MECHANISM OF GOLGI BREAKDOWN DURING MITOSIS

我们的目的是了解动物高尔基体膜 细胞在分裂过程中保持其连续性。 开始时 在动物细胞的有丝分裂中，高尔基复合体的膜分解成一个 大量离散碎片。 这些碎片被认为 随机分布在子细胞之间，在那里它们组装成一个 每个子细胞中有一个高尔基复合体。 这 已提出分解/改革过程，以确保每个 子细胞在细胞分裂过程中接受高尔基复合体的拷贝。 的 高尔基体衍生片段的特点，其机制， 生产，它们在子细胞之间的分布和它们的重组 形成高尔基体膜仍然是个谜。 具体来说，我们计划开发一种体外检测方法来监测这一过程 高尔基体分解 对于这种间期高尔基体膜，要么是孤立的， 或在半完整细胞中，将与来自 爪蟾卵 高尔基体膜分解成离散的碎片 将通过跟踪高尔基体特异性标记的分布来监测 通过免疫荧光。 我们的假设是在这段时间里 下行过程中，两种类型的碎片产生于每个池的 高尔基复合体。 第一类包含脑池特异性的常驻蛋白 而第二类含有在细胞中起结构作用的多肽， 高尔基池的动态。 我们将通过分离出 有丝分裂高尔基体片段从体外孵育的组合， 免疫亲和吸附和速度及平衡蔗糖密度 梯度离心法 我们将制备针对纯化的有丝分裂高尔基体成分的抗体 片段 有丝分裂事件被认为是由 MPF激活后启动的翻译后修饰 激酶。 因此，有丝分裂高尔基体中的许多多肽可能是 与它们的天然形式相比，以修饰形式存在于间期 高尔基 上述抗体的收集将用于 鉴定这些多肽和相应的修饰，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.