Functional analysis of cis-acting DNA sequences controlling transcription of the human type I collagen genes.
The 3500-base pair region located immediately upstream of the transcriptional start site of the human pro-alpha 2(I) collagen gene contains all the sequences necessary for cell-specific transcription. In transient expression assays, the pro-alpha 2(I) collagen promoter directed the production of high levels of bacterial chloramphenicol acetyltransferase in collagen-producing human fetal fibroblasts. Enzyme activity, on the other hand, was nearly undetectable in extracts from collagen-nonproducing immortalized lymphoblasts. Deletion experiments narrowed the active segment of the human promoter to a phylogenetically conserved sequence comprised between nucleotides-376 and -108, relative to the initiation site of transcription. In similar analyses, the pro-alpha 1(I) collagen gene failed to direct cell-specific transcription. As part of this study, the controversial issue surrounding the putative enhancer element in the first intron of the human pro-alpha 1(I) collagen gene also has been reconsidered. Accordingly, we now propose a more restricted definition of this cis-acting DNA element since its action is exerted in an orientation-preferred manner and with a strong specificity for its own promoter. Moreover, stimulation does not appear to be tissue-specific. Finally, evidence is presented supporting the notion that although structurally different and distinctly arranged, the regulatory sequences of the type I collagen genes may bind similar trans-acting factors.
Boast
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Department of Microbiology and Immunology, Morse Institute of Molecular Genetics, State University of New York Health Science Center, Brooklyn 11203.
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Ramirez
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Sanchez
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Avvedimento
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EV
D002460:Cell Line; D002872:Chromosome Deletion; D003094:Collagen / Q000235:genetics*; D004247:DNA / Q000235:genetics*; D004742:Enhancer Elements, Genetic; D005333:Fetus; D005796:Genes; D006801:Humans; D007438:Introns; D011347:Procollagen / Q000235:genetics*; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic; D014162:Transfection
D011347:Procollagen; D003094:Collagen; D004247:DNA