VicK激酶活性对变异链球菌的生物学影响

Functional Analysis of VicK Kinase Activity in Streptococcus Mutans

中文关键词:  变异链球菌 双组分信号传导系统 VicK 生物学作用

英文关键词:Streptococcus mutans Two-component signal transduction systems VicK Biological function

中文摘要:

      目的 研究VicK蛋白的激酶活性对变异链球菌（S.mutans）生理及毒力因子的调控作用。方法 使用PCR连接突变技术构建vicK基因敲出株，利用质粒搭载、表达VicK激酶活性废除蛋白。研究实验株菌落形态、隔夜培养菌液的变化、生物膜形成以及生物膜形成相关重要基因转录水平的改变。结果 VicK^H217A的菌落表面较野生株UA159及互补株SMCVicK平滑，且菌落也较之高耸；VicK^H217A隔夜培养的菌液中细胞共聚堆积在玻璃管底部； VicK^H217A形成的生物膜未发生明显改变；gbpB、ftf、gtfD的表达受抑制而gtfB/C基因的表达上调（P<0.05）。结论 VicK的激酶活性对变异链球菌正常生长、生物膜形成及与编码生物膜形成相关蛋白基因的表达起着重要的调节作用。

英文摘要:

      Objective To investigate the regulatory function on physiology and virulence of VicK kinase activity in Streptococcus mutans. Methods PCR ligation mutagenesis was used to construct a vicK knock-out mutant, and kinase activity abolished VicK was expressed by a streptococcal vector in this vicK null mutant. Colony morphology, overnight culture, biofilm formation and gene expression involved in biofilm formation were analyzed. ΔVicK, strains harboring a complemented wild-type vicK, and a vector without insert were used as controls. Results Colonies of VicK^H217A were smoother and more elevated than that of wild-type UA159 and complementary strain SMCVicK; cells from VicK^H217A overnight culture coaggregated on the bottom of glass tubes; no obvious alteration was observed in VicK^H217A biofilm; expressions of gbpB, ftf, gtfD were repressed while gtfB/C were up-regulated (P<0.05). Conclusion VicK kinase activity is important for maintaining normal growth, biofilm formation and expression of genes involved in biofilm formation in Streptococcus mutans.