2015年人腺病毒C亚属辽宁分离株的全基因组序列特征及其分子进化分析

Characteristics of the Full-length Genome and Molecular Evolution of Human Mastadenovirus Species C Isolated in Liaoning Province,China,in 2015

人腺病毒C亚属(Human mastadenovirus species C,HAdV-C)是呼吸系统疾病最常见的病原体。本文从辽宁省2015年急性弛缓性麻痹(AFP)监测病例的粪便标本中分离出一株HAdV-C的重组毒株LN2015,对其全基因组序列进行了测序和分析,并对HAdV-C的分子进化机制进行了研究。我们从GenBank数据库中选取了77条代表各个地区各个年份毒株的全(近)基因组序列,以猴腺病毒SAdV-40.1和SAdV-42.1为外类群,分别构建了基于邻接法和最大似然法的系统发育树,并用软件simplot3.5.1对基因组特征进行分析。结果表明,LN2015与北京株BJ09(MF315029)序列一致性最高,其Penton base、DBP、pV、pVI和HAdV-1相似,Hexon和Fiber为HAdV-2,3’端的E1B和5’的E4和HAdV-5相似,其基因型为P1H2F2。在两个系统发育树中,HAdV-2都聚为5个不同的谱系,每个谱系几乎都没有HAdV-6基因的参与,因此推测出HAdV-C的一条进化路线,即先由HAdV-5(或其共同祖先病毒)进化出HAdV-1,然后再进化出HAdV-2。HAdV-6和HAdV-2是HAdV-C两条独立的进化分支。未来有必要对HAdV-C的进化和变异进行更深入的研究。

Human mastadenovirus species C(HAdV-C) is the most common etiologic agent of respiratory disease in young children.A recombinant HAdV-C strain(LN2015) was isolated from fecal specimens of patients with acute flaccid paralysis in Liaoning Province,China.Samples were collected in 2015.Full-length genomic and molecular evolution analysis of the LN2015 strain was performed.The genome sequence of the LN2015 strain was determined.Then,phylogenetic trees were constructed using the whole genome or near-fulllength genomes of HAdV-C based on the neighbor-joining(NJ) method and Maximum-Likelihood(ML) method by analyzing the LN2015 strain together with other 77 reference strains from different countries and times downloaded from GenBank as well as outgroups is SAdV-40.1 and SAdV-42.1.Whole-genome characterization and comparative genomic analysis were carried out using SimPlot3.5.1.Strain LN2015 showed the highest identity with HAdV-C strain BJ09(MF315029) isolated from a toddler(<1year of age) clinically diagnosed with infection of the upper respiratory tract,collected in 2013.The Penton base gene,DBP gene,pV gene and pVI gene of the LN2015 strain showed highest sequence identity to HAdV-1.The Hexon and Fiber proteins were highly similar to those in HAdV-2.The E1B protein of 3' end and E4 protein of 5' end were highly similar to those of HAdV-5,and the genotype was P1H2F2.Serotype HAdV-2 was clustered in five lineages both in the NJ tree and ML tree,and virtually no serotype HAdV-6 genes were involved in each lineage.Evolutionary analysis suggested that HAdV-1 evolved from HAdV-5 or their common ancestor,then HAdV-2 evolved.HAdV-6 and HAdV-2 are two independent evolutionary branches of HAdV-C.Further study of the evolution and variation of HAdV-C is needed.