Dissection of a type VI secretion system in Edwardsiella tarda
Dissection of a type VI secretion system in Edwardsiella tarda
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DOI：
10.1111/j.1365-2958.2007.05993.x
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发表时间：
2007-12
影响因子：
3.6
通讯作者：
Jun Zheng;K. Leung
中科院分区：
文献类型：
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作者：
Jun Zheng;K. Leung
细菌病原体使用不同的蛋白质分泌系统来递送毒力因子。最近，在几种革兰氏阴性细菌病原体中发现了一种新的分泌系统，并将其命名为VI型分泌系统（T6SS）。迟缓爱德华氏菌（Edwardsiella tarda）的E.慢毒蛋白（EVP）基因簇与蛋白分泌有关。在此，我们将整个EVP簇鉴定为T6SS，并发现另外两个分泌蛋白（EvpI，VgrG的同源物，和EvpP）。我们系统地诱变所有16个EVP基因，发现EvpP的分泌依赖于13个EVP蛋白，包括EvpC（HCP的同源物）和EvpI，而不是EvpD和EvpJ。除Δ evpD外，所有EVP突变体在蓝刺鱼中均表现为弱毒。这16种EVP蛋白可以根据其功能和细胞位置进行分组。第一组包括11种非分泌的和可能的细胞内装置蛋白。其中，含有步行者A基序的ATP酶EvpO可能与EVP的三种蛋白（EvpA，EvpL和EvpN）相互作用。第二组包括三种分泌蛋白（EvpC、EvpI和EvpP）。EvpC和EvpI的分泌是相互依赖的，并且它们是EvpP分泌所必需的。证明了EvpC和EvpP之间的相互作用。最后，两种蛋白质（EvpD和EvpJ）不是T6SS依赖性分泌所必需的。
Bacterial pathogens use different protein secretion systems to deliver virulence factors. Recently, a novel secretion system was discovered in several Gram‐negative bacterial pathogens, and was designated as the type VI secretion system (T6SS). In Edwardsiella tarda, a partial E. tardavirulent protein (EVP) gene cluster was implicated in protein secretion. Here, we identified the entire EVP cluster as a T6SS and two additional secreted proteins (EvpI, a homologue of VgrG, and EvpP) were found. We systematically mutagenized all the 16 EVP genes and found that the secretion of EvpP was dependent on 13 EVP proteins including EvpC (a homologue of Hcp) and EvpI but not EvpD and EvpJ. All EVP mutants except ΔevpD were attenuated in blue gourami fish. The 16 EVP proteins can be grouped according to their functions and cellular locations. The first group comprises 11 non‐secreted and possibly intracellular apparatus proteins. Among them, EvpO, a putative ATPase which contained a Walker A motif, showed possible interactions with three EVP proteins (EvpA, EvpL and EvpN). The second group includes three secreted proteins (EvpC, EvpI and EvpP). The secretion of EvpC and EvpI is mutually dependent, and they are required for the secretion of EvpP. The interaction between EvpC and EvpP was demonstrated. Lastly, two proteins (EvpD and EvpJ) are not required for the T6SS‐dependent secretion.