Genetic characterization of the hemagglutinin genes of wild-type measles virus circulating in china, 1993-2009.
BACKGROUND: China experienced several large measles outbreaks in the past two decades, and a series of enhanced control measures were implemented to achieve the goal of measles elimination. Molecular epidemiologic surveillance of wild-type measles viruses (MeV) provides valuable information about the viral transmission patterns. Since 1993, virologic surveillnace has confirmed that a single endemic genotype H1 viruses have been predominantly circulating in China. A component of molecular surveillance is to monitor the genetic characteristics of the hemagglutinin (H) gene of MeV, the major target for virus neutralizing antibodies. PRINCIPAL FINDINGS: Analysis of the sequences of the complete H gene from 56 representative wild-type MeV strains circulating in China during 1993-2009 showed that the H gene sequences were clustered into 2 groups, cluster 1 and cluster 2. Cluster1 strains were the most frequently detected cluster and had a widespread distribution in China after 2000. The predicted amino acid sequences of the H protein were relatively conserved at most of the functionally significant amino acid positions. However, most of the genotype H1 cluster1 viruses had an amino acid substitution (Ser240Asn), which removed a predicted N-linked glycosylation site. In addition, the substitution of Pro397Leu in the hemagglutinin noose epitope (HNE) was identified in 23 of 56 strains. The evolutionary rate of the H gene of the genotype H1 viruses was estimated to be approximately 0.76×10(-3) substitutions per site per year, and the ratio of dN to dS (dN/dS) was
Song-Tao Xu, Yan Zhang, Zhen Zhu, Chunyu Liu, Naiying Mao, Yixin Ji, Hui-Ling Wang, Xiao Hong Jiang, Chongshan Li, Wei Tang, Daxing Feng, Changyin Wang, Lei Zheng, Yu eLei, Hua Ling, Chunfang Zhao, Yan MA, Jilan He, Yan Wang, Ping Li, Ronghui Guan, Shujie Zhou, Jian-Hui Zhou, Shuang Wang, Hong Zhang, Huanying Zheng, Leng Liu, Hemuti Ma, Jing Guan, Peishan Lu, Yan Feng, Yanjun Zhang, Shunde Zhou, Ying Xiong, Zhuoma Ba, Hui Chen, Xiuhui Yang, Fang Bo, Yujie Ma, Yong Liang, Yake Lei, Suyi Gu, Wei Liu, Meng Chen, David Featherstone, Youngmee Jee, William J. Bellini, Paul A. Rota, Wenbo Xu