title: Bleomycin-induced DNA synthesis in a cell-free system using a permeable mouse sarcoma cell extract.
abstract: To investigate factors involved in excision repair DNA synthesis, a soluble extract was prepared from permeable mouse sarcoma (SR-C3H/He) cells by homogenization and ultracentrifugation. DNA synthesis measured by using native calf thymus DNA as the template-primer and the extract as the polymerase source showed low activity. The DNA synthesis was enhanced more than ten-fold by the addition of an appropriate concentration of bleomycin, a radiomimetic DNA-damaging drug. Using selective inhibitors of DNA polymerases, it was shown that the DNA polymerase involved in the bleomycin-induced DNA synthesis was DNA polymerase beta. In addition to DNA polymerase beta, an exonuclease which converts bleomycin-damaged DNA into suitable template-primers for repair DNA synthesis appeared to be present in the permeable cell extract.
mesh_terms: D000818:Animals; D001761:Bleomycin / Q000494:pharmacology*; D002457:Cell Extracts; D002474:Cell-Free System / Q000187:drug effects; D004247:DNA / Q000096:biosynthesis*; D004256:DNA Polymerase I / Q000378:metabolism; D004260:DNA Repair / Q000187:drug effects*; D051379:Mice; D012513:Sarcoma, Experimental / Q000201:enzymology / Q000378:metabolism*
chemical_list: D002457:Cell Extracts; D001761:Bleomycin; D004247:DNA; D004256:DNA Polymerase I