Shesheer Kumar Munpally, Venkateswara Rao Khareedu, Mohammed Habeebullah Chittor, Dashavantha Reddy Vudem
Centre for Plant Molecular Biology, Osmania University, Hyderabad 500 007, AP, India.
Infect Genet Evol. 2008 May;8(3):374-7. doi: 10.1016/j.meegid.2007.12.008. Epub 2008 Jan 5.
Apart from the core (21kD), a novel hepatitis C virus (HCV) frame shift protein (F1) is synthesized from the initiation codon of the polyprotein sequence followed by ribosomal frame shift into the -2/+1 reading frame. To date, no information is available on F1 protein of Indian isolates, and hence detection of antibodies for F1 protein in Indian patients assumes great relevance. Specific primers have been designed to amplify sequence coding for 120aa of truncated F1 (tF1). The amplified tF1 has been cloned in bacterial expression vector, pET21b for expression in Escherichia coli. Partially purified expressed protein has been subjected to western blot analysis using patients' sera. Three HCV positive sera employed in western analysis showed positive signals to tF1, while sera from uninfected individuals failed to give any signals. Further, results of western blots, carried out with patients sera titrated with purified core protein, confirmed the presence of antibodies specific to F1. The positive signal observed for F1 in western analysis with HCV infected sera suggests that F1 protein is synthesized in the natural course of HCV infection in Indian patients as well. Presence of antibodies against F1 protein of subtype 1c has been demonstrated, for the first time, in Indian patients.
除核心蛋白（21kD）外，一种新型丙型肝炎病毒（HCV）移码蛋白（F1）由多聚蛋白序列的起始密码子合成，随后核糖体移码进入-2/+1读码框。迄今为止，尚无关于印度分离株F1蛋白的信息，因此检测印度患者中F1蛋白的抗体具有重要意义。已设计特异性引物来扩增编码截短型F1（tF1）120个氨基酸的序列。扩增的tF1已克隆到细菌表达载体pET21b中，用于在大肠杆菌中表达。部分纯化的表达蛋白已用患者血清进行蛋白质印迹分析。蛋白质印迹分析中使用的三份HCV阳性血清对tF1显示出阳性信号，而未感染个体的血清未给出任何信号。此外，用纯化核心蛋白滴定的患者血清进行的蛋白质印迹结果证实了存在针对F1的特异性抗体。在HCV感染血清的蛋白质印迹分析中观察到的F1阳性信号表明，F1蛋白也在印度患者HCV感染的自然过程中合成。首次在印度患者中证实了存在针对1c亚型F1蛋白的抗体。
