Modulation of transcription of the platelet-derived growth factor A-chain gene by a promoter region sensitive to S1 nuclease.
Homodimers of the platelet-derived growth factor (PDGF) A-chain are strong mitogens for cells of mesenchymal origin. Differences in the levels of expression of the PDGF A-chain gene have been reported in both normal and transformed cell lines, suggesting that transcription of the PDGF A-chain gene is highly regulated. We have now identified two S1-hypersensitive sites which flank a 13-base pair oligo(dG).oligo(dC) sequence located 70-82 base pairs upstream of the transcription initiation site. Three lines of evidence suggest that these S1-sensitive sites contribute to optimum promoter activity. Nuclear protein(s) binding to these sites were detected in gel mobility shift assays. Deletion of the S1-sensitive sites results in a 2-3-fold decrease in the transcriptional activity and eliminated sensitivity to S1 nuclease. Deletions in the oligo(dG).oligo(dC) motif also eliminated sensitivity to S1 and resulted in a 2.5-fold decrease of the promoter activity in the stable transfection assays. The results suggest that the highly G+C-rich region in the PDGF A-chain gene promoter locally induces the formation of non-B-form DNA under torsional stress which appears to be important in the transcriptional regulation of the PDGF A-chain gene in vivo.
Wang
Z
Z
Department of Medicine, Jewish Hospital, Washington University Medical Center, St. Louis, Missouri 63110.
Lin
X H
XH
Qiu
Q Q
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Deuel
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TF
D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000378:metabolism; D005091:Exons; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D010957:Plasmids; D010982:Platelet-Derived Growth Factor / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015183:Restriction Mapping; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000378:metabolism*; D013379:Substrate Specificity; D016385:TATA Box; D014158:Transcription, Genetic
D046911:Macromolecular Substances; D015345:Oligonucleotide Probes; D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; D004247:DNA; D015719:Single-Strand Specific DNA and RNA Endonucleases