COMPASS核心成员Ash2l通过调控细胞周期影响神经祖细胞增殖

为探究Ash2l(absent, small, or homeotic 2-like, Ash2l)对小鼠大脑皮质神经祖细胞(neural progenitor cells, NPCs)的增殖能力和细胞周期的影响。本研究利用NPCs标志物PAX6和TBR2,检测NPCs数量和分布的改变情况。结果显示,Ash2l敲除导致NPCs数量显著减少(P<0.05),且分布紊乱。对E16.5小鼠进行在体30 min EdU标记实验,检测NPCs 增殖能力,Ash2l敲除导致30 min EdU几乎无法进入NPCs(P<0.001)。结果表示,NPCs增殖能力受到严重的影响。用细胞周期M期标志物pH3,检测大脑皮质中处于M期的NPCs分布情况,同时提取了E16.5小鼠大脑皮质蛋白质,检测细胞周期蛋白 A的表达量。Ash2l敲除的NPCs的 M期细胞核分布紊乱,G₂期标志蛋白质细胞周期蛋白 A表达量减少。利用EdU和BrdU双标记法,计算NPCs的S期长度。Ash2l敲除后的NPCs的S期长度缩短(P<0.05)。因此,Ash2l调控NPCs细胞周期进程,进而影响NPCs的增殖能力,敲除小鼠大脑皮质发育异常。本研究强调了表观遗传调控对胚胎期神经系统发育的重要作用,并对表型进行了深入探索。

The COMPASS Core Member Ash2l Regulates the Cell Cycle of Neural Progenitor Cells

To investigate the role of Ash2l (absent, small, or homeotic 2-like, Ash2l) on the proliferation ability and cell cycle of mouse cerebral cortical neural progenitor cells (NPCs), We examined the number and distribution of NPCs, using the radial glial cell marker PAX6 and intermediate progenitor cell marker TBR2. E16.5 mice were labeled with EdU for 30 min to detect the proliferation ability of NPCs. Conditional knockout of Ash2l resulted in a dramatic reduction in the number of NPCs and a disordered distribution. The 30 min EdU insertion experiment showed that EdU could hardly be inserted into NPCs, indicating that the proliferation ability of NPCs was severely affected. Using the mitotic cell cycle marker pH3, the distribution of dividing NPCs was observed. We then detected the expressed level of Cyclin A by Western blotting. The distribution of cell nuclei of M-phase is disordered and the expression of G₂ phase marker Cyclin A was decreased after Ash2l knocked out. The S-phase length of NPCs was calculated using the EdU and BrdU double labeling, and the length of S-phase in Ash2l-cKO NPCs were decreased. In conclusion, the epigenetic molecule Ash2l regulates cell cycle progression, which in turn affects the proliferative capacity of NPCs and impairs the development of the mouse cerebral cortex. This study highlights the important role of epigenetic regulation in embryonic nervous system development.