Oct4 and Sox2 Directly Regulate Expression of Another Pluripotency Transcription Factor, Zfp206, in Embryonic Stem Cells

Zheng-Xu Wang,Christina Hui-Leng Teh,Jacqueline L.L Kueh,Thomas Lufkin,Paul Robson,Lawrence W Stanton

doi:10.1074/jbc.m611814200

Abstract

It is well known that Oct4 and Sox2 play an important role in the maintenance of embryonic stem cell pluripotency. These transcription factors bind to regulatory regions within hundreds of target genes to control their expression. Zfp206 is a recently characterized transcription factor that has a role in maintaining stem cell pluripotency. We have demonstrated here that Zfp206 is a direct downstream target of Oct4 and Sox2. Two composite sox-oct binding sites have been identified within the first intron of Zfp206. We have demonstrated binding of Oct4 and Sox2 to this region. In addition, we have shown that Oct4 or Sox2 alone can activate transcription via one of these sox-oct elements, although the presence of both Oct4 and Sox2 gave rise to a synergistic effect. These studies extend our understanding of the transcriptional network that operates to regulate the differentiation potential of embryonic stem cells.

Highlights

Embryonic stem cells (ESCs)2 are derived from the inner cell mass of the blastocyst and exhibit both pluripotency and selfrenewing capabilities
Expression of Zfp206 Is Regulated by Oct4 and Sox2—A recent report [14] and our own data3 have identified Zfp206 as a transcription factor that plays a key role in maintaining the pluripotency of ESCs
When mouse ESCs were transfected with gene-specific small inhibitory RNA (siRNA) against Nanog, Oct4, and Sox2, a 50% knockdown of expression was observed 1 day after transfection and a 70 –90% reduction of the targeted gene was observed at day 5 (Fig. 1)

Summary

Introduction

Embryonic stem cells (ESCs) are derived from the inner cell mass of the blastocyst and exhibit both pluripotency and selfrenewing capabilities. Two structures for a POU1⁄7HMG ternary complex bound to composite sox-oct motifs have been solved, revealing that that the POU and HMG domains are capable of mediating specific proteinprotein and DNA-protein interactions [20, 21] This finding reinforces the importance of Oct and Sox at the top of the hierarchy in the maintenance of pluripotency in ESCs. Based on previous chromatin immunoprecipitation experiments, two Oct and two Sox binding sites were found on the Zfp206 genomic locus [12]. We have established that Oct and Sox are direct regulators of Zfp206 expression These results position Zfp206 within the transcriptional regulatory network that maintains pluripotency and controls the differentiation of ESCs

Methods

Results

Conclusion