The Influence of DNA Repair by Ogt Alkyltransferase on the Distribution of Alkylnitrosourea-Induced Mutations in Escherichia coli

✍ Scribed by Antonio Vidal; Nieves Abril; Carmen Pueyo

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 144 KB
• Volume: 29
• Category: Article
• ISSN: 0893-6692
• DOI: 10.1002/(sici)1098-2280(1997)29:2<180::aid-em9>3.0.co;2-i

✦ Synopsis

To determine the influence of DNA repair by Ogt alkyltransferase. The Ogt protein appears more efalkyltransferase on the distribution of alkylnitro-ficient at repairing O 6 -ethylguanine lesions, which sourea-induced mutations, we have analysed in are flanked 5 by a G or C, in agreement with pre-Ogt-proficient and Ogt-deficient bacterial strains viously reported data from our group for ethylmeththe DNA sequence changes of a total of 357 inde-ane sulfonate. In contrast, no preference could be pendent mutations occurring within the initial part inferred for the repair of O 6 -methylguanine lesions of the lacI gene of Escherichia coli. The majority by Ogt protein. These results seem to indicate that (ú80%) of mutations induced by either N-ethyl-Nthe preference of the Ogt alkyltransferase to repair nitrosourea (ENU) or N-methyl-N-nitrosourea (MNU) certain DNA sequences might be a function of the in the two genetic backgrounds were G:C r A:T size of the alkyl group. The importance of the alkyl transitions, consistent with the predominant role of group length has been described also at the level the O 6 -alkylguanine miscoding lesion in mutagene-of the (A)BC excinuclease machinery that seems to sis by alkylating agents. The analysis of the distribu-have a DNA sequence specificity opposite to that tion of G:C r A:T transitions induced by ENU in of Ogt alkyltransferase. Environ. Mol. Mutagen. Ogt / and Ogt 0 bacteria reveals an influence of the 29:180-188, 1997 ᭧ 1997 Wiley-Liss, Inc. 5-flanking base at the level of repair by Ogt