title: Sequencing and phylogenetic analysis of the gp51 gene from Korean bovine leukemia virus isolates.
abstract: BACKGROUND
  Bovine Leukemia virus (BLV) infection of cattle has been reported in Korea for more than three decades. However, to date, there have been few studies regarding Korean BLV since 1980s. Thus, the purpose of this study is to perform a diagnosis and molecular characterization of BLV strains circulating in Korea and to estimate genetic diversity of different genotypes of BLV.
  
  
  METHODS
  To investigate the distribution of BLV variants in the world and assess the evolutionary history of Korean BLV isolates, a comprehensive molecular analysis of the BLV env gp51 gene was conducted using recent worldwide BLV isolates. The isolates included 50 samples obtained from two cattle farms in southeastern Korea in 2014.
  
  
  RESULTS
  Sequence and phylogenetic analyses of partial 444-nt fragment sequences and complete gp51 sequences of BLV revealed eight distinct genotypes of BLV showing geographic distribution of the world. Most Korean BLV isolates were found to belong to genotype 1 which is a major genotype prevailed throughout the world, and only four isolates from one farm were classified as genotype 3 related to the US and Japan isolates. Analysis of amino acids of Korean BLV isolates showed several sequence substitutions in the leader peptide, conformational epitope, and neutralizing domain regions. The observations suggest the possibility of affecting on viral infectivity and formation.
  
  
  CONCLUSIONS
  Korean BLV isolates showed the close relationship to genotype 1 and 3. Further study to identify the diversity of BLV circulating in Korea is necessary with samples collected nationwide because this study is the first report of BLV genotype 3 being in circulation in Korea.
authors: Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyangro, Anyang, Gyeonggido, 430-757, Republic of Korea. sys305@korea.kr.
authors: EunJung
authors: E
authors: Lee
authors: Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyangro, Anyang, Gyeonggido, 430-757, Republic of Korea. happylion00@korea.kr.
authors: Eun-Ju
authors: EJ
authors: Kim
authors: Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyangro, Anyang, Gyeonggido, 430-757, Republic of Korea. immalra@korea.kr.
authors: Ha-Kyung
authors: HK
authors: Joung
authors: Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyangro, Anyang, Gyeonggido, 430-757, Republic of Korea. lordpraiser@korea.kr.
authors: Bo-Hye
authors: BH
authors: Kim
authors: Veterinary Drugs and Biologics Division, Anyang, 430-757, Gyeonggido, Republic of Korea. songjysong@korea.kr.
authors: Jae-Young
authors: JY
authors: Song
authors: Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyangro, Anyang, Gyeonggido, 430-757, Republic of Korea. chois38@korea.kr.
authors: In-Soo
authors: IS
authors: Cho
authors: Animal Disease Diagnostic Division, Animal and Plant Quarantine Agency, Anyang, 430-757, Gyeonggido, Republic of Korea. naturelkk@korea.kr.
authors: Kyoung-Ki
authors: KK
authors: Lee
authors: Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyangro, Anyang, Gyeonggido, 430-757, Republic of Korea. shinyk2009@korea.kr.
authors: Yeun-Kyung
authors: YK
authors: Shin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D016583:Enzootic Bovine Leukosis / Q000175:diagnosis / Q000821:virology*; D019143:Evolution, Molecular; D014644:Genetic Variation; D005838:Genotype; D001909:Leukemia Virus, Bovine / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010802:Phylogeny; D056910:Republic of Korea; D016415:Sequence Alignment; D014759:Viral Envelope Proteins / Q000235:genetics*
chemical_list: D014759:Viral Envelope Proteins