GENETIC CONTROL OF NEAR-UV SENSITIVITY INDEPENDENT OF EXCISION DEFICIENCY (uvrA6) IN ESCHERICHIA COLI K12

By appropriate matings, recombinant strains carrying all four possible combinations of genes controlling near-UV (nur vs nur⁺) and far-UV (uvrA6 vs uvrA⁺, excision repair function) sensitivity have been constructed. Near and far-UV inactivation experiments with the four recombinant strains reveal that inactivating events induced by near and far-UV do not appear to overlap. These results are analogous to our previously reported experiments (Tuveson and Jonas, 1979) with recombinant strains carrying all four possible combinations of genes controlling near-UV sensitivity (nur vs nur⁺) and recombination proficiency (far-UV sensitivity, recA1 vs recA⁺). The results of these two sets of experiments taken together may mean that any recA⁺ or uvrA⁺ repairable lesions induced by near-UV are repaired equally well by either system and do not require the simultaneous participation of both repair systems.