Fibroblast growth factor receptor 2 homodimerization rapidly reduces transcription of the pluripotency gene Nanog without dissociation of activating transcription factors.
Nanog or Gata6-positive cells co-exist and are convertible within the inner cell mass of murine blastocysts and embryonic stem (ES) cells. Previous studies demonstrate fibroblast growth factor receptor 2 (FGFR2) triggers Nanog gene down-regulation and differentiation to primitive endoderm (PE); however, the underlying mechanisms responsible for reversible and fluctuating cell fate are poorly understood. Using an inducible FGFR2 dimerization system in ES cells, we demonstrate that FGFR2 activation rapidly down-regulated Nanog gene transcription through activation of the Mek pathway and subsequently differentiated ES cells into PE cells. FGFR2 rather selectively repressed the Nanog gene with minimal effect on other pluripotency genes, including Oct4 and Sox2. We determined the Nanog promoter region containing minimum Oct4/Sox2 binding sites was sufficient for this transcriptional down-regulation by FGFR2, when the reporter transgenes were integrated with insulators. Of interest, FGFR2-mediated Nanog transcriptional reduction occurred without dissociation of RNA polymerase II, p300, Oct4, Sox2, and Tet1 from the Nanog proximal promoter region and with no increase in repressive histone methylation marks or DNA methylation, implying the gene repression is in the early and transient phase. Furthermore, addition of a specific FGFR inhibitor readily reversed this Nanog repression status. These findings illustrate well how FGFR2 induces rapid but reversible Nanog repression within ES cells.
Departments of Pathology, University of Florida College of Medicine, Gainesville, FL 32610, USA.
Katherine E
KE
Santostefano
Takashi
T
Hamazaki
Carolina E
CE
Pardo
Michael P
MP
Kladde
Naohiro
N
Terada
D000818:Animals; D002460:Cell Line; D019175:DNA Methylation / Q000502:physiology; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D004707:Endoderm / Q000166:cytology / Q000196:embryology; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000502:physiology*; D051379:Mice; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization / Q000502:physiology*; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism; D051497:Receptor, Fibroblast Growth Factor, Type 2 / Q000235:genetics / Q000378:metabolism*; D055748:SOXB1 Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology*
D018398:Homeodomain Proteins; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse; C496354:Fgfr2 protein, mouse; D051497:Receptor, Fibroblast Growth Factor, Type 2; D012319:RNA Polymerase II