结核分枝杆菌Pup-蛋白酶体系统与不同毒力结核分枝杆菌致病性的相关性研究

Study of the correlation between the prokaryotic ubiquitin-like protein(Pup)-proteasome system of Mycobacterium tuberculosis and the pathogenicity of Mycobacterium tuberculosis

目的通过比较分析不同毒力结核分枝杆菌Pup、Dop、PafA和Mpa基因的表达差异,探讨Pup-蛋白酶体系统与不同毒力结核分枝杆菌致病性的相关性。方法分别提取卡介苗菌株(BCG)、结核分枝杆菌国际标准无毒珠(H37Ra)、结核分枝杆菌国际标准强毒珠(H37Rv)、新疆地区流行的优势强毒结核分枝杆菌临床分离株总RNA,并进行纯度鉴定。运用SYBR GreenⅠ实时荧光定量PCR检测结核分枝杆菌Pup、Dop、PafA和Mpa基因的表达,比较分析不同毒力结核分枝杆菌Pup、Dop、PafA和Mpa基因的表达差异。结果 H37Rv菌株和新疆地区流行的优势强毒结核分枝杆菌临床分离株与BCG菌株相比,Pup基因表达分别上调1.67、2.65倍,Dop基因表达分别上调2.42、3.69倍,PafA基因表达分别上调4.09、7.36倍,Mpa基因表达分别上调2.65、3.91倍,差异有统计学意义(P<0.05);BCG、H37Ra、H37Rv菌株与新疆地区流行的优势强毒结核分枝杆菌临床分离株相比,Pup基因表达分别下调62%、59%、37%倍,Dop基因表达分别下调63%、64%、34%倍,PafA基因表达分别下调87%、86%、44%倍,Mpa基因表达分别下调64%、67%、32%倍,差异有统计学意义(P<0.05)。结论在BCG、H37Ra、H37Rv、新疆地区流行的优势强毒结核分枝杆菌临床分离株Pup、Dop、PafA和Mpa基因的表达有差异性,且与菌株毒力呈正相关。Pup-蛋白酶体系统与不同毒力结核分枝杆菌致病性具有相关性。

Objective Different levels of expression of the genes Pup,Dop,PafA,and Mpa in Mycobacterium tuberculosis with different levels of virulence were comparatively analyzed to explore the correlation between the prokaryotic ubiquitin-like protein（Pup）-proteasome system of M.tuberculosis and the pathogenicity of M.tuberculosis with different levels of virulence. Methods Total RNA was extracted from the BCG,H37 Ra,and H37 Rv strains of M.tuberculosis and from virulent clinical isolates of M.tuberculosis predominant in the Xinjiang region.The purity of the RNA was determined.The level of expression of the genes Pup,Dop,PafA,and Mpa by M.tuberculosis strains was quantified using SYBR Green I qRT-PCR in order to identify differences in expression of the genes Pup,Dop,PafA,and Mpagenes by M.tuberculosis with different levels of virulence. Results In the H37 Rv strain and virulent clinical isolates of M.tuberculosis predominant in the Xinjiang region,expression of the Pup gene was up-regulated 1.67 and 2.65-fold,expression of the Dop gene was up-regulated 2.42 and 3.69-fold,expression of the PafA gene was up-regulated 4.09 and 7.36-fold,and expression of the Mpagene was up-regulated 2.65 and 3.91-fold in comparison to expression in the BCG strain.Differences in the levels of expression were statistically significant（P〈0.05）.In the BCG,H37 Ra,and H37 Rv strains,expression of the Pup gene was down-regulated 0.62,0.59,and 0.37-fold,expression of the Dop gene was down-regulated 0.63,0.64,and 0.34-fold,expression of the PafA gene was down-regulated 0.87,0.86,and 0.44-fold,expression of the Mpagene was down-regulated 0.64,0.67,and 0.32-fold in comparison to the virulent clinical isolates of M.tuber-culosis predominant in the Xinjiang region. Conclusion Significant differences in the levels of Pup,Dop,PafA,and Mpa expression were noted in the BCG,H37 Ra,and H37 Rv strains and in virulent clinical isolates of M.tuberculosis predominant in the Xinjiang region.These levels of expression were correlated with different levels of virulence.The Pupproteasome system of M.tuberculosisis correlated with the pathogenicity of M.tuberculosis with different levels of virulence.