Functional analysis of two Sp1/Sp3 binding sites in murine Nanog gene promoter

<正> Nanog gene plays a key role in maintaining pluripotency of ES cells and early embryonic cells.A 5' flank sequenceof the Nanog gene has been reported to be regulated differentially,and two regulatory elements within the Nanog pro-moter,namely Oct-4 and Sox-2 binding sites,have been identified to regulate the transcriptional activity ofNanog gene.In this report,we identified the role of two putative Sp 1 binding sites located in the Nanog gene 5'-flanking region inregulation of murine Nanog gene transcription.Mutation studies showed that the two sites were essential for the Nanogpromoter activity.Gel shift and supershift analysis showed that both sites specifically bind Spl and Sp3.Furthermore,overexpression of dominant-negative Sp 1 or Sp3 mutants significantly inhibits Nanog promoter activity.These resultssuggest that the transcription factor Spl and Sp3 are important for Murine Nanog gene expression.