CYTOKINESIS IN CAENORHABDITIS ELEGANS

胞质分裂，即母细胞分裂成两个子细胞， 最基本的细胞过程，但人们对其了解甚少。 胞质分裂的调节和执行是所有方面的中心 动物的发展和许多病理学，如癌症。 动物 细胞胞质分裂涉及赤道面的进行性收缩， 而植物细胞的胞质分裂则涉及细胞的组装 在成膜体上的板（纺锤体中体的特化）。 这些机制中的每一个都被认为是不同的。 在这 假设动物细胞的终末期 胞质分裂实际上使用与植物中使用的机制相似的机制 胞质分裂 在这种观点中，胞质分裂包括两个阶段： 最初的开沟阶段是独立于任何中间体微管 以及终端阶段，其涉及中间体装置， 最后将两个子细胞分离开来 类似于植物成膜体的功能。 拟 通过研究胞质分裂的终末期来探索这一假说 在秀丽隐杆线虫中， 结构和遗传策略。 研究的三个主要领域是 提出了：1）研究septins在胞质分裂后期的作用。Septins 是一种结构蛋白，最初被认为是 对于芽殖酵母的胞质分裂（没有卵裂沟） 随后显示为动物细胞胞质分裂所需。 它 利用反义基因研究septins的作用 septins的失活、超微结构定位， 正常胚胎细胞纺锤体中段的微管 与那些在后期阶段失败的突变体一起， 胞质分裂和分离隔蛋白突变体的抑制子或增强子 来鉴定相互作用的蛋白质。2)研究可能的 钙调蛋白和肌球蛋白轻链激酶在调节 细胞质分裂的后期，通过使用特定的光活化 这些蛋白质的抑制剂。 这些抑制剂将被光敏化， 纺锤体中部区域。3)研究以确定是否分泌 是胞质分裂末期所必需的， 有证据表明， 超微结构水平，并通过药物阻断分泌，看看是否 这扰乱了胞质分裂的晚期。

Cytokinesis, the cleavage of a mother cell into two daughters, is one of the most fundamental cellular processes yet it is poorly understood. The regulation and execution of cytokinesis are central to all aspects of animal development and to many pathologies such as cancer. Animal cell cytokinesis involves the progressive constriction of an equatorial ring whereas plant cell cytokinesis involves the assembly of a cell plate on a phragmoplast (a specialization of the spindle mid-body). Each of these mechanisms has been considered to be distinct. In this proposal it is hypothesized that the terminal phase of animal cell cytokinesis in fact uses a similar mechanism to that used in plant cytokinesis. In this view, cytokinesis consists of two phases: an initial furrowing phase that is independent of any mid-body microtubules and a terminal phase that involves the mid-body apparatus acting to finally pinch off and separate the two daughter cells in a manner analogous to the function of the phragmoplast of plants. It is proposed to explore this hypothesis by studying the terminal phase of cytokinesis in Caenorhabditis elegans using a combination of cell biological, structural and genetic strategies. Three main areas of study are proposed: 1) Studies of the role of septins in late cytokinesis. Septins are a class of structural protein initially identified as being required for cytokinesis in budding yeast (which do not have cleavage furrows) and subsequently shown to be required for animal cell cytokinesis. It is proposed to investigate the role of septins by antisense gene inactivation, ultrastructural localization of septins with respect to the microtubules of the spindle mid-body in normal embryonic cells together with those of mutants that fail in the late phase of cytokinesis, and isolation of suppressors or enhancers of septin mutants in order to identify interacting proteins. 2) Studies of the possible roles of calmodulin and myosin light chain kinase in the regulation of the late phase of cytokinesis by the use of specific photoactivatable inhibitors of these proteins. The inhibitors will be photoactivated in the spindle mid-body region. 3) Studies to determine whether secretion is required for the terminal phase of cytokinesis by looking for evidence of secretion in the vicinity of the mid-body at an ultrastructural level and by blocking secretion by drugs to see whether this perturbs the late phase of cytokinesis.