Cao L G, Wang Y L
Cell Biology Group, Worcester Foundation for Biomedical Research, Shrewsbury, Massachusetts 01545, USA.
Mol Biol Cell. 1996 Feb;7(2):225-32. doi: 10.1091/mbc.7.2.225.
The interaction between the mitotic spindle and the cellular cortex is thought to play a critical role in stimulating cell cleavage. However, little is understood about the nature of such interactions, particularly in tissue culture cells. We have investigated the role of the spindle midzone in signaling cytokinesis by creating a barrier in cultured epithelial cells with a blunted needle, to block signals that may emanate from this region. When the barrier was created during metaphase or early anaphase, cleavage took place only on the sides of the cortex facing the mitotic spindle. Microtubules on the cleaving side showed organization typical of that in normal dividing cells. On the noncleaving side, most microtubules passed from one side of the equator into the other without any apparent organization, and actin filaments failed to organize in the equatorial region. When the barrier was created after the first minute of anaphase, cells showed successful cytokinesis, with normal organization of microtubules and actin filaments on both sides of the barrier. Our study suggests that transient signals from the midzone of early anaphase spindles are required for equatorial contraction in cultured cells and that such signaling may involve the organization of microtubules near the equator.
有丝分裂纺锤体与细胞皮层之间的相互作用被认为在刺激细胞分裂中起关键作用。然而，对于这种相互作用的本质，尤其是在组织培养细胞中，人们了解甚少。我们通过用钝针在培养的上皮细胞中制造一个屏障，来阻断可能从该区域发出的信号，从而研究纺锤体中间区在细胞分裂信号传导中的作用。当在中期或早后期制造屏障时，细胞分裂仅发生在皮层面向有丝分裂纺锤体的一侧。分裂侧的微管呈现出正常分裂细胞中典型的组织形式。在非分裂侧，大多数微管从赤道的一侧穿过到另一侧，没有任何明显的组织形式，并且肌动蛋白丝在赤道区域未能组织起来。当在后期开始的第一分钟后制造屏障时，细胞显示出成功的细胞分裂，屏障两侧的微管和肌动蛋白丝都有正常的组织形式。我们的研究表明，早后期纺锤体中间区的瞬时信号是培养细胞赤道收缩所必需的，并且这种信号传导可能涉及赤道附近微管的组织。
