Identification of a virulence gene cluster of Mycobacterium tuberculosis by signature-tagged transposon mutagenesis
Identification of a virulence gene cluster of Mycobacterium tuberculosis by signature-tagged transposon mutagenesis
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DOI：
10.1046/j.1365-2958.1999.01593.x
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发表时间：
1999-10-01
影响因子：
3.6
通讯作者：
Guilhot, C
中科院分区：
文献类型：
--
作者：
Camacho, LR;Ensergueix, D;Guilhot, C
结核病仍然是全球由单一病原体导致死亡的最主要原因。为了确定结核分枝杆菌致病性所需的基因，一种功能基因组学方法被研发出来。构建了该细菌的标记标签转座子突变体文库，并筛选在小鼠肺部繁殖受影响的突变体。在测试的1927个突变体中，有16个毒力减弱。所选突变体所含的插入片段被定位在结核分枝杆菌基因组上，大多数突变位点似乎涉及脂质代谢或跨膜运输。四个独立的突变确定了位于一个50kb染色体区域的一组毒力基因。这些基因可能参与结核菌醇和酚结核菌醇衍生物的产生，这是一组仅限于八种分枝杆菌的分子，其中七种是严格或机会性病原体。研究了五种突变株与小鼠骨髓巨噬细胞的相互作用。这五种突变株仍然能够在这种细胞类型中繁殖，然而，在三种情况下，与野生型菌株相比存在生长缺陷。在这个模型中，另外两种菌株与有毒力的菌株MT103没有明显差异。这项研究是对结核分枝杆菌毒力因子的首次全面研究，为更好地理解在这种病原体与其宿主相互作用中起关键作用的分子开辟了道路。
Tuberculosis remains the greatest cause of death worldwide due to a single pathogen, In order to identify the genes required for the pathogenicity of Mycobacterium tuberculosis, a functional genomic approach was developed. A library of signature-tagged transposon mutants of this bacterium was constructed and screened for those affected in their multiplication within the lungs of mice. From 1927 mutants tested, 16 were attenuated for their virulence. The insertions harboured by the selected mutants were mapped on the M. tuberculosis genome and most of the mutated loci appeared to be involved in lipid metabolism or transport across the membrane. Four independent mutations identified a cluster of virulence genes located on a 50 kb chromosomal region. These genes might be involved in the production of phthiocerol and phenolphthiocerol derivatives, a group of molecules restricted to eight mycobacterial species, seven of them being either strict or opportunistic pathogens. The interaction of five mutant strains with mouse bone marrow macrophages was investigated. These five mutants were still able to multiply in this cell type, However, in three cases, there was a growth defect in comparison with the wild-type strain. The other two strains exhibited no clear difference from the virulent strain, MT103, in this model. This study, which is the first global research of virulence factors of M. tuberculosis, opens the way to a better understanding of the molecules that are key players in the interaction of this pathogen with its host.