Shapira Suzanne N, Lim Hee-Woong, Rajakumari Sona, Sakers Alexander P, Ishibashi Jeff, Harms Matthew J, Won Kyoung-Jae, Seale Patrick
Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Department of Cell and Developmental Biology, Smilow Center for Translational Research, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Genes Dev. 2017 Apr 1;31(7):660-673. doi: 10.1101/gad.294405.116. Epub 2017 Apr 20.
The transcription factor early B-cell factor 2 (EBF2) is an essential mediator of brown adipocyte commitment and terminal differentiation. However, the mechanisms by which EBF2 regulates chromatin to activate brown fat-specific genes in adipocytes were unknown. ChIP-seq (chromatin immunoprecipitation [ChIP] followed by deep sequencing) analyses in brown adipose tissue showed that EBF2 binds and regulates the activity of lineage-specific enhancers. Mechanistically, EBF2 physically interacts with the chromatin remodeler BRG1 and the BAF chromatin remodeling complex in brown adipocytes. We identified the histone reader protein DPF3 as a brown fat-selective component of the BAF complex that was required for brown fat gene programming and mitochondrial function. Loss of DPF3 in brown adipocytes reduced chromatin accessibility at EBF2-bound enhancers and led to a decrease in basal and catecholamine-stimulated expression of brown fat-selective genes. Notably, is a direct transcriptional target of EBF2 in brown adipocytes, thereby establishing a regulatory module through which EBF2 activates and also recruits DPF3-anchored BAF complexes to chromatin. Together, these results reveal a novel mechanism by which EBF2 cooperates with a tissue-specific chromatin remodeling complex to activate brown fat identity genes.
转录因子早期B细胞因子2(EBF2)是棕色脂肪细胞定向分化和终末分化的重要调节因子。然而,EBF2在脂肪细胞中调节染色质以激活棕色脂肪特异性基因的机制尚不清楚。对棕色脂肪组织进行的染色质免疫沉淀测序(ChIP-seq)分析表明,EBF2结合并调节谱系特异性增强子的活性。从机制上讲,EBF2在棕色脂肪细胞中与染色质重塑因子BRG1和BAF染色质重塑复合物发生物理相互作用。我们将组蛋白读取蛋白DPF3鉴定为BAF复合物中棕色脂肪选择性成分,它是棕色脂肪基因编程和线粒体功能所必需的。棕色脂肪细胞中DPF3的缺失降低了EBF2结合的增强子处的染色质可及性,并导致棕色脂肪选择性基因的基础表达和儿茶酚胺刺激表达下降。值得注意的是, 是EBF2在棕色脂肪细胞中的直接转录靶点,从而建立了一个调控模块,通过该模块EBF2激活并将DPF3锚定的BAF复合物募集到染色质上。这些结果共同揭示了一种新机制,即EBF2与组织特异性染色质重塑复合物协同作用以激活棕色脂肪特征基因。