A widespread family of polymorphic contact-dependent toxin delivery systems in bacteria.
A widespread family of polymorphic contact-dependent toxin delivery systems in bacteria.
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作者：
细菌已经发展出在不同环境中相互交流和竞争的机制。接触依赖性生长抑制（CDI）是近年来在大肠杆菌中发现的一种新的细胞间通讯方式。CDI由CdiB/CdiA双伴侣分泌系统介导。CdiB促进CdiA“外蛋白”分泌到细胞表面上。另外一种免疫蛋白（CdiI）可保护CDI+细胞免受自身抑制。CDI阻断细胞生长和CdiI抵消这种生长停滞的机制尚不清楚。此外，尚未探索其他细菌中CDI活性的存在。在这里，我们表明，CDI的生长抑制活性驻留在CdiA（CdiA-CT）的羧基末端区域内，CdiI结合并灭活同源CdiA-CT，但不异源CdiA-CT。生物信息学和实验分析表明，多种细菌物种编码功能性CDI系统，在CdiA-CT和CdiI编码区具有高序列变异性。CdiA-CT异质性意味着在CDI期间利用了一系列毒性活性。事实上，来自尿路致病性E.大肠杆菌和植物病原体Dickeya dadantii具有不同的核酸酶活性，各自提供不同的生长抑制机制。最后，我们表明，缺乏CdiA-CT和CdiI编码区的细菌是无法与同基因野生型CDI+细胞在实验室介质和真核宿主的竞争。综上所述，这些结果表明，CDI系统构成了一个复杂的免疫网络，在细菌竞争中起着重要作用。
Bacteria have developed mechanisms to communicate and compete with one another in diverse environments. A new form of intercellular communication, contact-dependent growth inhibition (CDI), was discovered recently in Escherichia coli . CDI is mediated by the CdiB/CdiA two-partner secretion system. CdiB facilitates secretion of the CdiA ‘exoprotein’ onto the cell surface. An additional immunity protein (CdiI) protects CDI+ cells from autoinhibition. The mechanisms by which CDI blocks cell growth and CdiI counteracts this growth arrest are unknown. Moreover, the existence of CDI activity in other bacteria has not been explored. Here we show that the CDI growth inhibitory activity resides within the carboxy-terminal region of CdiA (CdiA-CT), and that CdiI binds and inactivates cognate CdiA-CT, but not heterologous CdiA-CT. Bioinformatic and experimental analyses show that multiple bacterial species encode functional CDI systems with high sequence variability in the CdiA-CT and CdiI coding regions. CdiA-CT heterogeneity implies that a range of toxic activities are utilized during CDI. Indeed, CdiA-CTs from uropathogenic E. coli and the plant pathogen Dickeya dadantii have different nuclease activities, each providing a distinct mechanism of growth inhibition. Finally, we show that bacteria lacking the CdiA-CT and CdiI coding regions are unable to compete with isogenic wild-type CDI+ cells in both laboratory media and upon a eukaryotic host. Taken together, these results suggest that CDI systems constitute an intricate immunity network that plays an important role in bacterial competition.
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影响因子：
3.2
作者：
Aoki, S. K.;Webb, J. S.;Low, D. A.
通讯作者：
Low, D. A.
影响因子：
3.5
作者：
Ham, JH;Cui, Y;Collmer, A
通讯作者：
Collmer, A
影响因子：
3.6
作者：
Aoki, Stephanie K.;Malinverni, Juliana C.;Jacoby, Kyle;Thomas, Benjamin;Pamma, Rupinderjit;Trinh, Brooke N.;Remers, Susan;Webb, Julia;Braaten, Bruce A.;Silhavy, Thomas J.;Low, David A.
通讯作者：
Low, David A.
DOI：
10.1038/nrmicro2259
发表时间：
2010-01
期刊：
Nature reviews. Microbiology
影响因子：
--
作者：
通讯作者：
--
影响因子：
3.1
作者：
Dobrindt, U;Blum-Oehler, G;Hacker, J
通讯作者：
Hacker, J