The cDNA nucleotide sequence of genome segment B encoding the VP1 protein was determined for the aquatic birnavirus GC1 isolated from the rockfish Sebastes schlegeli in Korea. The VP1 protein of GC1 contains a 2,538 bp open reading frame, which encodes a protein comprising 846 amino acid residues that has a predicted MW of 94 kDa. The sequence contains 6 potential Asn-X-Ser/Thr motifs. Eight potential Ser phosphorylation sites and 1 potential Tyr phophorylation site were also identified. GC1 contains the Leu-Lys-Asn (LKN) motif instead of the typical Gly-Asp- Asp (GDD) motif found in other aquatic birnaviruses. We also identified the GLPYIGKT motif, the putative GTPbinding site at amino acid position 248. In total, the VP1 regions of 22 birnavirus strains were compared for analyzing the genetic relationship among the family Birnaviridae. Based on the deduced amino acid sequences, GC1 was observed to be more closely related to the infectious pancreatic necrosis virus (IPNV) from the USA, Japan, and Korea than the IPNV from Europe. Further, aquatic birnaviruses containing GC1 and IPNV have genogroups that are distinct from those in the genus Avibirnaviruses and Entomo-birnaviruses. The birnavirusstrains were clustered into 5 genogroups based on their amino acid sequences. The marine aquatic birnaviruses (MABVs) containing GC1 were included in the MABV genogroup; the IPNV strains isolated from Korea, Japan, and the USA were included in genogroup 1 and the IPNV strains isolated primarily from Europe were included in genogroup 2. Avibirnaviruses and entomobirnaviruses were included in genogroup 3 and 4, respectively.
Amino Acid Sequence ; Animals ; Base Sequence ; Birnaviridae/classification/*genetics ; Capsid Proteins/chemistry/*genetics ; Cell Line ; Fishes/*virology ; Korea ; Molecular Sequence Data ; Phylogeny

Tissue samples of Fabricius' bursa collected from Nanning, Yulin, Beihai and Wuzhou in the provinces of Guangxi in China during the years of 2000-2007, were detected by a established reverse transcriptase polymerase chain reaction (RT-PCR) technique for IBDV. Viral isolation was performed on the positive samples by chicken embryo inoculation via chorio-allantoic membrane (CAM). Results showed that 27 isolates of IBDV were obtained. A set of primers were designed to amplify the vVP2 of 27 isolates by RT-PCR and the PCR products were sequenced. The sequences of all the isolates and reference viruses were analyzed and compared, and their phylogenetic trees were constructed based on the nucleotide sequences. The results indicated that isolate BH11, TZ(3), 050222, YL051, NN0603, NN0611and QX0602 etc, altogether 17 isolates, which accounted for 62.96 percent of total isolates, were identified to be very virulent IBDV (vvIBDV) and have the highest homology to vvIBDV reference strains. In the phylogenetic analysis, they are divided into 3 groups and have a long distance to commonly used vaccine stains. Isolate NN040124 and YL052 were identified as intermediate-plus virulent strains and showed a highest homology to classical strains of 52-70 and STC. 8 isolates of YLZF2, 040131 etc were identified as attenuated vaccine strains and showed a highest homology to classical strain of CU1. The results from the study demonstrated that the viruses prevailing in chickens in these 4 regions in Guangxi province in the recently 7 years were vvIBDV and their origins were complex. The antigenicity of some isolates may have been drifted.
Amino Acid Sequence ; Animals ; Birnaviridae Infections ; epidemiology ; veterinary ; virology ; Chickens ; China ; epidemiology ; Infectious bursal disease virus ; chemistry ; classification ; genetics ; isolation & purification ; Molecular Epidemiology ; Molecular Sequence Data ; Phylogeny ; Poultry Diseases ; epidemiology ; virology ; Sequence Alignment ; Viral Proteins ; chemistry ; genetics