title: Cumulus cell gene expression associated with pre-ovulatory acquisition of developmental competence in bovine oocytes.
abstract: The final days before ovulation impact significantly on follicular function and oocyte quality. This study investigated the cumulus cell (CC) transcriptomic changes during the oocyte developmental competence acquisition period. Six dairy cows were used for 24 oocyte collections and received FSH twice daily over 3 days, followed by FSH withdrawal for 20, 44, 68 and 92 h in four different oestrous cycles for each of the six cows. Half of the cumulus-oocyte complexes were subjected to in vitro maturation, fertilisation and culture to assess blastocyst rate. The other half of the CC underwent microarray analysis (n=3 cows, 12 oocyte collections) and qRT-PCR (n=3 other cows, 12 oocyte collections). According to blastocyst rates, 20 h of FSH withdrawal led to under-differentiated follicles (49%), 44 and 68 h to the most competent follicles (71% and 61%) and 92 h to over-differentiated ones (51%). Ten genes, from the gene lists corresponding to the three different follicular states, were subjected to qRT-PCR. Interestingly, CYP11A1 and NSDHL gene expression profiles reflected the blastocyst rate. However most genes were associated with the over-differentiated status: GATM, MAN1A1, VNN1 and NRP1. The early period of FSH withdrawal has a minimal effect on cumulus gene expression, whereas the longest period has a very significant one and indicates the beginning of the atresia process.
authors.affiliation: Centre de Recherche en Biologie de la Reproduction, Faculté des Sciences de l'Agriculture et de l'Alimentation, Département des Sciences Animales, Université Laval, Québec, QC G1V 0A6, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Bunel
authors.affiliation: Centre de Recherche en Biologie de la Reproduction, Faculté des Sciences de l'Agriculture et de l'Alimentation, Département des Sciences Animales, Université Laval, Québec, QC G1V 0A6, Canada.
authors.forename: A L
authors.initials: AL
authors.lastname: Nivet
authors.affiliation: L'Alliance Boviteq, 19320 Grand rang St-François, Saint-Hyacinthe, Québec, QC J2T 5H1, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Blondin
authors.affiliation: L'Alliance Boviteq, 19320 Grand rang St-François, Saint-Hyacinthe, Québec, QC J2T 5H1, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Vigneault
authors.affiliation: Centre de Recherche en Biologie de la Reproduction, Faculté des Sciences de l'Agriculture et de l'Alimentation, Département des Sciences Animales, Université Laval, Québec, QC G1V 0A6, Canada.
authors.forename: F J
authors.initials: FJ
authors.lastname: Richard
authors.affiliation: Centre de Recherche en Biologie de la Reproduction, Faculté des Sciences de l'Agriculture et de l'Alimentation, Département des Sciences Animales, Université Laval, Québec, QC G1V 0A6, Canada.
authors.forename: M A
authors.initials: MA
authors.lastname: Sirard
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism; D002417:Cattle / Q000196:embryology / Q000235:genetics; D002478:Cells, Cultured; D054885:Cumulus Cells / Q000378:metabolism*; D047108:Embryonic Development / Q000235:genetics; D005260:Female; D005498:Follicular Phase / Q000235:genetics*; D015870:Gene Expression; D020869:Gene Expression Profiling; D046228:Microarray Analysis; D009865:Oocytes / Q000502:physiology*; D009866:Oogenesis / Q000235:genetics*