BRD4

Bromodomain-containing protein 4 is a protein that in humans is encoded by the BRD4 gene.

BRD4 is a member of the BET (bromodomain and extra terminal domain) family, which also includes BRD2, BRD3, and BRDT. BRD4, similar to other BET family members, contains two bromodomains that recognize acetylated lysine residues. BRD4 also has an extended C-terminal domain with little sequence homology to other BET family members.

Structure

The two bromodomains in BRD4, termed BD1 and BD2, consist of 4 alpha-helices linked by 2 loops. The ET domain structure is made up of 3 alpha-helices and a loop. The C-terminal domain of BRD4 has been implicated in promoting gene transcription through interaction with the transcription elongation factor P-TEFb and RNA polymerase II.

Function

The protein encoded by this gene is homologous to the murine protein MCAP, which associates with chromosomes during mitosis, and to the human RING3 protein, a serine/threonine kinase. Each of these proteins contains two bromodomains, a conserved sequence motif which may be involved in chromatin targeting. This gene has been implicated as the chromosome 19 target of translocation t(15;19)(q13;p13.1), which defines the NUT midline carcinoma. Two alternatively spliced transcript variants have been described.