论文部分内容阅读
为分析四份中国丙型肝炎病毒(HCV)阳性血清中包膜蛋白E1/E2基因的准种特征。本研究对从4份中国HCV阳性血清(1b亚型:274、366和383;2a亚型:283)中提取的HCV核酸,采用逆转录-聚合酶反应扩增编码全长E1/E2蛋白(191～764aa)的基因片段,随机挑取多个克隆测序。根据E1/E2基因核苷酸的序列与其他相关序列(来自于GenBank)构建亲缘性关系进化树,进行核苷酸与氨基酸同源性分析并对重要的基因位点进行分析。共获得阳性克隆序列43个(274株10个,283株12个,366株13个,383株8个),发现高变区HVR1、HVR2的基因异质性高,而其他抗体中和表位及跨膜区I、II及N末端糖基化位点相对保守。并首次发现在HCV 2a亚型(283血清)中多个准种序列存在1 279nt(E1区,313aa)处单碱基插入优势基因突变,导致HCV包膜蛋白编码突变与中断(E2区,398aa)。本研究对中国HCV代表株包膜蛋白E1/E2编码基因的准种多样性及一种新型插入突变进行了描述,可为进一步研究HCV免疫逃避与慢性化机制提供重要信息。
To analyze the quasispecies characteristics of four envelope protein E1 / E2 genes in Chinese hepatitis C virus (HCV) positive sera. In this study, HCV nucleic acids extracted from 4 Chinese HCV positive sera (subtypes 1b: 274, 366 and 383; subtype 2a: 283) were used to amplify the full length E1 / E2 protein 191 ~ 764aa) gene fragments, multiple clones randomly selected sequencing. The phylogenetic tree was constructed based on the nucleotide sequence of E1 / E2 gene and other related sequences (from GenBank), nucleotide and amino acid homology analysis was performed, and important gene loci were analyzed. A total of 43 positive clones (274, 10, 283, 12, 366, 383, and 8) were obtained. The HVR1 and HVR2 genes in the hypervariable regions were found to be highly heterogeneous, whereas other antibody neutralizing epitopes And transmembrane region I, II and N-terminal glycosylation sites are relatively conservative. And found for the first time that the presence of a single nucleotide insertion at 1 279 nt (E1 region, 313 aa) in multiple quasispecies sequences in HCV 2a subtype (283 serum) resulted in mutations and interruptions in HCV envelope protein encoding (E2 region, 398 aa ). This study described the quasispecies diversity and a novel insertion mutation of the E1 / E2 coding gene of the envelope protein of HCV in China, which may provide important information for further study on immune evasion and chronic mechanism of HCV.