title: Natural genetic variations in bovine leukemia virus envelope gene: possible effects of selection and escape.
abstract: Bovine leukemia virus (BLV) is an oncogenic virus widespread in cattle. It belongs to the genus Deltaretrovirus of the family Retroviridae along with human and simian T-lymphotropic viruses. Here we report the addition of 28 new sequences to the current literature of 16 full-length BLV envelope gene sequences. The phylogenetic clustering, genotyping, and geographic distribution of BLV env variations corresponded in most cases. Most natural variations are mapped to the surface of the proposed conformational models of BLV gp51 N-terminus and gp30 external domain, overlapping with or adjacent to immunogenic epitopes. Analyses for evidence of possible selection pressures suggest the BLV env is under stringent negative selection overall, while strong positive selection is indicated for immunogenic epitope G. Natural env deletions bounded by similar flanking sequences were observed in multiple isolates and would result in truncated signal peptides, missing gp51, and aberrant coding frames for other proteins.
authors.affiliation: Graduate Program in Endocrinology, 3060 Valley Life Science Building, University of California, Berkeley, CA 94720-3140, USA. xzhao@berkeley.edu
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Zhao
authors.forename: Gertrude C
authors.initials: GC
authors.lastname: Buehring
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D016384:Consensus Sequence; D017124:Conserved Sequence; D014644:Genetic Variation; D016679:Genome, Viral; D005843:Geography; D001909:Leukemia Virus, Bovine / Q000145:classification / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D011487:Protein Conformation; D012641:Selection, Genetic; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics*
chemical_list: D014759:Viral Envelope Proteins