UV Microbeam Analysis of Microtubule Dynamics

在细胞分裂之前，它们的遗传信息被精确复制，这些信息包含在称为染色体的结构中。在细胞分裂期间，复制的染色体被分配到两个子细胞中，因此每个子细胞随后包含完全相同类型和数量的染色体。负责执行这一关键过程的细胞器统称为有丝分裂纺锤体。纺锤体主要由微管电缆组成的复杂网络组成，微管电缆一端连接到单个染色体，另一端锚定到称为细胞极的位置。在细胞分裂的过程中，这些缆线以某种方式将染色体拉到各自的极点，而这种机制的细节还知之甚少。在这份新颖且写得很好的建议书中，首席研究员将设计、建造和校准一台紫外线微束装置。这种设备能够照射活细胞中的单个微管纤维，并因此切断这些纤维。所描述的实验将使研究人员能够区分染色体运动过程中微管功能的几种当前模型。之所以如此，是因为不同的模型对GAP的产生对纤维的稳定性和动力学、染色体的运动以及辐射诱导的GAP修复的性质的影响做出了不同的预测。

Before cells divide, their genetic information, contained in structures called chromosomes, is duplicated precisely. During cell division, the duplicated chromosomes are distributed into the two daughter cells so that each daughter subsequently contains exactly the same kind and number of chromosomes. The cellular organelles responsible for carrying out this crucial process are collectively called the mitotic spindle. The spindle is composed primarily of a complex network of microtubule cables that attach to individual chromosomes at one end, and become anchored at their other end to sites called the cell poles. During the course of cell division these cables somehow pull the chromosomes to their respective poles, by a mechanism whose details are only poorly understood. In this novel and well written proposal, the principal investigator will design, construct, and calibrate an ultraviolet microbeam apparatus. This device is capable of irradiating and thereby cutting a single microtubule fiber in a living cell. The experiments described will allow the investigator to distinguish between several current models of microtubule function during chromosome movement. This is the case because the various models made different predictions with respect to the effect of gap production on the stability and dynamics of the fiber, the movement of chromosomes, and the nature of irradiation-induced gap repair.