title: Genetic diversity of the envelope glycoprotein E2 of classical swine fever virus: recent isolates branched away from historical and vaccine strains.
abstract: The envelope glycoprotein E2 of classical swine fever virus (CSFV) plays multiple roles in the viral life cycle, interaction with host and pathogenesis. We sequenced the E2 gene of 34 CSFV isolates from southeastern China for analysis of genetic diversity in this particular region. Phylogenetic analysis revealed that genotype 2.1b viruses became predominant in southeastern China with 33 isolates clustered in 2.1b and only 1 isolate belonged to 2.2. Pairwise comparisons demonstrated isolates in this study showed a homology of 78.4-82.6% to Chinese C-strain in the 190nt of the E2 fragment. The minimum similarity within the 2.1b isolates was 91.1%. Variability of the full length E2 amino acid sequences of 45 CSFV isolates representative of three main groups of CSFV including 19 from southeastern China during 2004--2007 and 26 from other parts of China and other countries was analyzed by the differences between non-synonymous (dN) and synonymous (dS) rates and the entropy values. Two variable and three conserved regions as well as some specific positions under positive selection were defined. Our results suggest that recent isolates from southeastern China have shifted away from historical CSFV isolates including the vaccine strains probably as a result of their adaptive abilities to the selection forces within the host.
authors.affiliation: Institute of Preventive Veterinary Medicine, Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Zhejiang University, 268 Kaixuan Road, Hangzhou 310029, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Chen
authors.forename: Hongxia
authors.initials: H
authors.lastname: Hu
authors.forename: Zhanfeng
authors.initials: Z
authors.lastname: Zhang
authors.forename: Jiangbing
authors.initials: J
authors.lastname: Shuai
authors.forename: Lingli
authors.initials: L
authors.lastname: Jiang
authors.forename: Weihuan
authors.initials: W
authors.lastname: Fang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D006691:Classical Swine Fever / Q000821:virology*; D006692:Classical Swine Fever Virus / Q000145:classification / Q000235:genetics*; D016000:Cluster Analysis; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D016415:Sequence Alignment / Q000662:veterinary; D012689:Sequence Homology, Nucleic Acid; D034421:Sus scrofa / Q000821:virology; D013552:Swine; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D004279:DNA, Viral; D014759:Viral Envelope Proteins; C087086:glycoprotein E2, classical swine fever virus