Growth-phase-dependent mobility of the Ivh-encoding region in Legionella pneumophila strain Paris
Growth-phase-dependent mobility of the Ivh-encoding region in Legionella pneumophila strain Paris
复制标题
DOI：
10.1099/mic.0.29227-0
复制
发表时间：
2006-12-01
期刊：
影响因子：
2.8
通讯作者：
Jarraud, Sophie
中科院分区：
文献类型：
--
作者：
Doleans-Jordheim, Anne;Akermi, Mongi;Jarraud, Sophie
编码IV型分泌系统的嗜肺军团菌基因组的Ivh区域位于菌株巴黎（pP36）和Philadelphia（pLP 45）中的质粒样元件上。已经描述了pP36元件以与pLP 45类似的方式整合到染色体中或作为多拷贝质粒切除。本文描述了pP36在巴黎株基因组中的染色体整合，其发生是通过在连接位点之间的重组在转移信使RNA基因的3'末端的位点特异性重组，以类似于致病岛的方式。这种整合是生长阶段依赖性的，发生在指数期。几个pP36携带的基因在细菌生长的滞后期表达，与pP36的附加体形式的峰值量一致。在指数期和稳定期，由于整合现象和pP36附加型拷贝的丢失，相同基因的表达下降。在透镜菌株基因组中描述了类似的质粒样元件，表明lvh区域的移动性是军团菌属中普遍存在的现象。
The Ivh region of the Legionella pneumophila genome, which encodes a type IV secretion system, is located on a plasmid-like element in strains Paris (pP36) and Philadelphia (pLP45). The pP36 element has been described either integrated in the chromosome or excised as a multi-copy plasmid, in a similar manner to pLP45. In this paper, the chromosomal integration of pP36 in the Paris strain genome was described, occurring through site-specific recombination at the 3' end of a transfer-messenger RNA gene by recombination between attachment sites, in a similar manner to pathogenicity islands. This integration was growth-phase dependent, occurring during the exponential phase. Several pP36-borne genes were expressed during the lag phase of bacterial growth, coinciding with the peak amount of the episomal form of pP36. Expression of the same genes decreased during the exponential and stationary phases, owing to the integration phenomenon and a loss of episomal copies of pP36. A similar plasmid-like element was described in the Lens strain genome, suggesting that the mobility of the lvh region is a phenomenon widespread among Legionella sp.