Affiliation:
1. Departments of Medicine1 and
2. Microbiology,2 University of Alabama at Birmingham, Birmingham, Alabama 35294-2170
Abstract
ABSTRACT
A putative cleavage site of the human foamy virus (HFV) envelope glycoprotein (Env) was altered. Transient
env
expression revealed that the R572T mutant Env was normally expressed and modified by asparagine-linked oligosaccharide chains. However, this single-amino-acid substitution was sufficient to abolish all detectable cleavage of the gp130 precursor polyprotein. Cell surface biotinylation demonstrated that the uncleaved mutant gp130 was transported to the plasma membrane. The uncleaved mutant protein was incapable of syncytium formation. Glycoprotein-driven virion budding, a unique aspect of HFV assembly, occurred despite the absence of Env cleavage. We then substituted the R572T mutant
env
into a replication-competent HFV molecular clone. Transfection of the mutant viral DNA into BHK-21 cells followed by viral titration with the FAB (foamy virus-activated β-galactosidase expression) assay revealed that proteolysis of the HFV Env was essential for viral infectivity. Wild-type HFV Env partially complemented the defective virus phenotype. Taken together, these experimental results established the location of the HFV Env proteolytic site; the effects of cleavage on Env transport, processing, and function; and the importance of Env proteolysis for virus maturation and infectivity.
Publisher
American Society for Microbiology
Subject
Virology,Insect Science,Immunology,Microbiology
Cited by
17 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献