Functional analysis of the interaction between the mismatch repair protein MutS and the replication processivity factor â clamp in Pseudomonas aeruginosa

MONTI MARIELA R.*; MIGUEL VIRGINIA; BORGOGNO MARÍA VICTORIA; ARGARAÑA CARLOS E.*; *AUTORES RESPONSABLES

DNA REPAIR

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2012 vol. 11 p. 463 - 469

1568-7864

Interaction between MutS and the replication factor b clamp has been extensively studied in a Mismatch Repair context; however, its functional consequences are not well understood. We have analyzed the role of the MutS- clamp interaction in Pseudomonas aeruginosa by characterizing a  clamp binding motif mutant, denominated MutS, which does not interact with the replication factor. A detailed characterization of P. aeruginosa strain PAO1 harboring a chromosomal mutS allele demonstrated that this mutant strain exhibited mutation rates to rifampicin and ciprofloxacin resistance comparable to that of the parental strain. mutS PAO1 was as proficient as the parental strain for DNA repair under highly mutagenic conditions imposed by the adenine base analogue 2-aminopurine. In addition, using a tetracycline resistance reversion assay to assess the repair of a frameshift mutation, we determined that the parental and mutS strains exhibited similar reversion rates. Our results clearly indicate that the MutS- clamp interaction does not have a central role in the methylation-independent Mismatch Repair of P. aeruginosa.