The Double Bromodomain-containing Chromatin Adaptor Brd4 and Transcriptional Regulation

Brd4 is a double bromodomain-containing protein that binds preferentially to acetylated chromatin. It belongs to the BET (bromodomains and extraterminal) family that includes mammalian Brd2, Brd3, Brd4, Brdt, Drosophila Fsh, yeast Bdf1, Bdf2, and corresponding homologues in other species. Brd4 is essential for cellular growth and has been implicated in cell cycle control, DNA replication, and gene rearrangement found in t(15;19)-associated carcinomas. Recently, Brd4 has been found in several transcription complexes, including the general cofactor Mediator and the P-TEFb elongation factor, and is capable of stimulating HIV-1 transcription in a Tat-independent manner. In addition, Brd4 is used as a cellular…