【摘要】 表皮葡萄球菌是一种条件致病菌,它形成生物膜(biofilm)之后会产生耐药性并降低宿主的免疫力.由icaRADBC操纵子控制合成的胞间多糖黏附素(PIA)是生物膜的主要组成成分.在金黄色葡萄球菌已发现icaADBC的表达受到sarA基因表达的SarA蛋白的调控.SarA是一种DNA结合蛋白,可以激活ica操纵子中结构基因的表达.为了研究表皮葡萄球菌中sarA基因是否有类似作用,将能形成生物膜的表皮葡萄球菌RP62A的sarA基因克隆到pET-28a(+)上,在大肠杆菌BL21中实现了表达并进行了纯化,还对其结构进行了模拟;同时,利用穿梭质粒pHPS9将sarA基因通过电转化导入sarA基因缺失的表皮葡萄球菌S.epidermidis(ΔsarA)中.RT-PCR实验证明SarA对icaA基因转录有促进作用.药物敏感实验证实sarA的表达对表皮葡萄球菌的抗药性有重要影响.更多还原

【Abstract】 Staphylococcus epidermidis is a conditional pathogen.It is drug-fast and can weaken the immunocompenence of host after the formation of its biofilm.PIA is a primary component of biofilm whose formation is controlled by the operon icaRABCD.SarA,a DNA-binding protein encoded by sarA gene,activates the expression of icaA in S.aureus.To investigate the role of SarA in S.epidermidis,our lab cloned the sarA,expressed SarA protein in Escherichia coli BL21,purified this protein and simulated its structure.sarA gene was also guided in S.epidermidis RP62A(ΔsarA) by utilizing shuttle plasmid pHPS9.RT-PCR was used to detect the expression of sarA gene in S.epidermidis RP62A(ΔsarA) and its function.Our data indicated that SarA consists of a four α-helix region and a β-hairpin,can regulate ica operon in Staphylococcus epidermidis and is crucial factor to express resistance to antibiotics.更多还原