Colocalization of TD-60 and INCENP throughout G2 and mitosis: evidence for their possible interaction in signalling cytokinesis
Colocalization of TD-60 and INCENP throughout G2 and mitosis: evidence for their possible interaction in signalling cytokinesis
复制标题
DOI：
10.1007/s004120050330
复制
发表时间：
1998-12-01
期刊：
影响因子：
1.6
通讯作者：
Margolis, RL
中科院分区：
文献类型：
--
作者：
Martineau-Thuillier, S;Andreassen, PR;Margolis, RL
TD-60和INCENP是染色体过客蛋白家族的两个成员，并且已经被认为在胞质分裂的控制中发挥作用。在这里，我们通过共聚焦免疫荧光显微镜证明TD-60和INCENP在整个细胞周期中分布相同。两者协调出现在G2期细胞核中，并在前期集中在着丝粒。TD-60和INCENP都在分裂后期将染色体留在一起，并重新分布到纺锤体中间区，就像其他染色体乘客蛋白一样，并从皮层到皮层穿过整个赤道直径。通过图像叠加和像素计数分析，我们发现TD-60和INCENP在已知的染色体乘客蛋白中是不同的，它们延伸到纺锤体以外的皮层。此外，我们表明，与蛋白激酶AIM-1也共享这种分布特性。我们认为，这种重新分配是必要的信号胞质分裂。TD-60和INCENP在存在二氢细胞松弛素B（DCB）（一种肌动蛋白组装抑制剂）的情况下退出有丝分裂的细胞中也显示出相同的定位。这样的细胞可以在去除DCB后恢复切割，并且在仅在一侧切割的恢复亚群中，这些蛋白质都共定位于仅形成切割沟的皮质。鉴于TD-60和INCENP在间期和有丝分裂期间的一致分布，我们认为这些蛋白质可能在蛋白质复合物内合作，在信号细胞质分裂中。这样的机制，使用染色体乘客蛋白质，可以确保胞质分裂只发生在分离的染色单体之间，并且只在它们分离之后。
TD-60 and INCENP are two members of the chromosome passenger protein family, and each has been suggested to play a role in the control of cytokinesis. Here we demonstrate by confocal immunofluorescence microscopy that TD-60 and INCENP distribute identically throughout the cell cycle. Both appear coordinately in G2-phase nuclei and become concentrated at centromeres during prophase. TD-60 and INCENP both then leave the chromosome together during anaphase and redistribute to the spindle midzone, as do other chromosome passenger proteins, and traverse the entire equatorial diameter from cortex to cortex. By image overlay and pixel count analysis we show that TD-60 and INCENP are distinct among known chromosome passenger proteins in extending beyond the spindle to the cortex. Further, we show that the cytokinesis-associated protein kinase AIM-1 also shares this distribution property. We suggest that this redistribution is required to signal cytokinesis. TD-60 and INCENP also show identical localization in cells that exit mitosis in the presence of dihydrocytochalasin B (DCB), an inhibitor of actin assembly. Such cells can resume cleavage upon removal of DCB and in a recovery subpopulation that cleaves only on one side, these proteins both colocalize to the cortex only where a cleavage furrow forms. Given the coincident distribution of TD-60 and INCENP during both interphase and mitosis, we suggest that these proteins may cooperate, perhaps within a protein complex, in signalling cytokinesis. Such a mechanism, using chromosome passenger proteins, may ensure that cytokinesis occurs only between the separated chromatids, and only after they have segregated.