title: [Substrate of a UV-induced repair system providing for W-reactivation of lambda phage].
abstract: Escherichia coli uvrA, polA and uvrD cells carrying non-UV-inducible prophage lambdac1857ind- were infected with 3H-thymidine labelled homoimmune phage lambdac1857, and the effect of UV-irradiation of super-infecting phage and lysogenic bacterial cells on the content of intracellular covalently-closed lambda DNA circles (cccDNA) and pyrimidine dimer content in lambda DNA are studied. UV-irradiation of host cells results in two-fold increase of relative content of cccDNA of UV-irradiated phage lambda in uvrD mutant, while there is no such an effect in uvrA and polA mutants. In UV-irradiated or intact uvrA lysogens cccDNA molecules, forming after the infection with UV-irradiated phage lambda, contain pyrimidine dimers, but in uvrD mutant cccDNA in free of dimers. The data indicate that the repair system induced by UV-irradiation of uvrA and polA cells acts exclusively on the DNA defects appearing after (or in the course) of phage genomes replication. UV-inducible repair system in uvrD mutant can operate also on some intermediates of abortive excision repair, possibly on long single straided excision gaps.
mesh_terms: D003090:Coliphages / Q000528:radiation effects*; D004260:DNA Repair; D004270:DNA, Circular; D004279:DNA, Viral; D008242:Lysogeny; D014466:Ultraviolet Rays
chemical_list: D004270:DNA, Circular; D004279:DNA, Viral
vernacular_title: O substrate UF-indutsiruemoĭ reparatsionnoĭ sistemy, obespechivaiushcheĭ W-reaktivatsiiu faga lambda