Individual RD1-region genes are required for export of ESAT-6/CFP-10 and for virulence of Mycobacterium tuberculosis
Individual RD1-region genes are required for export of ESAT-6/CFP-10 and for virulence of Mycobacterium tuberculosis
复制标题
DOI：
10.1046/j.1365-2958.2003.03844.x
复制
发表时间：
2004-01-01
影响因子：
3.6
通讯作者：
Sherman, DR
中科院分区：
文献类型：
--
作者：
Guinn, KM;Hickey, MJ;Sherman, DR
RD1 基因组区域存在于结核分枝杆菌 (MTB) 的强毒株中，但在疫苗株牛分枝杆菌 BCG 中缺失，并且其对毒力的重要性已通过实验确定。基于计算机分析，有人认为 RD1 可能编码一种新的分泌系统，但该区域影响毒力的机制尚不清楚。在这里，我们检查了五个单独 RD1 基因中被破坏的突变体。在体外和体内，每个突变体都表现出与缺失整个 RD1 区域的突变体非常相似的减毒表型。单个基因的遗传互补恢复了毒力。减毒突变体可以在THP-1细胞内繁殖，但无法扩散到未感染的巨噬细胞。我们还检查了两种免疫显性 RD1 蛋白 CFP-10 和 ESAT-6 的输出。在每个减毒突变体中，这些蛋白质的输出大大减少或消除。基因互补再次恢复了野生型表型。我们的结果表明 RD1 基因共同作用形成单一毒力决定簇，并认为 RD1 编码 MTB 发病机制所需的新型专门分泌系统。
The RD1 genomic region is present in virulent strains of Mycobacterium tuberculosis (MTB), missing from the vaccine strain M. bovis BCG, and its importance to virulence has been established experimentally. Based on in silico analysis, it has been suggested that RD1 may encode a novel secretion system, but the mechanism by which this region affects virulence is unknown. Here we examined mutants disrupted in five individual RD1 genes. Both in vitro and in vivo, each mutant displayed an attenuated phenotype very similar to a mutant missing the entire RD1 region. Genetic complementation of individual genes restored virulence. Attenuated mutants could multiply within THP-1 cells, but they were unable to spread to uninfected macrophages. We also examined export of two immunodominant RD1 proteins, CFP-10 and ESAT-6. Export of these proteins was greatly reduced or abolished in each attenuated mutant. Again, genetic complementation restored a wild-type phenotype. Our results indicate that RD1 genes work together to form a single virulence determinant, and argue that RD1 encodes a novel specialized secretion system that is required for pathogenesis of MTB.