Isolation and genetic properties of a bacteriophage T4 uvsX mutant

A technique for isolating UV-sensitive mutants of bacteriophage T4 and a relatively simple method for localizing the UV-sensitive mutations on the genetic map are described. Of 13 mutants isolated 5 were shown to be den V mutants and 1 was shown to be a uvsX mutant. Of the remainder, 4 are probably uvsX mutants (based on their map location) while the indentity of the remaining 3 has not been determined. The uvsX mutant (uvsX102) had enhanced UV and gamma-ray sensitivity compared to the only other well characterized mutant in this gene, uvsX1 (T4x). Both uvsX1 and uvxX102 were more UV-sensitivity when plated on the su- E. coli B hosts, B and S/6, compared to the su+ K12 host CR63, and both reduced the frequency of recombination to the same extent (2--3-fold). The uvsX gene is located between gene 41 and beta gt.