浙江省宁波市2015年麻疹野毒株核蛋白和血凝素蛋白基因分析

Genetic Characteristics of Nucleoprotein and Hemagglutinin of Measles Virus Isolated in Ningbo of Zhejiang Province,2015

目的了解宁波市2015年麻疹野毒株核蛋白（N）基因及血凝素蛋白（H）基因特征。方法对宁波市2015年分离的麻疹野毒株进行逆转录-聚合酶链反应（RT-PCR）扩增N基因,随机选取20株扩增H基因,序列测定后与基因库中麻疹病毒各基因型参考株比对分析。结果宁波2015年分离麻疹病毒38株,均为H1a基因亚型,核苷酸和氨基酸的同源性分别为98.2%~100%和98%~100%,与H1a亚型参考株china93-7的同源性分别为98.0%~98.9%和97.3%~99.3%;与H1b亚型参考株china94-7的同源性分别为96.6%~96.8%和96%~98%;与中国疫苗株S191的同源性为90.6%~91.7%和87%~89.3%。H基因核苷酸和氨基酸之间的同源性分别为97.9%~99.9%和98.9%~100%;与疫苗株S191的同源性分别为93.7%~94.1%和94.7%~95.4%。H蛋白240位和397位氨基酸分别发生从Ser到Asn、从Pro到Leu的变化。结论宁波市2015年流行的麻疹野毒株主要为H1a基因亚型。与S191相比有较大变异,H基因有较大差异,应加强对H、N基因的常规监测。

Objective This study was to analyze the genetic characteristic of nucleoprotein（N） and hemagglutinin（H） of measles virus strains isolated in Ningbo,2015.Methods The N genes of all 38 strains and H genes of 20 selected strains were amplified by reverse transcription-polymerase chain reaction（RT-PCR）.Sequencing results were compared with reference strains of measles viruses published in Gene Bank.Results All isolated strains from 38 measles cases belonged to genotype H1 a.Homologies in nucleotides（nt） and amino acids（aa） were 98.2%-100% and 98%-100%,respectively,with homologies of 98.0%-98.9% and 97.3%-99.3% compared with the China93-7strain and homologies of96.6%-96.8% and 96%-98% compared with the China94-7 strain.Homologies of H genes in nt and aa among 20 strains were 97.9%-99.9% and 98.9%-100%,respectively,with homologies of 93.7%-94.1% and 94.7%-95.4% compared with the S191 strain.The 240 thaa and the 397 thaa of H protein changed from Ser to Asn and from Pro to Leu,respectively.Conclusions Genotype H1a was the predominant epidemic strain of measles virus circulating in Ningbo,2015,with significant difference in H protein compared with China vaccine strain S191.It is necessary to strengthen the monitoring of measles virus genotype and its variation in the future.