FIG. 7.

UL21 and UL16 directly interact, but this is not essential for UL21 packaging. The indicated GST-fusion proteins were expressed in bacteria and purified on glutathione-Sepharose beads. These were incubated with increasing amounts of soluble His₆-UL16 (100, 200, or 400 ng), which was also purified from bacteria. The beads were washed, and the associated proteins were separated by SDS-PAGE and then transferred to nitrocellulose. (A) The amounts of input His₆-UL16 and each of the GST-fusion proteins were revealed by Ponceau S staining. (B) The amount of His₆-UL16 bound to the beads was measured by immunoblotting with a rabbit antibody that recognizes the His₆ tag. (C) Media from Vero cells infected with either wild-type or ΔUL16 HSV were collected 24 h postinfection and centrifuged to pellet the virions. Samples of the cell lysates and virions were separated by SDS-PAGE and analyzed by immunoblotting with the indicated antibodies.