Bragonzi Alessandra, Wiehlmann Lutz, Klockgether Jens, Cramer Nina, Worlitzsch Dieter, Döring Gerd, Tümmler Burkhard
Institute for Experimental Treatment of Cystic Fibrosis, DIBIT - HS Raffaele, Milano, Italy.
Institute of Medical Microbiology and Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany.
Microbiology (Reading). 2006 Nov;152(Pt 11):3261-3269. doi: 10.1099/mic.0.29175-0.
The mucA gene of the muc operon, which is instrumental in the control of the biosynthesis of the exopolysaccharide alginate, is a hotspot of mutation in Pseudomonas aeruginosa, a micro-organism that chronically colonizes the airways of individuals with cystic fibrosis (CF). The mucA, mucB and mucD genes were sequenced in nine environmental isolates from aquatic habitats, and in 37 P. aeruginosa strains isolated from 10 patients with CF, at onset or at a late stage of chronic airway colonization, in order to elucidate whether there was any association between mutation and background genotype. The 61 identified single nucleotide polymorphisms (SNPs) segregated into 18 mucABD genotypes. Acquired and de novo stop mucA mutations were present in 14 isolates (38 %) of five mucABD genotypes. DeltaG430 was the most frequent and recurrent mucA mutation detected in four genotypes. The classification of strains by mucABD genotype was generally concordant with that by genome-wide SpeI fragment pattern or multilocus SNP genotypes. The exceptions point to intragenic mosaicism and interclonal recombination as major forces for intraclonal evolution at the mucABD locus.
muc操纵子的mucA基因在胞外多糖藻酸盐生物合成的控制中起重要作用，它是铜绿假单胞菌中的一个突变热点，铜绿假单胞菌是一种长期定植于囊性纤维化（CF）患者气道的微生物。对来自水生栖息地的9株环境分离株以及从10例CF患者中分离出的37株铜绿假单胞菌菌株（在慢性气道定植的起始阶段或晚期）的mucA、mucB和mucD基因进行测序，以阐明突变与背景基因型之间是否存在关联。鉴定出的61个单核苷酸多态性（SNP）分为18种mucABD基因型。在5种mucABD基因型的14株分离株（38%）中存在获得性和新生的mucA终止突变。DeltaG430是在4种基因型中检测到的最常见和反复出现的mucA突变。按mucABD基因型对菌株进行的分类通常与按全基因组SpeI片段模式或多位点SNP基因型进行的分类一致。例外情况表明基因内镶嵌现象和克隆间重组是mucABD位点克隆内进化的主要驱动力。
