Human recombinant BRD3, tandem construct comprising bromodomains 1 and 2, expressed in E. coli. BRD3, like other human members of the BET family of chromatin-binding proteins (BRD2, BRD4, BRDT), comprises two bromodomains, protein modules that bind epsilon-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 the nucleosomes. Although BRD3-2 (BRD3 bromodomain 2) has been shown to bind tetracetylated histone H4 tail sequence (H4K5AcK8AcK12AcK16Ac), the interaction is weaker than that of BRD3-1.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, e.g. BCL2, upregulated by the MLL-fusions.

SUPPLIED AS: Solution of purified recombinant protein in 50 mM Tris/HCl, pH 7.5, 150 mM NaCl, 1.0 mM TCEP, 10% glycerol (v/v).

STORAGE: -80°C, aliquot and snap-freeze after first use.