丙型肝炎病毒3′非编码区终止密码子变异

Gene mutation of stop coden in 3' untranslated region of hepatitis C Virus

目的探讨中国大陆1b型丙型肝炎病毒(HCV)3'非编码区(3'UTR)一级结构的变异规律,为进一步研究其在HCV复制、翻译中的调控机制、开发新的抗HCV药物奠定基础。方法利用逆转录套式聚合酶链反应(RT-PCR)限制性内切酶长度多态性分析(RFLP)初步筛选出1b型HCV感染者,采用半套式RT-PCR法扩增出约400 bp的cDNA片段,克隆测序。结果获得了全长1b型HCV 3'端序列,发现终止密码子存在两种突变,由TGA突变为TAA或TGG,从而丧失了终止密码子功能,可导致NS5B的翻译不能及时终止。结论中国大陆1b型丙型肝炎病毒终止密码子存在多种突变,其中TGG突变可导致NS5B区延长,3'UTR缩短;该发现对了解HCV的复制和翻译机制可能有一定的理论和实践意义。

Objective To obtain full-length cDNA of hepatitis C virus （HCV） 3＇untranslated region （3＇UTR）, and to analysis its primary structure. Methods By using reverse transcription-nested polymerase chain reaction （RT-PCR） and restriction fragment length polymorphism （RFLP） assay, patients with infected genotype lb HCV were identified. Fragments of the 3＇UTR eDNA were amplified by using semi-nested RT-PCR, and then subjected to cloning and sequencing. Results The sequence of 3; UTR in genotype 1 b HCV was obtained. Two kinds of mutations were found in the stop codon. The stop codon TGA was mutated into TAA or TGG and the translation could not stop promptly. Conclusion There are various mutations in the stop codon Of genotype 1 b HCV. The mutations of stop coden may lead to the extension of NS5B and decurtation of 3＇UTR. The research is helpful for further study of HCV gene replication and translation.