HCV核心蛋白与截短型HBV表面抗原中蛋白的协同反式激活功能

Synergetic transactivating functions of HCV core and truncated HBV middle surface protein

目的 探讨HCV核心蛋白与截短型HBV表面抗原中蛋白的协同反式激活作用。方法 构建表达HCV核心蛋白的重组质粒 pcDNA3.1（-）-core和表达截短型 HBV表面抗原中蛋白的重组质粒pcDNA3.1（-）-Mt;转染HepG2细胞,从转录和翻译水平鉴定病毒基因的瞬时表达;与报告质粒pSV—lacZ共转染HepG2细胞,检测β-半乳糖苷酶（β-gal）表达活性,酶的活性反映了表达的肝炎病毒蛋白对SV40病毒早期启动子（增强子）功能的影响。结果 构建成HCV核心蛋白及截短型HBV 表面抗原中蛋白的重组表达载体pcDNA3.1（-）-core、pcDNA3.1（-）-Mt;在HepG2细胞均能瞬时表达相应的病毒蛋白;单独的共转染实验中pcDNA3.1（-）-core、pcDNA3.1（-）-Mt组的β-gal的表达分别是对照的4.6和3.2倍,两种质粒共同转染时酶的表达是对照组的8.4倍;表达质粒对β-gal表达的激活作用呈剂量依赖性。结论HepG2细胞中表达的HCV核心蛋白和截短型HBV表面抗原中蛋白均具有反式激活SV40早期启动子（增强子）的功能,并且两种蛋白的反式激活功能具有协同特性。本实验有助于解释HCV、HBV感染,尤其是共同感染的致病（癌）机制。

Objective To investigate the synergetic transactivating functions of HCV core and truncated HBV middle surface proteins. Methods Two recombinant expression plasmids harboring HCV core and C-terminally truncated HBV middle surface protein gene were constructed, respectively. The plasmids were transfected into HepG2 cells and cotransfected HepG2 cells with reporter plasmid pSV-lacZ by lipofectamine plus reagents. The transient expressed viral proteins were identified at the transcription and translation levels. The activity of β-galactosidase was detected, which reflected the transactivating function of the proteins. Results The protein expression of plasmids was detected in soluble cell extracts of transiently transfected HepG2 cells. HCV core protein activated the β-galactosidase expression at a value of 4.6 times higher than the control, while C-terminally truncated HBV middle surface protein activated at a value of 3.2 times. It reached 8.4 times transfected with the plasmids simultaneously. The transactivating effect was dose dependent. Conclusions It is suggested that the two kinds of virus proteins have transactivating effect on SV40 early promoter/enhancer, and they act synergistically. These contribute to explain the mechanisms of liver injury or tumorigenesis induced by HCV or/and HBV infection.