Adaptive response of Escherichia coli to alkylation damage
Treatment of cells with low levels of alkylating agents for extended periods of time causes them to become resistant to the lethal and mutagenic effects of subsequent high-level challenge treatments with alkylating agents. This increased resistance has been called the adaptive response to alkylation damage and results from the induction of an alkylation-specific DNA repair response. The adaptive response is most efficiently induced by methylating agents and is most effective against the lethal and mutagenic effects of methylation damage to DNA. Four genes have been identified as components of this response, ada, alkA, alkB and aidB. The functions of two of these genes are known. AlkA protein functions as a glycosylase that repairs N/sup 3/-meA, N/sup 3/-meG, O/sup 2/meT, and O/sup 2/-meC residues in DNA, and Ada protein functions as an alkyltransferase that removes alkyl groups from O/sup 6/-meG, O/sup 4/-meT residues as well as methylphosphotriesters. After it interacts with methylated DNA, Ada protein functions as a positive regulatory element that controls the expression of the adaptive response by stimulating the expression of the ada-alkB operon, and the alkA and aidB genes.
- Research Organization:
- Univ. of Massachusetts Medical School, Worcester (USA)
- OSTI ID:
- 6855755
- Journal Information:
- Environ. Mol. Mutagen.; (United States), Vol. 11:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALKYLATING AGENTS
BIOLOGICAL EFFECTS
ESCHERICHIA COLI
DNA REPAIR
GENES
GLYCOSYL HYDROLASES
NITROSO COMPOUNDS
TRANSFERASES
BACTERIA
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
ENZYMES
HYDROLASES
MICROORGANISMS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
RECOVERY
REPAIR
560300* - Chemicals Metabolism & Toxicology