The role of pre- and post-anaphase microtubules in the cytokinesis phase of the cell cycle
The role of pre- and post-anaphase microtubules in the cytokinesis phase of the cell cycle
复制标题
DOI：
10.1016/s0960-9822(00)00490-5
复制
发表时间：
2000-05-18
期刊：
影响因子：
9.2
通讯作者：
Salmon, ED
中科院分区：
文献类型：
--
作者：
Canman, JC;Hoffman, DB;Salmon, ED
细胞周期的细胞质分裂期或C期导致有丝分裂完成后一个细胞分裂成两个子细胞。虽然已知微管对于细胞动力学沟的正确定位是必需的[1,2]，但由于三个关键原因，后期前微管在细胞动力学中的作用尚未明确定义。首先，在后期开始前诱导微管解聚或稳定，通过纺锤体检查点[3]阻止进入后期和细胞分裂。其次，随着有丝分裂激酶Cdc2-cyclin B失活，微管组织在后期开始迅速改变。第三，后期开始和细胞质分裂开始之间的时间非常短，这使得很难在细胞质分裂之前明确地改变微管聚合物水平，但在纺锤体检查点失活之后。在这里，我们利用了在前期注射梭形检查点蛋白Mad2（有丝分裂停止缺陷）抗体的发现，废除了梭形检查点，产生过早的染色体分离、分离和正常的细胞质分裂[5,6]。为了检测后期前微管在细胞分裂中的作用，在前期和中期细胞中拆卸微管，然后给细胞注射抗mad2抗体并记录C期。结果表明，在没有微管的情况下退出有丝分裂会触发50分钟的皮质收缩期，而这种收缩期与微管无关。此外，在这个收缩的c期，微管重组后，大约30%的细胞进行染色体极向运动，形成中间区微管复合体，完成细胞质分裂。
The cytokinesis phase, or C phase, of the cell cycle results in the separation of one cell into two daughter cells after the completion of mitosis. Although it is known that microtubules are required for proper positioning of the cytokinetic furrow [1,2], the role of pre-anaphase microtubules in cytokinesis has not been clearly defined for three key reasons. First, inducing microtubule depolymerization or stabilization before the onset of anaphase blocks entry into anaphase and cytokinesis via the spindle checkpoint [3]. Second, microtubule organization changes rapidly at anaphase onset as the mitotic kinase, Cdc2-cyclin B, is inactivated [4]. Third, the time between the onset of anaphase and the Initiation of cytokinesis is very short, making it difficult to unambiguously alter microtubule polymer levels before cytokinesis, but after inactivation of the spindle checkpoint. Here, we have taken advantage of the discovery that microinjection of antibodies to the spindle checkpoint protein Mad2 (mitotic arrest deficient) in prometaphase abrogates the spindle checkpoint, producing premature chromosome separation, segregation, and normal cytokinesis [5,6]. To test the role of pre-anaphase microtubules in cytokinesis, microtubules were disassembled in prophase and prometaphase cells, the cells were then injected with anti-Mad2 antibodies and recorded through C phase. The results show that exit from mitosis in the absence of microtubules triggered a 50 minute period of cortical contractility that was independent of microtubules. Furthermore, upon microtubule reassembly during this contractile C-phase period, similar to 30% of the cells underwent chromosome poleward movement, formed a midzone microtubule complex, and completed cytokinesis.