口蹄疫病毒株China/99 P3区一级结构及与参考毒株的比较分析

The Basic Structure of P3 Region from FMDV Strain China/99 and Comparison with Reference Strain's

用RT -PCR法 ,以口蹄疫病毒China/ 99感染的牛舌水泡皮为材料 ,扩增目的cDNA ,与pGEM TEasy载体连接并转化JM1 0 9菌株 ,再经重组质粒电泳、PCR和EcoR1酶切鉴定。序列测定和分析结果表明 ,猪源毒在 3A基因内缺失 1 0个密码子 ,与牛源毒的核苷酸和氨基酸序列差异较大。A G和T C的转换率较高 ,而且A G转换导致氨基酸变异的几率大于T C转换 ,它们是影响氨基酸稳定的因素之一。China/ 99P3区编码产物在第 8、1 2 0、1 2 1、1 2 7、1 32、1 93、493、50 1和 538位具有特征性氨基酸 ,可能与该毒株的表型如毒力等有关。 3A基因突变率较高 ,3B、3C和 3D较低 ,3D最为保守 ,这对维持 3C和 3D蛋白酶和

The sequence of P3 region of a virulent foot and mouth disease virus strain China/99 RNA from infected bovine tongue epithelium was determined by cloning of cDNA fragments obtained from RT PCR.The cDNA fragments were inserted in pGEM T Vectors and transformed into JM109,then the recombinant plasmids were identified by electrophoresis,EcoR1 cleavage and PCR.The nucleotide and amino acid sequence of FMDV strain China/99 P3 region was compared with other six reference strain's.It was shown that the differential ratio of China/99 with A12,A10 61,twcp/97 and twty/97 were 8 48%,9 02%,7 89%,2 67%,13 87%,13 80%,respectively and that of amino acid sequences was 4 52%,4 62%,3 74%,2 75%,7 82%,7 38%,respectively.The sequence alignment of these strains showed that the differential ratio of the nucleotide and amino acid sequences was remarkable between the viruses that isolated from cattle and the viruses that came from swine,we speculated that the event might relate with the species of animals.The higher conversions in T C and A C that are hot nucleotides mostly affect the stable of amino acid residues.The mutant rate of 3A gene was highest in four genes others,and 3D gene was most conservative in these genes.The product encoded by China/99 P3 region had characteristics at 8th,120th,121th,127th,132th,193th,493th,501th and 538th,the sites above waredistinct different from others',might be related with the characteristics of the strain China/99,such as virulent.etc.