Figure 2.

Association of Tat with p300 and CBP in vivo. Whole-cell lysates prepared from HL3T1 cells either untreated (lanes 3 and 7) or treated with GST-Tat added to the culture medium in the presence of chloroquine (lanes 1, 2, 4–6, and 8) were immunoprecipitated with the indicated antibodies. Bound proteins were resolved by SDS/PAGE (5% acrylamide, Upper; 10%, Lower) and transferred to a nitrocellulose membrane, which subsequently was cut into three parts. The lower portion of the filter was reacted with an anti-Tat antibody, while the upper two parts were reacted with anti-CBP (Upper Left) or anti-p300 (Upper Right) antibodies. The positions of the p300, Tat, and CBP proteins are indicated. IgH, Ig heavy chain.