Human recombinant BRD3, full-length construct expressed in Sf9 insect cells with an N-terminal His-tag. BRD3, like other human members of the BET family of chromatin-binding proteins (BRD2, BRD4, BRDT), comprises two bromodomains, protein modules that bind e-N-acetyllysine residues. Recent results suggest an important role for BRD3 in linking acetylation of both histones and non-histone proteins to gene transcription. When overexpressed in 293 cells, BRD3, along with BRD2, binds the hyperacetylated chromatin of transcribed genes, regions enriched in acetylated histone H4 lysine-5 (H4K5Ac), (H4K12Ac), H3K14Ac, but deficient in H4K16Ac and H3K9me. In an in vitro RNA polymerase II transcription system, binding of either BRD3 or BRD2 to a chromatin template assembled with hyperacetylated histones enabled transcription through nucleosomes. In addition to acetylated histones, BRD3-1 has been found to bind the hematopoietic transcription factor GATA1 tand to enhance its chromatin binding and activation of target genes. Like the binding of the bromodomains-1 of BRDT and BRD4 to H4K5Ac/K8Ac, interaction of BRD3-1 with GATA1 occurs via the simultaneous binding of K312Ac and K315Ac. The BET family inhibitor, I-BET151, has shown efficacy in mouse models of MLL-fusion leukemias, displacing BRD3 and BRD4 from chromatin and inhibiting transcription of genes.

SUPPLIED AS: Solution of purified recombinant protein in 50 mM Tris/HCl, pH 7.5, 500 mM NaCl, 1.0 mM TCEP, 10% glycerol (w/v).

STORAGE: -70 °C