MutS deficiency and activity of the error-prone DNA polymerase IV are crucial for determining mucA as the main target for mucoid conversion in Pseudomonas aeruginosa

MOYANO A.J.,; LUJÁN A.; ARGARAÑA C.E.,; SMANIA A. M.

MOLECULAR MICROBIOLOGY

Blackwell

Año: 2007 vol. 64 p. 547 - 547

0950-382X

seudomonas aeruginosa colonizes the respiratory tract of cystic fibrosis (CF) patients, where mutators along with mucoid variants emerge leading to chronic infection. Mucoid conversion generally involves mutations inactivating the mucA gene. This study correlates the frequency and nature of mucA mutations with the activity of factors determining the mutation rate, such as MutS and polymerase IV (Pol IV). Results show that: (i) the emergence frequency of mucoid variants was higher in isolates arising from mutS populations compared with the wild-type strain; (ii) in both strains mucoid conversion occurred mainly by mucA mutations; (iii) however, the mutator strain harboured mostly mucA22 (a common allele in CF isolates), while the wild type showed a wider spectrum of mucA mutations with low incidence of mucA22; (iv) disruption of dinB in the wild-type and mutS strains decreased drastically the emergence frequency of mucoid variants; (v) furthermore, the incidence of mucA mutations