HMGA2 links promoter-specific H2A.X deposition and active DNA demethylation [ChIP-Seq]. HMGA2 links promoter-specific H2A.X deposition and active DNA demethylation [ChIP-Seq]

During transcriptional activation, chromatin undergoes structural changes with the help of various proteins such as chromatin remodeling factors and histone modifiers in order to make the DNA accessible for the transcription factors and RNA polymerase. We combined ChIP-, MNase- and RNA-sequencing analyzing the Hmga2 knock-out mice and found that HMGA2 is required for promoter specific deposition of the histone variant H2A.X. Consequently, the promoter specific H2A.X deposition resulted in an accumulation of active RNA Polymerase II at these promoters. Stimulation with TGFB1 resulted in increased accumulation of pH2A.X and expression of those “primed” target genes, whereas cells expressing no Hmga2 where not able to respond. Overall design: ChIP-Seq Data from chromatin extracts after ultracentrifugation from Hmga2+/+ and Hmga2-/- mouse embryonic fibroblasts

在转录激活过程中，染色质会在多种蛋白质（如染色质重塑因子、组蛋白修饰因子）的协助下发生结构重塑，以使DNA可被转录因子与RNA聚合酶结合利用。本研究结合染色质免疫共沉淀测序（ChIP-Seq）、微球菌核酸酶测序（MNase-Seq）与RNA测序技术，对Hmga2基因敲除小鼠开展分析，发现HMGA2是启动子特异性沉积组蛋白变体H2A.X所必需的。由此，启动子特异性的H2A.X沉积会导致活性RNA聚合酶II在这些启动子区域富集。用转化生长因子β1（TGFB1）刺激细胞后，磷酸化H2A.X（pH2A.X）的富集水平与这些"致敏"靶基因的表达量均显著升高，而不表达Hmga2的细胞则无法产生此类应答。实验整体设计：取自Hmga2野生型（Hmga2+/+）与Hmga2基因敲除型（Hmga2-/-）小鼠胚胎成纤维细胞，经超速离心获取染色质提取物后进行的ChIP-Seq数据。