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。 在大脑皮层形成过程中的迁移。它是由Lis1单倍体不足引起的，原因是 Lis1基因的零星突变。Lis1参与了血小板活化因子和 细胞质动力蛋白通路，但目前的证据表明，后者的缺陷导致了 大脑发育疾病。本实验室的研究表明，Lis1与细胞质一起发挥作用 动力蛋白位于动粒和分裂细胞的皮质，在迁移的成纤维细胞的前沿，以及 在生长锥体重塑期间。来自该实验室的最新结果已确定了Lis1 RNAi对 神经前体细胞在整个放射状迁移过程中的行为 对脑片进行成像。该项目的目标I将是描述进一步的功能相互作用 Lis1和细胞质dynein及其相互结合的伙伴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 机械力化学活性将被确定.目标二将是定义Lis1、裸体和Nudel在 双极神经前体细胞的形态发生和运动。目标三将确定LIS1的作用， 神经前体细胞运动间期核振荡和细胞分裂周期中的nude和nudel 放射状胶质细胞阶段。将对胚胎啮齿类动物脑片和分离的神经前体细胞进行实时成像 在对照、突变或RNAi处理的动物上进行实验，以评估对核分裂、细胞分裂、 核位置、神经胶质引导的迁移和过程动力学对分裂的控制。他们的行为 将监测微管细胞骨架、中心体、核、Lis1、裸体和Nudel，以了解 观察到的脑表型效应的潜在细胞原因。这些研究具有相当大的意义 与了解大脑正常和异常发育、细胞迁移、细胞分裂及其原因的相关性 精神发育迟滞和干细胞行为。

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.