Role of alpha-Tubulin Mutations in Lissencephaly

α-微管蛋白突变在无脑畸形中的作用

• 批准号: 7862424
• 负责人: NICHOLAS COWAN
• 金额: $ 44.74万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-05 至 2012-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7862424
• 关键词: Accounting; Affinity; Affinity Chromatography; Architecture; Behavior; Binding; Brain; Categories; Cell-Free System; Cells; Cerebellum; Characteristics; Cultured Cells; Cytoplasmic Protein; Data; Defect; Development; Disease; Dynein ATPase; Elements; Embryo; Event; Extracellular Matrix Proteins; GTP Binding; Genes; Genetic; Hippocampus (Brain); Homologous Gene; Human; In Vitro; Individual; Insecta; Intractable Epilepsy; Label; Lead; Lesion; Link; Mass Spectrum Analysis; Microtubules; Molecular Chaperones; Motor; Mus; Muscle hypotonia; Mutant Strains Mice; Mutation; Names; Neuronal Migration Disorder; Neurons; Pathway interactions; Patients; Phenotype; Platelet Activating Factor; Play; Process; Production; Profound Mental Retardation; Property; Protein Binding; Proteins; Rattus; Reaction; Role; Screening procedure; Site; Structure; Surface; Testing; Tubulin; VLDL receptor; abstracting; alpha Tubulin; base; chaperonin CCT; cohort; cytosolic chaperonin; developmental disease; doublecortin protein; falls; gel electrophoresis; in vivo; infancy; lissencephaly; migration; mutant; polymerization; reconstitution; research study

Lissencephaly is a catastrophic developmental disease characterized by a smooth surface of the brain, four abnormal cortical layers, and a variably hypoplastic cerebellum. The condition is associated with intractable epilepsy, hypotonia, and profound mental retardation from infancy. Mutations in at least three genes – LIS1, DCX and RELN – lead to very similar defects in neuronal migration that are associated with the disease. Together, these account for about 70% of cases of lissencephaly, but the underlying cause of the remaining cases is unknown. We have recently discovered that a mutation in close proximity to the GTP binding pocket of the tuba1 α-tubulin gene causes abnormal neuronal migration events in mice that are reminiscent of lissencephaly. Indeed, screening of a cohort of patients who do not carry mutations in either LIS1, DCX or RELN has revealed that mutations in TUBA1A, the human homolog of tuba1, cause neuronal migration defects including lissencephaly and pachygyria. These data reinforce the notion that microtubule based events play a central role in neuronal migration during development, and that cortical migration disorders results from disruption of critical microtubule processes. We have found that 10 different disease-causing α-tubulin mutations fall into two categories: those that could lead to haploinsufficiency (Class I), and those that do not (Class II). 1) In the case of Class I mutations, we propose to establish the defect(s) in the heterodimer assembly pathway that lead to a diminished yield of tubulin heterodimers. To do this, we will analyze the products of in vitro folding reactions done using individual purified components (chaperones) required for de novo heterodimer assembly. 2) In the case of Class II mutations, we will test the hypothesis that disruption of key elements of microtubule behavior can occur via a mechanism in which proper interactions between α-tubulin and critical effectors of microtubule function are compromised. a) We will generate a supply of tubulin heterodimers that is homogeneous in that it will contain α- and β-subunits consisting of only a single isotype that is either wild type or mutant. b) We will compare the dynamic properties of isotypically pure wild type and mutant forms of TUBA1A.

无脑畸形是一种灾难性的发育性疾病，其特征是大脑表面光滑、四个异常皮质层和不同程度的发育不全的小脑。这种疾病与顽固性癫痫、肌张力低下和婴儿期严重智力低下有关。至少三个基因（LIS1、DCX 和 RELN）的突变会导致与该疾病相关的神经元迁移中非常相似的缺陷。这些合计约占无脑畸形病例的 70%，但其余病例的根本原因尚不清楚。我们最近发现，靠近 tuba1 α-微管蛋白基因的 GTP 结合袋的突变会导致小鼠出现异常的神经元迁移事件，让人想起无脑畸形。事实上，对一组不携带 LIS1、DCX 或 RELN 突变的患者进行的筛查显示，TUBA1A（tuba1 的人类同源物）的突变会导致神经元迁移缺陷，包括无脑畸形和脑回肥大。这些数据强化了这样的观念：基于微管的事件在发育过程中的神经元迁移中发挥着核心作用，并且皮质迁移障碍是由关键微管过程的破坏引起的。我们发现 10 种不同的致病 α-微管蛋白突变分为两类：可能导致单倍剂量不足的突变（I 类）和不会导致单倍剂量不足的突变（II 类）。 1) 对于 I 类突变，我们建议在异二聚体组装途径中确定导致微管蛋白异二聚体产量减少的缺陷。为此，我们将分析使用从头异二聚体组装所需的单独纯化组分（分子伴侣）进行的体外折叠反应的产物。 2）在II类突变的情况下，我们将测试这样的假设：微管行为的关键要素的破坏可以通过一种机制发生，在该机制中，α-微管蛋白和微管功能的关键效应器之间的适当相互作用受到损害。 a) 我们将生成一批均质的微管蛋白异二聚体，因为它将包含仅由野生型或突变体的单一同种型组成的 α 和 β 亚基。 b) 我们将比较 TUBA1A 的同型纯野生型和突变型的动态特性。

项目成果

Mutations in the β-tubulin gene TUBB5 cause microcephaly with structural brain abnormalities.

• DOI: 10.1016/j.celrep.2012.11.017
• 发表时间: 2012-12-27
• 期刊: Cell reports
• 影响因子: 8.8
• 作者: Breuss M;Heng JI;Poirier K;Tian G;Jaglin XH;Qu Z;Braun A;Gstrein T;Ngo L;Haas M;Bahi-Buisson N;Moutard ML;Passemard S;Verloes A;Gressens P;Xie Y;Robson KJ;Rani DS;Thangaraj K;Clausen T;Chelly J;Cowan NJ;Keays DA
• 通讯作者: Keays DA