小RNA SbfR增强伤寒沙门菌动力和侵袭力

Small RNA SbfR promotes motility and invasion of Salmonella enterica serovar Typhi

目的:探究小RNA SbfR对伤寒沙门菌动力和侵袭力的影响及其潜在机制。方法:用前期构建的SbfR缺陷株(△SbfR+pBAD/Myc-HisA)、SbfR回补株(△SbfR+pBAD/Myc-HisA-SbfR)和空载体株(WT+pBAD/Myc-HisA)进行细菌动力实验和HeLa细胞侵袭实验,观察SbfR对伤寒沙门菌的动力和对HeLa细胞侵袭力的影响。通过基因芯片分析SbfR缺陷株与回补株全基因组表达的差异,并进一步用qRT-PCR分析SbfR对2个鞭毛和2个侵袭相关基因的调控作用。结果:与空载体株、SbfR回补株比较,SbfR缺陷株动力和侵袭力均明显下降(P<0.01或0.05);缺陷株鞭毛和侵袭相关基因的转录表达水平均比回补株明显下降(均P<0.05)。结论:SbfR通过促进鞭毛和侵袭相关基因的表达,增强伤寒沙门菌的动力和侵袭力。

To investigate the effect of small RNA SbfR on the motility and invasion of Salmonella enterica serovar Typhi and its potential mechanism.Methods:The effect of SbfR on the bacterial phenotype was observed using motility assay on swimming agar plates and the invasion assay of HeLa cells.The muted strains were as follows the empty vector strain(WT+pBAD/Myc-HisA),the SbfR deletion mutant(△SbfR+pBAD/Myc-HisA)and the SbfR complementary strain(△SbfR+pBAD/Myc-HisA-SbfR).In addition,gene microarray and qRT-PCR were used to analyze the regulation of SbfR on the expression of flagella and invasion related genes.Results:Compared to the control strain,the SbfR deletion mutant showed significantly weaker motility and invasion(P<0.01),while the SbfR complementary strain did not cause any change.Furthermore,expressional levels of flagella and invasion related genes in the SbfR deletion mutant were lower than that in the complementary SbfR strain(P<0.05or P<0.01).Conclusion:SbfR up-regulates the transcriptional levels of flagella and invasion related genes,and promotes the motility and invasion of S.Typhi.