The avian retrovirus env gene family: molecular analysis of host range and antigenic variants.
The nucleotide sequence of the env gp85-coding domain from two avian sarcoma and leukosis retrovirus isolates was determined to identify host range and antigenic determinants. The predicted amino acid sequence of gp85 from a subgroup D virus isolate of the Schmidt-Ruppin strain of Rous sarcoma virus was compared with the previously reported sequences of subgroup A, B, C, and E avian sarcoma and leukosis retroviruses. Subgroup D viruses are closely related to the subgroup B viruses but have an extended host range that includes the ability to penetrate certain mammalian cells. There are 27 amino acid differences shared between the subgroup D sequence and three subgroup B sequences. At 16 of these sites, the subgroup D sequence is identical to the sequence of one or more of the other subgroup viruses (A, C, and E). The remaining 11 sites are specific to subgroup D and show some clustering in the two large variable regions that are thought to be major determinants of host range. Biological analysis of recombinant viruses containing a dominant selectable marker confirmed the role of the gp85-coding domain in determining the host range of the subgroup D virus in the infection of mammalian cells. We also compared the sequence of the gp85-coding domain from two subgroup A viruses, Rous-associated virus type 1 and a subgroup A virus of the Schmidt-Ruppin strain of Rous sarcoma virus. The comparison revealed 24 nonconservative amino acid changes, of which 6 result in changes in potential glycosylation sites. The positions of 10 amino acid differences are coincident with the positions of 10 differences found between two subgroup B virus env gene sequences. These 10 sites identify seven domains in the sequence which may constitute determinants of type-specific antigenicity. Using a molecular recombinant, we demonstrated that type-specific neutralization of two subgroup A viruses was associated with the gp85-coding domain of the virus.
Bova
C A
CA
Department of Biochemistry, University of North Carolina, Chapel Hill 27599.
Olsen
J C
JC
Swanstrom
R
R
D001355:Alpharetrovirus / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D000940:Antigenic Variation; D000954:Antigens, Surface / Q000235:genetics; D000956:Antigens, Viral / Q000235:genetics*; D001483:Base Sequence; D002645:Chickens / Q000382:microbiology; D005814:Genes, Viral; D008322:Mammals / Q000382:microbiology; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D011991:Receptors, Virus / Q000502:physiology; D011995:Recombination, Genetic; D013045:Species Specificity; D014759:Viral Envelope Proteins / Q000235:genetics* / Q000276:immunology; D014779:Virus Replication
D000954:Antigens, Surface; D000956:Antigens, Viral; D011991:Receptors, Virus; D014759:Viral Envelope Proteins