title: Two distinct enhancers with different cell specificities coexist in the regulatory region of polyoma.
abstract: Two distinct nonoverlapping enhancer elements can be defined within the polyoma enhancer region. In mouse fibroblasts, element A provides a 3-fold higher enhancement of the alpha 2-collagen promoter than element B. In mouse embryonal carcinoma cells, element B shows the same efficiency as in fibroblasts, whereas that of element A decreases by a factor of 3.5. Moreover, a single point mutation (PyEC F9.1) increases the efficiency of element B in both cell types, making it superior to element A in embryonal carcinoma cells. The core of element A is located within a 35 bp region tandem duplicated in several wild-type strains, mostly homologous to a crucial repeated sequence of adenovirus E1a enhancer (Hearing and Shenk, 1983). Element B contains the consensus sequence of Weiher et al. (1982). These two homologies are precisely adjacent to the two DNAase l-hypersensitive sites present in viral chromatin.
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002478:Cells, Cultured; D004262:DNA Restriction Enzymes; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D005796:Genes; D005809:Genes, Regulator; D005814:Genes, Viral; D051379:Mice; D008815:Mice, Inbred Strains; D010957:Plasmids; D011120:Polyomavirus / Q000235:genetics*; D013539:Simian virus 40 / Q000235:genetics; D013724:Teratoma; D014158:Transcription, Genetic; D014162:Transfection; D001616:beta-Galactosidase / Q000235:genetics
chemical_list: D004262:DNA Restriction Enzymes; D001616:beta-Galactosidase