Comparison of mammalian cell entry operons of mycobacteria: in silico analysis and expression profiling
Comparison of mammalian cell entry operons of mycobacteria: in silico analysis and expression profiling
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DOI：
10.1016/j.femsim.2004.08.013
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发表时间：
2005-02-01
影响因子：
--
通讯作者：
Bose, M
中科院分区：
文献类型：
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作者：
Kumar, A;Chandolia, A;Bose, M
哺乳动物细胞进入(MCE)操纵子与分枝杆菌进入宿主细胞有关，存在于致病和腐生物种中。这些操纵子中的基因很可能具有进入宿主细胞所需的功能以外的功能。在电子分析中，我们已经确定了mce操纵子中的结构域，这些结构域可能证明它们在腐生物种中的存在是合理的，比如污垢分枝杆菌。我们的分析发现，除了mce结构域外，还存在Tt2B和Ttg2C结构域，这两个结构域是参与运输的典型蛋白质。我们还分析和比较了不同生长条件下结核分枝杆菌、牛分枝杆菌和耻垢分枝杆菌的mce操纵子的表达谱。在耻垢分枝杆菌中，每个操纵子至少有一个基因的结构域被截断。我们观察了在不同培养条件下生长的耻垢分枝杆菌操纵子之间的差异表达。在有曝气的营养丰富的培养基中生长的杆菌，只表达mce4操纵子，而在静置培养阶段，所有四个mce操纵子都表达。在牛分枝杆菌中，除了缺少mce3操纵子外，其他操纵子编码的几个蛋白结构域也被截断。我们检测到mce2操纵子在指数生长期和稳定期的表达，而mce1操纵子只在稳定期表达。鉴于我们的结果，我们讨论了分枝杆菌大多数成员基因组中mce操纵子的差异表达及其冗余。(C)2004年，由Elsevier B.V.代表欧洲微生物学会联合会出版。
Mammalian cell entry (mce) operons, implicated in the entry of mycobacteria into host cells, are present in pathogenic and saprophytic species. It is likely that the genes in these operons have functions other than those required for entry into host cells. Using in silico analysis we have identified domains within the mce operons that might justify their occurrence in saprophytic species like Mycobacterium smegmatis. Our analysis identified in addition to the mce domain, the presence of the Tt2B and Ttg2C domains, typical of proteins involved in transport. We have also analysed and compared the expression profile between mce operons of Mycobacterium tuberculosis, Mycobacterium bovis and M. smegmatis under different growth conditions. In case of M. smegmatis, each operon presented domain truncation for at least one gene. We observe differential expression among the operons in M. smegmatis growing under different culture conditions. Bacilli growing in nutritionally rich medium with aeration, only the mce4 operon was expressed while during stationary phase of a standing culture, all four mce operons were expressed. In M. bovis, in addition to the absence of the mce3 operon, several protein domains encoded by the other operons were truncated. We detected expression of the mce2 operon in the exponential and stationary growth phase, while the mce1 operon was only expressed in the stationary growth phase. Differential expression of mce operons and their redundancy in the genome of the majority members of mycobacteria are discussed in view of our results. (C) 2004 Published by Elsevier B.V. on behalf of the Federation of European Microbiological Societies.