丝氨酸/苏氨酸激酶调控猪链球菌2型毒力的分子机制

项目名称： 丝氨酸/苏氨酸激酶调控猪链球菌2型毒力的分子机制

项目编号： No.31302114

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 农业科学

项目作者： 祝昊丹

作者单位： 江苏省农业科学院

项目金额： 25万元

中文摘要： 细菌中存在真核生物型的丝氨酸/苏氨酸激酶(STK)，STK通过对靶蛋白丝氨酸/苏氨酸残基的磷酸化，调控细胞内的各种生命活动，如生长、代谢和毒力等。前期工作表明，猪链球菌2型(SS2)中存在丝氨酸/苏氨酸激酶，STK基因敲除后，毒力因子和黏附素的转录水平下降，对CD1小鼠的致病力明显降低。本项目以强毒株SS2-1和STK基因缺失株△Stk为研究对象，拟通过基因芯片和比较蛋白组学方法，分别从转录水平和蛋白水平，比较缺失株与亲本株差异表达的基因和蛋白，鉴定STK调控的基因和蛋白表达谱；利用体外磷酸化试验鉴定STK磷酸化的候选靶蛋白，如CovR、CiaR、SalR、VirR和IRR等；在体外对重组靶蛋白的氨基酸定点突变，确定STK磷酸化的作用位点。在此基础上，确定STK作为信号分子的基本特点，揭示其调控SS2致病性的分子机制，促进对SS2分子致病机理的认识，为分子疫苗研究和靶标药物的设计提供理论依据。

中文关键词： 丝氨酸/苏氨酸激酶；猪链球菌；毒力；分子机制；

英文摘要： Like many eukaryotes, the analogous serine/threonine kinases (STKs) is abundantly present in bacterial genomes. The eukaroytic-type signal molecule STK untilize phosphorylation/dephosphorylation of serine/threonine residue on the target proteins to regulate various cellular processes, including growth, metabolism and virulence. In previous studies, an eukaryotic-type serine/threonine kinase (STK) in Streptococcus suis type 2 (SS2) virulent strain was identified as a potential virulent factor and defined the role of STK in SS2 infection. In the STK-deletion mutant strain, the expression levels of putative adhesin genes and virulence genes(gapdh, fbps,ef, mrp sly,sspA and ssnA) were decreased. The virulence of the STK-deletion strain was attenuated in a CD1 murine model. These data suggest that STKis involved in the pathogenesis of SS2.However,the molecular mechanism of regulation virulence by STK in SS2 is unclear. The present study is to gain further insights into the network mediated by STK, microarray is applied to compare the transcription profiles of the parental wildtype strain with that of its STK mutant strain. The comparative proteomics approach is used to distinguish between the 2-D profiles of whole cell proteins in the the parental wildtype strain and ΔStk, with the aim of revealing proteins probably

英文关键词： serine/threonine kinase；Streptococcus suis；virulence；molecular mechanism；