猪链球菌2型srtF基因敲除突变株的构建及其毒力

Construction and Virulence Assays of the sortase F Gene Knock-out Mutant of Streptococcus suis 2

摘要:

利用同源重组基因敲除方法构建猪链球菌2型强毒株05ZYH33 srtF同源突变体。组合PCR、交叉酶切、RT-PCR结果均显示srtF突变体构建成功。突变株与强毒株的菌落形态、生长速率以及对小鼠的致病力均无显著性差异。小鼠竞争实验结果提示, 突变株在心脏的定殖及感染能力显著减弱。成功构建的srtF突变株为进一步研究srtF 的生物学功能奠定了基础。

关键词:猪链球菌2型, sortase F, 基因敲除, 毒力

Abstract:

To approach the relationship between the srtF gene and the high pathogenicity of S. suis 2 05ZYH33, an isogenic knockout mutant of srtF was generated based on the principle of homologous recombination and confirmed by PCR, restriction analysis and reverse transcription polymerase chain reaction. The resulting mutant strain exhibited growth kinetics equivalent to those of the WT parent strain upon cultivation in standard laboratory used in our in vitro assays. A similar absence of difference between parent strain and mutant was observed when competition infection mice by the WT and mutant strains was evaluated. Taken together, these results suggest that srtF might in fact not critical for the full virulence of S. suis 2. It is to expect that future study carried out with S. suis 2 to verification the conclusions.

Key words:Streptococcus suis 2, sortase F, Gene knock-out, Virulence assay