丙型肝炎病毒高变区基因变异特点初探

Genetic Variation Characteristics of Hepatitis C Virus Hypervariable Region

对两例ＨＣＶＲＮＡ持续阳性者分三个时间点随访五年，测定了ＨＣＶ的高变区基因序列，每个时间点平均测定２８个克隆，总共测定了１６８个克隆。研究发现ＨＣＶ高变区基因变异有五个明显特点：（１）变异程度大，高变区至少有８９％的核苷酸位点都可能发生变异；（２）变异形式多样，除常见的替代突变外，缺失突变（缺失１、２或３个核苷酸）的克隆数占总克隆数的２２．５％；（３）优势克隆明显，即有若干个克隆高变区的核苷酸和氨基酸序列相同；（４）类似株现象严重；（５）变异幅度大。该研究说明ＨＣＶ高变区基因变异具有高度复杂多样性。

At three time points duing the period of five years, the hypervaviable region gene of HCV from two patients with HCV persistent infection was amplified, sequenced and analyzed. The results demonstrated that there were five significant characteristics in genetic variation of HCV HVR. 1. Wide mutation degree and range. HVR is consistent of 81 nt and 27 aa, 89%nt (72/81) and 96%aa (26/27) mutated in 168 clones; 2.Different mutation types. Except the common substitution mutation, deletion was 22.5%; 3. Apparently dominant clones. Dominant clones always existed, although genetic variation was significant among clones at one time point;4. Phenomenon of quasispecies is very severe. In conclusion, this study demonstrated that the genetic variation of HCV HVR showed high complexity and diversity.