title: Biosynthesis and chemical and immunological characterization of avian reticuloendotheliosis virus env gene-encoded proteins.
abstract: Two glycosylated proteins designated gp90 and gp20 were purified from replication-competent avian reticuloendotheliosis associated virus (REV-A). The N-terminal sequences of gp90 and gp20 were determined and found to match the REV-A-env-gene sequence. The alignments of the determined amino acid sequences with the predicted sequence indicate that gp20 and gp90 are the REV-A-encoded viral transmembrane and surface glycoprotein, respectively, and predict a signal peptide of 36 residues on the 5' end of the env-gene. Furthermore, gp90 of REV-A was detected by Western blot analysis with antibodies to a tridecapeptide corresponding to an env-gene nucleotide segment immediately preceding gp20 and thus representing the C-terminal portion of gp90. The env-gene precursor polyprotein gPr75-79env and Pr22(E), the precursor to gp20 and p2(E) were identified in the infected cells by monospecific antibodies raised against purified gp20. Thus the organization of gPR75-79env is likely to be N-gp90-gp20-p2(E), resembling that of M-MuLV gp85env. Sequence comparisons showed that the env gene of REV-A is highly related to both baboon endogenous virus and Type D retroviruses. In Western blot analyses, antibodies to REV-A gp20 cross-reacted with a panel of mammalian Type C and Type D viruses. Evolutionary aspects of these findings are discussed.
mesh_terms: D000595:Amino Acid Sequence; D000956:Antigens, Viral / Q000276:immunology* / Q000302:isolation & purification; D005814:Genes, Viral; D008970:Molecular Weight; D011498:Protein Precursors / Q000235:genetics; D011499:Protein Processing, Post-Translational; D001356:Reticuloendotheliosis virus / Q000276:immunology / Q000378:metabolism*; D012190:Retroviridae / Q000378:metabolism*; D012191:Retroviridae Proteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D014759:Viral Envelope Proteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D000956:Antigens, Viral; D011498:Protein Precursors; D012191:Retroviridae Proteins; D014759:Viral Envelope Proteins