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

MONTI MR; MIGUEL V; BORGOÑO MV; ARGARAÑA CE

DNA REPAIR

ELSEVIER SCIENCE BV

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-B clamp interaction in Pseudomonas aeruginosa by characterizing a B clamp binding motif mutant, denominated MutSB,  which  does not interact with the replication factor. A detailed characterization of P. aeruginosa strain PAO1 harboring a chromosomal mutSB  allele demonstrated that this mutant strain  exhibited mutation rates to rifampicin and ciprofloxacin resistance comparable to that of the parental strain. mutSB  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 mutSB  strains exhibited similar reversion rates. Our results clearly indicate that the MutS-B clamp interaction does not  have a central role in the methylation-independent Mismatch Repair of P. aeruginosa.