The ultraviolet-sensitizing function of plasmid R391 interferes with a late step of postreplication repair in Escherichia coli.
The conjugative plasmid R391 increases the UV radiation sensitivity of wild-type, uvrA, and lexA cells of Escherichia coli, but not recA strains. To investigate the UV-sensitizing function of R391, we examined the effect of R391 on the repair of DNA daughter-strand gaps and on the UV radiation sensitivities of various repair and/or recombination-deficient mutants. The presence of R391 did not significantly inhibit the repair of DNA daughter-strand gaps in uvrB cells. The presence of R391 increased the UV radiation sensitivity of uvrA, uvrA recF, uvrB, uvrB recF, uvrB recB, and uvrB ssb-113 cells to UV irradiation, but did not significantly increase the UV radiation sensitivity of uvrA ruvA and uvrA ruvC strains. Based on these results, we propose that the UV-sensitizing activity of R391 acts by inhibiting or interfering with the ruvABC-mediated postsynapsis step of recombinational repair.
Wang
T C
TC
Department of Molecular Biology, Chang Gung College of Medicine and Technology, Kwei-San, Tao-Yuan, Taiwan.
de Saint Phalle
B
B
Millman
K L
KL
Fowler
R G
RG
D003227:Conjugation, Genetic; D004260:DNA Repair / Q000528:radiation effects; D004261:DNA Replication; D004307:Dose-Response Relationship, Radiation; D004926:Escherichia coli / Q000235:genetics* / Q000528:radiation effects; D005838:Genotype; D011815:R Factors; D011995:Recombination, Genetic; D014466:Ultraviolet Rays