The export pathway of the pseudorabies virus gB homolog gII involves oligomer formation in the endoplasmic reticulum and protease processing in the Golgi apparatus

Abstract

The pseudorabies virus gII gene shares significant homology with the gB gene of herpes simplex virus type 1. Unlike gB, however, gII is processed by specific protease cleavage events after the synthesis of its precursor. The processed forms are maintained in an oligomeric complex that includes disulfide linkages. In this report, we demonstrate the kinetics of modification, complex formation, and subsequent protease processing. In particular, we suggest that gII oligomer formation in the endoplasmic reticulum is an integral part of the export pathway and that protease cleavage occurs only after oligomers have formed. Furthermore, through the use of glycoprotein gene fusions between the gIII glycoprotein and the gII glycoprotein genes of pseudorabies virus, we have mapped a functional cleavage domain of gII to an 11-amino-acid segment.