REPAIR IN ESCHERICHIA-COLI ALKB MUTANTS OF ABASIC SITES AND 3-METHYLADENINE RESIDUES IN DNA

Escherichia coli alkB mutants an sensitive to methyl methanesulfonate and dimethylsulphate, and are defective in the processing of methylate d DNA, The function of the AlkB protein has not been determined, Here we show that alkB mutants are not defective in repairing several diffe rent types of potentially toxic DNA lesions that are known to be gener ated by MMS, including apyrimidinic and apurinic sites, and secondary lesions that could arise at these sites (DNA-protein cross-links and D NA interstrand cross-links). Also, alkB mutants were not sensitive to MeOSO2-(CH2)(2)-Lex, a compound that alkylates the minor groove of DNA generating primarily 3-methyladenine. (C) 1998 Elsevier Science B.V.