一株Ⅲ型WU多瘤病毒的分离培养和全基因组进化分析

Isolation and genome-wide evolutionary analysis of a typeⅢWU polyomavirus strain

目的分离培养WU多瘤病毒(WU polyomavirus,WUPyV)并分析全基因组系统进化、同源性及种群动态特征。方法采用实时荧光定量PCR检测2020—2022年间北京友谊医院呼吸道感染住院患儿鼻咽抽吸物样本,利用气液两相的原代人呼吸道上皮细胞模型对WUPyV阳性样本进行病毒分离培养,Sanger测序获得全基因组,结合GenBank数据库中已公布的全基因组信息进行系统发育和进化动力学研究。结果WUPyV在2020—2022年的检出率为4.7%(31/659),并成功分离1株Ⅲc型WUPyV临床病毒株BJ0593。WUPyV全基因组及各基因片段同源性较高,VP2基因的平均进化速率约为每年1.256×10^(-4)个氨基酸替换/位点,种群动态在近十年内趋于平缓。结论本研究首次成功分离Ⅲ型WUPyV临床病毒株,为WUPyV的分子进化及致病性研究提供基础。

Objective To isolate and culture WU polyomavirus(WUPyV),and to analyze the genome-wide evolutionary patterns,homology and population dynamics.Methods Real-time quantitative PCR was used to detect the nasopharyngeal aspirate samples of hospitalized children with respiratory tract infection in Beijing Friendship Hospital during 2020 to 2022.Primary human airway epithelial cells cultured at the air-liquid interface were used to isolate and culture WUPyV.Whole genome sequence of the isolated strain was obtained by Sanger sequencing.For phylogenetic and evolutionary dynamics analysis,the whole genome was compared with the published whole genome sequences in GenBank database.Results The detection rate of WUPyV was 4.7%(31/659)during 2020 to 2022,and a clinical strain BJ0593 of WUPyV typeⅢc was successfully isolated.The homology of the whole genome and gene fragments of WUPyV was high.The average evolutionary rate of VP2 gene was about 1.256×10^(-4) substitution/site every year,and the population dynamics of WUPyV tended to be flat in the last decade.Conclusions This study successfully isolated a clinical WUPyV typeⅢstrain for the first time,which provided the basis for further investigation on the molecular evolution and pathogenicity of WUPyV.