title: Involvement of Ras in extraembryonic endoderm differentiation of embryonic stem cells.
abstract: Embryonic stem (ES) cells, derived from the inner cell mass of blastocyst can differentiate into multiple cell lineages. In this study, we examined the possible involvement of Ras in ES cell differentiation. We found that Ras was activated upon formation of embryoid bodies (EBs), an initial step in ES cell differentiation. When expressed during EB differentiation, a dominant-negative mutant of Ras suppressed induction of marker genes for extraembryonic endoderm differentiation, including GATA-4, GATA-6, alpha-fetoprotein, and hepatocyte nuclear factor 3beta, while an activated mutant promoted their induction. Expression of a Ras mutant that selectively activates the Raf/MEK/Erk pathway also enhanced induction of extraembryonic endoderm markers, and treatment with a MEK inhibitor resulted in their decreased expression. In addition, Ras stimulated downregulation of Nanog, a suppressor of endoderm differentiation in ES cells. These data suggest that Ras activation during EB differentiation plays a crucial role in initiation of extraembryonic endoderm differentiation.
authors.affiliation: Department of Stem Cell Biology, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8640, Japan.
authors.forename: Urara
authors.initials: U
authors.lastname: Yoshida-Koide
authors.forename: Takahiko
authors.initials: T
authors.lastname: Matsuda
authors.forename: Kunikazu
authors.initials: K
authors.lastname: Saikawa
authors.forename: Yasuni
authors.initials: Y
authors.lastname: Nakanuma
authors.forename: Takashi
authors.initials: T
authors.lastname: Yokota
authors.forename: Makoto
authors.initials: M
authors.lastname: Asashima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Koide
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D019070:Cell Lineage; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism; D015536:Down-Regulation; D004707:Endoderm / Q000166:cytology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D050991:GATA4 Transcription Factor; D050993:GATA6 Transcription Factor; D005799:Genes, Dominant; D005819:Genetic Markers; D006160:Guanosine Triphosphate / Q000378:metabolism; D051542:Hepatocyte Nuclear Factor 3-beta; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D051379:Mice; D009154:Mutation; D000071317:Nanog Homeobox Protein; D009687:Nuclear Proteins / Q000096:biosynthesis; D010957:Plasmids / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology*; D013997:Time Factors; D014157:Transcription Factors / Q000096:biosynthesis; D014162:Transfection; D000509:alpha-Fetoproteins / Q000096:biosynthesis; D018631:ras Proteins / Q000378:metabolism*
chemical_list: D017077:Culture Media, Conditioned; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; C496502:FOXA2 protein, human; C496503:Foxa2 protein, mouse; D050991:GATA4 Transcription Factor; D050993:GATA6 Transcription Factor; C494759:GATA6 protein, human; C494760:Gata6 protein, mouse; D005819:Genetic Markers; D018398:Homeodomain Proteins; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D000509:alpha-Fetoproteins; D051542:Hepatocyte Nuclear Factor 3-beta; D006160:Guanosine Triphosphate; D018631:ras Proteins