Some mismatch repair activities in Escherichia coli.

Abstract
Heterozygous bacteriophage .lambda. DNa molecules, whose replication requires mismatch correction of a mutant nucleotide in the transcribed strand, provide an assay for localized mismatch repair in Escherichia coli. We described two systems: one removes the A in C .cntdot. A or G .cntdot. A mismatches and the other removes one or the other C in a C .cntdot. C mismatch. Mutations disabling the first system result in a mutator phenotype that may be identical to mutY.