Alginate-regulating genes are identified in the clinical cystic fibrosis isolate of Pseudomonas aeruginosa PA2192 (original) (raw)

ABSTRACTCystic fibrosis (CF) is a genetic disorder that leads to a buildup of mucus in the lungs ideal for bacterial colonization. When Pseudomonas aeruginosa enters the CF lung, it undergoes a conversion from nonmucoid to mucoid; colonization by a mucoid strain of P. aeruginosa greatly increases mortality. The mucoid phenotype is due to the production of alginate. The regulator of alginate production is the AlgT/U sigma factor. The observed phenotypic conversion is due to a mutation in the mucA gene coding for an anti-sigma factor, MucA, which sequesters AlgT/U. This mucoid phenotype is unstable when the strains are removed from the lung as they acquire second-site mutations. This in vitro reversion phenomenon is utilized to identify novel genes regulating alginate production. Previously, second-site mutations were mapped to algT/U, algO, and mucP, demonstrating their role in alginate regulation. Most of these studies were performed using a non-CF isolate. It was hypothesized that ...