Biology Department, Utah State University, Logan, Utah 84322-5305, USA.
Can J Microbiol. 2012 Jan;58(1):102-11. doi: 10.1139/w11-093. Epub 2011 Dec 21.
Mycobacterium sp. strain KMS utilizes pyrene, a high-molecular weight polycyclic aromatic hydrocarbon (PAH), as a sole carbon source. Bioinformatic analysis of the genome of isolate KMS predicted 25 genes with the potential to encode 17 pyrene-induced proteins identified by proteomics; these genes were clustered on both the chromosome and a circular plasmid. RT-PCR analysis of total RNA isolated from KMS cells grown with or without pyrene showed that the presence of pyrene increased the transcript accumulation of 20 of the predicted chromosome- and plasmid-located genes encoding pyrene-induced proteins. The transcribed genes from both the chromosome and a circular plasmid were within larger regions containing genes required for PAH degradation constituting PAH-degrading gene islands. Genes encoding integrases and transposases were found within and outside the PAH-degrading gene islands. The lower GC content of the genes within the gene island (61%-64%) compared with the average genome content (68%) suggested that these mycobacteria initially acquired these genes by horizontal gene transfer. Synteny was detected for the PAH-degrading islands in the genomes of two additional Mycobacterium isolates from the same PAH-polluted site and of two other pyrene-degrading Mycobacterium from different sites in the United States of America. Consequently, the gene islands have been conserved from a common ancestral strain.
分枝杆菌菌株 KMS 利用芘，一种高分子量的多环芳烃 (PAH)，作为唯一的碳源。对分离株 KMS 的基因组进行生物信息学分析，预测了 25 个具有编码通过蛋白质组学鉴定的 17 种芘诱导蛋白的潜力的基因；这些基因在染色体和一个圆形质粒上都有聚类。从用或不用芘培养的 KMS 细胞中分离的总 RNA 的 RT-PCR 分析表明，芘的存在增加了编码芘诱导蛋白的 20 个预测的染色体和质粒定位基因的转录物积累。来自染色体和圆形质粒的转录基因都位于包含多环芳烃降解所需基因的较大区域内，构成多环芳烃降解基因岛。整合酶和转座酶基因位于多环芳烃降解基因岛内外。与平均基因组含量 (68%) 相比，基因岛内基因的 GC 含量较低（61%-64%），表明这些分枝杆菌最初通过水平基因转移获得了这些基因。在来自同一多环芳烃污染地点的另外两个分枝杆菌分离株的基因组中以及在美国不同地点的另外两个芘降解分枝杆菌的基因组中检测到了 PAH 降解岛的同线性。因此，这些基因岛从共同的祖先菌株中得到了保守。
