Marsh I B, Whittington R J
Faculty of Veterinary Science, University of Sydney, Private Bag 3, Camden, NSW 2570, Australia.
Mol Cell Probes. 2005 Dec;19(6):371-84. doi: 10.1016/j.mcp.2005.06.005. Epub 2005 Oct 14.
Mycobacterium avium subsp. paratuberculosis (M. a. paratuberculosis) can be divided into two major strains, sheep (S) and cattle (C), based on cultural requirements, host specificity, degree of clumping of cells in suspension and minor genomic differences including copy number of insertion elements and point mutations. Representational difference analysis (RDA) with S strain as driver and C strain as tester was used to identify unique genomic regions. Three sequences (RDA1, RDA3 and RDA4) were identified. RDA1 (229bp) contained a single base difference between S and C strains. RDA4 (163bp) was an artefact. RDA3 (206bp) was similar to several sequences in the incomplete genome sequences of M. avium subsp. paratuberculosis K10 and M. avium subsp. avium 104. In silico analysis led to the identification of a deletion that may be as large as 17kb in the sheep strain of M. a. paratuberculosis. PCR analysis of this region confirmed the deletion of 11,584bp that included 10 genes (MAP1734 to MAP1743c) of the M. a. paratuberculosis K10 genome. This included the loss of mmpL5 and mmpS5 genes and homologues of the M. tuberculosis genes: Rv2002 (fabG3), Rv2017c (lipW), Rv3132c (devS), Rv2032 (acg) and the conserved hypothetical genes Rv2005c and Rv2026c. PCR reactions designed to detect the single nucleotide polymorphism in RDA1 and the deletion in the mmpL region can be used to distinguish these strains. MmpL genes, found in M. tuberculosis and other mycobacteria are part of the resistance-nodulation-division (RND) family but contain domains unique to mycobacteria thought to play a role in cell wall biogenesis, virulence and other phenotypic characteristics. Absence of mmpL5 in the S strain of M. a. paratuberculosis is unlikely to account for the difference in clumping in suspension but may explain the difference in cultural requirements and host specificity compared to the C strain but the impact of the remainder of the deletion is yet to be ascertained.
副结核分枝杆菌（Mycobacterium avium subsp. paratuberculosis，M. a. paratuberculosis）可根据培养条件、宿主特异性、悬浮液中细胞的聚集程度以及包括插入元件拷贝数和点突变在内的微小基因组差异，分为两个主要菌株，即羊型（S）和牛型（C）。以S菌株为驱动株、C菌株为检测株进行代表性差异分析（RDA），以鉴定独特的基因组区域。鉴定出了三个序列（RDA1、RDA3和RDA4）。RDA1（229bp）在S和C菌株之间存在一个单碱基差异。RDA4（163bp）是一个假象。RDA3（206bp）与副结核分枝杆菌K10亚种和鸟分枝杆菌104亚种的不完整基因组序列中的几个序列相似。通过计算机分析鉴定出羊型副结核分枝杆菌中可能存在一个长达17kb的缺失。对该区域进行PCR分析证实了11584bp的缺失，该缺失包括副结核分枝杆菌K10基因组的10个基因（MAP1734至MAP1743c）。这包括mmpL5和mmpS5基因的缺失以及结核分枝杆菌基因的同源物：Rv2002（fabG3）、Rv2017c（lipW）、Rv3132c（devS）、Rv2032（acg）以及保守的假定基因Rv2005c和Rv2026c。设计用于检测RDA1中的单核苷酸多态性和mmpL区域缺失的PCR反应可用于区分这些菌株。在结核分枝杆菌和其他分枝杆菌中发现的MmpL基因是抗药-结瘤-分裂（RND）家族的一部分，但含有分枝杆菌特有的结构域，这些结构域被认为在细胞壁生物合成、毒力和其他表型特征中起作用。羊型副结核分枝杆菌S菌株中mmpL5的缺失不太可能解释悬浮液中聚集的差异，但可能解释与C菌株相比培养条件和宿主特异性的差异，不过缺失其余部分的影响尚待确定。
