Chromatin dynamics in interphase cells revealed by tracking in a two-photon excitation microscope
Chromatin dynamics in interphase cells revealed by tracking in a two-photon excitation microscope
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DOI：
10.1529/biophysj.105.066670
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发表时间：
2005-12-01
影响因子：
3.4
通讯作者：
Gratton, E
中科院分区：
文献类型：
--
作者：
Levi, V;Ruan, QQ;Gratton, E
越来越多的证据表明细胞核的动态区室化，但间期染色质移动和定位在核内的机制仍不清楚。在这里，我们研究染色质在体内的动态应用一种新的粒子跟踪方法在双光子显微镜，提供了10倍的空间和时间分辨率比以前的测量。我们在稳定表达与增强型绿色荧光蛋白融合的乳糖阻遏物的细胞中跟踪含有乳糖操纵子重复序列的染色质序列的运动，观察到长时间的明显受限扩散被持续0.3-2秒的类似于150 nm的相对突然的跳跃中断。在这些跳跃中，粒子的平均移动速度比跳跃之间的时间快四倍，并且路径比随机扩散运动预测的更直线。此外，跳跃对温度敏感，ATP耗尽后消失。这些实验结果指出，驱动染色质在间期细胞中快速运动的能量依赖性机制。
Increasing evidence points to a dynamical compartmentalization of the cell nucleus, yet the mechanisms by which interphase chromatin moves and is positioned within nuclei remain unclear. Here, we study the dynamics of chromatin in vivo applying a novel particle-tracking method in a two-photon microscope that provides; 10-fold higher spatial and temporal resolutions than previous measurements. We followed the motion of a chromatin sequence containing a lac-operator repeat in cells stably expressing lac repressor fused with enhanced green fluorescent protein, observing long periods of apparent constrained diffusion interrupted by relatively abrupt jumps of similar to 150 nm lasting 0.3-2 s. During these jumps, the particle moved an average of four times faster than in the periods between jumps and in paths more rectilinear than predicted for random diffusion motion. Additionally, the jumps were sensitive to the temperature and absent after ATP depletion. These experimental results point to an energy-dependent mechanism driving fast motion of chromatin in interphase cells.