Interplay of the liver-enriched trans-acting factors, DBP and HNF1, in the transactivation of human IGFBP-1 promoter.
In the liver, expression of insulin-like growth factor binding protein-1 (IGFBP-1) is regulated essentially at the transcriptional level, at least in part by HNF1. In this study, the functional role of DBP and C/EBP (which have several potential binding sites on the IGFBP-1 proximal promoter) have been investigated. Transient co-transfection of the reporter plasmid, pBP-1341 and eukaryotic expression vectors which code for DBP and C/EBP in human cell lines Hep3B, HepG2 and C33 showed that IGFBP-1 promoter activity was unchanged by C/EBP, but increased between 2 and 7 times by DBP (depending on the cell line). In addition, DBP and HNF1 were capable of functional co-operation in activating the IGFBP-1 promoter. Our results support the notion of DBP being involved in limited tissue specificity of IGFBP-1 expression.
Babajko
S
S
Unité de Recherches sur la Régulation de la Croissance, Institut National de la Santé et de la Recherche Médicale U.142, Hôpital Saint-Antoine, Paris, France.
Groyer
A
A
D022762:CCAAT-Enhancer-Binding Proteins; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics*; D002584:Cervix Uteri / Q000166:cytology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D051537:Hepatocyte Nuclear Factor 1; D051538:Hepatocyte Nuclear Factor 1-alpha; D051539:Hepatocyte Nuclear Factor 1-beta; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1; D008099:Liver / Q000166:cytology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured
D022762:CCAAT-Enhancer-Binding Proteins; D002352:Carrier Proteins; C063898:DBP protein, human; D004268:DNA-Binding Proteins; C496487:HNF1A protein, human; C496495:HNF1B protein, human; D051538:Hepatocyte Nuclear Factor 1-alpha; D018970:Insulin-Like Growth Factor Binding Protein 1; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014157:Transcription Factors; D051537:Hepatocyte Nuclear Factor 1; D051539:Hepatocyte Nuclear Factor 1-beta