Sulfated components of enveloped viruses

The glycoproteins of several enveloped viruses, grown in a variety of cell types, are labeled with ³⁵SO₄^-2, whereas the nonglycosylated proteins are not. This was shown for the HN and F glycoproteins of SV₅ and Sendai virus, the E₁ and E₂ glycoproteins of Sindbis virus, and for the major glycoprotein gp69, as well as for a minor glycoprotein, gp52, of Rauscher leukemia virus. The minor glycoprotein of Rauscher leukemia virus is more highly sulfated, with a ratio of ³⁵SO₄- [³H]glucosamine about threefold greater than that of gp69. The G protein of vesicular stomatitis virus was labeled when virions were grown in the MDBK line of bovine kidney cells, although no significant incorporation of ³⁵SO₄^-2 into this protein was observed in virions grown in BHK21 F line of baby hamster kidney cells. In addition to the viral glycoproteins, sulfate was also incorporated into a heterogeneous component with an electrophoretic mobility lower than that of any of the viral proteins in polyacrylamide gel electrophoresis. For virions doubly labeled with ³⁵SO₄^-2 and [³H]leucine, this component had a much greater ³⁵S ³H ratio than any of the viral polypeptides and thus could not represent aggregated viral proteins. This material is believed to be a cell derived mucopolysaccharide and can be removed from virions by treatment with hyaluronidase without affecting the amount of sulfate present on the glycoproteins.