Effect of ogt expression on mutation induction by methyl-, ethyl- and propylmethanesulphonate in Escherichia coli K12 strains.
AffiliationDepartamento de Genética, Facultad de Ciencias, Universidad de Córdoba, España.
MetadataShow full item record
AbstractWe have previously reported the isolation of an Escherichia coli K12 mutant that is extremely sensitive to mutagenesis by low doses of ethylating agents. We now show by Southern analysis that the mutation involves a gross deletion covering at least the ogt and fnr genes and that no O6-alkylguanine-DNA-alkyltransferase activity is present in cell-free extracts of an ada::Tn10 derivative of these bacteria. Confirmation that sensitisation to ethylation-induced mutagenesis was attributable to ogt and not to any other loci covered by the deletion was obtained by constructing derivatives. Thus an ogt::kanr disruption mutation was introduced into the parental ogt+ bacteria, and the ogt::kanr mutation was then eliminated by cotransduction of ogt+ with the closely linked Tetr marker (zcj::Tn10). The delta(ogt-fnr) deletion or ogt::kanr disruption mutants were highly sensitive to ethyl methanesulphonate-induced mutagenesis, as measured by the induction of forward mutations to L-arabinose resistance (Arar). Furthermore, the number of Arar mutants increased linearly with dose, unlike the case in ogt+ bacteria, which had a threshold dose below which no mutants accumulated. Differences in mutability were even greater with propyl methanesulphonate. Overproduction of the ogt alkyltransferase from a multicopy plasmid reduced ethylmethanesulphonate-induced mutagenesis in the ogt- mutant strains and also methylmethanesulphonate mutagenesis in ada- bacteria. A sample of AB1157 obtained from the E. coli K12 genetic stock centre also had a deletion covering the ogt and fnr genes. Since such deletions greatly influence the mutagenic responses to alkylating agents, a survey of the presence of the ogt gene in the E. coli K12 strain being used is advisable.
CitationEffect of ogt expression on mutation induction by methyl-, ethyl- and propylmethanesulphonate in Escherichia coli K12 strains. 1994, 242 (6):744-8 Mol. Gen. Genet.
JournalMolecular & General Genetics
- Mutagenesis and DNA repair for alkylation damages in Escherichia coli K-12.
- Authors: Abril N, Roldán-Arjona T, Prieto-Alamo MJ, van Zeeland AA, Pueyo C
- Issue date: 1992
- Increased spontaneous mutation and alkylation sensitivity of Escherichia coli strains lacking the ogt O6-methylguanine DNA repair methyltransferase.
- Authors: Rebeck GW, Samson L
- Issue date: 1991 Mar
- Expression of the ogt gene in wild-type and ada mutants of E. coli.
- Authors: Potter PM, Kleibl K, Cawkwell L, Margison GP
- Issue date: 1989 Oct 25
- Influence of DNA repair by (A)BC excinuclease and Ogt alkyltransferase on the distribution of mutations induced by n-propyl-N-nitrosourea in Escherichia coli.
- Authors: Ferrezuelo F, Prieto-Alamo MJ, Jurado J, Pueyo C
- Issue date: 1998
- ogt alkyltransferase enhances dibromoalkane mutagenicity in excision repair-deficient Escherichia coli K-12.
- Authors: Abril N, Luque-Romero FL, Prieto-Alamo MJ, Margison GP, Pueyo C
- Issue date: 1995 Feb