Structure and genetic variability of envelope glycoproteins of two antigenic variants of caprine arthritis-encephalitis lentivirus.
To define the structure of the caprine arthritis-encephalitis virus (CAEV) env gene and characterize genetic changes which occur during antigenic variation, we sequenced the env genes of CAEV-63 and CAEV-Co, two antigenic variants of CAEV defined by serum neutralization. The deduced primary translation product of the CAEV env gene consists of a 60- to 80-amino-acid signal peptide followed by an amino-terminal surface protein (SU) and a carboxy-terminal transmembrane protein (TM) separated by an Arg-Lys-Lys-Arg cleavage site. The signal peptide cleavage site was verified by amino-terminal amino acid sequencing of native CAEV-63 SU. In addition, immunoprecipitation of [35S]methionine-labeled CAEV-63 proteins by sera from goats immunized with recombinant vaccinia virus expressing the CAEV-63 env gene confirmed that antibodies induced by env-encoded recombinant proteins react specifically with native virion SU and TM. The env genes of CAEV-63 and CAEV-Co encode 28 conserved cysteines and 25 conserved potential N-linked glycosylation sites. Nucleotide sequence variability results in 62 amino acid changes and one deletion within the SU and 34 amino acid changes within the TM.
Knowles
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USDA Agricultural Research Service Animal Disease Research Unit, College of Veterinary Medicine, Washington State University, Pullman 99164-7040.
Cheevers
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McGuire
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Brassfield
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Harwood
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D000595:Amino Acid Sequence; D000818:Animals; D000940:Antigenic Variation; D016088:Arthritis-Encephalitis Virus, Caprine / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003062:Codon / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D015686:Gene Products, env / Q000235:genetics* / Q000276:immunology; D015752:Genes, env; D016679:Genome, Viral; D006041:Goats; D008969:Molecular Sequence Data; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
D003062:Codon; D004279:DNA, Viral; D015686:Gene Products, env; D012367:RNA, Viral