Large non-homology in heteroduplex DNA is processed differently than single base pair mismatches.
Unmethylated DNA heteroduplexes with a large single stranded loop in one strand have been prepared from separated strands of DNA from two different strains of bacteriophage lambda, one of which has a approximately 800 base pair IS1 insertion in the cI gene. The results of transfections with these heteroduplexes into wild-type and mismatch repair deficient bacteria indicate that such large non-homologies are not repaired by the Escherichia coli mismatch repair system. However, the results do suggest that some process can act to repair such large non-homologies in heteroduplex DNA. Transfections of a series of recombination and excision repair deficient mutants suggest that known excision or recombination repair systems of E. coli are not responsible for the repair. Repair of large non-homologies may play a role in gene conversion involving large insertion or deletion mutations.
Dohet
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Dzidić
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Wagner
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Radman
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M
D001482:Base Composition; D001483:Base Sequence; D003090:Coliphages / Q000235:genetics; D004260:DNA Repair; D004269:DNA, Bacterial / Q000235:genetics*; D009154:Mutation; D009692:Nucleic Acid Heteroduplexes / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D014162:Transfection
D004269:DNA, Bacterial; D009692:Nucleic Acid Heteroduplexes