Legionella pneumophila Strain 130b Possesses a Unique Combination of Type IV Secretion Systems and Novel Dot/Icm Secretion System Effector Proteins
Legionella pneumophila Strain 130b Possesses a Unique Combination of Type IV Secretion Systems and Novel Dot/Icm Secretion System Effector Proteins
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DOI：
10.1128/jb.00778-10
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发表时间：
2010-11-01
影响因子：
3.2
通讯作者：
Frankel, Gad
中科院分区：
文献类型：
--
作者：
Schroeder, Gunnar N.;Petty, Nicola K.;Frankel, Gad
嗜肺军团菌是环境水库中普遍存在的居民。这种细菌可以感染多种原生动物，并在意外吸入后感染人类肺泡巨噬细胞，从而导致严重的肺炎。吞噬性宿主的生长能力依赖于Dot/Icm IV型分泌系统（T4SS），该系统可将多种效应蛋白转运到宿主细胞中。在这项研究中，我们确定了嗜肺乳杆菌菌株130b （Wadsworth）的草图基因组序列。我们发现130b基因组编码一组独特的T4SS，即Dot/Icm T4SS， trb -1样T4SS和两个Lvh T4SS基因簇。序列分析证实，在测序的嗜肺L.菌株Philadelphia-1、Lens、Paris、Corby、Alcoy和130b中，有107个Dot/Icm T4SS效应子的核心序列是保守的。我们还鉴定了新的候选效应物，并验证了10个新的Dot/Icm T4SS效应物的易位，这些效应物不存在于嗜肺乳杆菌菌株Philadelphia-1中。我们检测了87株环境和临床嗜肺乳杆菌中新效应基因的流行情况。在34 - 62%的菌株中发现了5种新的效应物，而在其他5种基因中检测呈阳性的菌株不到15%。总的来说，我们的数据表明，保守的Dot/Icm T4SS效应蛋白的核心集被可变的附属效应蛋白补充，这可能部分解释了特定嗜肺乳杆菌菌株的毒力和流行差异。
Legionella pneumophila is a ubiquitous inhabitant of environmental water reservoirs. The bacteria infect a wide variety of protozoa and, after accidental inhalation, human alveolar macrophages, which can lead to severe pneumonia. The capability to thrive in phagocytic hosts is dependent on the Dot/Icm type IV secretion system (T4SS), which translocates multiple effector proteins into the host cell. In this study, we determined the draft genome sequence of L. pneumophila strain 130b (Wadsworth). We found that the 130b genome encodes a unique set of T4SSs, namely, the Dot/Icm T4SS, a Trb-1-like T4SS, and two Lvh T4SS gene clusters. Sequence analysis substantiated that a core set of 107 Dot/Icm T4SS effectors was conserved among the sequenced L. pneumophila strains Philadelphia-1, Lens, Paris, Corby, Alcoy, and 130b. We also identified new effector candidates and validated the translocation of 10 novel Dot/Icm T4SS effectors that are not present in L. pneumophila strain Philadelphia-1. We examined the prevalence of the new effector genes among 87 environmental and clinical L. pneumophila isolates. Five of the new effectors were identified in 34 to 62% of the isolates, while less than 15% of the strains tested positive for the other five genes. Collectively, our data show that the core set of conserved Dot/Icm T4SS effector proteins is supplemented by a variable repertoire of accessory effectors that may partly account for differences in the virulences and prevalences of particular L. pneumophila strains.