Epigenetic function of RUNX1 with PRMT6 in normal and aberrant myeloid differentiation

转录因子RUNX1(AML1，急性髓系白血病1)对于最终的造血干细胞(HSC)的发育至关重要。在人类髓系白血病中，RUNX1活性常因突变、缺失和染色体易位而改变。在正常的造血分化过程中，RUNX1对染色质修饰辅因子的募集导致染色质结构的调整，也介导了基因表达的表观遗传变化。RUNX1的这种表观遗传功能在白血病中受到干扰。我们可以证明RUNX1与精氨酸甲基转移酶6(PRMT6)蛋白相互作用，该蛋白介导了抑制性的H3R2me2a组蛋白修饰标记。我们证明RUNX1和PRMT6在造血祖细胞的靶基因亚集上处于抑制性表观遗传复合体中。基于这些结果，我们希望通过芯片序列识别基因组范围内共同的RUNX1/PRMT6靶基因，并将RUNX1/PRMT6的占位与表观遗传组蛋白标记联系起来。此外，我们希望破译分化过程中RUNX辅因子交换的机制，并揭示由此产生的表观遗传学变化。同时，我们将研究PRMT6对RUNX1依赖的表观遗传学功能的特定贡献，并研究PRMT6活性与辅因子募集和下游组蛋白修饰标记的相关性。此外，我们收集的数据暗示了PRMT6对细胞生长的影响，这可能是通过RUNX1/PRMT6对生长抑制靶基因的直接影响而介导的。出于这个原因，我们想评估PRMT6抑制剂作为一种表观遗传药物的潜力，它具有抑制生长的作用。RUNX1的正常功能可以通过突变导致白血病，一个突出的例子是染色体易位t(8；21)导致RUNX1-ETO融合蛋白。我们想要检查RUNX1-ETO是否可以干扰表观遗传的RUNX1/PRMT6复合体，并且这种方式有助于解除调控的表观遗传标记，从而导致白血病。

The transcription factor RUNX1 (AML1, acute myeloid leukemia 1) is crucial for the development of definitive hematopoietic stem cells (HSC). RUNX1 activity is often altered in human myeloid leukemia by mutation, deletion and chromosomal translocation. During normal hematopoietic differentiation the recruitment of chromatin modifying cofactors by RUNX1 leads to adjustments of the chromatin structure and also mediates epigenetic changes of gene expression. This epigenetic function of RUNX1 is disturbed in leukemia. We could show that RUNX1 interacts with the protein arginine methyltransferase 6 (PRMT6), which mediates the repressive H3R2me2a histone modification mark. We demonstrated that RUNX1 and PRMT6 are in a repressive epigenetic complex on a subset of target genes in hematopoietic progenitor cells. Based on these results, we want to identify common RUNX1/PRMT6 target genes genome wide by ChIP-Seq and relate RUNX1/PRMT6 occupancy to epigenetic histone marks. Furthermore, we want to decipher the mechanisms of RUNX cofactor exchange during differentiation and uncover the resulting epigenetic changes. Concomitantly, we will study the specific contribution of PRMT6 to RUNX1 dependent epigenetic functions and study the dependence of PRMT6 activity on cofactor recruitment and downstream histone modification marks. Additionally, we collected data, which hint towards an influence of PRMT6 on cell growth, which might be mediated by a direct influence of RUNX1/PRMT6 on growth inhibitory target genes. For this reason we want to evaluate the potential of PRMT6 inhibitors as an epigenetic drug, which acts growth inhibitory. The normal function of RUNX1 can be altered by mutations leading to leukemia, a prominent example is the chromosomal translocation t(8;21) leading to the RUNX1-ETO fusion protein. We want to examine if RUNX1-ETO can interfere with the epigenetic RUNX1/PRMT6 complex and this way contributes to deregulated epigenetic marks, which contribute to leukemia.