Id2 is a primary partner for the E2-2 basic helix-loop-helix transcription factor in the human placenta

Mol Cell Endocrinol. 2004 Jul 30;222(1-2):83-91. doi: 10.1016/j.mce.2004.04.016.


We screened a term placental cDNA library by the yeast two-hybrid approach with Id2, a negative regulator of basic helix-loop-helix (bHLH) factors. Of the clones obtained, approximately one-third were the E2-2 bHLH transcription factor. Id2 and E2-2 were shown to interact in direct two-hybrid assays in yeast cells, as well as immunoprecipitation assays in mammalian cells. Immunohistochemical analysis demonstrated co-localization of both Id2 and E2-2 in placental trophoblasts. Co-transfection of JEG-3 cells with E2-2 and Id2, and a luciferase reporter construct under the control of the human chorionic gonadotropin alpha-subunit promoter revealed that E2-2 had a negative effect on CGalpha-subunit transcription, which could be relieved by overexpression of Id2. The library was in turn rescreened with E2-2, and Id2 and Id1 were essentially the only clones obtained. We conclude that Id2 is a primary binding partner for the bHLH transcription factor E2-2 in the human placenta.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cells, Cultured
  • Choriocarcinoma / metabolism
  • Choriocarcinoma / pathology
  • DNA-Binding Proteins / metabolism*
  • Gene Library
  • Glycoprotein Hormones, alpha Subunit / genetics
  • Helix-Loop-Helix Motifs*
  • Humans
  • Immunoenzyme Techniques
  • Immunoprecipitation
  • Inhibitor of Differentiation Protein 2
  • Luciferases / metabolism
  • Placenta / physiology
  • Promoter Regions, Genetic / genetics*
  • Protein Subunits
  • Repressor Proteins / metabolism*
  • Saccharomyces cerevisiae
  • TCF Transcription Factors
  • Transcription Factor 7-Like 2 Protein
  • Transcription Factors / metabolism*
  • Transfection
  • Trophoblasts / metabolism
  • Trophoblasts / pathology
  • Two-Hybrid System Techniques


  • DNA-Binding Proteins
  • Glycoprotein Hormones, alpha Subunit
  • ID2 protein, human
  • Inhibitor of Differentiation Protein 2
  • Protein Subunits
  • Repressor Proteins
  • TCF Transcription Factors
  • TCF7L2 protein, human
  • Transcription Factor 7-Like 2 Protein
  • Transcription Factors
  • Luciferases