Naslov
Effects of ruv and recG mutations on lambda prophage thermoinducibility in UV-irradiated Escherichia coli

Autori
Vlahović, Ksenija ; Petranović, Mirjana ; Zahradka, Davor ; Petranović, Dragutin

Izvornik
Periodicum biologorum (0031-5362) 100 (1998), 3; 383-388

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Escherichia coli; lambda prophage; DNA recombination; recombinational DNA repair; ruv genes; recG gene; Holliday junctions

Sažetak
Background and purpose: Our previous results showed that thermoinducible mutant of lambda prophage progressively lost its thermoinducibility when kept for up to 5 hours in the chromosome of E. coli cells dying after gamma- or UV-irradiation. The inactivation process was shown to depend on the functional recA and recB gene products. These gene products are known to be involved in the early phases of DNA recombination and recombinational repair. In the present work, the studies of the inactivation process are extended to bacterial hosts carrying mutations in ruvA, ruvB, ruvC or recG genes. The products of these genes are known to participate in a later phase of recombination and recombinational repair named the processing of Holliday junctions. The aim of this work was to determine whether the ruv and recG gene products were involved in the post-UV loss of prophage thermoinducibility. Material and methods: E. coli strains carrying mutations in ruvA, ruvB, ruvC, recG or ruvC recG genes were used. They were lysogenized with the thermoinducible phage mutant lambda cIts857ind1. Lysogenic bacteria were irradiated with UV and incubated for up to 5 hours at 30°C. At the intervals during postirradiation incubation samples were plated for colonies and plaques. Colony-forming ability was determined by incubating the plates overnight at 30°C. Plaque-forming ability of the thermoinducible prophage was determined by incubating the plates for 1 hour at 42°C and subsequent night at 37°C. Results: The ruvA, ruvB, ruvC, recG and ruvC recG mutants exhibited the loss of prophage thermoinducibility at much reduced rate compared to the wild-type cells. The products of these genes are obviously involved in the radiation-induced process leading to the loss of prophage thermoinducibility. Conclusion: Taken together, our previous and present results suggest that the processing of Holliday junctions (mediated by RuvA, RuvB, RuvC and/or RecG) during unsuccessful RecBCD-dependent recombinational repair of cell chromosome gives some products which may prevent the site-specific recombination responsible for the excision of prophage from bacterial chromosome.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA