title: The c-Ha-ras oncogene and a tumor promoter activate the polyoma virus enhancer.
abstract: A c-Ha-ras oncogene, to a lesser extent the c-Ha-ras proto-oncogene, and the tumor promoter 12-O-tetradecanoylphorbol-13-acetate activate the inactive polyoma virus (Py) enhancer in a myeloma cell line and the partially active Py enhancer in NIH 3T3 fibroblasts, but have no effect on the active Py enhancer in LMTK- fibroblasts. In addition, c-Ha-ras can stimulate the inactive Py enhancer in embryonal carcinoma F9 cells. c-Ha-ras activation in embryonal carcinoma cells does not appear to involve reversal of "E1A-like" inhibition of the enhancer. We suggest that modulation of cellular enhancer activity could play a key role in tumorigenesis by oncogenes.
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D054278:Embryonal Carcinoma Stem Cells; D004742:Enhancer Elements, Genetic / Q000187:drug effects; D005809:Genes, Regulator / Q000187:drug effects; D051379:Mice; D014411:Neoplastic Stem Cells; D009857:Oncogenes; D011120:Polyomavirus / Q000235:genetics*; D011519:Proto-Oncogenes; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014162:Transfection
chemical_list: D013755:Tetradecanoylphorbol Acetate