Characterization of interaction of gH and gL glycoproteins of varicella-zoster virus: their processing and trafficking

Varicella-zoster virus (VZV) glycoproteins gH and gL were examined in a rec ombinant vaccinia virus system. Single expression of glycoprotein gL produc ed two molecular forms: an 18 kDa form and a 19 kDa form differing in size by one endoglycosidase H-sensitive N-linked oligosaccharide. Coexpression o f gL and gH resulted in binding of the 18 kDa gL form with the mature form of gH, while the 19 kDa gL form remained uncomplexed. The glycosylation pro cessing of gL was not dependent on gH; however, gL was required for the con version of precursor gH (97 kDa) to mature gH (118 kDa). Subsequent analyse s indicated that gL(18 kDa) was a more completely processed gL (19 kDa). Sc reening of the culture media revealed that gH and gL were secreted, but onl y if coexpressed and complexed together. The secreted form of gL was 18 kDa while that of gH was 114 kDa, The fact that secreted gH was smaller than i ntracytoplasmic gH suggested a proteolytic processing event prior to secret ion. The 19 kDa form of gL was never secreted. These findings support a VZV gL recycling pathway between the endoplasmic reticulum and the cis-Golgi a pparatus.