Larbig Karen D, Christmann Andreas, Johann André, Klockgether Jens, Hartsch Thomas, Merkl Rainer, Wiehlmann Lutz, Fritz Hans-Joachim, Tümmler Burkhard
Klinische Forschergruppe, Medizinische Hochschule Hannover, Hannover, Germany.
J Bacteriol. 2002 Dec;184(23):6665-80. doi: 10.1128/JB.184.23.6665-6680.2002.
Intraclonal genome diversity of Pseudomonas aeruginosa was studied in one of the most diverse mosaic regions of the P. aeruginosa chromosome. The ca. 110-kb large hypervariable region located near the lipH gene in two members of the predominant P. aeruginosa clone C, strain C and strain SG17M, was sequenced. In both strains the region consists of an individual strain-specific gene island of 111 (strain C) or 106 (SG17M) open reading frames (ORFs) and of a 7-kb stretch of clone C-specific sequence of 9 ORFs. The gene islands are integrated into conserved tRNA(Gly) genes and have a bipartite structure. The first part adjacent to the tRNA gene consists of strain-specific ORFs encoding metabolic functions and transporters, the majority of which have homologs of known function in other eubacteria, such as hemophores, cytochrome c biosynthesis, or mercury resistance. The second part is made up mostly of ORFs of yet-unknown function. Forty-seven of these ORFs are mutual homologs with a pairwise amino acid sequence identity of 35 to 88% and are arranged in the same order in the two gene islands. We hypothesize that this novel type of gene island derives from mobile elements which, upon integration, endow the recipient with strain-specific metabolic properties, thus possibly conferring on it a selective advantage in its specific habitat.
在铜绿假单胞菌染色体最多样化的镶嵌区域之一中研究了铜绿假单胞菌的克隆内基因组多样性。对主要的铜绿假单胞菌克隆C的两个成员菌株C和菌株SG17M中位于lipH基因附近的约110 kb大的高变区进行了测序。在这两个菌株中，该区域由一个包含111个（菌株C）或106个（SG17M）开放阅读框（ORF）的个体菌株特异性基因岛和一段由9个ORF组成的7 kb克隆C特异性序列组成。基因岛整合到保守的tRNA（Gly）基因中，具有二分结构。与tRNA基因相邻的第一部分由编码代谢功能和转运蛋白的菌株特异性ORF组成，其中大多数在其他真细菌中具有已知功能的同源物，如运铁蛋白、细胞色素c生物合成或汞抗性。第二部分主要由功能未知的ORF组成。这些ORF中有47个是相互同源物，其成对氨基酸序列同一性为35%至88%，并以相同顺序排列在两个基因岛中。我们假设这种新型基因岛源自移动元件，这些元件在整合后赋予受体菌株特异性代谢特性，从而可能使其在其特定栖息地中具有选择优势。
