FUNCTIONAL ROBES OF HEPATITIS A VIRUS NONSTRUCTURAL PROTEINS IN SIGNAL TRANSDUCTION

甲型肝炎病毒（HAV）感染仍然是世界范围内的一个主要问题。感染不会引起任何明显的细胞病变，也没有证据表明甲肝病毒干扰其宿主细胞的大分子合成。最近，在乙型和丙型肝炎病毒感染中，细胞内信号被诱导。为了阐明HAV感染的影响，我们检测了9种FLAG-HAV （VP2、VP3、VP1-2A、2B、2C、3A、3BC、3C、3D）蛋白对各种细胞内信号通路的影响。将病毒蛋白表达载体与报告质粒共转染到HeLa细胞中，由一个合成的启动子控制，该启动子分别包含4个循环AMP反应元件（CRE）、5个血清反应因子（SRF）、7个激活蛋白1 （AP 1）、5个核因子kB （NF-kB）和5个血清反应元件（SRE）。移植42小时后收获细胞，进行荧光素酶测定。试验至少进行了三次，病毒蛋白激活比对照组大两倍被定义为显著。HAV FLAG-VP3蛋白显著激活HeLa细胞中sre相关信号，激活值为对照组的2.2±0.3倍。然而，FLAG-VP3蛋白没有激活CRE-（1.1±0.1）、SRF-（1.6±0.2）、AP-1-（1.1±0.1）、NF-kB-（0.7±0.1）相关通路。其他HAV蛋白在CRE-、SRF-、AP-1-、NF-kB-和sre相关通路中没有信号激活。我们发现，在HeLa细胞中，HAV VP3蛋白激活了sre相关信号，即与细胞增殖、分化相关的细胞内信号通路。

Hepatitis A virus (HAV) infection is still a major problem worldwide. The infection does not induce any visible cytopathic effects, and there is no evidence that HAV interferes with the macromolecular synthesis of its host cells. Recently, in the hepatitis B and C virus infection, intracellular signals have been reported to be induced. To Clarify the effects of HAV infection, we examined the influence of 9 FLAG-HAV (VP2, VP3, VP1-2A, 2B, 2C, 3A, 3BC, 3C, 3D) proteins on various intracellular signaling pathways. Viral protein expression vectors were cotransfacted into HeLa cells with the reporter plasmids, controlled by a synthetic promoter that contains direct 4 repeats of the cyclic AMP response element (CRE), 5 repeats of the serum response factor (SRF), 7 repeats of the activator protein 1 (AP 1), 5 repeats of the nuclear factor kB (NF-kB), and 5 repeats of the serum response element (SRE), respectively. Cells were harvested 42 hours after transfaction, and luciferase assays were performed. Assays were conducted at least in triplicate, and a viral protein activation twice greater than that of the control was defined as significant. HAV FLAG-VP3 protein significantly activated the SRE-associated signal in HeLa cells at a value 2.2± 0.3 times higher than control. However, FLAG-VP3 protein did not activate the CRE-(1.1±0.1), SRF-(1.6± 0.2), AP-1-(1.1±0.1), NF-kB-(0.7±0.1) associated pathways. The other HAV proteins showed no signal activation in the CRE-, SRF-, AP-1-, NF-kB-, and SRE-associated pathways. We found that HAV VP3 protein activated the SRE-associated signal, intracellular signaling pathways associated with cell proliferation, differentiation, in HeLa cells.