A Tcf/Lef element within the enhancer region of the human NANOG gene plays a role in promoter activation

Biochem Biophys Res Commun. 2011 Jul 8;410(3):637-42. doi: 10.1016/j.bbrc.2011.06.044. Epub 2011 Jun 13.

Abstract

NANOG is a homeodomain-containing transcription factor that is essential for the maintenance of pluripotency and self-renewal in embryonic stem cells. However, the molecular mechanisms underlying the regulation of NANOG expression in human cells remain largely unknown. Here, we investigated the role of Tcf/Lef response elements located in the enhancer of the human NANOG gene. We found that forced expression of Lef1 or β-catenin stimulated human NANOG promoter activity, while shRNA-mediated knockdown of β-catenin reduced Lef1-induced NANOG promoter activation. Deletion or mutation of the Tcf/Lef element within the enhancer region of the human NANOG gene completely abrogated Lef1-induced NANOG promoter activity. The results of a chromatin immunoprecipitation assay demonstrated that Lef1 and β-catenin bind to the Tcf/Lef element in the enhancer region of the NANOG gene. Forced expression of GSK-3β inhibited basal, Lef1-induced, and β-catenin-induced NANOG promoter activity, while treatment with the GSK-3β inhibitor SB216763 resulted in the accumulation of β-catenin and NANOG protein. Furthermore, Dvl-1-induced NANOG promoter activity was abrogated by the expression of β-catenin shRNA. Stable overexpression of Dvl-1 caused β-catenin and NANOG to accumulate. These results indicate that the Tcf/Lef response element in the enhancer region of the human NANOG gene is able to stimulate NANOG gene transcription.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Dishevelled Proteins
  • Enhancer Elements, Genetic*
  • Genes, Reporter
  • Glycogen Synthase Kinase 3 / metabolism
  • Glycogen Synthase Kinase 3 beta
  • HEK293 Cells
  • Homeodomain Proteins / genetics*
  • Humans
  • Lymphoid Enhancer-Binding Factor 1 / metabolism
  • Nanog Homeobox Protein
  • Phosphoproteins / metabolism
  • Promoter Regions, Genetic*
  • TCF Transcription Factors / metabolism*
  • Transcription, Genetic
  • Transcriptional Activation
  • beta Catenin / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • DVL1 protein, human
  • Dishevelled Proteins
  • Homeodomain Proteins
  • LEF1 protein, human
  • Lymphoid Enhancer-Binding Factor 1
  • NANOG protein, human
  • Nanog Homeobox Protein
  • Phosphoproteins
  • TCF Transcription Factors
  • beta Catenin
  • GSK3B protein, human
  • Glycogen Synthase Kinase 3 beta
  • Glycogen Synthase Kinase 3