title: Different mutations in mucA gene of Pseudomonas aeruginosa mucoid strains in cystic fibrosis patients and their effect on algU gene expression.
abstract: Alginate biosynthesis in Pseudomonas aeruginosa is a highly regulated process in which algU and mucA genes are key elements. Mutations in mucA gene determine alginate operon overexpression and exopolysaccharide overproduction. In our study, 119 strains of P. aeruginosa were isolated from sputa of 96 cystic fibrosis patients and 84/119 showed nonmucoid phenotype, while 35/119 showed mucoid phenotypes. mucA gene was amplified and sequenced in all strains revealing mutations in 29/35 mucoid strains (82%) and in one non-mucoid strain. 4/29 strains showed mutations never described that generated premature stop and much shorter MucA proteins. In all mutated strains, algU gene expression was analyzed to determine if mutations in mucA, resulting in a strong loss of its protein, could significantly influence its function and subsequently the biosynthetic pathways under algU control. Analysis of algU expression disclosed that the length significantly affects the expression of genes involved in the production of alginate and in the motility and hence survival of P. aeruginosa strains in cystic fibrosis lungs.
authors: Department of Molecular and Cellular Biology and Pathology, University of Naples, Federico II, Naples, Italy. giovannapulcrano@libero.it
authors: Giovanna
authors: G
authors: Pulcrano
authors: Dora Vita
authors: DV
authors: Iula
authors: Valeria
authors: V
authors: Raia
authors: Fabio
authors: F
authors: Rossano
authors: Maria Rosaria
authors: MR
authors: Catania
mesh_terms: D000464:Alginates / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D003550:Cystic Fibrosis / Q000382:microbiology* / Q000473:pathology; D004269:DNA, Bacterial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D020723:Glucuronic Acid / Q000235:genetics / Q000378:metabolism; D006603:Hexuronic Acids / Q000378:metabolism; D006801:Humans; D008124:Locomotion; D008168:Lung / Q000382:microbiology / Q000473:pathology; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D013183:Sputum / Q000382:microbiology
chemical_list: C079619:AlgU protein, Pseudomonas aeruginosa; D000464:Alginates; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D006603:Hexuronic Acids; C107895:MucA protein, Pseudomonas; D012808:Sigma Factor; D020723:Glucuronic Acid