Figure 1. Overview of herpesvirus egress.

Capsids undergo primary envelopment (nuclear budding) at the inner nuclear membrane where they pinch off into the perinuclear space in a process mediated by the nuclear egress complex. The resulting perinuclear enveloped vesicles fuse with the outer nuclear membrane and release the capsid into the cytoplasm (de-envelopment). The resulting virion gains necessary tegument proteins before undergoing secondary envelopment during which it acquires a glycoprotein envelope derived from the trans Golgi network or early endosomes. The mature virion then hijacks the host secretory pathway and is released into the extracellular space via exocytosis to spread infection.