Important note: Information in this article was accurate in 1990. The state of the art may have changed since the publication date.
GENOTYPIC AND PHENOTYPIC VARIATION IN THE ENV GENE OF AVIAN RETROVIRUSES
Diss Abstr Int [B]; 50(3):937 1989. Unique Identifier : AIDSLINE ICDB/90659530 Hill CB; Univ. of North Carolina at Chapel Hill
Abstract:
Avian retroviruses have been classified into five distinct subgroups based on host range (specific receptor recognition), antigenicity (response to specific neutralizing antibodies), and interference (masking of the receptor by the viral glycoprotein). Using recombinant viruses made from cloned DNA isolates, the role of the gp85-coding domain of env in both receptor recognition and recognition by subgroup-specific neutralizing antibodies was defined. The gp85-coding domains from four different virus isolates (subgroups A, B, D, and E) were sequenced and compared to the known sequence of a subgroup C isolate. Four variable regions in the nucleotide sequence (and the predicted amino acid sequence) were defined that correlate with subgroup specificity. An extreme conservation of secondary structure was predicted for the different subgroup viruses by computer analysis of secondary structure. From sequence comparisons of viruses of the same subgroup, seven hypervariable domains were identified along the gp85-coding domain. The heterogeneity in the sequence did not appear to influence receptor binding by the individual viruses; however, the heterogeneity was shown to be distinguishable by neutralizing antibodies. If the neutralizing antibodies act to block receptor interaction, then the occurrence of the hypervariable domains within the variable domains supports the role of the variable domains in defining the receptor binding domain. The sequence of a host range variant, a subgroup D virus, was analyzed to address the role of sequence variability in gp85 that enables the virus to penetrate mammalian cells. The host range of recombinant subgroup B and subgroup D viruses was analyzed in a susceptible mammalian cell line. The extended host range phenotype of the subgroup D virus appears to be caused by multiple domains along the primary gp85-coding sequence. The results of the recombinant virus study suggest that the ability of the subgroup D virus to penetrate mammalian cells involves a destabilization of the glycoprotein complex perhaps enabling the viral envelope to nonspecifically fuse with the cell membrane. (Full text available from University Microfilms International, Ann Arbor, MI, as Order No. AAD89-14427)
Keywords: Animal Base Sequence Birds/*MICROBIOLOGY DNA, Viral/GENETICS Gene Products, env/*GENETICS *Genes, Viral Genotype Phenotype Recombination, Genetic Retroviridae/CLASSIFICATION/*GENETICS Retroviridae Proteins/*GENETICS Variation (Genetics) THESIS 900530
M9051027
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Important note: Information in this article was accurate in 1990. The state of the art may have changed since the publication date.
