Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
EXOSC10 is a catalytic subunit of the exosome that processes biologically active transcripts, degrades aberrant mRNAs and targets certain long non-coding RNAs (lncRNAs). The yeast orthologue Rrp6 is required for efficient growth and gametogenesis, and becomes unstable during meiosis. However, nothing is known about the localization, stability and function of EXOSC10 in the rodent male germline. We detect the protein in nucleoli and the cytoplasm of mitotic and meiotic germ cells, and find that it transiently associates with the XY body, a structure targeted by meiotic sex chromosome inactivation (MSCI). Finally, EXOSC10 becomes unstable at later stages of gamete development. To determine Exosc10's meiotic function, we inactivated the gene specifically in male germ cells using cre recombinase controlled by Stra8 or Ddx4/Vasa promoters. Mutant mice have small testes, show impaired germ cell differentiation and are subfertile. Our results demonstrate that EXOSC10 is post-translationally regulated in germ cells, associate the protein with epigenetic chromosome silencing, and reveal its essential role in germ cell growth and development.
ISSN: 2045-2322

hal-01647082
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01647082
DOI : 10.1038/s41598-017-14643-y
PUBMED : 29118343

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
STUDY QUESTION: Can protein biomarkers of the male genital tract be identified in human seminal plasma? SUMMARY ANSWER: We identified potential biomarkers for each of the organs participating in the secretions of the human seminal plasma. WHAT IS KNOWN ALREADY: The seminal plasma fulfills critical functions for fertility by providing spermatozoa with a protective milieu, promoting their final maturation and modulating the immune responsiveness of the female reproductive tract. It is also considered to be a promising source of biomarkers of male infertility and/or pathologies of the male genital tract. STUDY DESIGN, SIZE, DURATION: This study combines proteomic analyses of normal seminal plasma together with transcriptomic gene expression profiling of human healthy tissues. MATERIALS, SETTING, METHODS: Non-liquefied seminal plasma proteins from a healthy donor were prefractionated using two sequential Proteominer™ libraries. Eight subproteome fractions were collected, trypsin digested and subjected to three successive mass spectrometry analyses for peptide characterization. The list of identified proteins was compared with and merged with other available data sets of the human seminal plasma proteome. The expression of corresponding genes was then investigated using tissue transcriptome profiles to determine where, along the male reproductive tract, these proteins were produced. Finally, tissue specificity of a selected subset of biomarker candidates was validated on human tissues. MAIN RESULTS AND THE ROLE OF CHANCE: We first performed a proteomic analysis of the human seminal plasma and identified 699 proteins. By comparing our protein list with other previous proteomic data sets, we found that 2545 unique proteins have been described so far in the human seminal plasma. We then profiled their expression at the gene level and identified 83 testis, 42 epididymis, 7 seminal vesicle and 17 prostate candidate protein markers. For a subset of testis-specific candidates, i.e. TKTL1, LDHC and PGK2, we further validated their germ cell expression and demonstrated that such markers could distinguish between semen from fertile and infertile men. LIMITATIONS, REASONS FOR CAUTION: While some of the markers we identified are well-known tissue-specific products, further dedicated studies to validate the biomarker status of new candidates will be required. Additionally, whether or not the abundance of these proteins is indeed decreased in some specific pathological situations remains to be determined. WIDER IMPLICATIONS OF THE FINDINGS: Using an integrative genomics approach, we identified biomarker candidates for each of the organs participating in the seminal plasma production. In this study, we essentially focused on germ cell markers and their potential application for the diagnosis of male infertility. Other types of markers also deserve a focused attention given their potential predictive value for various reproductive disorders, notably for prostate cancers. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Proteomics Core Facility at Biogenouest and was funded by Conseil Régional de Bretagne, IBiSA and Agence de la Biomédecine grants. The authors declare that there exists a competing financial interest in this work that is related to a patent application on the use of identified germ cell-specific proteins in an antibody-based assay (Fertichip™) to predict the successful testicular biopsy outcomes in human non-obstructive azoospermia.
ISSN: 0268-1161

inserm-00814146
http://www.hal.inserm.fr/inserm-00814146
DOI : 10.1093/humrep/des360
PUBMED : 23024119

Éditeur(s) : HAL CCSD Oxford University Press
Résumé : International audience
It was recently reported that the sizes of many mRNAs change when budding yeast cells exit mitosis and enter the meiotic differentiation pathway. These differences were attributed to length variations of their untranslated regions. The function of UTRs in protein translation is well established. However, the mechanism controlling the expression of distinct transcript isoforms during mitotic growth and meiotic development is unknown. In this study, we order developmentally regulated transcript isoforms according to their expression at specific stages during meiosis and gametogenesis, as compared to vegetative growth and starvation. We employ regulatory motif prediction, in vivo protein-DNA binding assays, genetic analyses and monitoring of epigenetic amino acid modification patterns to identify a novel role for Rpd3 and Ume6, two components of a histone deacetylase complex already known to repress early meiosis-specific genes in dividing cells, in mitotic repression of meiosis-specific transcript isoforms. Our findings classify developmental stage-specific early, middle and late meiotic transcript isoforms, and they point to a novel HDAC-dependent control mechanism for flexible transcript architecture during cell growth and differentiation. Since Rpd3 is highly conserved and ubiquitously expressed in many tissues, our results are likely relevant for development and disease in higher eukaryotes.
ISSN: 0305-1048

Droits : http://creativecommons.org/licenses/by/
hal-01122128
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122128
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122128/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122128/file/The%20conserved%20histone%20deacetylase.pdf
DOI : 10.1093/nar/gku1185

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BACKGROUND: Environmental factors such as pesticides can cause phenotypic changes in various organisms, including mammals. We studied the effects of the widely used herbicide atrazine (ATZ) on meiosis, a key step of gametogenesis, in male mice. METHODS: Gene expression pattern was analysed by Gene-Chip array. Genome-wide mapping of H3K4me3 marks distribution was done by ChIP-sequencing of testis tissue using Illumina technologies. RT-qPCR was used to validate differentially expressed genes or differential peaks. RESULTS: We demonstrate that exposure to ATZ reduces testosterone levels and the number of spermatozoa in the epididymis and delays meiosis. Using Gene-Chip and ChIP-Seq analysis of H3K4me3 marks, we found that a broad range of cellular functions, including GTPase activity, mitochondrial function and steroid-hormone metabolism, are affected by ATZ. Furthermore, treated mice display enriched histone H3K4me3 marks in regions of strong recombination (double-strand break sites), within very large genes and reduced marks in the pseudoautosomal region of X chromosome. CONCLUSIONS: Our data demonstrate that atrazine exposure interferes with normal meiosis, which affects spermatozoa production
ISSN: 1471-2164

hal-01225493
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01225493
DOI : 10.1186/s12864-015-2095-y
PUBMED : 26518232

Éditeur(s) : HAL CCSD Oxford University Press
Résumé : International audience
The epigenetic events imposed during germline reprogramming and affected by harmful exposure can be inherited and transferred to subsequent generations via gametes inheritance. In this study, we examine the transgenerational effects promoted by widely used herbicide atrazine (ATZ). We exposed pregnant outbred CD1 female mice and the male progeny was crossed for three generations with untreated females. We demonstrate here that exposure to ATZ affects meiosis, spermiogenesis and reduces the spermatozoa number in the third generation (F3) male mice. We suggest that changes in testis cell types originate from modified transcriptional network in undifferentiated spermatogonia. Importantly, exposure to ATZ dramatically increases the number of transcripts with novel transcription initiation sites, spliced variants and alternative polyadenylation sites. We found the global decrease in H3K4me3 occupancy in the third generation males. The regions with altered H3K4me3 occupancy in F3 ATZ-derived males correspond to altered H3K4me3 occupancy of F1 generation and 74% of changed peaks in F3 generation are associated with enhancers. The regions with altered H3K4me3 occupancy are enriched in SP family and WT1 transcription factor binding sites. Our data suggest that the embryonic exposure to ATZ affects the development and the changes induced by ATZ are transferred up to three generations.
ISSN: 0305-1048

hal-01477213
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01477213
DOI : 10.1093/nar/gkw840
PUBMED : 27655631

Éditeur(s) : HAL CCSD Nature Publishing Group
Résumé : International audience
The widely-used herbicide atrazine (ATZ) is detected in ground and surface water in many countries. Several studies in animals have demonstrated that ATZ has endocrine-disrupting effects on male and female reproduction in many vertebrate species. In this study, we investigated the effects of ATZ exposure on meiosis, a key step in gametogenesis in mammals. The treatment was initiated before oocyte entry into meiosis, which occurs during the embryonic period in females. We found that embryonic exposure to ATZ increases the level of 8-oxo-guanine in the nucleus of meiotic cells, reflecting oxidative stress and affecting meiotic double-strand break repair, chromosome synapsis and crossover numbers. Finally, embryonic exposure to ATZ reduces the number of primordial follicles and increases the incidence of multi-oocyte follicles in adult mice. Our data demonstrate that embryonic exposure to ATZ disrupts prophase I of meiosis and affects normal follicle formation in female mice.
ISSN: 2045-2322

hal-01560149
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01560149
DOI : 10.1038/s41598-017-03738-1
PUBMED : 28615648

Éditeur(s) : HAL CCSD Society for the Study of Reproduction
Résumé : International audience
ISSN: 0006-3363

hal-01122125
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122125
PUBMED : 25609838
DOI : 10.1095/biolreprod.114.126250