title: An overview of gene expression dynamics during early ovarian folliculogenesis: specificity of follicular compartments and bi-directional dialog.
abstract: BACKGROUND
  Successful early folliculogenesis is crucial for female reproductive function. It requires appropriate gene specific expression of the different types of ovarian cells at different developmental stages. To date, most gene expression studies on the ovary were conducted in rodents and did not distinguish the type of cell. In mono-ovulating species, few studies have addressed gene expression profiles and mainly concerned human oocytes.
  
  
  RESULTS
  We used a laser capture microdissection method combined with RNA-seq technology to explore the transcriptome in oocytes and granulosa cells (GCs) during development of the sheep ovarian follicle. We first documented the expression profile of 15 349 genes, then focused on the 5 129 genes showing differential expression between oocytes and GCs. Enriched functional categories such as oocyte meiotic arrest and GC steroid synthesis reflect two distinct cell fates. We identified the implication of GC signal transduction pathways such as SHH, WNT and RHO GTPase. In addition, signaling pathways (VEGF, NOTCH, IGF1, etc.) and GC transzonal projections suggest the existence of complex cell-cell interactions. Finally, we highlighted several transcription regulators and specifically expressed genes that likely play an important role in early folliculogenesis.
  
  
  CONCLUSIONS
  To our knowledge, this is the first comprehensive exploration of transcriptomes derived from in vivo oocytes and GCs at key stages in early follicular development in sheep. Collectively, our data advance our understanding of early folliculogenesis in mono-ovulating species and will be a valuable resource for unraveling human ovarian dysfunction such as premature ovarian failure (POF).
authors.affiliation: INRA, UMR444 Génétique Cellulaire, Auzeville, BP52627, F-31326, Castanet-Tolosan, France. agnes.bonnet@toulouse.inra.fr.
authors.forename: Agnes
authors.initials: A
authors.lastname: Bonnet
authors.forename: Cedric
authors.initials: C
authors.lastname: Cabau
authors.forename: Olivier
authors.initials: O
authors.lastname: Bouchez
authors.forename: Julien
authors.initials: J
authors.lastname: Sarry
authors.forename: Nathalie
authors.initials: N
authors.lastname: Marsaud
authors.forename: Sylvain
authors.initials: S
authors.lastname: Foissac
authors.forename: Florent
authors.initials: F
authors.lastname: Woloszyn
authors.forename: Philippe
authors.initials: P
authors.lastname: Mulsant
authors.forename: Beatrice
authors.initials: B
authors.lastname: Mandon-Pepin
mesh_terms: D000818:Animals; D002450:Cell Communication / Q000235:genetics; D016000:Cluster Analysis; D019295:Computational Biology; D005260:Female; D005786:Gene Expression Regulation; D006107:Granulosa Cells / Q000378:metabolism; D006801:Humans; D058977:Molecular Sequence Annotation; D009865:Oocytes / Q000378:metabolism; D009928:Organ Specificity / Q000235:genetics; D006080:Ovarian Follicle / Q000502:physiology*; D015203:Reproducibility of Results; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D059467:Transcriptome
chemical_list: D014157:Transcription Factors