Figure 3. Envelopment and Budding during viral egress.

Viral particles assembled in the nucleus or the cytoplasm are enveloped by a cellular membrane to leave the cell in the absence of cell lysis. There are two different ways to acquire this membrane. A Virions can be enveloped using an intracellular compartment, such as the Golgi apparatus, and travel through the membrane trafficking system to be released by fusion of its outer membrane with the cell surface. B In contrast, budding at the plasma membrane directly releases extracellular viral particles. Both strategies involve similar processes that require membrane bending toward the luminal or extracellular space and scission of the neck to generate membrane-bound virions.