Glycoprotein 300 is encoded by gene 28 of equine herpesvirus type 1: a new family of herpesvirus membrane proteins?

A portion of equine herpesvirus type 1 (EHV-1) gene 28, which is homologous to herpes simplex virus type 1 gene UL32, was expressed using a prokaryotic system to yield a fusion protein which reacted on Western blots with P19, a monoclonal antibody (MAb) that reacts with EHV-1 glycoprotein 300 (gp300), confirming that this gene encodes gp300. Hydrophobicity analysis showed that gp300 is a glycoprotein with multiple hydrophobic domains that might interact with, or span, the membrane several times. As such, it may represent the first member of a new family of herpesvirus glycoproteins to be identified as a virus structural component. Gp300 was also shown to be modified by palmitic acid residues, and a second MAb (1G12) directed against gp300 inhibited fusion between EHV-1-infected cells.