title: Indirect ultraviolet-reactivation of phage lambda.
abstract: When an F(-) recipient Escherichia coli K12 bacterium receives Hfr or F-lac(+) DNA from an ultraviolet-irradiated donor, its capacity to promote DNA repair and mutagenesis of ultraviolet-damaged phage lambda is substantially increased. We call this phenomenon indirect ultraviolet-reactivation, since its features are essentially the same as those of ultraviolet-reactivation; this repair process occurs in pyrimidine dimer excision-deficient strains and produces clear plaque mutations of the restored phage. Moreover, this process is similar to indirect ultraviolet-induction of prophage lambda, since it is promoted by conjugation. However, contrarily to indirect induction, it is produced by Hfr donors and occurs in recipients restricting the incoming ultraviolet-damaged donor DNA. The occurrence of indirect ultraviolet-reactivation provides evidence for the existence in E. coli of an inducible error-prone mechanism for the repair of DNA.
mesh_terms: D003090:Coliphages / Q000254:growth & development / Q000528:radiation effects*; D003227:Conjugation, Genetic; D004260:DNA Repair / Q000528:radiation effects*; D004279:DNA, Viral / Q000096:biosynthesis / Q000528:radiation effects*; D004926:Escherichia coli / Q000378:metabolism*; D008242:Lysogeny; D009154:Mutation / Q000528:radiation effects; D014466:Ultraviolet Rays; D010948:Viral Plaque Assay
chemical_list: D004279:DNA, Viral