73 research outputs found

    Le plasma séminal à l'heure de la postgénomique.

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    Cette revue a pour objectif de faire le point sur l'état des études à grande échelle de l'expression des gènes et des protéines au niveau du gamète mâle et du plasma séminal, depuis la spermatogenèse jusqu'à la maturation et la capacitation du spermatozoïde. Nous reverrons les avantages et limites de la transcriptomique et de la protéomique dans ce contexte. En conclusion, le concept de biologie de systèmes intégrant les données de génomique, transcriptomique et protéomique, de même que la bio-informatique et la modélisation, seront discutés. En effet, de nouveaux axes de recherche reposant sur des approches de génomique intégrative offrent des perspectives importantes qui devraient nous aider à mieux comprendre la biologie du gamète mâle et à terme d'aider au traitement des infertilités masculines

    Recherche et analyse fonctionnelle de protéines stades-spécifiques de la spermatogenèse chez le rat par des approches de protéomique

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    Chez les mammifères, la spermatogenèse est un processus complexe de prolifération et de différentiation cellulaire conduisant à la production journalière de millions de spermatozoïdes au sein du testicule. Le travail présenté dans cette thèse s inscrit dans un vaste programme initié au sein de l unité Inserm U625 et ayant pour but le décryptage à long terme des réseaux régulateurs de la spermatogenèse, par des approches globales en protéomique. J ai ainsi pu au cours de ma thèse mettre en évidence par la technologie Proteinchip® l expression spécifique de cinquante protéines au sein des cellules germinales mâles de rat, parmi lesquelles deux ont pu être identifiées dans les spermatogonies comme étant l histone H4 et la protéine chaperonne HSPE1. Par ailleurs, le décryptage du protéome des cellules germinales réalisé grâce à la technique 2D-DIGE a permis d'identifier la protéine CLPH (Casein-like phosphoprotein), un facteur jusqu'alors inconnu spécifiquement exprimé au cours de la spermiogenèse. Après avoir explicité l'expression de l'ARN messager et de la protéine chez le rat, la souris et l'homme, j'ai pu démontrer que CLPH était une protéine intrinsèquement désordonnée possédant une forte affinité pour le calcium. Par ailleurs, j ai pu établir que CLPH tait capable de former des oligomères de grandes tailles, aussi bien chez l homme que chez le rat. Les résultats obtenus au cours de cette thèse sur CLPH regroupent ainsi des données solides sur les propriétés essentielles de cette protéine, bientôt complétées par l étude à venir de l invalidation non conditionnelle du gène Clph chez la souris.In mammals, spermatogenesis is a complex process of proliferation and cell differentiation leading to the daily production of millions of spermatozoids within the testicle. The work that has been carried out in this thesis is part of a large program undertaken by the INSERM U625 Unit and whose purpose is to decipher in the long run the regulating networks involved in the course of spermatogenesis, by means of an overall approach in proteomics. In this context, the differential analysis of spermatogenesis achievd with the Proteinchip® technique has allowed me to highlight the specific expression of fifty proteins within rat male germ cells, among which two were clearly identified in spermatogonia, namely histone H4 and chaperone protein HSPE1. On the other hand, deciphering the proteome of male germ cells thanks to the 2D-DIGE technique had enabled the identification of CLPH protein (Casein-like phosphoprotein), a previously unknown factor specifically expressed during spermiogenesis. In addition to the study of both transcript and protein expression within rat, mouse and human testis, I was able to demonstrate that CLPH is an intrinsically disordered protein which strongly binds calcium. Besides, I could demonstrate through the analysis of CLPH structure that the protein was able to give large oligomers, both in man and rat. The results that were obtained in the course of my thesis about CLPH thus include sound data on the essential properties of this protein that will be completed by the on-coming study of knock-out mouse model.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

    Petits ARN non condants et spermatogenèse

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    The continuous production of spermatozoa is a tightly regulated biological process, both at the transcriptional and post-transcriptional levels. Recently, different classes of small non-coding RNAs have emerged as important regulators of spermatogenesis. Available molecular and genetic data, although still fragmented, underscore their crucial role in regulating the fine tuning of gene expression required for testicular function. Here, we review the latest advances accomplished in this domain, spanning from the biogenesis of these small non-coding RNAs to their roles in male reproductive function

    Spermatogenesis in mammals: proteomic insights.

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    International audienceSpermatogenesis is a highly sophisticated process involved in the transmission of genetic heritage. It includes halving ploidy, repackaging of the chromatin for transport, and the equipment of developing spermatids and eventually spermatozoa with the advanced apparatus (e.g., tightly packed mitochondrial sheat in the mid piece, elongating of the tail, reduction of cytoplasmic volume) to elicit motility once they reach the epididymis. Mammalian spermatogenesis is divided into three phases. In the first the primitive germ cells or spermatogonia undergo a series of mitotic divisions. In the second the spermatocytes undergo two consecutive divisions in meiosis to produce haploid spermatids. In the third the spermatids differentiate into spermatozoa in a process called spermiogenesis. Paracrine, autocrine, juxtacrine, and endocrine pathways all contribute to the regulation of the process. The array of structural elements and chemical factors modulating somatic and germ cell activity is such that the network linking the various cellular activities during spermatogenesis is unimaginably complex. Over the past two decades, advances in genomics have greatly improved our knowledge of spermatogenesis, by identifying numerous genes essential for the development of functional male gametes. Large-scale analyses of testicular function have deepened our insight into normal and pathological spermatogenesis. Progress in genome sequencing and microarray technology have been exploited for genome-wide expression studies, leading to the identification of hundreds of genes differentially expressed within the testis. However, although proteomics has now come of age, the proteomics-based investigation of spermatogenesis remains in its infancy. Here, we review the state-of-the-art of large-scale proteomic analyses of spermatogenesis, from germ cell development during sex determination to spermatogenesis in the adult. Indeed, a few laboratories have undertaken differential protein profiling expression studies and/or systematic analyses of testicular proteomes in entire organs or isolated cells from various species. We consider the pros and cons of proteomics for studying the testicular germ cell gene expression program. Finally, we address the use of protein datasets, through integrative genomics (i.e., combining genomics, transcriptomics, and proteomics), bioinformatics, and modelling
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