The acetylation of histone lysine residues plays a crucial role in the epigenetic regulation of gene transcription. A bromodomain is a protein domain that recognizes acetylated lysine residues such as those on the N-terminal tails of histones. This recognition is often a prerequisite for protein-histone association and chromatin remodeling. These domains function in the linking of protein complexes to acetylated nucleosomes, thereby controlling chromatin structure and gene expression. Thus, bromodomains serve as “readers” of histone acetylation marks regulating the transcription of target promoters. BRG1 is a member of the SWI/SNF protein family, which forms part of a large ATP-dependent chromatin remodeling complex. This complex is required for transcriptional activation of genes normally repressed by chromatin. BRG1 is mutated in many cancer cell lines, such as breast, prostate, lung, pancreas and colon. Further, BRG1 has an important role as a tumor suppressor. This protein can be used for the study of bromodomain binding assays, screening inhibitors, and selectivity profiling.