Biochemical characterization of the human placental transcription factor GCMa/1.
Glial cells missing (GCM) proteins are a novel family of zinc-containing transcription factors. Human GCMa/1 is primarily expressed in placental trophoblast cells and regulates SYNCYTIN gene expression, which mediates fusion of cytotrophoblasts to form the syncytiotrophoblast layer of the human placenta. To biochemically characterize the transcriptional activity of GCMa/1, we set up an in vitro transcription system for human GCMa/1 (hGCMa/1). Using G-free reporter constructs carrying multiple copies of wild-type or mutant GCMa-binding site (GBS) in front of a synthetic TATA box, we observed specific transcriptional activities of recombinant hGCMa/1 proteins prepared from a baculovirus--insect cell or Escherichia coli expression system. We further characterized GCMa/1-mediated transcriptional activation on the native syncytin promoter. Using G-free reporter constructs containing the native syncytin promoter, a TATA box downstream of the proximal GBS in the syncytin promoter was shown to be essential for the transcription activation directed by hGCMa/1. Therefore, our results demonstrate positive transcriptional activities of GCMa/1 in vitro and provide a better understanding of GCMa/1-mediated SYNCYTIN gene expression.
Lin
Chenchen
C
Graduate Institute of Biochemical Sciences, National Taiwan University, Taipei.
Lin
Meiyao
M
Chen
Hungwen
H
D001665:Binding Sites; D004268:DNA-Binding Proteins; D005786:Gene Expression Regulation; D015686:Gene Products, env / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins; D010920:Placenta / Q000378:metabolism; D011257:Pregnancy Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D016385:TATA Box / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D014158:Transcription, Genetic; D015533:Transcriptional Activation / Q000235:genetics*
D004268:DNA-Binding Proteins; C491089:GCM1 protein, human; D015686:Gene Products, env; D009479:Neuropeptides; D009687:Nuclear Proteins; D011257:Pregnancy Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C405335:syncytin