Concentration dependence of variability in growth rates of microtubules.
Concentration dependence of variability in growth rates of microtubules.
复制标题
微管生长速率变异性的浓度依赖性。
DOI：
10.1016/s0006-3495(02)73946-5
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
WilliamsJr,RobleyC
中科院分区：
文献类型：
--
作者：
Pedigo,Susan;WilliamsJr,RobleyC
以前已经观察到微管在聚合和解聚过程中的生长和缩短以可变的速率发生。为了深入了解这种显著变化的意义，我们研究了其大小取决于实验观察和计算机模拟微管的生长速率的方式。用视频增强微分干涉显微镜真实的观察了不同微管蛋白浓度下衣原体鞭毛轴丝成核的正端微管的动力学特性。通过蒙特卡罗算法，微管的群体进行了模拟，具有类似的生长和动态特性的实验观察到的微管。通过比较实验观察到的微管群体和计算机模拟的微管群体，我们发现：1）单个微管显示出内在的变异性，这种变异性不会随着群体增长率的增加而改变; 2）变异性大约是亚基添加和丢失的简单模型预测的5倍。用于模拟微管生长的模型没有规定纳入任何类型的晶格缺陷，也没有复杂的几何形状的增长结束。因此，排除了这些以及不受控制的实验变量作为显著变异性的原因。
Growth and shortening of microtubules in the course of their polymerization and depolymerization have previously been observed to occur at variable rates. To gain insight into the meaning of this prominent variability, we studied the way in which its magnitude depends on the growth rate of experimentally observed and computer-simulated microtubules. The dynamic properties of plus-ended microtubules nucleated by pieces ofChlamydomonasflagellar axonemes were observed in real time by video-enhanced differential interference contrast light microscopy at differing tubulin concentrations. By means of a Monte Carlo algorithm, populations of microtubules were simulated that had similar growth and dynamic properties to the experimentally observed microtubules. By comparison of the experimentally observed and computer-simulated populations of microtubules, we found that 1) individual microtubules displayed an intrinsic variability that did not change as the rate of growth for a population increased, and 2) the variability was approximately fivefold greater than predicted by a simple model of subunit addition and loss. The model used to simulate microtubule growth has no provision for incorporation of lattice defects of any type, nor sophisticated geometry of the growing end. Thus, these as well as uncontrolled experimental variables were eliminated as causes for the prominent variability.