Loss of an apurinic/apyrimidinic site endonuclease increases the mutagencity of N-methyl-N'-nitro-N-nitrosoguanidine to Escherichia coli
xthA/sup -/ Escherichia coli, which are missing a major cellular apurinic/apyrimidinic (AP) endonuclease, are 5- to 10-fold more sensitive than xthA/sup +/ bacteria to mutagenesis by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) under conditions that induce the adaptive response. The xthA/sup -/-dependent mutations are also dependent on SOS mutagenic processing and consists of both transversion and transition base substitutions. When MNNG-adapted xthA/sup -/ bacteria are challenged with a high dose of MNNG, more xthA/sup -/-dependent SOS-dependent mutations are induced, and transversions are enhanced relative to transitions. The mutations induced by challenge are eliminated in xthA/sup -/ alkA/sup -/ bacteria, which are also deficient for 3-methyladenine glycosylase II activity. these data are consistent with the hypothesis that AP sites, at least some of which are produced by glycosylase activity, are mutagenic intermediates following cellular DNA alkylation.
- Research Organization:
- Boston Univ. School of Medicine, MA
- OSTI ID:
- 5932790
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 84:9
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DNA REPAIR
BIOCHEMISTRY
NITROSO COMPOUNDS
GENETIC EFFECTS
ALKYLATION
DNA
ESCHERICHIA COLI
MUTAGENESIS
MUTATION FREQUENCY
MUTATIONS
NUCLEASES
REVERTANTS
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CHEMICAL REACTIONS
CHEMISTRY
ENZYMES
ESTERASES
HYDROLASES
MICROORGANISMS
MUTANTS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOSPHODIESTERASES
RECOVERY
REPAIR
560300* - Chemicals Metabolism & Toxicology