Due to its minor groove selectivity, Me-lex preferentially generates N3-methyladenine (3-MeA) adducts in double-stranded DNA. We undertook a genetic approach in yeast to establish the influence of base excision repair (BER) defects on the processing of Me-lex lesions on plasmid DNA that harbors the p53 cDNA as target. We constructed a panel of isogenic strains containing a reporter gene to test p53 function and the following gene deletions: deltamag1, deltaapn1apn2, and deltaapn1apn2mag1. When compared with the wild-type strain, a decrease in survival was observed in deltamag1, deltaapn1apn2, and deltaapn1apn2mag1. The Me-lex-induced mutation frequency increased in the following order: wild type < deltamag1< deltaapn1apn2 = deltaapn1apn2mag1. A total of 77 mutants (23 in wild type, 31 in deltamag1, and 23 in deltaapn1apn2) were sequenced. Eighty-one independent mutations (24 in wild type, 34 in deltamag1, and 23 in deltaapn1apn2) were detected. The majority of base pair substitutions were AT-targeted in all strains (14/23, 61% in wild type; 20/34, 59%, in deltamag1; and 14/23, 61%, in deltaapn1apn2). The Mag1 deletion was associated with a significant decrease of GC > AT transitions when compared with both the wild-type and the AP endonuclease mutants. This is the first time that the impact of Mag1 and/or AP endonuclease defects on the mutational spectra caused by 3-MeA has been determined. The results suggest that 3-MeA is critical for Me-lex cytotoxicity and that its mutagenicity is slightly elevated in the absence of Mag1 glycosylase activity but significantly higher in the absence of AP endonuclease activity.

Influences of base excision repair defects on the lethality and mutagenicity induced by Me-lex, a sequence-selective N3-adenine methylating agent / Monti, P.; Campomenosi, P.; Ciribilli, Y.; Iannone, R.; Inga, A.; Shah, D.; Scott, G.; Burns, P. A.; Menichini, P.; Abbondandolo, A.; Gold, B.; Fronza, G.. - In: THE JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 0021-9258. - 277:32(2002), pp. 28663-28668. [10.1074/jbc.M203384200]

Influences of base excision repair defects on the lethality and mutagenicity induced by Me-lex, a sequence-selective N3-adenine methylating agent

Monti P.;Ciribilli Y.;Inga A.;
2002-01-01

Abstract

Due to its minor groove selectivity, Me-lex preferentially generates N3-methyladenine (3-MeA) adducts in double-stranded DNA. We undertook a genetic approach in yeast to establish the influence of base excision repair (BER) defects on the processing of Me-lex lesions on plasmid DNA that harbors the p53 cDNA as target. We constructed a panel of isogenic strains containing a reporter gene to test p53 function and the following gene deletions: deltamag1, deltaapn1apn2, and deltaapn1apn2mag1. When compared with the wild-type strain, a decrease in survival was observed in deltamag1, deltaapn1apn2, and deltaapn1apn2mag1. The Me-lex-induced mutation frequency increased in the following order: wild type < deltamag1< deltaapn1apn2 = deltaapn1apn2mag1. A total of 77 mutants (23 in wild type, 31 in deltamag1, and 23 in deltaapn1apn2) were sequenced. Eighty-one independent mutations (24 in wild type, 34 in deltamag1, and 23 in deltaapn1apn2) were detected. The majority of base pair substitutions were AT-targeted in all strains (14/23, 61% in wild type; 20/34, 59%, in deltamag1; and 14/23, 61%, in deltaapn1apn2). The Mag1 deletion was associated with a significant decrease of GC > AT transitions when compared with both the wild-type and the AP endonuclease mutants. This is the first time that the impact of Mag1 and/or AP endonuclease defects on the mutational spectra caused by 3-MeA has been determined. The results suggest that 3-MeA is critical for Me-lex cytotoxicity and that its mutagenicity is slightly elevated in the absence of Mag1 glycosylase activity but significantly higher in the absence of AP endonuclease activity.
2002
32
Monti, P.; Campomenosi, P.; Ciribilli, Y.; Iannone, R.; Inga, A.; Shah, D.; Scott, G.; Burns, P. A.; Menichini, P.; Abbondandolo, A.; Gold, B.; Fronza...espandi
Influences of base excision repair defects on the lethality and mutagenicity induced by Me-lex, a sequence-selective N3-adenine methylating agent / Monti, P.; Campomenosi, P.; Ciribilli, Y.; Iannone, R.; Inga, A.; Shah, D.; Scott, G.; Burns, P. A.; Menichini, P.; Abbondandolo, A.; Gold, B.; Fronza, G.. - In: THE JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 0021-9258. - 277:32(2002), pp. 28663-28668. [10.1074/jbc.M203384200]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/282074
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