ROLE OF MUTAGENIC DNA POLYMERASES IN THE MUTAGENESIS OF LasR IN Pseudomonas aeruginosa

FIGUEROA E; SMANIA AM; LUJAN AM

Paraná

Congreso; LIV Reunión Anual de la Sociedad Argentina de Bioquímica y Biología Molecular; 2018

Pseudomonas aeruginosa (PA) causes chronic airway infections (CAI) in cystic fibrosis (CF) patients by unique strains, which persist duringtheir total life-span. PA bases its strategy on a process of genetic adaptation that underlies the characteristic phenotypic diversification processthat favors its marked persistence. This diversification usually involves point mutations in specific genes, so the control of the mutation rateconstitutes a key factor associated with the persistence of the infection. Under environmental stress conditions, such as chronic infections, stressresponse mechanisms are induced in order to survive. Part of this response involves the induction of mutagenic DNA polymerases, which lackprof-reading activity and consequently increase mutation rates. PA possesses at least three of these DNA polymerases: Pol IV, ImuB and DnaE2,however little is known about their participation in PA diversification processes. Here, we evaluate the involvement of these Pols in themutagenesis of a key gene for the adaptation of PA during CAI, lasR. By performing in vitro diversification assays using Pols mutant strains wedetermined that neither of the Pols were involved in lasR mutagenesis since the emergence of lasRvariants were similar to the parental strain. Ithas been reported that the action of this Pols could be DNA strand specific. We investigated this possibility by measuring the mutagenesis in agene that was in an opposite location to lasR: rpoB. Results obtained showed that Pol IV was involved in rpoB but not lasR, suggesting that theaction of this Pol is gene specific.