In vivo expression technology identifies a type VI secretion system locus in Burkholderia pseudomallei that is induced upon invasion of macrophages
In vivo expression technology identifies a type VI secretion system locus in Burkholderia pseudomallei that is induced upon invasion of macrophages
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DOI：
10.1099/mic.0.2007/006585-0
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发表时间：
2007-08-01
期刊：
影响因子：
2.8
通讯作者：
Thomas, Mark S.
中科院分区：
文献类型：
--
作者：
Shalom, Gil;Shaw, Jonathan G.;Thomas, Mark S.
革兰氏阴性变形菌类鼻疽伯克霍尔德氏菌可以在多种真核细胞（包括巨噬细胞）中存活和繁殖。据信，这种特性对于在包括人类在内的多种动物物种中引起类鼻疽病的能力非常重要。为了确定对类鼻疽杆菌在巨噬细胞内存活的能力重要的决定因素，采用了体内表达技术（IVET）。鉴定出几个可能有助于拟鼻疽杆菌毒力的推定巨噬细胞诱导基因，包括位于同一 VI 型分泌系统簇 (tss-5) mntH 内的三个基因 (tssH-5、tssl-5 和 tssM-5)，mntH，编码天然抗性相关巨噬细胞蛋白 (NRAMP) 样锰离子转运蛋白，以及血红素获得基因 bhuT。报告基因分析证实了 tss-5 基因簇的巨噬细胞诱导能力。 tssH-5和bhuT无效突变体的构建表明，巨噬细胞内存活不需要tss-5单位和bhu操纵子的表达。在类鼻疽杆菌基因组中还鉴定出了 5 个 tss 单位，它们与 tss-5 一起约占总基因组大小的 2.3%。该生物体中存在六种 VI 型分泌系统可能是使该细菌成为多功能病原体的一个重要因素。
The Gram-negative proteobacterium Burkholderia pseudomallei can survive and multiply within a variety of eukaryotic cells, including macrophages. This property is believed to be important for its ability to cause the disease melioidosis in a wide range of animal species, including humans. To identify determinants that are important for the ability of B. pseudomallei to survive within macrophages, in vivo expression technology (IVET) was employed. Several putative macrophage-inducible genes were identified that are likely to contribute to the virulence of B. pseudomallei, including three genes (tssH-5, tssl-5 and tssM-5) located within the same type VI secretion system cluster (tss-5), mntH, encoding a natural resistance-associated macrophage protein (NRAMP)-like manganese ion transporter, and a haem acquisition gene, bhuT The macrophage-inducibility of the tss-5 gene cluster was confirmed by reporter gene analysis. Construction of tssH-5 and bhuT null mutants indicated that expression of the tss-5 unit and the bhu operon were not required for intramacrophage survival. A further five tss units were identified within the B. pseudomallei genome that, together with tss-5, account for approximately 2.3 % of the total genome size. The presence of six type VI secretion systems in this organism is likely to be an important factor in making this bacterium such a versatile pathogen.