GENETIC ANALYSIS OF MUTATIONS INDIRECTLY SUPPRESSING recB AND recC MUTATIONS

[摘要] Mutations in sbcB inactivate exonuclease I and suppress the UV-sensitive, mitomycin-sensitive, recombination-deficient phenotypes associated with recB and recC mutations. Mapping experiments have located sbcB about 0.4 minutes from the his operon at 38.0 on the standard map of E. coli . This places sbcB between supD and his . A four-point cross shows that sbcB lies between P2 attH and his . P2 eduction deleting the his operon beginning with P2 attH also deletes sbcB and produces the expected exonuclease I deficiency and suppression of recB -. The occurrence of chemical-mutagen-induced and spontaneous mutations indirectly suppressing recB - and recC - is examined. Three lines of strains produce only sbcA mutations while only sbcB mutations occur in a fourth line. Explanations for this behavior are proposed in light of the ability of the first three lines to express sbcB mutations which they inherit by transduction.

[学科分类] 医学（综合）