UMMS Affiliation

Department of Biochemistry and Molecular Pharmacology

Publication Date


Document Type



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.

DOI of Published Version



Nucleic Acids Res. 1987 Oct 26;15(20):8205-15. Link to article on publisher's website

Journal/Book/Conference Title

Nucleic acids research

Related Resources

Link to Article in PubMed

PubMed ID