不同甲型肝炎病毒株间部分编码VP_1N端的核苷酸序列比较

COMPARISON OF PARTIAL NUCLEOTIDE SEQUENCE CODING FOR VP_1 N-TERMINUS AMONG HEPATITIS A VIRUS STRAINS

为估计从毛蚶中提取的甲肝病毒的VP_(1)N端核苷酸和氨基酸的变异,本实验用DNA多聚酶链反应特异性地扩增该区域基因,并将其次级克隆到M13载体作双脱氧核苷酸序列分析。与发表的HM-175、CR326和HAS-15株相应区域比较,除HAS-15株从第76位至93位存在18个核苷酸缺失外,测得的204个核苷酸序列中分别存在15、12和4个碱基替换。其中大多数碱基替换发生在不引起氨基酸改变的第三密码子上,仅第86、91和176位核苷酸改变在第一或第二密码子上。据此推导出不同地区甲肝病毒株的VP_(1)N端前68个氨基酸,除HAS-15株有6个氨基酸缺失外,只存在1至2个氨基酸区别。考虑到病毒是否经传代培养,无明显证据表明绒猴传代与这一区域核苷酸变异有关。

To assass the nuclear acid and amino acid variability within the VP1 N-terminus of Hepatitis A virus isolated from clams, the genome of this region was specifically amplified by the polymerase chain reaotion(PCR). Then the purified PCR, product was directly subcloned into the M13 vector for dideoxynucleotide sequence analysis. As compared with the previously published data of HM-175, CR326 and HAS-15 strains, a total of 15,12, and 4 possible base substitutions, out of 201 nucleotides sequenoed, has been identified respectively in addition to the HAS-15 isolate containing an eighteen nucleotide deletion from position 76 to 93. Because of the most substitutions occuring at the third ooden except position 86, 91 and 176, the first 68 amino acids of the VP1 N-terminus derived from the nucleotide sequence of the strains from different region is highly conserved, which shows only one or two amino acid difference with the exception of the HAS-15 isolato containing a six amino acid deletion. In view of the propagation of the Hepatitis A virus there is no obvious evidence for the relationship between the marmoset passage and nucleotide variability in this region.