title: Reduced DNA repair in mouse satellite DNA after treatment with methylmethanesulfonate, and N-methyl-N-nitrosourea.
abstract: We have measured DNA repair in mouse satellite and main band DNA as resolved by Ag+-Cs2SO4 centrifugation in response to treatment with the alkylating agents, methyl methanesulfonate, and N-methyl-N-nitrosourea. We find that there is a statistically significant lower incorporation of 3H-Tdr into the satellite DNA as compared to the main band at varying periods after treatment with the alkylating agents. This suggests a reduced repair activity in the satellite DNA. We have measured the extent of binding of 14C-methyl methanesulfonate to the satellite, and main band DNA, and no difference in binding was observed, indicating that the reduced repair activity of satellite DNA is not due to a difference in binding of alkylating agents. We believe that the reduced incorporation of 3H-Tdr into satellite DNA may be due to its location in the condensed chromatin fraction.
mesh_terms: D000818:Animals; D004247:DNA / Q000378:metabolism*; D004260:DNA Repair / Q000187:drug effects*; D004261:DNA Replication / Q000187:drug effects; D004276:DNA, Satellite / Q000378:metabolism*; D005260:Female; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000378:metabolism*; D008698:Mesylates / Q000494:pharmacology*; D008741:Methyl Methanesulfonate / Q000494:pharmacology*; D008770:Methylnitrosourea / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009607:Nitrosourea Compounds / Q000494:pharmacology*; D011247:Pregnancy
chemical_list: D004276:DNA, Satellite; D008698:Mesylates; D009607:Nitrosourea Compounds; D008770:Methylnitrosourea; D004247:DNA; D008741:Methyl Methanesulfonate