Abstract：Objective: To investigate the influence of RNase G on the regulation of non-coding RNA（ncRNA）T3956 in Salmonella enterica serovar Typhi（S . Typhi）. Methods: The rng deleted mutant of S . Typhi was prepared by the homologous recombination mediated by suicide plasmid; the rng complementary strain was generated by transferring the recombinant plasmid pBAD rng into the rng deleted mutant; qRT-PCR was performed to analyze the level of non-coding RNA T3956 in the wild strain，the rng mutant strain，the complementary strain and the control strain at different growth phases. Results: The rng deleted mutant of S . Typhi，the rng complementary strain and the control strain were constructed successfully. The results of qRT-PCR revealed that the cellular level of T3956 was increased in the rng mutant comparing to the wild type strain，especially at mid-log phase and stationary phase，and the level of T3956 was restored in the rng complementary strain. Conclusion: RNase G was involved in the regulation of the ncRNA T3956 levels in S . Typhi，and played a more important role in the regulation at mid-log and stationary phase.
［1］ Vogel J， Sharma CM. How to find small non-coding RNAs in bacteria［J］. Biol Chem， 2005， 386（12）: 1219 -1238. ［2］ Storz G， Opdyke JA， Zhang A. Controlling mRNA stability and translation with small non-coding RNAs［J］. Curr Opin Microbiol， 2004， 7（2）: 140-144. ［3］ Grke B， Vogel J. Noncoding RNA control of the making and breaking of sugars［J］. Genes Dev， 2008， 22（21）: 2914-2925. ［4］ Mass E， Gottesman S. A small RNA regulates the expression of genes involved in iron metabolism in Escherichia coli［J］. Proc Natl Acad Sci USA， 2002， 99（7）: 4620- 4625. ［5］ Lenz DH， Mok KC， Lilley BN， et al. The small RNA chaperone Hfq and multiple small RNAs control quorum sensing in Vibrio harvevi and Vibrio cholerae［J］. Cell， 2004， 118（1）: 69-82. ［6］ Romby P， Vandenesch F， Wagner EG. The role of RNAs in the regulation of virulence-gene expression［J］. Curr Opin Microbiol， 2006， 9（2）: 229-236. ［7］ Guillier M， Gottesman S. Remodelling of the Escherichia coli outer membrane by two small regulatory RNAs［J］. Mol Microbiol， 2006， 59（1）: 231-247. ［8］ Viegas SC， Pfeiffer V， Sittka A， et al. Characterization of the role of ribonucleases in salmonella small RNA decay ［J］. Nucleic Acids Res， 2007， 35（22）: 7651-7664. ［9］茅凌翔，朱超望，黄新祥，等.伤寒沙门菌phoP基因缺陷变异株的制备［J］.江苏大学学报:医学版， 2007， 17（2）: 145-149. ［10］ Arraiano CM， Andrade JM， Dominques S， et al. The critical role of RNA processing and degradation in the control of gene expression［J］. FEMS Microbiol Rev， 2010， 34（5）: 883-923. ［11］ Carpousis， AJ， Van Houwe G， Ehretsmann C， et al. Copuri cation of E. coli RNAase E and PNPase: evidence for a specific association between two enzymes important in RNA processing and degradation［J］. Cell， 1994， 76 （5）: 889-900. ［12］ Jiang X， Belasco JG. Catalytic activation of multimeric RNase E and RNase G by 5′-monophosphorylated RNA ［J］. Proc Natl Acad Sci USA， 2004， 101（25）: 9211- 9216. ［13］ Tock MR， Walsh AP， Carroll G， et al. The CafA protein required for the 5′-maturation of 16S rRNA is a 5′-end-dependent ribonuclease that has context-dependent broad sequence specificity［J］. J Biol Chem， 2000， 275（12）: 8726-8732. ［14］ Afonyushkin T， Vecerek B， Moll I， et al. Both RNase E and RNase III control the stability of sodB mRNA upon translational inhibition by the small regulatory RNA RyhB ［J］. Nucleic Acids Res， 2005， 33（5）: 1678-1689. ［15］ Andrade JM， Arraiano CM. PNPase is a key player in the regulation of small RNAs that control the expression of outer membrane proteins［J］. RNA， 2008， 14（3）: 543 -551. ［16］ Reichenbach B， Maes A， Kalamorz F， et al. The small RNA GlmY acts upstream of the sRNA GlmZ in the activation of glmS expression and is subject to regulation by polyadenylation in Escherichia coli［J］. Nucleic Acids Res， 2008， 36（8）: 2570-2580. ［17］ Viegas SC， Arraiano CM. Regulating the regulators: How ribonucleases dictate the rules in the control of small non-coding RNAs［J］. RNA Biol， 2008， 5（4）: 230-243. ［18］ Viegas SC， Silva IJ， Saramago M， et al. Regulation of the small regulatory RNA MicA by ribonuclease III: a target-dependent pathway［J］. Nucleic Acids Res， 2011， 39 （7）: 2918-2930.
2012, Vol. 22 
