Dax1 binds to Oct3/4 and inhibits its transcriptional activity in embryonic stem cells.
Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of blastocysts. Transcription factor Oct3/4 is an indispensable factor in the self-renewal of ES cells. In this study, we searched for a protein that would interact with Oct3/4 in ES cells and identified an orphan nuclear hormone receptor, Dax1. The association of Dax1 with Oct3/4 was mediated through the POU-specific domain of Oct3/4. Ectopic expression of Dax1 inhibited Oct3/4-mediated activation of an artificial Oct3/4-responsive promoter. Expression of Dax1 in ES cells also reduced the activities of Nanog and Rex1 promoters, while knockdown of Dax1 increased these activities. Pulldown and gel shift assays revealed that the interaction of Dax1 with Oct3/4 abolished the DNA binding activity of Oct3/4. Chromatin immunoprecipitation assay results showed that Dax1 inhibited Oct3/4 binding to the promoter/enhancer regions of Oct3/4 and Nanog. Furthermore, overexpression of Dax1 resulted in ES cell differentiation. Taken together, these data suggest that Dax1, a novel molecule interacting with Oct3/4, functions as a negative regulator of Oct3/4 in ES cells.
Sun
Chuanhai
C
Department of Stem Cell Biology, Graduate School of Medical Science, Kanazawa University, Ishikawa 920-8640, Japan.
Nakatake
Yuhki
Y
Akagi
Tadayuki
T
Ura
Hiroki
H
Matsuda
Takahiko
T
Nishiyama
Akira
A
Koide
Hiroshi
H
Ko
Minoru S H
MS
Niwa
Hitoshi
H
Yokota
Takashi
T
D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D053595:Embryonic Stem Cells / Q000166:cytology / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism*; D018168:Receptors, Retinoic Acid / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C539965:NR0B1 protein, human; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; C539966:Nr0b1 protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D018168:Receptors, Retinoic Acid; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins