MOLECULAR AND FUNCTIONAL-ANALYSIS OF THE RUV REGION OF ESCHERICHIA-COLI K-12 REVEALS 3 GENES INVOLVED IN DNA-REPAIR AND RECOMBINATION

Recombinant plasmids carrying ruvA, ruvB, or both were constructed and used to investigate the genetic defects in a collection of UV-sensitive ruv mutants. The results revealed that efficient survival of UV-irradiated cells depends on both ruvA and ruvB, and on a third gene, ruvC, located upstream of the ruvAB operon. Southern blotting analysis was used to locate insertions in ruv and to examine putative deletion mutants. Two Tn 10 insertions were located to the region encoding ruvA. Since these insertions caused a deficiency in the activities of both ruvA and ruvB, we concluded that they must exert a polar effect on ruvB. Two putative ruv deletion mutants were shown to be the result of deletion-inversion events mediated during imprecise excision of Tn 10. The relevant inversion breakpoints in these mutants were located to ruvA and ruvC. © 1990 Springer-Verlag.