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Differential suppressor effects of the ssb‐1 and ssb‐113 alleles on uvrD mutator of Escherichia coli in DNA repair and mutagenesis
Author(s) -
Quiñones Ariel,
Piechocki Reinhard
Publication year - 1987
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.3620270508
Subject(s) - mutant , mutagenesis , biology , allele , dna repair , microbiology and biotechnology , genetics , helicase , dna , homologous recombination , recbcd , dna mismatch repair , mutation , escherichia coli , gene , rna
We have constructed double mutants carrying eithre ssb‐1 or ssb‐113 alleles, which encode emperature‐sensitive single strand DNA binding proteins (SSB), and the uvrD :: Tn5 allele causing deficiency in DNA helicase II, and have examined sensitivity to ultraviolet light (UV), recombination and spontaneous as well as UV‐induced mutagenesis. We have found in a recA + background that (i) none of the ssb uvrD double mutants was more sensitive to UV than either single mutant; (ii) the ssb‐1 allel partially suppressed the strong UV sensitivity of uvrD :: Tn5 mutants; (iii) in the recA730 background with constitutive SOS expression, the ssb‐1 and ssb‐113 alleles suprpessed the strong UV‐sensitivity caused by the uvrD :: Tn5 mutantion; (iv) in ssb‐113 mutants, the level of recombination was reduced only 10‐fold but 100‐fold in ssb‐1 mutants, showing the there was no correlation ebtween the DNA repair deficiency and the recombination deficiency; (v) the hyper‐recombination phenotype of the uvrD :: Tn5 mutant was suppressed by the addition of either the ssb‐1 or the ssb‐113 allel: (vi) no addition of the spontaneous mutatior effects promoted by the uvrD :: Tn5 and the ssb‐113 alleles was observed. These results suggest a possible functional interactions between SSB and Helicase II in DNA repair and mutagenesis.