protein and characterize the properties of the modified proteins in vitro. This study defined the roles for both RNase PH core domains in polyadenylation, RNA 3’-end maturation and intron degradation. The results are described in the collaborative scientific manuscript (Germain et al 2011). The second part of the project aimed at the characterization of the two endoribonucleases, RNase E and RNase J, also in this case, in vivo and in vitro. Our results described the limited role of RNase E as compared to the pronounced one of RNase J in the elimination of antisense transcripts in the chloroplast (Schein et al 2008; Sharwood et al 2011). In addition, we characterized polyadenylation in the chloroplast of the green alga Chlamydomonas reinhardtii, and in Arabidopsis (Zimmer et al 2009). Our long term collaboration enabling in vivo and in vitro analysis, capturing the expertise of the two collaborating laboratories, has resulted in a biologically significant correlation of biochemical and in planta results for conserved and indispensable ribonucleases. These new insights into chloroplast gene regulation will ultimately support plant improvement for agriculture.
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Blumwald, Eduardo, et Avi Sadka. Citric acid metabolism and mobilization in citrus fruit. United States Department of Agriculture, octobre 2007. http://dx.doi.org/10.32747/2007.7587732.bard.

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Accumulation of citric acid is a major determinant of maturity and fruit quality in citrus. Many citrus varieties accumulate citric acid in concentrations that exceed market desires, reducing grower income and consumer satisfaction. Citrate is accumulated in the vacuole of the juice sac cell, a process that requires both metabolic changes and transport across cellular membranes, in particular, the mitochondrial and the vacuolar (tonoplast) membranes. Although the accumulation of citrate in the vacuoles of juice cells has been clearly demonstrated, the mechanisms for vacuolar citrate homeostasis and the components controlling citrate metabolism and transport are still unknown. Previous results in the PIs’ laboratories have indicated that the expression of a large number of a large number of proteins is enhanced during fruit development, and that the regulation of sugar and acid content in fruits is correlated with the differential expression of a large number of proteins that could play significant roles in fruit acid accumulation and/or regulation of acid content. The objectives of this proposal are: i) the characterization of transporters that mediate the transport of citrate and determine their role in uptake/retrieval in juice sac cells; ii) the study of citric acid metabolism, in particular the effect of arsenical compounds affecting citric acid levels and mobilization; and iii) the development of a citrus fruit proteomics platform to identify and characterize key processes associated with fruit development in general and sugar and acid accumulation in particular. The understanding of the cellular processes that determine the citrate content in citrus fruits will contribute to the development of tools aimed at the enhancement of citrus fruit quality. Our efforts resulted in the identification, cloning and characterization of CsCit1 (Citrus sinensis citrate transporter 1) from Navel oranges (Citrus sinesins cv Washington). Higher levels of CsCit1 transcripts were detected at later stages of fruit development that coincided with the decrease in the juice cell citrate concentrations (Shimada et al., 2006). Our functional analysis revealed that CsCit1 mediates the vacuolar efflux of citrate and that the CsCit1 operates as an electroneutral 1CitrateH2-/2H+ symporter. Our results supported the notion that it is the low permeable citrateH2 - the anion that establishes the buffer capacity of the fruit and determines its overall acidity. On the other hand, it is the more permeable form, CitrateH2-, which is being exported into the cytosol during maturation and controls the citrate catabolism in the juice cells. Our Mass-Spectrometry-based proteomics efforts (using MALDI-TOF-TOF and LC2- MS-MS) identified a large number of fruit juice sac cell proteins and established comparisons of protein synthesis patterns during fruit development. So far, we have identified over 1,500 fruit specific proteins that play roles in sugar metabolism, citric acid cycle, signaling, transport, processing, etc., and organized these proteins into 84 known biosynthetic pathways (Katz et al. 2007). This data is now being integrated in a public database and will serve as a valuable tool for the scientific community in general and fruit scientists in particular. Using molecular, biochemical and physiological approaches we have identified factors affecting the activity of aconitase, which catalyze the first step of citrate catabolism (Shlizerman et al., 2007). Iron limitation specifically reduced the activity of the cytosolic, but not the mitochondrial, aconitase, increasing the acid level in the fruit. Citramalate (a natural compound in the juice) also inhibits the activity of aconitase, and it plays a major role in acid accumulation during the first half of fruit development. On the other hand, arsenite induced increased levels of aconitase, decreasing fruit acidity. We have initiated studies aimed at the identification of the citramalate biosynthetic pathway and the role(s) of isopropylmalate synthase in this pathway. These studies, especially those involved aconitase inhibition by citramalate, are aimed at the development of tools to control fruit acidity, particularly in those cases where acid level declines below the desired threshold. Our work has significant implications both scientifically and practically and is directly aimed at the improvement of fruit quality through the improvement of existing pre- and post-harvest fruit treatments.
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Swartz, James. Using in vitro maturation and cell-free expression to explore [FeFe] hydrogenase activation and protein scaffolding requirements. Office of Scientific and Technical Information (OSTI), janvier 2017. http://dx.doi.org/10.2172/1341627.

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Flaishman, Moshe, Herb Aldwinckle, Shulamit Manulis et Mickael Malnoy. Efficient screening of antibacterial genes by juvenile phase free technology for developing resistance to fire blight in pear and apple trees. United States Department of Agriculture, décembre 2008. http://dx.doi.org/10.32747/2008.7613881.bard.

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Objectives: The original objectives of this project were to: Produce juvenile-free pear and apple plants and examine their sensitivity to E. amylovora; Design novel vectors, for antibacterial proteins and promoters expression, combined with the antisense TFL1 gene, and transformation of Spadona pear in Israel and Galaxy apple in USA. The original objectives were revised from the development of novel vectors with antibacterial proteins combined with the TFL-1 due to the inefficiency of alternative markes initially evaluated in pear, phoshomannose-isomerase and 2-deoxyglucose-6-phosphate phosphatase and the lack of development of double selection system. The objectives of project were revised to focus primarily on the development additional juvenile free systems by the use of another pear variety and manipulation of the FT gene under the control of several promoters. Based on the results creation of fire blight resistance pear variety was developed by the use of the juvenile free transgenic plant. Background: Young tree seedlings are unable to initiate reproductive organs and require a long period of shoot maturation, known as juvenile phase. In pear, juvenile period can last 5-7 years and it causes a major delay in breeding programs. We isolated the TFL1 gene from Spadona pear (PcTFL1-1) and produced transgenic ‘Spadona’ trees silencing the PcTFL1 gene using a RNAi approach. Transgenic tissue culture ‘Spadona’ pear flowered in vitro. As expected, the expression of the endogenous PcTFL1 was suppressed in the transgenic line that showed precocious flowering. Transgenic plants were successfully rooted in the greenhouse and most of the plants flowered after only 4-8 months, whereas the non-transformed control plants have flowered only after 5-6 years of development. Major achievements: Prior to flower induction, transgenic TFL1-RNAi ‘Spadona’ plants developed a few branches and leaves. Flower production in the small trees suppressed the development of the vegetative branches, thus resulting in compact flowering trees. Flowering was initiated in terminal buds, as described for the Arabidopsis tfl1 mutant. Propagation of the transgenic TFL1-RNAi ‘Spadona’ was performed by bud grafting on 'Betulifolia' rootstock and resulted in compact flowering trees. The transgenic flowering grafted plants were grown in the greenhouse under a long photoperiod for one year, and flowered continuously. Pollination of the transgenic flowers with ‘Costia‘ pear pollen generated fruits of regular shape with fertile F1 seeds. The F1 transgenic seedling grown in the greenhouse formed shoots and produced terminal flowers only five months after germination. In addition, grafted F1 transgenic buds flower and fruit continuously, generating hybrid fruits with regular shape, color and taste. Several pear varieties were pollinated with the transgenic TFL1-RNAi ‘Spadona’ pollen including `Herald Harw` that was reported to have resistance to fire blight diseases. The F-1 hybrid seedlings currently grow in our greenhouse. We conclude that the juvenile-free transgenic ‘Spadona’ pear enables the development of a fast breeding method in pear that will enable us to generate a resistance pear to fire blight. Implications: The research supported by this grant has demonstrated the use of transgenic juvenile free technology in pear. The use of the juvenile free technology for enhancement of conventional breeding in fruit tree will serve to enhance fast breeding systems in pear and another fruit trees.
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Funkenstein, Bruria, et Cunming Duan. GH-IGF Axis in Sparus aurata : Possible Applications to Genetic Selection. United States Department of Agriculture, novembre 2000. http://dx.doi.org/10.32747/2000.7580665.bard.

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Many factors affect growth rate in fish: environmental, nutritional, genetics and endogenous (physiological) factors. Endogenous control of growth is very complex and many hormone systems are involved. Nevertheless, it is well accepted that growth hormone (GH) plays a major role in stimulating somatic growth. Although it is now clear that most, if not all, components of the GH-IGF axis exist in fish, we are still far from understanding how fish grow. In our project we used as the experimental system a marine fish, the gilthead sea bream (Sparus aurata), which inhabits lagoons along the Mediterranean and Atlantic coasts of Europe, and represents one of the most important fish species used in the mariculture industry in the Mediterranean region, including Israel. Production of Sparus is rapidly growing, however, in order for this production to stay competitive, the farming of this fish species has to intensify and become more efficient. One drawback, still, in Sparus extensive culture is that it grows relatively slow. In addition, it is now clear that growth and reproduction are physiological interrelated processes that affect each other. In particular sexual maturation (puberty) is known to be closely related to growth rate in fish as it is in mammals, indicating interactions between the somatotropic and gonadotropic axes. The goal of our project was to try to identify the rate-limiting components(s) in Sparus aurata GH-IGF system which might explain its slow growth by studying the ontogeny of growth-related genes: GH, GH receptor, IGF-I, IGF-II, IGF receptor, IGF-binding proteins (IGFBPs) and Pit-1 during early stages of development of Sparus aurata larvae from slow and fast growing lines. Our project was a continuation of a previous BARD project and could be divided into five major parts: i) obtaining additional tools to those obtained in the previous project that are necessary to carry out the developmental study; ii) the developmental expression of growth-related genes and their cellular localization; iii) tissue-specific expression and effect of GH on expression of growth-related genes; iv) possible relationship between GH gene structure, growth rate and genetic selection; v) the possible role of the IGF system in gonadal development. The major findings of our research can be summarized as follows: 1) The cDNAs (complete or partial) coding for Sparus IGFBP-2, GH receptor and Pit-1 were cloned. Sequence comparison reveals that the primary structure of IGFBP-2 protein is 43-49% identical to that of zebrafish and other vertebrates. Intensive efforts resulted in cloning a fragment of 138 nucleotides, coding for 46 amino acids in the proximal end of the intracellular domain of GH receptor. This is the first fish GH receptor cDNA that had been cloned to date. The cloned fragment will enable us to complete the GH - receptor cloning. 2) IGF-I, IGF-II, IGFBP-2, and IGF receptor transcripts were detected by RT-PCR method throughout development in unfertilized eggs, embryos, and larvae suggesting that these mRNAs are products of both the maternal and the embryonic genomes. Preliminary RT-PCR analysis suggest that GH receptor transcript is present in post-hatching larvae already on day 1. 3) IGF-1R transcripts were detected in all tissues tested by RT-PCR with highest levels in gill cartilage, skin, kidney, heart, pyloric caeca, and brain. Northern blot analysis detected IGF receptor only in gonads, brain and gill cartilage but not in muscle; GH increased slightly brain and gill cartilage IGF-1R mRNA levels. 4) IGFBP-2 transcript were detected only in liver and gonads, when analyzed by Northern blots; RT-PCR analysis revealed expression in all tissues studied, with the highest levels found in liver, skin, gonad and pyloric caeca. 5) Expression of IGF-I, IGF-II, IGF-1R and IGFBP-2 was analyzed during gonadal development. High levels of IGF-I and IGFBP-2 expression were found in bisexual young gonads, which decreased during gonadal development. Regardless of maturational stage, IGF-II levels were higher than those of IGF-L 6) The GH gene was cloned and its structure was characterized. It contains minisatellites of tandem repeats in the first and third introns that result in high level of genetic polymorphism. 7) Analysis of the presence of IGF-I and two types of IGF receptor by immunohistochemistry revealed tissue- and stage-specific expression during larval development. Immunohistochemistry also showed that IGF-I and its receptors are present in both testicular and ovarian cells. Although at this stage we are not able to pinpoint which is the rate-limiting step causing the slow growth of Sparus aurata, our project (together with the previous BARD) yielded a great number of experimental tools both DNA probes and antibodies that will enable further studies on the factors regulating growth in Sparus aurata. Our expression studies and cellular localization shed new light on the tissue and developmental expression of growth-related genes in fish.
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Gafni, Yedidya, Moshe Lapidot et Vitaly Citovsky. Dual role of the TYLCV protein V2 in suppressing the host plant defense. United States Department of Agriculture, janvier 2013. http://dx.doi.org/10.32747/2013.7597935.bard.

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TYLCV-Is is a major tomato pathogen, causing extensive crop losses in Israel and the U.S. We have identified a TYLCV-Is protein, V2, which acts as a suppressor of RNA silencing. Intriguingly, the counter-defense function of V2 may not be limited to silencing suppression. Our recent data suggest that V2 interacts with the tomato CYP1 protease. CYP1 belongs to the family of papain-like cysteine proteases which participate in programmed cell death (PCD) involved in plant defense against pathogens. Based on these data we proposed a model for dual action of V2 in suppressing the host antiviral defense: V2 targets SGS3 for degradation and V2 inhibits CYP1 activity. To study this we proposed to tackle three specific objectives. I. Characterize the role of V2 in SGS3 proteasomal degradation ubiquitination, II. Study the effects of V2 on CYP1 maturation, enzymatic activity, and accumulation and, III. Analyze the effects of the CYP1-V2 interaction on TYLCV-Is infection. Here we describe results from our study that support our hypothesis: the involvement of the host's innate immune system—in this case, PCD—in plant defense against TYLCV-Is. Also, we use TYLCV-Is to discover the molecular pathway(s) by which this plant virus counters this defense. Towards the end of our study we discovered an interesting involvement of the C2 protein encoded by TYLCV-Is in inducing Hypersensitive Response in N. benthamianaplants which is not the case when the whole viral genome is introduced. This might lead to a better understanding of the multiple processes involved in the way TYLCV is overcoming the defense mechanisms of the host plant cell. In a parallel research supporting the main goal described, we also investigated Agrobacteriumtumefaciens-encoded F-box protein VirF. It has been proposed that VirF targets a host protein for the UPS-mediated degradation, very much the way TYLCV V2 does. In our study, we identified one such interactor, an Arabidopsistrihelix-domain transcription factor VFP3, and further show that its very close homolog VFP5 also interacted with VirF. Interestingly, interactions of VirF with either VFP3 or VFP5 did not activate the host UPS, suggesting that VirF might play other UPS-independent roles in bacterial infection. Another target for VirF is VFP4, a transcription factor that both VirF and its plant functional homolog VBF target to degradation by UPS. Using RNA-seqtranscriptome analysis we showed that VFP4 regulates numerous plant genes involved in disease response, including responses to viral and bacterial infections. Detailed analyses of some of these genes indicated their involvement in plant protection against Agrobacterium infection. Thus, Agrobacterium may facilitate its infection by utilizing the host cell UPS to destabilize transcriptional regulators of the host disease response machinery that limits the infection.
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Firon, Nurit, Prem Chourey, Etan Pressman, Allen Hartwell et Kenneth J. Boote. Molecular Identification and Characterization of Heat-Stress-Responsive Microgametogenesis Genes in Tomato and Sorghum - A Feasibility Study. United States Department of Agriculture, octobre 2007. http://dx.doi.org/10.32747/2007.7591741.bard.

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Exposure to higher than optimal temperatures - heat-stress (HS) - is becoming increasingly common to all crop plants worldwide. Heat stress coinciding with microgametogenesis, especially during the post-meiotic phase that is marked by starch biosynthesis, is often associated with starch-deficient pollen and male sterility and ultimately, greatly reduced crop yields. The molecular basis for the high sensitivity of developing pollen grains, on one hand, and factors involved in pollen heat-tolerance, on the other, is poorly understood. The long-term goal of this project is to provide a better understanding of the genes that control pollen quality under heat-stress conditions. The specific objectives of this project were: (1) Determination of the threshold heat stress temperature(s) that affects tomato and sorghum pollen quality whether: a) Chronic mild heat stress conditions (CMHS), or b) Acute heat stress (AHS). (2) Isolation of heat-responsive, microgametogenesis-specific sequences. During our one-year feasibility project, we have accomplished the proposed objectives as follows: Objectrive 1: We have determined the threshold HS conditions in tomato and sorghum. This was essential for achieving the 2nd objective, since our accumulated experience (both Israeli and US labs) indicate that when temperature is raised too high above "threshold HS levels" it may cause massive death of the developing pollen grains. Above-threshold conditions have additional major disadvantages including the "noise" caused by induced expression of genes involved in cell death and masking of the differences between heatsensitive and heat-tolerant pollen grains. Two different types of HS conditions were determined: a) Season-long CMHS conditions: 32/26°C day/night temperatures confirmed in tomato and 36/26°C day maximum/night minimum temperatures in sorghum. b) Short-term AHS: In tomato, 2 hour exposure to 42-45°C (at 7 to 3 days before anthesis) followed by transfer to 28/22±2oC day/night temperatures until flower opening and pollen maturation, caused 50% reduced germinating pollen in the heat-sensitive 3017 cv.. In sorghum, 36/26°C day/night temperatures 10 to 5 days prior to panicle emergence, occurring at 35 days after sowing (DAS) in cv. DeKalb28E, produced starch-deficient and sterile pollen. Objective 2: We have established protocols for the high throughput transcriptomic approach, cDNA-AFLP, for identifying and isolating genes exhibiting differential expression in developing microspores exposed to either ambient or HS conditions and created a databank of HS-responsivemicrogametogenesis-expressed genes. A subset of differentially displayed Transcript-Derived Fragments (TDFs) that were cloned and sequenced (35 & 23 TDFs in tomato and sorghum, respectively) show close sequence similarities with metabolic genes, genes involved in regulation of carbohydrate metabolism, genes implicated in thermotolerance (heat shock proteins), genes involved in long chain fatty acids elongation, genes involved in proteolysis, in oxidation-reduction, vesicle-mediated transport, cell division and transcription factors. T-DNA-tagged Arabidopsis mutants for part of these genes were obtained to be used for their functional analysis. These studies are planned for a continuation project. Following functional analyses of these genes under HS – a valuable resource of genes, engaged in the HS-response of developing pollen grains, that could be modulated for the improvement of pollen quality under HS in both dicots and monocots and/or used to look for natural variability of such genes for selecting heat-tolerant germplasm - is expected.
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Bostock, Richard M., Dov Prusky et Martin Dickman. Redox Climate in Quiescence and Pathogenicity of Postharvest Fungal Pathogens. United States Department of Agriculture, mai 2003. http://dx.doi.org/10.32747/2003.7586466.bard.

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Monilinia fructicola causes brown rot blossom blight and fruit rot in stone fruits. Immature fruit are highly resistant to brown rot but can become infected. These infections typically remain superficial and quiescent until they become active upon maturation of the fruit. High levels of chlorogenic acid (CGA) and related compounds occur in the peel of immature fruit but these levels decline during ripening. CGA inhibits cutinase expression, a putative virulence factor, with little or no effect on spore germination or hyphal growth. To better understand the regulation of cutinase expression by fruit phenolics, we examined the effect of CGA, caffeic acid (CA) and related compounds on the redox potential of the growth medium and intracellular glutathione (GSH) levels. The presence of CA in the medium initially lowered the electrochemical redox potential of the medium, increased GSH levels and inhibited cutinase expression. Conidia germinated in the presence of CA, CGA, or GSH produced fewer appressoria and had elongated germ tubes compared to the controls. These results suggest that host redox compounds can regulate fungal infectivity. In order to genetically manipulate this fungus, a transformation system using Agrobacterium was developed. The binary transformation vector, pPTGFPH, was constructed from the plasmid pCT74, carrying green fluorescent protein (GFP) driven by the ToxA promoter of Pyrenophora tritici-repentis and hygromycin B phosphotransferase (hph) under control of the trpC promoter of from Aspergillus nidulans, and the binary vector pCB403.2, carrying neomycin phosphotransferase (nptII) between the T-DNA borders. Macroconidia of M. fructicola were coincubated with A. tumefaciens strain LBA 4404(pPTGFPH) on media containing acetosyringone for two days. Hygromycin- and G418-resistant M. fructicola transformants were selected while inhibiting A. tumefaciens with cefotaxime. Transformants expressing GFP fluoresced brightly, and were formed with high efficiency and frequency of T-DNA integration frequency. The use of these transformants for in situ studies on stone fruit tissues is discussed.
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