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探讨HCV准种在NS2区的基因结构特征及变异状况。利用逆转录 巢式PCR从 1份HCV慢性携带者的阳性血清及 1份丙肝患者的血清中获得HCVNS2全长cDNA ,将其克隆于T载体 ,各随机挑取 5个阳性克隆进行序列测定。结果显示克隆到HCVNS2全长基因 ,所测克隆在核苷酸水平和氨基酸水平互不相同。该慢性携带者HCVNS2区序列以完整读码框架 (ORF)为主 ,一个于HCV多聚蛋白第 835位氨基酸的位置出现终止信号 ,而该丙型肝炎患者以NS2N端发现终止信号的序列为主 ,其中三个于第 835位氨基酸的位置出现终止信号 ,一个于第 887位氨基酸的位置出现终止信号 ,仅一个克隆的序列为完整ORF。对ORF完整的序列进行比较 ,发现丙型肝炎患者氨基酸变异主要集中于N端 ,蛋白二级结构模拟显示丙肝患者NS2与慢性携带者的优势二级结构类似。研究表明从我们选择的两例感染者的HCVNS2序列看 ,不同临床类型的HCV病人体内的HCV准种在NS2区存在差异 ,这种差异可能与病毒存在于机体的状态有一定的一致性。
To investigate the gene structure and variation of HCV quasispecies in the NS2 region. HCV NS2 full-length cDNA was obtained from the serum of 1 chronic hepatitis C carrier and 1 hepatitis C virus by reverse transcription nested PCR. The full length cDNA of HCV NS2 was cloned into T vector and 5 positive clones were randomly selected for sequencing. The results showed that the cloned HCV NS2 full-length gene, the measured clones in the nucleotide and amino acid levels are different from each other. The chronic HCVNS2 region of the chronic carrier is mainly composed of a complete reading frame (ORF), a stop signal appears at the position of the amino acid at position 835 of the HCV polyprotein, and the sequence of the stop signal is found mainly at the NS2N end of the hepatitis C virus , Three of which showed a stop signal at the 835th amino acid position, one at the 887th amino acid position, and only one of the cloned sequences was a complete ORF. Comparing the complete sequence of ORF, it was found that the amino acid variation in hepatitis C patients mainly concentrated on the N-terminal. The protein secondary structure simulation showed that the secondary structure of NS2 in chronic hepatitis C patients was similar to chronic carriers. The study shows that from the HCVNS2 sequences of two infected patients of our choice, HCV quasispecies in different clinical types of HCV patients have differences in the NS2 region, and this difference may be consistent with the existence of the virus in the body state.