【摘要】 哺乳动物细胞胞质分裂过程中伴随着一系列形态学改变,随着分裂沟不断收缩,形成连接两个子细胞的细胞间桥.间桥不断拉长、变细,直至断裂、生成两个子细胞.采用细胞力学和形态学测量及分析方法,通过施加肌球蛋白Ⅱ抑制剂,定量研究了NRK细胞间桥变细动力学;采用细胞免疫荧光技术,检测了早期胞质分裂肌动蛋白的分布,揭示肌球蛋白Ⅱ缺失细胞胞质分裂可能的机制.结果表明:施加肌球蛋白Ⅱ抑制剂的NRK细胞,其整体形态学和细胞间桥形态学曲线明显不同于0.3%DMSO组.根据流体力学特性和所测量的力学参数对曲线进行模拟发现,表面张力对肌球蛋白Ⅱ抑制组细胞的间桥动力学曲线轨迹影响很大.研究结果提示由细胞力学特性决定的拉普拉斯压力和细胞运动共同参与了肌球蛋白Ⅱ缺失细胞胞质分裂的调节.更多还原

【Abstract】 Adherent mammalian cells experience a series of elaborate,but simple morphological changes during cell division.This complex process was mediated by mechanics and biological molecules.As a kind of motor proteins,myosin II plays an important role in cell division.Recent investigations showed that cells on substrates in the absence of myosin II also could finish cytokinesis.However,its mechanism is still unclear. In this study,morphology of NRK cells treated with 0.3%DMSO and 30μmol blebbistatin(myosin II inhibitor) were investigated quantitatively by using micro-image collecting and analysis system.Intercellular bridge dynamics was simulated using mechanical model of intercellular bridge thinning coupled with mechanical parameters of NRK cells.The distribution of actin in early cytokinesis was examined using immunofluorescence method. Our results showed that intercellular bridge thinning trajectory and morphology of cells treated with 30/xmol blebbistatin were fundamentally different from cells treated with 0.3%DMSO.The surface tension contributed greatly to the trajectory of 30/xmol blebbistatin group from fluid mechanical considerations and the measured mechanical parameters.Immunofluorescence results indicated that a mass of actin was recruited to the fan- shaped leading lamellipodia of daughter cells from the cytoplasm in cells treated with 30/xmol blebbistatin. Our study indicated that Laplace pressure determined by mechanical properties and the motility of cell orchestrated to dictate a well-controlled cytokinesis of cells in the absence of myosin II.更多还原