title: Molecular characteristics of segment B of seven very virulent infectious bursal disease viruses isolated in China.
abstract: Infectious bursal disease virus (IBDV) is a birnavirus that causes immunosuppressive disease in chickens. Segment B of IBDV encodes the RNA-dependent RNA polymerase VP1, which is involved in virulence. We sequenced and analyzed segment B from seven Chinese IBDV isolates, all belonging to very virulent IBDV (vvIBDV), and clustered into Branches II and III. Phylogenetic analysis suggested that segment B of the HLJ isolates in Branch II might have originated from an unidentified host, and HuB-1 might have originated in Europe. Eight aa (4V, 61I, 145T, 287A, 508K, 511S, 646S, and 687P) were conserved in Branches II and III, and may contain potential segment B virulence determinants. Five aa (146D, 242E, 390M, 562P, and 695R) were found only in Branch III, and may be origin characteristics. Moreover, 55T and 63A in the 5'-untranslated region (UTR), and 2786C in the 3'-UTR were conserved in vvIBDV and may function in UTR secondary structure.
authors.affiliation: Division of Avian Infectious Diseases, National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China.
authors.forename: Fei
authors.initials: F
authors.lastname: Yu
authors.forename: Xiaole
authors.initials: X
authors.lastname: Qi
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Yuwen
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Wang
authors.forename: Honglei
authors.initials: H
authors.lastname: Gao
authors.forename: Yulong
authors.initials: Y
authors.lastname: Gao
authors.forename: Litin
authors.initials: L
authors.lastname: Qin
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Wang
mesh_terms: D000818:Animals; D018175:Birnaviridae Infections / Q000662:veterinary* / Q000821:virology; D002645:Chickens; D002681:China; D016000:Cluster Analysis; D005838:Genotype; D007243:Infectious bursal disease virus / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011201:Poultry Diseases / Q000473:pathology / Q000821:virology*; D012367:RNA, Viral / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D015678:Viral Structural Proteins / Q000235:genetics*; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D012367:RNA, Viral; C107669:VP1 protein, infectious bursal disease virus; D015678:Viral Structural Proteins; D037521:Virulence Factors