Fig. 7.

A BRD4 PID peptide suppresses Tat transactivation of the HIV LTR and reactivation from latency. (A) A synthetic peptide called PTD-BRD4 consists of the protein transduction domain of Tat (Tat-PTD) followed by BRD4(1318–1362). (B) HeLa cells were transfected with 25 ng of HIV LTR-luciferase with (+) or without (−) 5 ng of Tat expression plasmid. The PTD alone (pale gray), PTD-BRD4 peptide (gray), or DRB (black) was added to the cell-culture supernatant at concentrations ranging from 0.01 to 10 μM. Luciferase activities were assayed 24 h after transfection. (C) Clonal cell line A2 contains a single latent HIV provirus and expresses GFP after reactivation of HIV by TNF-α treatment. A2 cells were pretreated for 2 h with either the PTD-BRD4 peptide (gray circles), PTD alone (white circles), or DRB (black triangles) at the indicated concentrations, followed by the addition of TNFα (10 ng/ml). After 18 h, levels of HIV proviral transcription were measured by FACS for GFP.