title: Role of SF-1 and DAX-1 during differentiation of P19 cells by retinoic acid.
abstract: Retinoic acid (RA) is critical for embryonic development and cellular differentiation. Previous work in our laboratory has shown that blocking the RA-dependent increase in pre-β cell leukemia transcription factors (PBX) mRNA and protein levels in P19 cells prevents endodermal and neuronal differentiation. Dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1 (DAX-1) and steroidogenic factor (SF-1) were found by microarray analysis to be regulated by PBX in P19 cells. To determine the roles of DAX-1 and SF-1 during RA-dependent differentiation, P19 cells that inducibly express either FLAG-DAX-1 or FLAG-SF-1 were prepared. Unexpectedly, overexpression of DAX-1 had no effect on the RA-induced differentiation of P19 cells to either endodermal or neuronal cells. However, SF-1 overexpression prevented the RA-dependent loss of OCT-4, DAX-1 and the increase in COUP-TFI, COUP-TFII, and ETS-1 mRNA levels during the commitment stages of both endodermal and neuronal differentiation. Surprisingly, continued expression of SF-1 for 7 days caused the RA-independent loss of OCT-4 protein and RA-dependent loss of SSEA-1 expression. Despite the loss of well-characterized pluripotency markers, these cells did not terminally differentiate into either endodermal or neuronal cells. Instead, the cells gained the expression of many steroidogenic enzymes with a pattern consistent with adrenal cells. Finally, we found evidence for a feedback loop in which PBX reduces SF-1 mRNA levels while continued SF-1 expression blocks the RA-dependent increase in PBX levels. Taken together, these data demonstrate that SF-1 plays a dynamic role during the differentiation of P19 cells and potentially during early embryogenesis.
authors.affiliation: Department of Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.
authors.forename: Bryan W
authors.initials: BW
authors.lastname: Teets
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Soprano
authors.forename: Dianne Robert
authors.initials: DR
authors.lastname: Soprano
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D045744:Cell Line, Tumor; D057137:DAX-1 Orphan Nuclear Receptor / Q000235:genetics / Q000378:metabolism*; D047108:Embryonic Development / Q000187:drug effects / Q000502:physiology; D053595:Embryonic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004707:Endoderm / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D050814:Octamer Transcription Factor-3 / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D054339:Steroidogenic Factor 1 / Q000235:genetics / Q000378:metabolism*; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D057137:DAX-1 Orphan Nuclear Receptor; C539966:Nr0b1 protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D012333:RNA, Messenger; D011994:Recombinant Proteins; D054339:Steroidogenic Factor 1; D014212:Tretinoin