Very-Short-Patch Repair in Escherichia coli Requires the dam Adenine Methylase

AUTOR(ES)

Bell, Derek C.

FONTE

American Society for Microbiology

RESUMO

Strains of Escherichia coli which lack the dam-encoded adenine methylase are mutators due to a reduction in the efficiency of postreplication mismatch repair. In this study, we show that Dam− strains are also defective in very-short-patch repair, the system which corrects T/G mismatches arising from the deamination of 5-methylcytosine. This defect is associated with decreased levels of Vsr, the endonuclease which initiates short-patch repair. We also show that production of the dcm-encoded cytosine methylase is unaffected in Dam− strains. Since the dcm and vsr genes are cotranscribed, the regulation of Vsr by Dam is probably posttranscriptional.

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