蛋白质精氨酸甲基转移酶5的选择性剪切子PRMT5S在辐射损伤及细胞死亡中的作用及调控机制

蛋白质甲基化是表观遗传学调控的重要方式。蛋白质精氨酸甲基转移酶5（PRMT5）有多个不同的选择性剪切子，我们发现PRMT5S与全长PRMT5L在辐射损伤与细胞死亡中发挥不同作用，并首次证实H1C与BCL-2参与PRMT5S调控。本研究率先通过生物信息学筛选PRMT5互作蛋白（包括组蛋白、共结合蛋白和调控信号分子），进而构建PRMT5S与PRMT5L表达模型，在模型中分别从组蛋白甲基化（H1C、H3R8、H4R3）、共结合蛋白（MEP50、MBD2、pICIn、CoPR5）角度探讨表观遗传调控及其对染色质重塑的影响；同时针对PRMT5互作蛋白中自噬调控分子（P53、BCL-2、HSP90A、PDCD4、VPS34）分析其不同精氨酸位点甲基化的作用；最后通过动物荷瘤模型观察BH3类似物、自噬调控剂、甲基化调控剂对PRMT5S调控的辐射损伤的影响。本研究为完善辐射损伤的表观遗传调控机制提供依据。

The methylation of proteins is one of the most important epigenetic mechanisms. Protein arginine methyltransferase 5(PRMT5) could create various alternative splicers under different conditions. We have found that other than the full-length PRMT5(PRMT5L), a 67 kDa splicer named as PRMT5S takes on different regulatory function in radiation injury and cell death, histone H1 and BCL-2 might participate in the process. In this study we will firstly select out the potential interactors of PRMT5 by bioinformatic techniques,such as histones, targeted signal molecules and co-integrated proteins. Then the cell models with different PRMT5 phenotypes(PRMT5 Silencing, PRMT5L, PRMT5S) will be established, the epigenetic regulation and chromatin remodeling will be explored aiming at both histone methylation (H3R8、H4R3、H1C) and co-integrated proteins(MEP50、MBD2、pICIn、CoPR5) interaction. Thirdly although there are many interactors of PRMT5, the autophagy-relative proteins including P53、BCL-2、HSP90A、PDCD4、VPS34 will be selected, the effects of their expression and the methylation at different arginine sites on the radiation-induced cell death will be analyzed. Finally the xenograft models will be established and such regulators as BH3 mimics, autophagy inhibitors and methylation inhibitors will be administrated and their responses to radiation injury and their effects on radiosensitivity will be observed. This study will definitely fulfill the epigenetic regulation mechanisms after the treatment of ionizing radiation.