title: Germ Cell Nuclear Factor (GCNF) Represses Oct4 Expression and Globally Modulates Gene Expression in Human Embryonic Stem (hES) Cells.
abstract: Oct4 is considered a key transcription factor for pluripotent stem cell self-renewal. It binds to specific regions within target genes to regulate their expression and is downregulated upon induction of differentiation of pluripotent stem cells; however, the mechanisms that regulate the levels of human Oct4 expression remain poorly understood. Here we show that expression of human Oct4 is directly repressed by germ cell nuclear factor (GCNF), an orphan nuclear receptor, in hES cells. Knockdown of GCNF by siRNA resulted in maintenance of Oct4 expression during RA-induced hES cell differentiation. While overexpression of GCNF promoted repression of Oct4 expression in both undifferentiated and differentiated hES cells. The level of Oct4 repression was dependent on the level of GCNF expression in a dose-dependent manner. mRNA microarray analysis demonstrated that overexpression of GCNF globally regulates gene expression in undifferentiated and differentiated hES cells. Within the group of altered genes, GCNF down-regulated 36% of the genes, and up-regulated 64% in undifferentiated hES cells. In addition, GCNF also showed a regulatory gene pattern that is different from RA treatment during hES cell differentiation. These findings increase our understanding of the mechanisms that maintain hES cell pluripotency and regulate gene expression during the differentiation process.
authors.affiliation: From the Department of Pediatrics, Dell Pediatric Research Institute, University of Texas at Austin Dell Medical School, Austin, Texas 78723.
authors.forename: Hongran
authors.initials: H
authors.lastname: Wang
authors.affiliation: Stem Cell Center, Texas Heart Institute, Houston, Texas 77030, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, and.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, and.
authors.forename: Xueping
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Pediatrics, Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota 55454.
authors.forename: Michael
authors.initials: M
authors.lastname: Kyba
authors.affiliation: From the Department of Pediatrics, Dell Pediatric Research Institute, University of Texas at Austin Dell Medical School, Austin, Texas 78723, austin.cooney@austin.utexas.edu.
authors.forename: Austin J
authors.initials: AJ
authors.lastname: Cooney
mesh_terms: D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D005786:Gene Expression Regulation / Q000502:physiology*; D000066449:Human Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D057136:Nuclear Receptor Subfamily 6, Group A, Member 1 / Q000235:genetics / Q000378:metabolism*; D050814:Octamer Transcription Factor-3 / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C539950:NR6A1 protein, human; D057136:Nuclear Receptor Subfamily 6, Group A, Member 1; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human; D012333:RNA, Messenger; D012097:Repressor Proteins
keywords: Germ cell nuclear factor; Oct4; cell differentiation; embryonic stem cell; gene expression; gene regulation; pluripotency