Güvener Zehra Tüzün, Tifrea Delia F, Harwood Caroline S
Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
Mol Microbiol. 2006 Jul;61(1):106-18. doi: 10.1111/j.1365-2958.2006.05218.x.
Pseudomonas aeruginosa has sets of sensory genes designated che and che2. The che genes are required for flagella-mediated chemotaxis. The che2 genes are expressed in the stationary phase of growth and are probably also involved in flagella-mediated behavioural responses. P. aeruginosa also has 26 chemoreceptor genes, six of which are preferentially expressed in stationary phase. Subcellular localization experiments indicated that Che proteins form signal transduction complexes at cell poles throughout growth. Cyan fluorescent protein (CFP)-tagged McpA, a stationary phase-expressed chemoreceptor, appeared and colocalized with yellow fluorescent protein (YFP)-tagged CheA when cells entered stationary phase. This indicates that P. aeruginosa chemotaxis protein complexes are subject to remoulding by chemoreceptor proteins that are expressed when cells stop growing. CheA-CFP and CheY2-YFP tagged proteins that were coexpressed in the same cell had separate subcellular locations, indicating that Che2 proteins do not enter into direct physical interactions with Che proteins. Che2 protein complex formation required McpB, another stationary phase induced chemoreceptor that is predicted to be soluble. This implies that Che2 complexes have a function that depends on just one chemoreceptor. Our results suggest that motile P. aeruginosa cells have signal transduction systems that are adapted to allow non-growing cells to sense and respond to their environment differently from actively growing cells.
铜绿假单胞菌有一组名为che和che2的传感基因。che基因是鞭毛介导的趋化作用所必需的。che2基因在生长的稳定期表达,可能也参与鞭毛介导的行为反应。铜绿假单胞菌还有26个化学感受器基因,其中6个在稳定期优先表达。亚细胞定位实验表明,Che蛋白在整个生长过程中在细胞极形成信号转导复合物。当细胞进入稳定期时,用青色荧光蛋白(CFP)标记的McpA(一种在稳定期表达的化学感受器)出现并与用黄色荧光蛋白(YFP)标记的CheA共定位。这表明铜绿假单胞菌趋化蛋白复合物会被细胞停止生长时表达的化学感受器蛋白重塑。在同一细胞中共表达的CheA-CFP和CheY2-YFP标记蛋白有不同的亚细胞定位,表明Che2蛋白不与Che蛋白进行直接的物理相互作用。Che2蛋白复合物的形成需要McpB,McpB是另一种在稳定期诱导表达的化学感受器,预计是可溶的。这意味着Che2复合物具有仅依赖一种化学感受器的功能。我们的结果表明,运动性铜绿假单胞菌细胞具有信号转导系统,该系统能够使非生长细胞以与活跃生长细胞不同的方式感知和响应其环境。