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| Identification of the key amino acid residues in hypervariable region 1 for hepatitis C virus infection |
| XIE Bing; LAO Wen-Guang; LIU Wen-Yu; GUAN Mo; LIU Xiao-Qing; TAO Qing-Yuan; WANG Yan; ZHAO Ping; QI Zhong-Tian |
| Department of Microbiology, Second Military Medical University, Shanghai 200433, China |
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Abstract The hypervariable region 1 (HVR1) of hepatitis C virus (HCV), consisting of 27 amino acids at the amino terminus of envelope protein 2 (E2), is the most variable region in HCV polyprotein. HVR1 contains dominant neutralizing epitopes and plays an important role in HCV cell entry. Despite these observations, the relationship between the structure and the function of HVR1 remains unknown. In this study, a serial of deletion mutants in HVR1 of envelope gene of H77 isolate were prepared, and the respective expression plasmids were co-transfected with pseudoparticles package plasmids into human embryo kidney (HEK) 293T cells. The expression of E2 in HEK 293T cells were assayed by using Western blot, and the level of HCV pseudoviral particle (HCVpp) in supernatants were detected by using fluorescence quantitative polymerase chain reaction (PCR). Human hepatoma Huh7.5 cells were used as the target cells to assay the infectivity of HCVpp. The results showed that deletion of the complete HVR1 or partial amino acid residues in HVR1 did not affect either the expression of E2 protein or the production of HCVpp. Deletion of the amino acids at positions 16-24 increased HCVpp infectivity, and deletion of the amino acids at positions 1-8 or 1-12 only partially decreased HCVpp infectivity. Importantly, deletion of any residue at positions 13-15 or 25-27 decreased HCVpp infectivity to below 5% of the prototype pseudoparticles. The results indicate that the six amino acids at position 13-15 and 25-27 are the key residues mediating HCV cell entry.
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Received: 30 April 2011
Published: 01 January 2011
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Corresponding Authors:
ZHAO Ping; QI Zhong-Tian
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