MECHANISM OF GOLGI BREAKDOWN DURING MITOSIS

我们的目的是了解动物高尔基体膜的机制 细胞在分裂过程中保持其连续性。在……开始时 高尔基复合体在动物细胞膜上的有丝分裂 大量的离散碎片。这些碎片被认为是 在子细胞之间随机分布，在那里它们聚集形成一个 每一子细胞中高尔基复合体的单拷贝。这 已经提出了分解/改革流程，以确保每个 子细胞在细胞分裂过程中收到高尔基复合体的拷贝。这个 高尔基体衍生片段的特征及其形成机制 生产、它们在子代细胞中的分布及其重组 然而，形成高尔基膜仍然难以捉摸。 具体地说，我们计划开发一种体外试验来监测这一过程 高尔基人崩溃的证据。对于这种相间高尔基膜，无论是分离的 或在半完整的细胞中，将与来自 非洲爪哇蛋。高尔基膜被分解成离散的碎片 将通过跟踪高尔基体特异性标记的分布进行监测 通过免疫荧光法。我们的工作假设是，在这个休息期间 下过程从每个池中产生两种类型的碎片 高尔基情结。第一类包含Cisterna特定的驻留蛋白 和类型2包含在结构上起作用的多肽。 高尔基体池的动态观察我们将通过隔离来检验这个假设 体外孵育的有丝分裂高尔基体片段 免疫亲和吸附速度与平衡蔗糖密度 梯度离心法。 我们将制备针对纯化的有丝分裂高尔基体组分的抗体 碎片。有丝分裂事件被认为是由 激活MPF时启动的翻译后修改 激活剂。因此，有丝分裂高尔基体中的一些多肽可能是 以修改的形式存在，而不是以原始形式存在于相间 高尔基。上述抗体的收集将用于 鉴定这些多肽和各自的修饰，以确定 它们在高尔基体分解过程中的作用。

Our aim is to understand the mechanism by which Golgi membranes of animal cells maintain their continuity during cell division. At the onset of mitosis in animal cells membranes of the Golgi complex breakdown into a large number of discrete fragments. These fragments are thought to distribute randomly between daughter cells, where they assemble to form a single copy of Golgi complex in each daughter cell. This breakdown/reformation process has been proposed to ensure that each daughter cell receives a copy of Golgi complex during cell division. The characteristics of Golgi-derived fragments, the mechanisms of their production, their distribution between daughter cells and their reassembly to form Golgi membranes however, remain elusive. Specifically, we plan to develop an in vitro assay to monitor the process of Golgi breakdown. For this interphase Golgi membranes, either isolated or in semi-intact cells, will be incubated with mitotic extracts from Xenopus eggs. The breakdown of Golgi membranes into discrete fragments will be monitored by following the distribution of Golgi specific markers by immunofluorescence. Our working hypothesis is that during this break down process two types of fragments are produced from each cisterna of the Golgi complex. Type one contains the cisterna specific resident proteins and type two contains polypeptides that play a structural role in the dynamics of Golgi cisternae. We will test this hypothesis by isolating mitotic Golgi fragments from the in vitro incubations by a combination of immunoaffinity adsorption and velocity and equilibrium sucrose density gradient centrifugation. We will prepare antibodies against the components of purified mitotic Golgi fragments. The mitotic events are thought to be controlled by posttranslational modifications that are initiated upon activation of MPF kinase. A number of polypeptides in mitotic Golgi may therefore, be present in a modified form compared to their native from in interphase Golgi. The collection of antibodies mentioned above will be used to identify such polypeptides and the respective modifications, to ascertain their function in the Golgi break down process.