Characterization of che W Genes of Leptospira interrogans and Their Effects in Escherichia coli  

作　　者：Zhen-Hong LI Ke DONG Jing-Chun SUN Jian-Ping YUAN Bao-Yu HU Jing-Xing LIU Guo-Ping ZHAO Xiao-Kui GUO 

机构地区：[1]Department of Microbiology and Parasitology, Medicine School of Shanghai Jiaotong University, Shanghai 200025, China [2]School of Life Sciences and Technology, Shanghai Jiaotong University, Shanghai 200240, China [3]Chinese National Human Genome Center at Shanghai, Shanghai 201203, China

出　　处：《Acta Biochimica et Biophysica Sinica》2006年第2期79-88,共10页生物化学与生物物理学报（英文版）

基　　金：This work was supported by the grants from the National-Natural Science Foundation of China （No. 30370071 and 30300197）, the National High Technology Research and Development Program of China （2003AA223030） and Shanghai Leading Academic Discipline Project （T0206）.Acknowledgements We are extremely grateful to Dr.J.S. PARKINS0N （University of Utah. Sah Lake City. USA） for kindly providing the E coli strains, and to Dr. H. STEINMAN （ Albert Einstein College of Medicine. Bronx. USA ） for the critical reading of the manuscript. We also thank Dr. Wei WU and Dr. Zhi-Wei CA0 for their useful information.

摘　　要：The motility and chemotaxis systems are critical for the virulence of leptospires. In this study, the phylogenetic profiles method was used to predict the interaction of chemotaxis proteins. It was shown that CheW1 links to CheA1, CheY, CheB and CheW2, CheW3 links to CheA2, MCP （LA2426）, CheB3 and CheD1; and CheW2 links only to CheW1. The similarity analysis demonstrated that CheW2 of Leptospira interrogans strain Lai had poor homology with Chew of Escherichia coli in the region of residues 30-50. In order to verify the function of these proteins, the putative cheW genes were cloned into pQE31 vector and expressed in wild-type E. coli strain RP437 or chew defective strain RP4606. The swarming results indicated that CheW1 and CheW3 could restore swarming of RP4606 while CheW2 could not. Overexpression of CheW1 and CheW3 in RP437 inhibited the swarming of RP437, whereas the inhibitory effect of CheW2 was much lower. Therefore, we presumed that CheW1 and CheW3 might have the function of CheW while CheW2 does not. The existence of multiple copies of chemotaxis homologue genes suggested that L. interrogans strain Lai might have a more complex chemosensory pathway.The motility and chemotaxis systems are critical for the virulence of leptospires. In this study, the phylogenetic profiles method was used to predict the interaction of chemotaxis proteins. It was shown that CheW1 links to CheA1, CheY, CheB and CheW2, CheW3 links to CheA2, MCP （LA2426）, CheB3 and CheD1; and CheW2 links only to CheW1. The similarity analysis demonstrated that CheW2 of Leptospira interrogans strain Lai had poor homology with Chew of Escherichia coli in the region of residues 30-50. In order to verify the function of these proteins, the putative cheW genes were cloned into pQE31 vector and expressed in wild-type E. coli strain RP437 or chew defective strain RP4606. The swarming results indicated that CheW1 and CheW3 could restore swarming of RP4606 while CheW2 could not. Overexpression of CheW1 and CheW3 in RP437 inhibited the swarming of RP437, whereas the inhibitory effect of CheW2 was much lower. Therefore, we presumed that CheW1 and CheW3 might have the function of CheW while CheW2 does not. The existence of multiple copies of chemotaxis homologue genes suggested that L. interrogans strain Lai might have a more complex chemosensory pathway.

关 键 词：Leptospira interrogans CHEMOTAXIS cheW 

分 类 号：R378[医药卫生—病原生物学]