Id2 is a primary partner for the E2-2 basic helix-loop-helix transcription factor in the human placenta.
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.
Liu
Yi-Ping
YP
Wisconsin National Primate Research Center and the Department of Obstetrics and Gynecology, University of Wisconsin Medical School, Madison, WI 53715, USA.
Burleigh
David
D
Durning
Maureen
M
Hudson
Lori
L
Chiu
Ing-Ming
IM
Golos
Thaddeus G
TG
D002478:Cells, Cultured; D002822:Choriocarcinoma / Q000378:metabolism / Q000473:pathology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015723:Gene Library; D015292:Glycoprotein Hormones, alpha Subunit / Q000235:genetics; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D051797:Inhibitor of Differentiation Protein 2; D008156:Luciferases / Q000378:metabolism; D010920:Placenta / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000235:genetics*; D021122:Protein Subunits; D012097:Repressor Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D051820:TCF Transcription Factors; D058118:Transcription Factor 7-Like 2 Protein; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection; D014327:Trophoblasts / Q000378:metabolism / Q000473:pathology; D020798:Two-Hybrid System Techniques
D004268:DNA-Binding Proteins; D015292:Glycoprotein Hormones, alpha Subunit; C497450:ID2 protein, human; D051797:Inhibitor of Differentiation Protein 2; D021122:Protein Subunits; D012097:Repressor Proteins; D051820:TCF Transcription Factors; C544894:TCF7L2 protein, human; D058118:Transcription Factor 7-Like 2 Protein; D014157:Transcription Factors; D008156:Luciferases