Fig. 4.

GST-pulldown assays were completed to determine whether the UL4 protein directly interacts with general transcription factors. Purified GST, GST-IR2, or GST-UL4 fusion proteins were incubated with GST-Bind resin beads for 1.5 h before being combined with (A) TATA box-binding protein (TBP) or (B) RNA polymerase II carboxy-terminal domain (Pol II CTD) for an additional 1.5 h incubation. Captured proteins were eluted and resolved by SDS-PAGE and western blot using TBP or Pol II CTD specific antibodies. MW, molecular weight marker