InvA Protein Is a Nudix Hydrolase Required for Infection by Pathogenic Leptospira in Cell Lines and Animals (Retracted Article)
InvA Protein Is a Nudix Hydrolase Required for Infection by Pathogenic Leptospira in Cell Lines and Animals (Retracted Article)
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DOI：
10.1074/jbc.m111.219931
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发表时间：
2011-10-21
影响因子：
4.8
通讯作者：
Yan, Jie
中科院分区：
文献类型：
--
作者：
Luo, Yihui;Liu, Yan;Yan, Jie
由钩端螺旋体属致病物种引起的钩端螺旋体病是一种新出现的人畜共患疾病，影响宿主种类繁多，并通过受污染的水传播。几种致病钩端螺旋体的基因组含有一个名为invA的基因，该基因含有一个Nudex结构域。然而，这个基因的功能从未被描述过。在这里，我们证明了invA基因在蛋白质序列中高度保守，并且存在于所有测试的致病钩端螺旋体物种中。问号钩端螺旋体致病株LAI的重组invA蛋白能对几种特异的寡磷酸二核苷底物进行降解，反映了钩端螺旋体中Nudex的酶活性。致病钩端螺旋体在培养上清液中不表达该蛋白，但在感染巨噬细胞和肾上皮细胞的早期阶段(60min内)暂时表达该蛋白。与野生型相比，inA缺陷型突变体的感染力明显降低，巨噬细胞和肾上皮细胞的存活率显著降低。此外，与野生型钩端螺旋体相比，缺失INVA的钩端螺旋体在仓鼠体内的毒力减弱，造成轻微的组织病理损害，并在尿液中传播数量较少。通过用invA基因补充invA缺失突变体而获得的invA回复突变体，在体外和体内获得了与野生型相似的毒力。在仓鼠中，inA缺失突变体的LD50是invA回复突变体和野生型的1000倍。这些结果表明，invA蛋白是一种Nudex水解酶，并且invA基因对致病性钩端螺旋体的毒力是必不可少的。
Leptospirosis caused by pathogenic species of the genus Leptospira is a re-emerging zoonotic disease, which affects a wide variety of host species and is transmitted by contaminated water. The genomes of several pathogenic Leptospira species contain a gene named invA, which contains a Nudix domain. However, the function of this gene has never been characterized. Here, we demonstrated that the invA gene was highly conserved in protein sequence and present in all tested pathogenic Leptospira species. The recombinant InvA protein of pathogenic L. interrogans strain Lai hydrolyzed several specific dinucleoside oligophosphate substrates, reflecting the enzymatic activity of Nudix in Leptospira species. Pathogenic leptospires did not express this protein in media but temporarily expressed it at early stages (within 60 min) of infection of macrophages and nephric epithelial cells. Comparing with the wild type, the invA-deficient mutant displayed much lower infectivity and a significantly reduced survival rate in macrophages and nephric epithelial cells. Moreover, the invA-deficient leptospires presented an attenuated virulence in hamsters, caused mild histopathological damage, and were transmitted in lower numbers in the urine, compared with the wild-type strain. The invA revertant, made by complementing the invA-deficient mutant with the invA gene, reacquired virulence similar to the wild type in vitro and in vivo. The LD50 in hamsters was 1000-fold higher for the invA-deficient mutant than for the invA revertant and wild type. These results demonstrate that the InvA protein is a Nudix hydrolase, and the invA gene is essential for virulence in pathogenic Leptospira species.