BRD4 bromodomains 1 and 2 (human, recombinant; aa 49-460)

Bromodomain-containing protein 4 (BRD4) is a member of the bromodomain and extra-terminal domain (BET) family.¹ It is a ubiquitously expressed nuclear protein with roles in a variety of cellular processes, including regulation of gene transcription, cell cycle progression, and viral genome segregation.^1,2 BRD4 is comprised of two N-terminal bromodomains (BD1 and BD2) that can bind to acetylated lysine residues in histones, serving to couple histone acetylation marks to the transcriptional regulation of target promoters, an extra-terminal (ET) domain that facilitates protein-protein interactions, and a C-terminal motif, and can be expressed as either a long or short isoform generated via alternative splicing.^1,2,3 In addition to binding acetylated lysine residues on histones, BRD4 can bind to a variety of non-histone proteins and protein complexes, including positive transcription elongation factor b (P-TEFb) and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) envelope (E) protein, a transmembrane protein involved in CoV virion assembly and pathogenesis of the related virus, SARS-CoV.^1,4,5,6 In mice, knock-down of Brd4 is embryonic lethal.² Chromosomal translocations leading to the fusion of BRD4 with the nuclear protein in testis (NUT) gene and resulting in expression of BRD4-NUT fusion proteins are associated with NUT midline carcinoma (NMC).^1,3 Inhibition of BRD4-NUT binding to chromatin by the BET bromodomain inhibitor (+)-JQ1 (Item No. 11187) induces tumor regression and prolongs survival in NMC mouse xenograft models.⁷ Cayman’s BRD4 bromodomains 1 and 2 (human, recombinant; aa 49-460) protein can be used for ELISA, Western blot (WB), and binding assay applications.

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1. Taniguchi, Y. The bromodomain and extra-terminal domain (BET) family: Functional anatomy of BET paralogous proteins. Int. J. Mol. Sci. 17(11), E1849 (2016).

2. Wu, S.Y., and Chiang, C.M. The double bromodomain-containing chromatin adaptor Brd4 and transcriptional regulation. The Journal of Biological Chemisty 282(18), 13141-13145 (2007).

3. Wang, C.Y., and Filippakopoulos, P. Beating the odds: BETs in disease. Trends Biochem. Sci. 40(8), 468-479 (2015).

4. Gordon, D.E., Jang, G.M., Bouhaddou, M., et al. A SARS-CoV-2 protein interaction map reveals targets for drug repurposing. Nature 583(7816), 459-468 (2020).

5. Kandeel, M., Ibrahim, A., Fayez, M., et al. From SARS and MERS CoVs to SARS-CoV-2: Moving toward more biased codon usage in viral structural and nonstructural genes. J. Med. Virol. 92(6), 660-666 (2020).

6. Schoeman, D., and Fielding, B.C. Coronavirus envelope protein: Current knowledge. Virol. J. 16(1), 69 (2019).

7. Goldstein, D.P., and Kosasa, T.S. The subunit radioimmunoassay for human chorionic gonadotropin - clinical applications. Progress in gynecology 145-184 (1975).