Fig. 1.

Schematic representation of HSV egress and the involvement of HSV glycoproteins in various steps. HSV capsids are assembled in the nucleus and bud into the INM by a process known as primary envelopment. No HSV glycoproteins have been shown to be essential for this step, although HSV glycoproteins are components of the INM and perinuclear virus particles. Deenvelopment, fusion with the ONM, requires HSV gB or gH/gL. Cytoplasmic capsids acquire additional tegument proteins and undergo secondary envelopment, which requires gB, gD, and gE/gI. Virions are then transported to cell surfaces in exocytic vesicles. There is evidence of directed exocytosis to specific cell surfaces in polarized cells, a process that requires gE/gI and likely other glycoproteins.