Human SP1 but not human AP1 binding to the TGF-beta element in the 5' flanking region of the rat PROalpha1(I) collagen gene.
The consensus TGF-beta element (TGCCCACGGCCAG) located at approximately -161Obp from the start site of transcription of the rat pro alpha1(I) collagen gene has recently been shown to be required for the basal promoter activity of this gene (Meisler et al., J. Cell Biochem. 75: 196, 1999). Site directed mutation of this TGF-beta element resulted in almost complete abolishment of the basal promoter activity of the fibroblasts transfected with the 3.6 ColCat plasmid which contains a 3.6 kb portion of the 5' flanking region of the rat pro alpha1(I) collagen gene linked to the reporter gene, chloramphenicol acetyltransferase (CAT). Southwestern analysis of the nuclear protein binding to the TGF-beta element revealed a 34,000 Da complex while after UV-crosslinking, studies revealed a TGF-beta element nuclear protein complex of 82,000 Da (Ritzenthaler et al., J. Biol. Chem. 268: 13625, 1993). Thus, a multiple protein TGF-beta DNA element complex may exist which may promote the transcription of the rat pro alpha1(I) collagen gene. Since literature findings indicate that a nuclear factor interacts with an SP1-like binding site of the human pro alpha1(I) collagen promoter and an AP-1 binding sequence has been shown to be involved in the regulation of the human pro alpha2(I) collagen gene and both these binding sequences are TGF-beta1 responsive, we determined whether the TGF-beta element located in the 5' flanking region of the rat pro alpha1(I) collagen gene formed complexes with either of these nuclear factors or both.
Department of Biochemistry, College of Medicine, University of Vermont, Burlington 05405, USA. kenneth.cutroneo@uvm.edu
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D020121:5' Untranslated Regions; D000818:Animals; D001761:Bleomycin / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D017930:Genes, Reporter; D006801:Humans; D011347:Procollagen / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D011485:Protein Binding; D051381:Rats; D020218:Response Elements / Q000187:drug effects / Q000235:genetics*; D016329:Sp1 Transcription Factor / Q000378:metabolism* / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000378:metabolism / Q000494:pharmacology; D015291:Transforming Growth Factors / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology
D020121:5' Untranslated Regions; D011347:Procollagen; D016329:Sp1 Transcription Factor; D018808:Transcription Factor AP-1; D001761:Bleomycin; D015291:Transforming Growth Factors