Mechanism of Action of the Lissencephaly Gene LIS-1

I型无脑畸形是一种严重的脑发育疾病，涉及神经前体细胞缺陷 大脑皮层形成过程中的迁移。它是由LIS1单倍不足引起的， LIS1基因的偶发突变。LIS1与血小板活化因子有关， 细胞质动力蛋白途径，但目前的证据表明，后者的缺陷是负责 脑发育疾病该实验室的工作表明，LIS1与细胞质中的 动力蛋白位于着丝粒和分裂细胞的皮质，位于迁移成纤维细胞的前缘， 在生长锥重塑过程中。该实验室的最新结果已经确定了LIS1 RNAi对 神经前体细胞的行为从神经发生通过整个过程的放射状迁移的生活 脑切片成像。本项目的目的是进一步描述 LIS1和细胞质动力蛋白及其相互结合伴侣NudE和NudEL。蛋白质的作用 调节这些相互作用的磷酸化，以及LIS1，NudE和NudEL对动力蛋白的影响 将测定机械化学活性。目的II将是定义LIS1，NudE和NudEL的作用， 双极神经祖细胞的形态发生和运动。目标三是确定LIS1的作用， NudE和NudEL在神经前体细胞核内振荡和细胞分裂周期中的作用 放射状胶质阶段。胚胎啮齿动物脑切片和分离的神经祖细胞的实时成像将在 在对照、突变体或RNAi处理的动物上进行，以评价对核分裂、细胞分裂 通过核位置控制分裂、胶质细胞引导的迁移和过程动力学。的行为 将监测微管细胞骨架、中心体、细胞核、LIS1、NudE和NudEL，以了解 观察到的大脑表型效应的潜在细胞原因。这些研究具有相当大的 相关了解正常和异常的大脑发育，细胞迁移，细胞分裂，原因 智力迟钝和干细胞行为。

Type I lissencephaly is a severe brain developmental disease which involves defects in neural progenitor cell migration during the formation of the cerebral cortex. It is caused by LIS1 haploinsufficiency, resulting from sporadic mutations in the LIS1 gene. LIS1 has been implicated in the platelet activating factor and cytoplasmic dynein pathways, but current evidence suggests that defects in the latter are responsible for the brain developmental disease. Work from this lab has indicated that LIS1 functions together with cytoplasmic dynein at kinetochores and the cortex of dividing cells, at the leading edge of migrating fibroblasts, and during growth cone remodeling. Recent results from this lab have identified severe effects of LIS1 RNAi on the behavior of neural progenitor cells from neurogenesis through the entire course of radial migration by live imaging of brain slices. Aim I of this project will be to characterize further functional interactions between LIS1 and cytoplasmic dynein and their mutual binding partners NudE, and NudEL. The role of protein phosphorylation in regulating these interactions, and the effects of LIS1, NudE, and NudEL on dynein mechanochemical activity will be'determined. Aim II will be to define the role of LIS1, NudE and NudEL in the morphogenesis and locomotion of bipolar neural progenitors. Aim III will be to define the role of LIS1, NudE and NudEL in the interkinetic nuclear oscillations and cell division cycle of neural progenitor cells at the radial glial stage. Live imaging of embryonic rodent brain slices and isolated neural progenitors will be performed on control, mutant, or RNAi-treated animals to evaluate effects on nucleokinesis, cell division, control of division by nuclear position, glial guided migration, and process dynamics. The behavior of the microtubule cytoskeleton, centrosomes, nuclei, LIS1, NudE, and NudEL will be monitored to understand the underlying cellular causes for observed brain phenotypic effects. These studies are of considerable relevance to understanding normal and abnormal brain development, cell migration, cell division, the causes of mental retardation, and stem cell behavior.