title: The effects of neighboring bases on N-methyl-N-nitrosourea alkylation of DNA.
abstract: Calf thymus DNA and the synthetic polynucleotides of defined sequence, poly(dG).poly(dC) and poly(dG-dC).poly(dG-dC) were reacted with N-methyl-N-nitrosourea (MNU) and the amounts of 7-methylguanine (7-MG) and O6-methylguanine (O6-MG) determined. It was found that the O6-MG/7-MG ratio for DNA was 0.13, for poly(dG).poly(dC) was 0.10, and for poly(dG-dC).poly(dG-dC) was 0.21. From these data, it is evident that the neighboring bases affect the alkylation pattern of guanine by MNU, a finding that can have significant relevance in defining 'hot spots' of alkylation in the genome which may be important in the processes of mutagenesis and carcinogenesis.
mesh_terms: D000478:Alkylation; D000818:Animals; D002417:Cattle; D004247:DNA; D006147:Guanine / Q000031:analogs & derivatives / Q000032:analysis; D008770:Methylnitrosourea; D009607:Nitrosourea Compounds; D011089:Polydeoxyribonucleotides; D013329:Structure-Activity Relationship; D013950:Thymus Gland
chemical_list: D009607:Nitrosourea Compounds; D011089:Polydeoxyribonucleotides; C019530:poly(dC-dG); D006147:Guanine; C008450:7-methylguanine; D008770:Methylnitrosourea; D004247:DNA; C008449:O-(6)-methylguanine