Transcriptional regulation of human Oct4 by steroidogenic factor‐1

Abstract

Oct4 encodes a transcription factor that is involved in the maintenance of self-renewal in stem cells. Recently, the molecular mechanisms that regulate Oct4 expression have come under investigation. In this study, we demonstrate that the orphan nuclear receptor steroidogenic factor-1 (SF-1) behaves as a transcriptional activator of human Oct4 (hOct4) through direct interaction with a SF-1 binding element in the hOct4 proximal promoter. We found that Oct4 and SF-1 were co-expressed in undifferentiated human embryonal carcinoma NCCIT cells and downregulated during retinoic acid-mediated differentiation. We examined the functional role played by SF-1 in regulation of hOct4 transcription using a luciferase reporter assay and Western blot analysis. Overexpression of SF-1 increased up to about threefold hOct4 promoter activity and endogenous hOct4 protein expression. Sequence analysis of the hOct4 promoter revealed that the transcriptional activity was closely linked to Conserved Regions 1 (CR1) and 2 (CR2), which contain three putative SF-1-binding sites (1st, 2nd, and 3rd SF-1). Binding assays and mutagenesis of binding sites indicated that the 1st and 2nd SF-1 elements (in CR1 and CR2, respectively) might be important cis-regulatory elements in hOct4 promoter activity. However, differences in response to SF-1 overexpression between wild-type and mutant hOct4 promoters revealed that the 1st SF-1 element is the key binding site for SF-1-mediated transcriptional activation. Thus, our data indicate that SF-1 plays a crucial role in the regulation of hOct4 transcription through direct binding to the 1st SF-1 in CR1 of the hOct4 proximal promoter.

Differential Expression of ETS Family Transcription Factors in NCCIT Human Embryonic Carcinoma Cells upon Retinoic Acid-Induced Differentiation

“…Previously, we showed that OCT4 expression is repressed during RA-mediated differentiation in NCCIT cells. 24,25) Indeed, OCT4 expression was significantly downregulated in RA-treated NCCIT cells, confirming that the cells differentiated (Fig. 1B).…”

Rapid and efficient reprogramming of somatic cells to induced pluripotent stem cells by retinoic acid receptor gamma and liver receptor homolog 1

“…However, among these loci, the Oct4 locus was the only one shared between the two species, suggesting functional significance of this element. Indeed, recent experimental evidence also supports a possible role for RAREoct in regulating Oct4 expression in human cells (29).…”

Models of human core transcriptional regulatory circuitries

“…ZIC3 directly activates Nanog expression in mouse ESCs (mESCs) and can contribute to reprogramming of human fibroblasts into an induced pluripotent state (Lim et al 2007;Declercq et al 2013). NR5A1 (also known as SF1) and RARG can influence the pluripotent state (Guo and Smith 2010;Wang et al 2011), and both bind to regulatory regions of the POU5F1 gene and regulate its expression (Barnea and Bergman 2000;Yang et al 2007;Guo and Smith 2010). The other three TFs-MYB, RORA, and SOX21-are best known for their roles in other stem cells.…”