title: Genetic analysis of the PB1-F2 gene of equine influenza virus.
abstract: Amino acid and phylogenetic analysis showed that PB1-F2 of H7N7 and H3N8 equine influenza virus (EIV) evolved into two and nine clades, respectively. The PB1-F2 gene of H7N7 EIV strains isolated after 1973 was identified as being replaced by that of H3N8 EIV circulating simultaneously. All H7N7 EIV strains before 1973 contained PB1-F2 of 34 aa, while 90 aa after 1973. Meanwhile, most H3N8 EIV strains contained PB1-F2 of 90 or 81 aa. Evolutionary rate of PB1-F2 of H3N8 EIV was similar with that of PB1 in previous study. Meanwhile, PB1-F2 of H7N7 EIV evolved in significantly higher rate when compared with PB1-F2 of H3N8 EIV. Codon usage analysis revealed that PB1-F2 gene of EIV was less biased, which was identified as being determined by three main factors: mutational bias, selection pressure, and gene length. Our studies first in details report the genetic evolution, evolutionary rate, and the factors influencing codon usage bias of PB1-F2 of EIV.
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150001, People's Republic of China.
authors.forename: Gang
authors.initials: G
authors.lastname: Lu
authors.forename: Wei
authors.initials: W
authors.lastname: Guo
authors.forename: Ting
authors.initials: T
authors.lastname: Qi
authors.forename: Jian
authors.initials: J
authors.lastname: Ma
authors.forename: Shihua
authors.initials: S
authors.lastname: Zhao
authors.forename: Zhige
authors.initials: Z
authors.lastname: Tian
authors.forename: Jialiang
authors.initials: J
authors.lastname: Pan
authors.forename: Chao
authors.initials: C
authors.lastname: Zhu
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Wang
authors.forename: Wenhua
authors.initials: W
authors.lastname: Xiang
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000235:genetics; D000818:Animals; D003062:Codon; D019143:Evolution, Molecular; D006734:Horse Diseases / Q000821:virology*; D006736:Horses; D053123:Influenza A Virus, H3N8 Subtype / Q000235:genetics* / Q000302:isolation & purification; D053126:Influenza A Virus, H7N7 Subtype / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009154:Mutation; D009976:Orthomyxoviridae Infections / Q000662:veterinary* / Q000821:virology; D012641:Selection, Genetic; D016415:Sequence Alignment; D014764:Viral Proteins / Q000235:genetics*
chemical_list: D000596:Amino Acids; D003062:Codon; C442816:PB1-F2 protein, Influenza A virus; D014764:Viral Proteins