FIG. 2.

CTIP2, but not CTIP1, inhibits Tat-mediated HIV-1 transcriptional activity. (A) Microglial cells were transfected with HIV-1 LTR-CAT (1 μg) in the presence of vectors expressing Tat (2 ng) and increasing amounts (0.1, 0.5, and 1 μg) of CTIP1 and CTIP2 as indicated. Histograms show CAT activities measured 2 days posttransfection and expressed relative to the value obtained with the LTR-CAT vector alone. Values correspond to an average of at least three independent experiments done in duplicate. Error bars, standard deviations. (B) Western blot analysis of nuclear proteins (20 μg) extracted from cells transfected with the plasmids corresponding to lanes 1 to 8 indicated in panel A. To detect Tat, 1 μg of expression vector was transfected. The blot was probed with monoclonal Tat antibodies.