Epigenetic activation during Th17 cell differentiation is impaired after TRIM28 deletion

Cell fate decision is mediated by epigenetic mechanisms. We have analyzed naive T cell differentiation into Th17 cells, which is regulated by environmental cytokines and their downstream transcription factors. ROR?t is a lineage-specific master transcription factor for Th17 cells. Although epigenetic mechanisms have been implicated in Th17 cell differentiation, how transcription factors interact to activate epigenetic program is unclear. Here we show that tripartite motif containing 28 (TRIM28) expression in Th17 cells is required for cytokine production and autoimmune diseases. Genome-wide occupancy analysis reveals that TRIM28 bound regions contain many super-enhancers, which are impaired after TRIM28 or STAT3 but not ROR?t deletion. Importantly, TRIM28 exists in a complex with STAT3 and ROR?t; TRIM28 recruitment to the Il17 gene requires STAT3, and further promotes ROR?t recruitment. TRIM28 thus is a key player in the epigenetic activation during T cell differentiation. Overall design: 8 samples in total: 2 RNA-seq samples; 6 ChIP-seq samples, including 3 control samples(input)细胞命运决定由表观遗传机制介导。本研究分析了初始T细胞向辅助性T细胞17（Th17）的分化过程，该过程受环境细胞因子及其下游转录因子调控。RORγt（ROR?t）是Th17细胞的谱系特异性主控转录因子。尽管已有研究将表观遗传机制与Th17细胞分化相关联，但转录因子如何协同激活表观遗传程序仍不明确。本研究发现，含三联基序蛋白28（TRIM28）在Th17细胞中的表达，是细胞因子产生与自身免疫疾病发生所必需的。全基因组结合占有率分析显示，TRIM28结合区域包含大量超级增强子；在TRIM28或信号转导与转录激活因子3（STAT3）缺失后，这些超级增强子的功能会受损，但ROR?t缺失则无此影响。重要的是，TRIM28可与STAT3及ROR?t形成复合物；TRIM28向白介素17（Il17）基因位点的招募依赖于STAT3，并可进一步促进ROR?t的招募。因此，TRIM28是T细胞分化过程中表观遗传激活的关键调控因子。实验整体设计：共包含8个样本：2个RNA测序（RNA-seq）样本；6个染色质免疫共沉淀测序（ChIP-seq）样本，其中包含3个input对照样本。