Construction and function study of galUª²deletion mutant in streptococcus pneumoniae

    MENG Jiangª²Ping, YIN Yiª²Bing, YUAN Jun, ZHANG Xueª²Mei, LAN Kai, CHEN Shuª²Hui ,WANG Hong, TU Zhiª²Guang

    Department of Laboratory Medicine£¬Chongqing University of Medical Science, Chongqing 400016,China

    ¡¾Abstract¡¿AIM£ºTo construct galU-deletion mutant of streptococcus pneumoniae and get the capsule deficient strain, which can be used in pneumococcal functional genome research. METHODS: LFHª²PCR was introduced to generate a gene disruption construct consisting of Emr cassette with long flanking homology regions to the target gene. The streptococcus pneumoniae was then transformed directly with this PCR product. The galUª²deletion mutant was obtained on the TSA agar containing erythromycin and identified by PCR. The deficient strain (5¡Á106 CFU) was applied to infect BALB/c mice to determine the virulence. RESULTS: GalU gene was replaced completely by erm cassette. The mutant had low virulence to BALB/c mice. CONCLUSION: The galUª²deletion mutant can be used to screen in vivoª²promoter in streptococcus pneumoniae because it is incapable of synthesizing capsular polysaccharide and hence loses virulence. The target gene can be replaced completely by LFHª²PCR product, so this method is simple, rapid and effective for functional genome research of streptococcus pneumoniae. ......