CVB32A蛋白酶抑制帽样结构依赖的蛋白翻译

目的探讨CVB3的蛋白酶2A对真核细胞帽样蛋白翻译和内部核糖体进入位点（IRES）翻译机制的影响。方法构建表达载体pcDNA3．1—2A，将此表达载体分别与pEGFP—N1、pGL3（F-luc）以及pIRES-GFP载体共转染细胞后，荧光显微镜观察绿色荧光蛋白（GFP）的表达，检测荧光素酶蛋白的表达。WesternBlot检测CVB3病毒和pcDNA3．1-2A对真核生物翻译起始因子4GI（eIF4GI）及多聚A尾结合蛋白（PABP）的影响。结果pcDNA3．1之A可以减少帽样依赖的GFP和荧光素酶蛋白的表达，但可以促进IRES依赖的GFP表达。CVB32A基因质粒转染和CVB3感染后，均可发现细胞内elF4G的切割现象；同时CVB3对PABP也有降解作用，而CVB32A基因转染对PABP无明显作用。结论CVB3的蛋白酶2A抑制真核细胞帽样途径蛋白翻译，促进IRES途径的翻译。

CVB3 2A proteinase inhibiting cap-dependent protein translation

Objective To study the impact of on eukaryotic cell protein translation by CVB3 2A protease. Methods 293T cells were transfeeted respectively with plasmids pcDNA3.1-2A, pEGFP-N1, wihch express cap-dependent Green fluoresce protein（GFP） protein or cap-indepent, pGL3 wihch express cap-dependent luciferase protein, pIRES-GFP wihch express cap-independent GFP protein. Green Fluoresce Protein（GFP） luciferase protein were observed and dectedted respectively. The change of eukaryotic translation initiation factor 4G （eIFgG） and the poly （A）-binding protein （PABP） after CVB3 virus infection or CVB3 2A transfectionprotease were detected by Western blotting. Results CVB3 2A inhibited cap-dependent translated both GFP and luciferase protein expression, however encourage the cap- independent GFP expression from plamid pIRES-GFP cleavage of eIFgG was detected after both CVB3 infection and CVB3 2A preotease transfection reduction of PABP only was observed after CVB3 infection. Conclusions CVB3 2A protease inhihited of cap-dependent protein translation and encouraged the IRES- dependent protein translation.