Department of Biochemistry and Molecular Pharmacology
Codon; *DNA Repair; DNA Replication; Escherichia coli; *Genes, Bacterial; *Mutation; Tetracycline Resistance
Life Sciences | Medicine and Health Sciences
The Dam-directed post-replicative mismatch repair system of Escherichia coli removes base pair mismatches from DNA. The products of the mutH, mutL and mutS genes, among others, are required for efficient mismatch repair. Absence of any of these gene products leads to persistence of mismatches in DNA with a resultant increase in spontaneous mutation rate. To determine the specificity of the mismatch repair system in vivo we have isolated and characterized 47 independent mutations from a mutH strain in the plasmid borne mnt repressor gene. The major class of mutations comprises AT to GC transitions that occur within six base pairs of the only two 5'-GATC-3' sequences in the mnt gene. In the wild type control strain, insertion of the IS1 element was the major spontaneous mutational event. A prediction of the Dam-directed mismatch repair model, that the mutation spectra of dam and mutH strains should be the same, was confirmed.
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Originally published: Nucleic Acids Res. 1987 Oct 26;15(20):8205-15. Link to article on publisher's website
DOI of Published Version
Nucleic acids research
Rewinski, Caroline and Marinus, Martin G., "Mutation spectrum in Escherichia coli DNA mismatch repair deficient (mutH) strain" (1987). Open Access Articles. 1717.