Chiang Cheng-Ming
Simmons Comprehensive Cancer Center, Department of Biochemistry, and Department of Pharmacology, University of Texas Southwestern Medical Center 5323 Harry Hines Boulevard, Dallas, Texas 75390 USA.
F1000 Biol Rep. 2009;1:98. doi: 10.3410/B1-98. Epub 2009 Dec 15.
Bromodomain-containing protein 4 (Brd4) contains two tandem bromodomains (BD1 and BD2) that bind preferentially to acetylated lysine residues found in histones and nonhistone proteins. This molecular recognition allows Brd4 to associate with acetylated chromatin throughout the cell cycle and regulates transcription at targeted loci. Recruitment of positive transcription elongation factor b, and possibly the general initiation cofactor Mediator as well, plays an important role in Brd4-regulated transcription. Selective contacts with acetyl-lysines in nucleosomal histones and chromatin-binding factors likely provide a molecular switch modulating the steps from chromatin targeting to transcriptional regulation, thus further expanding the 'acetylation code' for combinatorial regulation in eukaryotes.
含溴结构域蛋白4（Brd4）包含两个串联的溴结构域（BD1和BD2），它们优先结合组蛋白和非组蛋白中发现的乙酰化赖氨酸残基。这种分子识别使Brd4在整个细胞周期中与乙酰化染色质结合，并调节靶向基因座的转录。招募正性转录延伸因子b以及可能的通用起始辅因子中介体，在Brd4调节的转录中起重要作用。与核小体组蛋白和染色质结合因子中的乙酰赖氨酸的选择性接触可能提供一个分子开关，调节从染色质靶向到转录调控的步骤，从而进一步扩展真核生物中组合调控的“乙酰化密码”。
