Domains of glycoprotein H of herpes simplex virus type 1 involved in complex formation with glycoprotein L

The complex formation between glycoproteins H (gH) and L (gL) of herpes sim plex virus type 1 (HSV-1) was studied by using five recombinant baculovirus es expressing open reading frames that contain deletions in the coding regi on of the extracellular domain of gH. In addition, the gH-deletion mutants contained a C-terminal tag. Complex formation of gL and the gl-l-deletion m utants was studied by immunoprecipitations with anti-tag monoclonal antibod y (MAb) A16 and with the gH-specific MAbs 37S, 46S, and 52S. All gH-deletio n mutants were complexed to gL when analyzed by MAb A16. MAb 37S precipitat ed complexes between gL and the two gH-deletion mutants that contain the ep itope of this MAb. When the gH conformation-dependent MAbs 46S and 52S were used, gL was coprecipitated together with the gH-deletion mutant lacking a mino acids 31-299, but gL was not coprecipitated with the gH-deletion mutan t lacking amino acids 31-473. The data from the precipitation studies do al low at least two interpretations. There is either one site for gL binding o n gH (residue 300-473) or gL contacts multiple regions of gH. We were unabl e to demonstrate gL-dependent cell surface expression of either of the gH-d eletion mutants. This suggests that the coassociation of gH with gL is nece ssary but not sufficient for transport of gH to the cell surface. (C) 1999 Academic Press.