Selection of a subgroup A avian leukosis virus [ALV(A)] envelope resistant to soluble ALV(A) surface glycoprotein.
The host developing resistance to retroviral infection is believed to be a major force in the evolution of multiple receptor usage by retroviruses. The avian leukosis-sarcoma virus (ALV) group of retroviruses provides a powerful system for studying the envelope-receptor interactions involved in retrovirus entry; different members of this group of closely related viruses use distinct cellular receptors. Analysis of the ALV envelope subgroups suggests that the different ALVs evolved from a common ancestor by mutations in the env gene. Cells and animals that express subgroup A ALV envelope glycoproteins are highly resistant to ALV(A) infection due to receptor interference. In this study, we tested whether expression of a soluble form of subgroup A surface glycoprotein (SU) would result in receptor interference and whether this interference would select for resistant viruses with altered receptor usage. Chicken cells expressing the secreted ALV(A) SU immunoadhesin SU(A)-rIgG, which contains the subgroup A SU domain fused to the constant region of a rabbit immunoglobulin (IgG) heavy chain, showed significant receptor interference. A variant virus resistant to SU(A)-rIgG receptor interference was obtained. This virus had a six-amino-acid deletion in the subgroup A hr1 that altered receptor usage. This approach may identify regions of SU that play a critical role in receptor specificity.
Holmen
S L
SL
Molecular Medicine Program, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
Federspiel
M J
MJ
D001355:Alpharetrovirus; D000595:Amino Acid Sequence; D000818:Animals; D002213:Capsid; D036022:Capsid Proteins; D002469:Cell Separation; D002645:Chickens; D003001:Cloning, Molecular; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D008969:Molecular Sequence Data; D011817:Rabbits; D017452:Receptors, IgG / Q000378:metabolism; D012191:Retroviridae Proteins; D014758:Viral Core Proteins; D014759:Viral Envelope Proteins / Q000378:metabolism*
D036022:Capsid Proteins; D017452:Receptors, IgG; D012191:Retroviridae Proteins; D014758:Viral Core Proteins; D014759:Viral Envelope Proteins; C054897:nucleocapsid protein, Avian retrovirus