UV microbeam irradiations of the mitotic spindle. II. Spindle fiber dynamics and force production.
UV microbeam irradiations of the mitotic spindle. II. Spindle fiber dynamics and force production.
复制标题
有丝分裂纺锤体的紫外微束辐照。 ii。主轴纤维动力学和力产生。
DOI：
10.1083/jcb.111.4.1505
复制
发表时间：
1990-10
影响因子：
7.8
通讯作者：
Mole-Bajer, J
中科院分区：
文献类型：
--
作者：
Spurck, T P;Stonington, O G;Snyder, J A;Pickett-Heaps, J D;Bajer, A;Mole-Bajer, J
用紫外光(285nM)照射培养的Newt和PtK1细胞的中期和后期纺锤体，在S细胞中产生双折射(ARB)降低的区域，选择性地切断一些纤维或切断半纺锤体。在这两种情况下，ARB两极边缘的双折射迅速向两极消退，而在另一个动点边缘，双折射保持相当稳定。然而，较短的星形纤维仍然存在于扩大的ARB中；据推测，这些纤维没有被辐射切断。在ARB扩大后，当分离的极移回染色体时，中期纺锤体迅速恢复；当ARB关闭时，重新建立纺锤体纤维；当ARB切断一些纤维或横跨整个半纺锤体时，就会发生这种情况。我们从未检测到切断的动粒纤维的伸长。相反，从极点生长的星形纤维似乎在极点向染色体移动之前桥接并关闭了ARB。当第二次照射进入闭合的ARB时，向极地的运动再次停止，然后重新启动。在所有中期细胞中，一旦极点与染色体重新建立连接，未经照射的半纺锤体也会缩短，从而产生一个更小的对称纺锤体，能够在后期恢复正常。后期细胞不是以这种方式恢复的；被切断的极点仍然分离，但染色体继续以修改的形式运动，聚集成一个类似末期的群。从控制纺锤体微管稳定性和有丝分裂力产生机制的角度对结果进行了讨论。
Metaphase and anaphase spindles in cultured newt and PtK1 cells were irradiated with a UV microbeam (285 nM), creating areas of reduced birefringence (ARBs) in 3 s that selectively either severed a few fibers or cut across the half spindle. In either case, the birefringence at the polewards edge of the ARB rapidly faded polewards, while it remained fairly constant at the other, kinetochore edge. Shorter astral fibers, however, remained present in the enlarged ARB; presumably these had not been cut by the irradiation. After this enlargement of the ARB, metaphase spindles recovered rapidly as the detached pole moved back towards the chromosomes, reestablishing spindle fibers as the ARB closed; this happened when the ARB cut a few fibers or across the entire half spindle. We never detected elongation of the cut kinetochore fibers. Rather, astral fibers growing from the pole appeared to bridge and then close the ARB, just before the movement of the pole toward the chromosomes. When a second irradiation was directed into the closing ARB, the polewards movement again stopped before it restarted. In all metaphase cells, once the pole had reestablished connection with the chromosomes, the unirradiated half spindle then also shortened to create a smaller symmetrical spindle capable of normal anaphase later. Anaphase cells did not recover this way; the severed pole remained detached but the chromosomes continued a modified form of movement, clumping into a telophase-like group. The results are discussed in terms of controls operating on spindle microtubule stability and mechanisms of mitotic force generation.