ROLE OF MUTAGENIC DNA POLYMERASES IN THE MUTAGENESIS OF LasRIN Pseudomonas

FIGUEROA, ESTHER; SMANIA, ANDREA M; LUJAN, ADELA M

Paraná

Congreso; LIV Reunion Anual de la Sociedad Argentina de Investigacion de Bioquimica y Biologia Molecular; 2018

Sociedad Argentina de Investigacion de Bioquimica y Biologia Molecular (SAIB)

Pseudomonas aeruginosa (PA) causes chronic airway infections (CAI) in cystic fibrosis (CF) patients by unique strains, which persist during their total life-span. PA bases its strategy on a process of genetic adaptation that underlies the characteristic phenotypic diversification process that favors its marked persistence. This diversification usually involves point mutations in specific genes, so the control of the mutation rate constitutes a key factor associated with the persistence of the infection. Under environmental stress conditions, such as chronic infections, stress response mechanisms are induced in order to survive. Part of this response involves the induction of mutagenic DNA polymerases, which lack prof-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 the mutagenesis of a key gene for the adaptation of PA during CAI, lasR. By performing in vitro diversification assays using Pols mutant strains we determined that neither of the Pols were involved in lasR mutagenesis since the emergence of lasRvariants were similar to the parental strain. It has been reported that the action of this Pols could be DNA strand specific. We investigated this possibility by measuring the mutagenesis in a gene that was in a opposite location to lasR: rpoB. Results obtained showed that Pol IV was involved in rpoB but not lasR, suggesting that the action of this Pol is gene specific.