title: Expression of pluripotency master regulators during two key developmental transitions: EGA and early lineage specification in the bovine embryo.
abstract: Pluripotency genes are implicated in mouse embryonic genome activation (EGA) and pluripotent lineage specification. Moreover, their expression levels have been correlated with embryonic term development. In bovine, however, little information is available about dynamics of pluripotency genes during these processes. In this study, we charted quantitative and/or qualitative spatio-temporal expression patterns of transcripts and proteins of pluripotency genes (OCT4, SOX2 and NANOG) and mRNA levels of some of their downstream targets in bovine oocytes and early embryos. Furthermore, to correlate expression patterns of these genes with term developmental potential, we used cloned embryos, having similar in vitro but different full term development rates. Our findings affirm: firstly, the core triad of pluripotency genes is probably not implicated in bovine EGA since their proteins were not detected during pre-EGA phase, despite the transcripts for OCT4 and SOX2 were present. Secondly, an earlier ICM specification of transcripts and proteins of SOX2 and NANOG makes them pertinent candidates of bovine pluripotent lineage specification than OCT4. Thirdly, embryos with low term development potential have higher transcription rates; nevertheless, precarious balance between pluripotency genes is maintained. This balance presages normal in vitro development but, probably higher transcription rate disturbs it at later stage that abrogates term development.
authors.affiliation: INRA UMR 1198 Biologie du Développement et de la Reproduction, Jouy en Josas, France.
authors.forename: Daulat Raheem
authors.initials: DR
authors.lastname: Khan
authors.forename: Delphine
authors.initials: D
authors.lastname: Dubé
authors.forename: Laurence
authors.initials: L
authors.lastname: Gall
authors.forename: Nathalie
authors.initials: N
authors.lastname: Peynot
authors.forename: Sylvie
authors.initials: S
authors.lastname: Ruffini
authors.forename: Ludivine
authors.initials: L
authors.lastname: Laffont
authors.forename: Daniel
authors.initials: D
authors.lastname: Le Bourhis
authors.forename: Séverine
authors.initials: S
authors.lastname: Degrelle
authors.forename: Alice
authors.initials: A
authors.lastname: Jouneau
authors.forename: Véronique
authors.initials: V
authors.lastname: Duranthon
mesh_terms: D000818:Animals; D002417:Cattle; D019070:Cell Lineage; D019976:Cloning, Organism; D005307:Fertilization in Vitro; D005347:Fibroblasts / Q000166:cytology; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D016678:Genome; D018398:Homeodomain Proteins / Q000096:biosynthesis; D051379:Mice; D000071317:Nanog Homeobox Protein; D053652:Nuclear Transfer Techniques; D050814:Octamer Transcription Factor-3 / Q000096:biosynthesis; D009865:Oocytes / Q000166:cytology; D039904:Pluripotent Stem Cells / Q000166:cytology*; D055748:SOXB1 Transcription Factors / Q000096:biosynthesis; D013997:Time Factors
chemical_list: D018398:Homeodomain Proteins; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D055748:SOXB1 Transcription Factors