Stratmann Janin, Strommenger Birgit, Goethe Ralph, Dohmann Karen, Gerlach Gerald-F, Stevenson Karen, Li Ling-Ling, Zhang Qing, Kapur Vivek, Bull Tim J
Institute for Microbiology, Department of Infectious Diseases, School of Veterinary Medicine, Hannover, Germany.
Infect Immun. 2004 Mar;72(3):1265-74. doi: 10.1128/IAI.72.3.1265-1274.2004.
We have used representational difference analysis to identify a novel Mycobacterium avium subsp. paratuberculosis-specific ABC transporter operon (mpt), which comprises six open reading frames designated mptA to -F and is immediately preceded by two putative Fur boxes. Functional genomics revealed that the mpt operon is flanked on one end by a fep cluster encoding proteins involved in the uptake of Fe(3+) and on the other end by a sid cluster encoding non-ribosome-dependent heterocyclic siderophore synthases. Together these genes form a 38-kb M. avium subsp. paratuberculosis-specific locus flanked by an insertion sequence similar to IS1110. Expression studies using Western blot analyses showed that MptC is present in the envelope fraction of M. avium subsp. paratuberculosis. The MptD protein was shown to be surface exposed, using a specific phage (fMptD) isolated from a phage-peptide library, by differential screening of Mycobacterium smegmatis transformants. The phage fMptD-derived peptide could be used in a peptide-mediated capture PCR with milk from infected dairy herds, thereby showing surface-exposed expression of the MptD protein in the host. Together, these data suggest that the 38-kb locus constitutes an M. avium subsp. paratuberculosis pathogenicity island.
我们利用代表性差异分析鉴定出一种新型的副结核分枝杆菌特异性ABC转运蛋白操纵子（mpt），该操纵子由六个开放阅读框组成，分别命名为mptA至 -F，其紧邻两个假定的Fur框。功能基因组学研究表明，mpt操纵子一端侧翼是一个fep簇，编码参与摄取Fe(3+)的蛋白质，另一端侧翼是一个sid簇，编码非核糖体依赖性杂环铁载体合成酶。这些基因共同构成了一个38 kb的副结核分枝杆菌特异性基因座，两侧是一个类似于IS1110的插入序列。使用蛋白质免疫印迹分析的表达研究表明，MptC存在于副结核分枝杆菌的包膜组分中。通过从噬菌体 - 肽库中分离出的特异性噬菌体（fMptD）对耻垢分枝杆菌转化体进行差异筛选，结果显示MptD蛋白暴露于表面。噬菌体fMptD衍生的肽可用于对感染奶牛群的牛奶进行肽介导的捕获PCR，从而表明MptD蛋白在宿主体内有表面暴露表达。这些数据共同表明，这个38 kb的基因座构成了一个副结核分枝杆菌致病岛。
