Naslov
Mismatch repair in the antimutator Escherichia coli mud

Autori
Džidić, Senka ; Petranović, Mirjana

Izvornik
Mutation research. Fundamental and molecular mechanisms of mutagenesis (1386-1964) 522 (2003), 1-2; 27-32

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
E. coli; lambda heteroduplex DNA; antimutator; mismatch repair

Sažetak
Antimutators are genetic mutants that produce mutations at reduced rates compared to the wild type strain. They are interesting because they can provide insights into the mechanisms by which spontaneous mutations occur. We have investigated a reported antimutator strain of Escherichia coli termed mud for its possible mechnism. The mud strain exhibits a decrease in both spontaneous mutagenesis and mutability with alkylated agenses and base analogs. These types of DNA lesions are known to be the substrates for E.coli metyl-directed mismatch repair encoded by the mutHLSU system. We investigated whether the putative antimutator effect results from the increased expression or activity of the mutHLSU system. To directly measure the mismatch repair capacity of mud cells, we have transfected them with phage l heteroduplexes and scored the fraction of mixed ( unpaired) infective centers. This transfection system has been used routinely to assay mismatch repair capacity in E. coli and other organisms. No difference between mud and wild type cells is observed. From the results of the experiments we conclude that the reported antimutator effect of mud does not result from enhanced mismatch repair capacity. This conclusion is cosistent with recently published evidence that the mud effect does not represent a real antimutator effect, but is an artifact due to impaire growth of mud under

Izvorni jezik
Engleski

Znanstvena područja
Biologija

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