An interaction with UL11 is not essential for UL16 packaging. WT or ΔUL11 extracellular virus and cytoplasmic capsids were purified in 20-50% (wt/vol) sucrose gradients and the region of the gradient containing the virions and capsids were pulled with a needle syringe and pelleted through a sucrose cushion. Cell lysates, purified capsids, and virions were then analyzed for the presence of VP5, UL16, and UL11 by immunoblot. cyto, cytoplasmic.