Furthermore, in order to study the effects of UL23 expression on the localization of Nmi and STAT1 in the context of HCMV infection, U251 cells were treated with IFN-γ, infected with TowneBAC, ΔUL23, or R-ΔUL23, and the cell extracts were separated into nuclear and cytoplasmic fractions by centrifugation. Here, IFNG is linked to cytomegalovirus infection.