29 results on '"Chebrout M"'
Search Results
2. Les follicules polyovocytaires
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Reynaud, K., Halter, S., Tahir, Z., Thoumire, S., Chebrout, M., and Chastant-Maillard, S.
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- 2010
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3. Follicle population, cumulus mucification, and oocyte chromatin configuration during the periovulatory period in the female dog
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Reynaud, K., de Lesegno, C. Viaris, Chebrout, M., Thoumire, S., and Chastant-Maillard, S.
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- 2009
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4. Analysis of STAT1 expression and biological activity reveals interferon-tau-dependent STAT1-regulated SOCS genes in the bovine endometrium
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Vitorino Carvalho, A., primary, Eozenou, C., additional, Healey, G. D., additional, Forde, N., additional, Reinaud, P., additional, Chebrout, M., additional, Gall, L., additional, Rodde, N., additional, Padilla, A. Lesage, additional, Delville, C. Giraud, additional, Leveugle, M., additional, Richard, C., additional, Sheldon, I. M., additional, Lonergan, P., additional, Jolivet, G., additional, and Sandra, O., additional
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- 2016
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5. 183 CANINE EMBRYOS OBTAINED BY INTRACYTOPLASMIC SPERM INJECTION
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Chastant-Maillard, S., primary, Reynaud, K., additional, Thoumire, S., additional, and Chebrout, M., additional
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- 2014
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6. Analysis of STAT1 expression and biological activity reveals interferon-tau-dependent STAT1-regulated SOCS genes in the bovine endometrium.
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Carvalho, A. Vitorino, Eozenou, C., Healey, G. D., Forde, N., Reinaud, P., Chebrout, M., Gall, L., Rodde, N., Padilla, A. Lesage, Delville, C. Giraud, Leveugle, M., Richard, C., Sheldon, I. M., Lonergan, P., Jolivet, G., and Sandra, O.
- Subjects
STAT proteins ,INTERFERONS ,ENDOMETRIUM ,PHOSPHORYLATION ,CYTOKINES - Abstract
Signal transducer and activator of transcription (STAT) proteins are critical for the regulation of numerous biological processes. In cattle, microarray analyses identified STAT1 as a differentially expressed gene in the endometrium during the peri-implantation period. To gain new insights about STAT1 during the oestrous cycle and early pregnancy, we investigated STAT1 transcript and protein expression, as well as its biological activity in bovine tissue and cells of endometrial origin. Pregnancy increased STAT1 expression on Day 16, and protein and phosphorylation levels on Day 20. In cyclic and pregnant females, STAT1 was located in endometrial cells but not in the luminal epithelium at Day 20 of pregnancy. The expression of STAT1 during the oestrous cycle was not affected by progesterone supplementation. In vivo and in vitro, interferon-tau (IFNT) stimulated STAT1 mRNA expression, protein tyrosine phosphorylation and nuclear translocation. Using chromatin immunoprecipitation in IFNT-stimulated endometrial cells, we demonstrated an increase of STAT1 binding on interferon regulatory factor 1 (IRF1), cytokine-inducible SH2-containing protein (CISH), suppressor of cytokine signaling 1 and 3 (SOCS1, SOCS3) gene promoters consistent with the induction of their transcripts. Our data provide novel molecular insights into the biological functions of STAT1 in the various cells composing the endometrium during maternal pregnancy recognition and implantation. [ABSTRACT FROM AUTHOR]
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- 2016
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7. Are Oocytes from the Anestrous Bitch Competent for Meiosis?
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Chastant‐Maillard, S, primary, Saint‐Dizier, M, additional, Grimard, B, additional, Chebrout, M, additional, Thoumire, S, additional, and Reynaud, K, additional
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- 2012
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8. Chromatin Patterns of Immature Canine Oocytes after In Vitro Maturation
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Reynaud, K, primary, Chebrout, M, additional, Tanguy‐Dezaux, C, additional, de la Villéon, G, additional, and Chastant‐Maillard, S, additional
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- 2012
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9. 68 TRANSCRIPTIONAL GENOME ACTIVATION IN CANINE EMBRYOS COLLECTED IN VIVO
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Chastant-Maillard, S., primary, Viaris de Lesegno, C., additional, Thoumire, S., additional, Chebrout, M., additional, and Reynaud, K., additional
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- 2012
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10. 130 EXPRESSION OF STEROIDOGENIC ENZYMES IN THE CAT OVARY DURING FOLLICULAR GROWTH
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Halter, S., primary, Reynaud, K., additional, Malandain, E., additional, Chebrout, M., additional, Thoumire, S., additional, and Chastant-Maillard, S., additional
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- 2012
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11. 186 RELIABILITY OF HOECHST 33342 STAINING UNDER STANDARD EPIFLUORESCENCE MICROSCOPY FOR EVALUATION OF THE NUCLEAR STATUS OF LIVING DOG OOCYTES
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Chebrout, M., primary, Adenot, P. G., additional, Reynaud, K., additional, and Chastant-Maillard, S., additional
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- 2012
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12. Nuclear and cytoplasmic maturation of canine oocytes related to in vitro denudation
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Chebrout, M, primary, De Lesegno, C Viaris, additional, Reynaud, K, additional, Chat, S, additional, and Chastant‐Maillard, S, additional
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- 2009
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13. Folliculogenesis and Morphometry of Oocyte and Follicle Growth in the Feline Ovary
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Reynaud, K, primary, Gicquel, C, additional, Thoumire, S, additional, Chebrout, M, additional, Ficheux, C, additional, Bestandji, M, additional, and Chastant‐Maillard, S, additional
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- 2009
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14. In vivo meiotic resumption, fertilization and early embryonic development in the bitch
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Reynaud, K, primary, Fontbonne, A, additional, Marseloo, N, additional, Thoumire, S, additional, Chebrout, M, additional, de Lesegno, C Viaris, additional, and Chastant-Maillard, S, additional
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- 2005
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15. Expression of nuclear progesterone receptor and progesterone receptor membrane components 1 and 2 in the oviduct of cyclic and pregnant cows during the post-ovulation period
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Saint-Dizier Marie, Sandra Olivier, Ployart Stéphane, Chebrout Martine, and Constant Fabienne
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PR ,PGRMC1 ,PGRMC2 ,Oviduct ,Bovine ,Expression ,Gynecology and obstetrics ,RG1-991 ,Reproduction ,QH471-489 - Abstract
Abstract Background Progesterone (P4) may modulate oviductal functions to promote early embryo development in cattle. In addition to its nuclear receptor (PR), P4 may mediate its actions through P4 receptor membrane component 1 (PGRMC1) and its relative, PGRMC2. Two successive experiments were undertaken to characterise the expression of PR, PGRMC1 and PGRMC2 in the bovine oviduct during the post-ovulation period, and to relate their expression to the presence of an embryo, the proximity of the CL and to the region of the oviduct. Methods In the first experiment (Exp. I), whole oviduct sections were collected from Holstein cows at Day 1.5, Day 4 and Day 5 post-ovulation (n = 2 cows per stage). The expression of PR, PGRMC1 and PGRMC2 was studied in the ampulla and isthmus by RT-PCR, western-blot and immunohistochemistry. In Exp. II, oviduct epithelial cells were collected from cyclic and pregnant Charolais cows (n = 4 cows per status) at Day 3.5 post-ovulation and mRNA expression of PR, PGRMC1 and PGRMC2 was examined in the ampulla and isthmus by real-time quantitative PCR. Results In Exp. I, PR, PGRMC1 and PGRMC2 were expressed in all oviduct samples. PGRMC1 was mainly localised in the luminal epithelium whereas PR and PGRMC2 were localised in the epithelium as well as in the muscle and stroma layers of the oviduct. The expression was primarily nuclear for PR, primarily cytoplasmic for PGRMC1 and both nuclear and cytoplasmic for PGRMC2. In Exp. II, mRNA levels for PR, PGRMC1 and PGRMC2 were not affected by either the pregnancy status or the side relative to the CL. However, the expression of PR and PGRMC2 varied significantly with the region of the oviduct: PR was more highly expressed in the isthmus whereas PGRMC2 was more highly expressed in the ampulla. Conclusions This is the first evidence of PGRMC2 expression in the bovine oviduct. Our findings suggest that P4 regulates the functions of the bovine oviduct in a region-specific manner and through both classical and non classical pathways during the post-ovulation period.
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- 2012
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16. H3K27me3 at pericentromeric heterochromatin is a defining feature of the early mouse blastocyst.
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Pailles M, Hirlemann M, Brochard V, Chebrout M, Oudin JF, Marks H, Jouneau A, and Bonnet-Garnier A
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- Animals, Blastocyst metabolism, DNA Methylation, Epigenesis, Genetic, Mice, Heterochromatin metabolism, Histones metabolism
- Abstract
Early mouse development is characterized by structural and epigenetic changes while cells progress towards differentiation. At blastocyst stage, the segregation of the three primordial lineages is accompanied by establishment of differential patterns of DNA methylation and post-translational modifications of histones, such as H3K27me3. Here, we analysed the dynamics of H3K27me3 at pericentromeric heterochromatin (PCH) during early development. We also followed the localization of EZH2 and BEND3, previously shown in ESCs to drive PRC2 to hypomethylated PCH. We show that the location of H3K27me3 at PCH, in addition to H3K9me3, is a defining feature of embryonic cells in vivo. Moreover, it may play an important role in structuring PCH and preserving genomic integrity at a time of globally relaxed chromatin. At peri-implantation stages, while DNA methylation is still low, EZH2 and then H3K27me3, leave PCH in epiblast progenitors at the time of their spatial segregation from primitive endoderm cells, while BEND3 remains there up to implantation. The comparison with stem cells (ESCs and TSCs) reveals that the epigenetic marks (i.e. H3K9me3 and H3K27me3) of PCH are reset during in vitro derivation and only partially restored thereafter. This highlights possible divergences between in vitro and "in embryo" epigenetic regulation regarding constitutive heterochromatin., (© 2022. The Author(s).)
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- 2022
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17. Transcription of rRNA in early mouse embryos promotes chromatin reorganization and expression of major satellite repeats.
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Chebrout M, Koné MC, Jan HU, Cournut M, Letheule M, Fleurot R, Aguirre-Lavin T, Peynot N, Jouneau A, Beaujean N, and Bonnet-Garnier A
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- Animals, DNA, Ribosomal genetics, Embryo, Mammalian metabolism, Mice, Ribosomes metabolism, Transcription, Genetic, Chromatin genetics, Chromatin metabolism, RNA, Ribosomal genetics, RNA, Ribosomal metabolism
- Abstract
During the first cell cycles of early development, the chromatin of the embryo is highly reprogrammed while the embryonic genome starts its own transcription. The spatial organization of the genome is an important process that contributes to regulating gene transcription in time and space. It has, however, been poorly studied in the context of early embryos. To study the cause-and-effect link between transcription and spatial organization in embryos, we focused on ribosomal genes, which are silent initially but start to be transcribed in 2-cell mouse embryos. We demonstrated that ribosomal sequences and early unprocessed rRNAs are spatially organized in a very particular manner between 2-cell and 16-cell stage. By using drugs that interfere with ribosomal DNA transcription, we showed that this organization - which is totally different in somatic cells - depends on an active transcription of ribosomal genes and induces a unique chromatin environment that favors transcription of major satellite sequences once the 4-cell stage has been reached., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2022. Published by The Company of Biologists Ltd.)
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- 2022
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18. Three-dimensional analysis of nuclear heterochromatin distribution during early development in the rabbit.
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Bonnet-Garnier A, Kiêu K, Aguirre-Lavin T, Tar K, Flores P, Liu Z, Peynot N, Chebrout M, Dinnyés A, Duranthon V, and Beaujean N
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- Animals, Cell Nucleus metabolism, Centromere genetics, Centromere metabolism, Chromatin Assembly and Disassembly, Epigenesis, Genetic, Female, Heterochromatin metabolism, In Situ Hybridization, Fluorescence, Microscopy, Fluorescence, Rabbits, Cell Nucleus genetics, Embryonic Development genetics, Heterochromatin genetics
- Abstract
Changes to the spatial organization of specific chromatin domains such as constitutive heterochromatin have been studied extensively in somatic cells. During early embryonic development, drastic epigenetic reprogramming of both the maternal and paternal genomes, followed by chromatin remodeling at the time of embryonic genome activation (EGA), have been observed in the mouse. Very few studies have been performed in other mammalian species (human, bovine, or rabbit) and the data are far from complete. During this work, we studied the three-dimensional organization of pericentromeric regions during the preimplantation period in the rabbit using specific techniques (3D-FISH) and tools (semi-automated image analysis). We observed that the pericentromeric regions (identified with specific probes for Rsat I and Rsat II genomic sequences) changed their shapes (from pearl necklaces to clusters), their nuclear localizations (from central to peripheral), as from the 4-cell stage. This reorganization goes along with histone modification changes and reduced amount of interactions with nucleolar precursor body surface. Altogether, our results suggest that the 4-cell stage may be a crucial window for events necessary before major EGA, which occurs during the 8-cell stage in the rabbit.
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- 2018
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19. Contrasting epigenetic states of heterochromatin in the different types of mouse pluripotent stem cells.
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Tosolini M, Brochard V, Adenot P, Chebrout M, Grillo G, Navia V, Beaujean N, Francastel C, Bonnet-Garnier A, and Jouneau A
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- Animals, Cell Line, DNA Methylation, Heterochromatin genetics, Methylation, Mice, Protein Processing, Post-Translational, DNA, Satellite metabolism, Epigenesis, Genetic, Germ Layers metabolism, Heterochromatin metabolism, Histones metabolism, Mouse Embryonic Stem Cells metabolism
- Abstract
Mouse embryonic stem cells (ESCs) and epiblast stem cells (EpiSCs) represent naive and primed pluripotency states, respectively, and are maintained in vitro by specific signalling pathways. Furthermore, ESCs cultured in serum-free medium with two kinase inhibitors (2i-ESCs) are thought to be the ground naïve pluripotent state. Here, we present a comparative study of the epigenetic and transcriptional states of pericentromeric heterochromatin satellite sequences found in these pluripotent states. We show that 2i-ESCs are distinguished from other pluripotent cells by a prominent enrichment in H3K27me3 and low levels of DNA methylation at pericentromeric heterochromatin. In contrast, serum-containing ESCs exhibit higher levels of major satellite repeat transcription, which is lower in 2i-ESCs and even more repressed in primed EpiSCs. Removal of either DNA methylation or H3K9me3 at PCH in 2i-ESCs leads to enhanced deposition of H3K27me3 with few changes in satellite transcript levels. In contrast, their removal in EpiSCs does not lead to deposition of H3K27me3 but rather removes transcriptional repression. Altogether, our data show that the epigenetic state of PCH is modified during transition from naive to primed pluripotency states towards a more repressive state, which tightly represses the transcription of satellite repeats.
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- 2018
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20. Prosurvival effect of cumulus prostaglandin G/H synthase 2/prostaglandin2 signaling on bovine blastocyst: impact on in vivo posthatching development.
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Nuttinck F, Jouneau A, Charpigny G, Hue I, Richard C, Adenot P, Ruffini S, Laffont L, Chebrout M, Duranthon V, and Guienne BM
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- Animals, Blastocyst cytology, Cattle, Female, Fertilization in Vitro, In Vitro Oocyte Maturation Techniques, Pregnancy, Prostaglandin-Endoperoxide Synthases metabolism, Apoptosis, Blastocyst physiology, Dinoprostone physiology, Embryonic Development
- Abstract
Apoptotic activity is a common physiological process which culminates at the blastocyst stage in the preimplantation embryo of many mammals. The degree of embryonic cell death can be influenced by the oocyte microenvironment. However, the prognostic significance of the incidence of apoptosis remains undefined. Prostaglandin E2 (PGE2) derived from prostaglandin G/H synthase-2 (PTGS2) activity is a well-known prosurvival factor that is mainly studied in oncology. PGE2 is the predominant PTGS2-derived prostaglandin present in the oocyte microenvironment during the periconceptional period. Using an in vitro model of bovine embryo production followed by transfer and collection procedures, we investigated the impact of periconceptional PGE2 on the occurrence of spontaneous apoptosis in embryos and on subsequent in vivo posthatching development. Different periconceptional PGE2 environments were obtained using NS-398, a specific inhibitor of PTGS2 activity, and exogenous PGE2. We assessed the level of embryonic cell death in blastocysts at day 8 postfertilization by counting total cell numbers, by the immunohistochemical staining of active caspase-3, and by quantifying terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling signals and apoptosis regulator (BCL-2/BAX) mRNA expression. Morphometric parameters were used to estimate the developmental stage of the embryonic disk and the extent of trophoblast elongation on day 15 conceptuses. Our findings indicate that periconceptional PGE2 signaling durably impacts oocytes, conferring increased resistance to spontaneous apoptosis in blastocysts and promoting embryonic disk development and the elongation process during preimplantation development., (© The Authors 2017. Published by Oxford University Press on behalf of Society for the Study of Reproduction.)
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- 2017
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21. Three-Dimensional Distribution of UBF and Nopp140 in Relationship to Ribosomal DNA Transcription During Mouse Preimplantation Development.
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Koné MC, Fleurot R, Chebrout M, Debey P, Beaujean N, and Bonnet-Garnier A
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- Animals, Benzothiazoles, Female, Mice, Inbred C57BL, Naphthyridines, RNA Polymerase I antagonists & inhibitors, DNA, Ribosomal metabolism, Embryo, Mammalian metabolism, Embryonic Development, Nuclear Proteins metabolism, Phosphoproteins metabolism, Pol1 Transcription Initiation Complex Proteins metabolism
- Abstract
The nucleolus is a dynamic nuclear compartment that is mostly involved in ribosome subunit biogenesis; however, it may also play a role in many other biological processes, such as stress response and the cell cycle. Mainly using electron microscopy, several studies have tried to decipher how active nucleoli are set up during early development in mice. In this study, we analyzed nucleologenesis during mouse early embryonic development using 3D-immunofluorescent detection of UBF and Nopp140, two proteins associated with different nucleolar compartments. UBF is a transcription factor that helps maintain the euchromatic state of ribosomal genes; Nopp140 is a phosphoprotein that has been implicated in pre-rRNA processing. First, using detailed image analyses and the in situ proximity ligation assay technique, we demonstrate that UBF and Nopp140 dynamic redistribution between the two-cell and blastocyst stages (time of implantation) is correlated with morphological and structural modifications that occur in embryonic nucleolar compartments. Our results also support the hypothesis that nucleoli develop at the periphery of nucleolar precursor bodies. Finally, we show that the RNA polymerase I inhibitor CX-5461: 1) disrupts transcriptional activity, 2) alters preimplantation development, and 3) leads to a complete reorganization of UBF and Nopp140 distribution. Altogether, our results underscore that highly dynamic changes are occurring in the nucleoli of embryos and confirm a close link between ribosomal gene transcription and nucleologenesis during the early stages of development., (© 2016 by the Society for the Study of Reproduction, Inc.)
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- 2016
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22. Reliability of Hoechst 33342 staining under wide-field microscopy for evaluation of the nuclear status of living dog oocytes.
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Chebrout M, Adenot PG, Reynaud K, and Chastant-Maillard S
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- Animals, Dogs, Reproducibility of Results, Benzimidazoles metabolism, Cell Nucleus metabolism, Cytological Techniques methods, Microscopy, Fluorescence methods, Oocytes cytology, Oocytes physiology, Staining and Labeling methods
- Abstract
Due to the marked cytoplasmic opacity of canine oocytes, the diagnosis of their nuclear status is difficult. The objective of the present study was to evaluate the accuracy of Hoechst staining observed under epifluorescence wide-field microscopy [living oocyte observation (LivOO)] by comparison to a reference technique [DNA staining with ethidium homodimer-2 under confocal microscopy; fixed oocyte observation (FixOO)]. Four Hoechst 33342 concentrations (200 ng, 500 ng, 1 μg, 2 μg/mL) were tested and 1 μg/mL was the lowest one with the lowest proportion of oocytes in which DNA was missed. At this concentration, LivOO procedure did not affect the degeneration rate. On 379 oocytes observed individually with the two techniques successively, diagnosis of meiosis resumption by LivOO was exact in 87.3% of the cases, but the meiosis resumption rate was underestimated (23.5% versus 34.3% with FixOO; p < 0.001). Diagnosis for metaphase II was exact in 80% of the cases, but LivOO detected only 72.7% of the metaphase II oocytes present. Metaphase rates did not differ between LivOO and FixOO. This study contributes to a better interpretation of in vitro maturation results. The developmental potential of metaphase II canine oocytes sorted after Hoechst staining is to be evaluated.
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- 2012
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23. Genome organization and epigenetic marks in mouse germinal vesicle oocytes.
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Bonnet-Garnier A, Feuerstein P, Chebrout M, Fleurot R, Jan HU, Debey P, and Beaujean N
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- Animals, Cell Nucleolus genetics, Centromere genetics, Chromatin genetics, Chromatin metabolism, DNA, Ribosomal genetics, Epigenomics, Female, Heterochromatin genetics, Heterochromatin metabolism, Histones metabolism, In Situ Hybridization, Fluorescence, Methylation, Mice, Mice, Inbred C57BL, Mice, Inbred CBA, Microscopy, Fluorescence, Oocytes cytology, Oogenesis genetics, Cell Nucleus genetics, Epigenesis, Genetic, Genome genetics, Oocytes metabolism
- Abstract
During the final step of oogenesis, the oocyte nucleus is subject to large-scale modifications that correlate with transcriptional silencing. While oocytes with dense chromatin around the nucleolus are silent (SN, surrounded nucleolus), oocytes with uncondensed chromatin (NSN, non-surrounded nucleolus) are transcriptionally active. It is believed that epigenetic mechanisms that participate in gene expression regulation could play a role in this event. In this context, we examined the behaviour of heterochromatin and related histone modifications during the NSN to SN transition by immunostaining. Using fluorescent in situ hybridization on three dimensional-preserved nuclei (3D-FISH), we also studied the distribution of centromeric, pericentromeric and ribosomal (rDNA) sequences in relation to the nucleolus (also called the nucleolus-like body, NLB). We observed that in NSN-type oocytes, pericentromeric heterochromatin is aggregated within chromocenters. In SN-type oocytes, pericentromeric heterochromatin and centromeres form a discontinuous ring around the NLB. rDNA sequences, which initially present a pearl necklace structure, gather together in seven highly condensed foci at the NLB periphery. H3K9me3 and H4K20me3 heterochromatin marks clearly label chromocenters, whereas H3K4me3 and H4K5ac are totally excluded from heterochromatin regions, even in the very compact SN-nuclei. Remarkably, H3K27me3 displays an intermediate behavior. It appears that GV oocyte nuclei exhibit a specific epigenetic landscape. Histone modifications, related to both active and repressive chromatin structures, seem to follow the large-scale chromatin movements that occur during the NSN to SN transition. We also demonstrate that, while heterochromatin regions re-localize around the NLB, rDNA sequences adopt a highly compact structure in SN-type oocytes.
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- 2012
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24. The canine oocyte: uncommon features of in vivo and in vitro maturation.
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Chastant-Maillard S, Viaris de Lesegno C, Chebrout M, Thoumire S, Meylheuc T, Fontbonne A, Chodkiewicz M, Saint-Dizier M, and Reynaud K
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- Animals, Female, Fertilization in Vitro veterinary, Meiosis physiology, Ovarian Follicle cytology, Ovulation physiology, Dogs physiology, Oocytes cytology, Ovarian Follicle growth & development
- Abstract
The biology of the canine oocyte is unusual compared with that of other mammalian females. The present paper reviews both in vivo and in vitro specificities of canine oocytes. Final follicular growth in the bitch is characterised by an early appearance of LH binding sites in the granulosa, a high proportion of polyovular follicles and a preovulatory luteinisation, starting at the time of the LH surge. Through follicular fluid, preovulatory oocytes are thus exposed to high levels of progesterone, as high as 1000-fold plasma concentrations. The composition of the follicular fluid is affected by the size of the female. The more specific aspect of oocyte biology in the bitch is ovulation: oocytes are expelled immature, at the Prophase I stage. Ovulatory follicles are 6-8 mm in diameter, releasing oocytes from 110 µm, with dark cytoplasm. Resumption of meiosis occurs from 48 h postovulation, MII stages appearing 48-54 h after ovulation. The mechanisms controlling such a late meiotic resumption are still unknown. Granulosa cells seem to play a central role as in other mammalian species, but not with cAMP as the principal mediator. The importance of a transient reactivation of oocyte transcription a few hours before meiotic resumption is to be explored. These specific features may contribute to the low efficiency of IVM. Only 10-20% oocytes reach the metaphase stage and suffer from a poor cytoplasmic maturation. Moreover, in vitro culture of canine oocytes is associated with a high proportion of degeneration. To date, IVM of the oocytes is the main limiting factor for the development of assisted reproductive techniques in the canine. A better knowledge of the basic physiology of folliculogenesis and the molecular mechanisms controlling oocyte meiosis resumption in this species may allow us to overcome this obstacle.
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- 2011
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25. [Polyovular follicles].
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Reynaud K, Halter S, Tahir Z, Thoumire S, Chebrout M, and Chastant-Maillard S
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- Aging, Animals, Diethylstilbestrol administration & dosage, Dogs, Female, Humans, Marsupialia, Mice, Mutation, Ovarian Follicle growth & development, Ovulation, Ovulation Induction, Species Specificity, Oocytes cytology, Oocytes physiology, Ovarian Follicle cytology
- Abstract
Folliculogenesis covers the sequential steps in the development of a follicle, from primordial to preovulatory. Most of the time, one follicle contains a single oocyte, but some follicles are polyovular in that they contain several. These follicles were considered earlier as pathological, but they are, actually, fairly common in several species, from mice to humans. The frequency of polyovular follicles (number of polyovular/total number of follicles) varies among species, <0.1% to 14% in the dog, and with age (more polyovular follicles during the prepubertal period). More than 20 oocytes (and even more than 100 in the marsupials like the opossum) may be present in a single follicle. These follicles may form during the earliest stages of follicle formation, due to an imbalance between somatic and germinal cells, which induces an incomplete germ cell cyst breakdown. In polyovular follicles, the quality (size and maturity) of the various oocytes is often heterogeneous. Numerous authors reported that polyovular follicles are able to reach ovulation and ovulate. Polyovular follicles, naturally found in several species, may also be induced by exposure to therapy or agents in the environment, especially with estrogen activity such as pesticides or diethylstilbestrol/DES. Polyovular follicles are also observed in the ovaries of mutated rodents., (2010 Elsevier Masson SAS. All rights reserved.)
- Published
- 2010
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26. Embryo biotechnology in the dog: a review.
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Chastant-Maillard S, Chebrout M, Thoumire S, Saint-Dizier M, Chodkiewicz M, and Reynaud K
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- Animals, Dogs physiology, Female, Male, Pregnancy, Biotechnology methods, Dogs embryology, Reproductive Techniques, Assisted veterinary
- Abstract
Canine embryos are a scarce biological material because of difficulties in collecting in vivo-produced embryos and the inability, to date, to produce canine embryos in vitro. The procedure for the transfer of in vivo-produced embryos has not been developed adequately, with only six attempts reported in the literature that have resulted in the birth of 45 puppies. In vitro, the fertilisation rate is particularly low ( approximately 10%) and the incidence of polyspermy particularly high. So far, no puppy has been obtained from an in vitro-produced embryo. In contrast, cloning of somatic cells has been used successfully over the past 4 years, with the birth of 41 puppies reported in the literature, a yield that is comparable to that for other mammalian species. Over the same period, canine embryonic stem sells and transgenic cloned dogs have been obtained. Thus, the latest reproductive technologies are further advanced than in vitro embryo production. The lack of fundamental studies on the specific features of reproductive physiology and developmental biology in the canine is regrettable in view of the increasing role of dogs in our society and of the current demand for new biological models in biomedical technology.
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- 2010
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27. Ultrastructural evaluation of in vitro-matured canine oocytes.
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Viaris de Lesegno C, Reynaud K, Pechoux C, Chebrout M, and Chastant-Maillard S
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- Animals, Cell Nucleolus ultrastructure, Cell Size, Cells, Cultured, Cumulus Cells cytology, Female, Meiosis physiology, Models, Biological, Oocytes cytology, Oocytes growth & development, Dogs physiology, Oocytes ultrastructure, Oogenesis physiology
- Abstract
Cumulus-oocyte complexes (COCs) were recovered from ovaries of bitches during anoestrus. The ultrastructural organisation of COCs was determined before and after 72 h in vitro maturation (IVM) by transmission electron microscopy. The aim of the study was to determine the quality of oocytes used for IVM and to assess cytoplasmic maturation of IVM metaphase (M) II oocytes. In addition, we examined whether the oocytes that did not reach MII were engaged in an erratic maturation process or whether they were blocked during their progression through a normal maturation process. Before IVM, there were two populations of oocytes: (1) oocytes with a centrally located germinal vesicle, a transcriptionally active aspect and an immature cytoplasm; and (2) oocytes with an eccentric nucleus, a transcriptionally inactive aspect and a more mature cytoplasm. After IVM, most oocytes were still at the germinal vesicle stage with three different patterns and all showing a good synchronisation between nuclear and cytoplasmic maturation. MI oocytes had a similar cytoplasmic maturation to that observed in vivo, but failed to complete meiosis; however, IVM MII oocytes had a very poor cytoplasmic maturation. Ultrastructural analysis demonstrated that even when nuclear maturation is achieved, cytoplasmic maturation may not be obtained in vitro. Thus, all IVM systems should be evaluated on both criteria.
- Published
- 2008
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28. Presence of permanently activated signal transducers and activators of transcription in nuclear interchromatin granules of unstimulated mouse oocytes and preimplantation embryos.
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Truchet S, Chebrout M, Djediat C, Wietzerbin J, and Debey P
- Subjects
- Animals, Carrier Proteins genetics, Carrier Proteins metabolism, Chromatin metabolism, DNA-Binding Proteins genetics, Female, Interferon Regulatory Factor-1, Interferon-alpha physiology, Mice, Mice, Inbred C57BL, Mice, Knockout, Phosphoproteins genetics, Phosphoproteins metabolism, Phosphorylation, Pregnancy, Protein Transport physiology, RNA, Messenger analysis, Repressor Proteins genetics, Repressor Proteins metabolism, STAT1 Transcription Factor, Subcellular Fractions metabolism, Suppressor of Cytokine Signaling 1 Protein, Suppressor of Cytokine Signaling Proteins, Trans-Activators genetics, Transcription, Genetic physiology, Transcriptional Activation, Blastocyst metabolism, Cell Nucleus metabolism, DNA-Binding Proteins metabolism, Interferon-gamma physiology, Oocytes metabolism, Signal Transduction physiology, Trans-Activators metabolism
- Abstract
We previously described that mouse oocytes and preimplantation embryos express the two subunits of interferon-gamma receptor. We now report that, despite the presence of STAT1 (signal transducer and activator of transcription 1) at both the mRNA and protein levels, interferon gamma (IFNgamma) as well as IFNalpha are unable to trigger massive nuclear translocation of STAT1 in these cells, even at high cytokine concentrations. Conversely, nuclear accumulation of STAT1 was readily observed in murine L929 somatic cells under the same conditions. However, in the absence of any stimulation, both tyrosine (Y701p) and serine (S727p) phosphorylated forms of STAT1 were already detected in the nuclei of oocytes and early embryos. Phosphorylated STAT1 appeared concentrated in large nuclear dots, which were identified by indirect immunofluorescence and electron microscopy as clusters of interchromatin granules (IGCs or speckles). A similar distribution was also observed for the serine (S727p) phosphorylated form of STAT3 as well as for tyrosine (Y689p) phosphorylated STAT2. Western blot analysis confirmed that STAT factors present in mouse oocytes are predominantly phosphorylated. In parallel, we showed that the transcription of two IFNgamma-target genes, namely interferon regulatory factor-1 (IRF-1) and suppressor of cytokine signaling-1 (SOCS-1) is indeed increased in two-cell embryos in response to IFNgamma. Altogether, our results suggest that, despite the lack of massive nuclear accumulation of STAT1 in response to exogenous IFNs and the permanent presence of phosphorylated STATs in the nucleus, JAK/ STAT pathways are functional during early development.
- Published
- 2004
- Full Text
- View/download PDF
29. The step-wise assembly of a functional nucleolus in preimplantation mouse embryos involves the cajal (coiled) body.
- Author
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Zatsepina O, Baly C, Chebrout M, and Debey P
- Subjects
- Animals, Blotting, Western, Chromosomal Proteins, Non-Histone chemistry, Chromosomal Proteins, Non-Histone genetics, DNA, Ribosomal genetics, Embryo, Mammalian metabolism, Female, Genomic Imprinting, Mice, Mice, Inbred C57BL, Mice, Inbred CBA, Microscopy, Fluorescence, Nuclear Proteins chemistry, Nuclear Proteins genetics, Pregnancy, RNA Polymerase I metabolism, RNA, Ribosomal biosynthesis, Transcription, Genetic, Cell Nucleolus, Coiled Bodies, Embryo, Mammalian ultrastructure, Embryonic Development
- Abstract
After fertilization, ribosomal RNA synthesis is silenced during a period which depends on the species. Data concerning the reassembly of a functional nucleolus remain scarce. We have examined by immunocytochemistry, Western blots, and BrUTP microinjection the dynamics of major nucleolar proteins during the first cycles of mouse embryogenesis, in relation to rDNA transcription sites and coilin, a marker of Cajal bodies. We show that: (1) the reinitiation of rDNA transcription occurs at the two-cell stage, 44-45 h after hCG injection (hphCG), at the surface of the nucleolar precursor bodies (NPBs), where the RNA polymerase I (pol I) transcription complex is recruited 4-5 h before; (2) the NPBs are not equal in their ability to support recruitment of pol I and rDNA transcription; (3) maternally inherited fibrillarin undergoes a dynamic redistribution during the second cell stage, together with coilin, leading to the assembly of the Cajal body around 40 hphCG; and (4) the pol I complex is first recruited to the Cajal body before reaching its rDNA template. We also find that fibrillarin and B23 are both directly assembled around NPBs prior to ongoing pre-rRNA synthesis. Altogether, our results reveal a role of the Cajal bodies in the building of a functional nucleolus.
- Published
- 2003
- Full Text
- View/download PDF
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