Inducible binding of a factor to the c-fos enhancer.
We have identified a factor in nuclear extracts that binds to the c-fos enhancer. Treatment of A431 cells with epidermal growth factor results in a rapid increase in the level of transcription and a concomitant increase in binding of the factor to the enhancer. Surprisingly, as transcription decreases rapidly, the enhancer-binding activity remains elevated. In addition, although HeLa cells exhibit no detectable transcription of the c-fos gene, they contain significant amounts of binding activity, comparable to those in induced A431 cells. These results suggest that regulation of c-fos transcription involves more than simply an increased level of a factor capable of binding the enhancer. Finally, transcription of c-fos in A431 cells is markedly induced by the tumor promoter TPA and the calcium ionophore A23187, yet neither induced an increased level of the enhancer-binding activity. These agents thus appear to activate c-fos transcription via a mechanism distinct from that used by epidermal growth factors.
D002118:Calcium / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell; D002460:Cell Line; D004273:DNA, Neoplasm / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005809:Genes, Regulator; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D009363:Neoplasm Proteins / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016760:Proto-Oncogene Proteins c-fos; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic
D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D004815:Epidermal Growth Factor; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium