Bromodomain (BRD)-containing proteins are central mediators of gene regulation, serving as key components of chromatin remodeling complexes and histone recognition scaffolds. By specifically recognizing acetylated lysine residues on histones (Kac) via their conserved BRD, these proteins influence chromatin structure and gene expression. Although their overarching role is well-established, the precise molecular functions and mechanisms of individual BRD proteins remain incompletely characterized. The ciliate Tetrahymena thermophila, a unicellular eukaryote with a transcriptionally active macronucleus enriched in histone acetylation, is an excellent model for exploring the significance of BRD-containing proteins. In this comprehensive review, all BRD-containing proteins encoded in the T. thermophila genome are systematically examined, including their expression profiles, histone acetylation targets, interacting proteins, and potential roles. This review lays the groundwork for future investigations into the complex roles of BRD proteins in chromatin remodeling and transcription regulation, offering insights into basic eukaryotic biology and the molecular mechanisms underlying BRD-linked diseases.