Apr 20, 2012

Mutations in the GM1 binding site of simian virus 40 VP1 alter receptor usage and cell tropism

Journal of Virology
Thomas G MagaldiDaniel DiMaio


Polyomaviruses are nonenveloped viruses with capsids composed primarily of 72 pentamers of the viral VP1 protein, which forms the outer shell of the capsid and binds to cell surface oligosaccharide receptors. Highly conserved VP1 proteins from closely related polyomaviruses recognize different oligosaccharides. To determine whether amino acid changes restricted to the oligosaccharide binding site are sufficient to determine receptor specificity and how changes in receptor usage affect tropism, we studied the primate polyomavirus simian virus 40 (SV40), which uses the ganglioside GM1 as a receptor that mediates cell binding and entry. Here, we used two sequential genetic screens to isolate and characterize viable SV40 mutants with mutations in the VP1 GM1 binding site. Two of these mutants were completely resistant to GM1 neutralization, were no longer stimulated by incorporation of GM1 into cell membranes, and were unable to bind to GM1 on the cell surface. In addition, these mutant viruses displayed an infection defect in monkey cells with high levels of cell surface GM1. Interestingly, one mutant infected cells with low cell surface GM1 more efficiently than wild-type virus, apparently by utilizing a different ganglioside rec...Continue Reading

Mentioned in this Paper

Pathogenic Aspects
Antibiotic CV-1
Ganglioside receptor
Simian virus 40
Beta-Galactosidase Deficiency
Thyroid Hormone Plasma Membrane Transport Defect
Ganglioside GM1

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