云南省2009年埃可病毒6型分离株KM57—09全基因序列分析

目的对云南埃可病毒6型（Ech06）分离株KM57—09全基因序列进行分析和研究，了解其遗传特性。方法设计针对Ech06引物，提取病毒RNA、RT-PCR扩增和产物直接测序获得序列。利用Mega5．05、RDP3和SimPlot3．5．1等生物学软件分析全基因序列。结果获得KM57—09全基因组核苷酸序列长度为7419bp，编码含2191个氨基酸残基的多聚蛋白；与其他Ech06参考株核苷酸和氨基酸同源性分别为79．3％～80．2％和93．3％～94．4％，与原型株D’Amor核苷酸和氨基酸同源性分别为79．3％和93．6％。在基因组各个区段上，Ech06KM57—09分离株的2C和3A区，与HN-2-E25核苷酸同源性最高，分别为86-3％和85．0％，而其5’UTR、VP4、3D和3’UTR区则与CoxB5-Henan-2010核苷酸同源性最高，分别为91．7％、81．2％、89．7％和96．9％。在VP1区上，与中国其他省份分离株的核苷酸和氨基酸同源性分别为80．0％～96．0％和95．8％～99．0％，而与其他国家分离株的核苷酸和氨基酸同源性分别为77．6％～96．0％和95．2％-99．0％。进化分析发现Ech06可分为5个分支，中国分离株分属C和E分支，其中KM57—09属于E分支，且5个分支之间核苷酸的差异为15．6％～23．3％。3D基因序列种系进化分析以及RDP3和SimPlot3．5．1软件分析发现KM57—09序列在非结构区可能存在重组。结论Ech06可分为5个基因型，KM57—09分离株属于E基因型；中国大陆曾存在不同Ech06株传播链的流行。

Objective To analyze the genetic characterization of the complete genome from a human echovirus 6 (Echo6) strain KM57-09 isolated in Yunnan,China,in 2009.Methods Using the RT-PCR,eight fragments containing about 1000 nucleotides which covered the whole viral genome were sequenced.The sequences were aligned with other reference cnterovirus sequences downloaded from the GenBank,using Mega 5.05,RDP 3 and SimPlot 3.5.1 softwares.Results Similar to the other human cntcrovirus,KM57-09 isolate genome appeared to have 7419 nucleotides in length,encoding for 2191 amino acids.In the complete genome,the rates of homology on nucleotide and amino acid among the seven Echo6 isolates were 79.3％-80.2％ and 93.3％ 94.4％,respectively as well as 79.3％ and 93.6％ of the rates of homology when compared with that of D' Amor prototype strain.In different segment of genome.The 2C 3A genome region was most similar to the HN-2-E25 strain,the 5' UTR,VP4,3D and 3' UTR genomc region were most similar to the CoxB5-Henan2010.In the VP1 gene,the rates of homology on nuclcotide and amino acid among the China isolates were 80.0％-96.0％ and 95.8％-99.0％,respectively,and showed 77.6％-96.0％ and 95.2％-99.0％ of the rates on homology when compared to the other Echo6 reference strains isolated from other countries or areas,respectively.Results from phylogenetic analysis showed that the Echo6 formed five distinct groups,A-E.The KM57-09 strain belonged to clade E.The nucleotide divergence between clades was 15.6％-23.3％.The putative recombinant event for KM57-09 was detected with RDP 3,SimPlot 3.5.1 and 3D sequence phylogenetic analysis.Conclusion All the Echo6 isolates could be divided into five clades,the KM57-09 strain belonged to Clade E.The Echo6 strains isolated in China were contributed to several different chains of transmission.