Brain development phenotyping of IMPC lethal mutant mice

翻译后摘要：神经干细胞从一个简单的上皮管建立大脑的机制是一个复杂的过程。 令人信服的生物学奥秘小鼠遗传学是发现基因的最有力的工具之一 以及参与构建健康大脑的过程，或影响大脑的神经发育障碍， 结构或功能。由国际小鼠表型分析组织创建的靶向突变库 IMPC为理解这些基因和过程提供了非常有价值的资源。许多 导致神经发育表型的突变是致命的，无论是由于大脑缺陷还是多效性， 该基因在其他器官中的功能对生存力至关重要。因此，IMPC的致死突变体库提供了 大脑发育所需的一组丰富的候选基因。然而，大脑结构的变化或 如果没有合适的工具和专业知识，很难检测到布线。我们建议运用我们的专业知识， 表型选择的敲除品系可能具有神经发育缺陷，基于基因 表达、功能和/或已知的突变。这是为了回应一个 FOA用于表征致死IMPC突变体的发育缺陷。我们将联合收割机非假设驱动 通过假设驱动的分析，对一些选定的脑发育突变体进行了总体表型分析。增加价值 和效率，突变体的子集也将由合作研究者进行测试， 发育表型和胎盘、原肠胚形成或神经管缺陷。对于第一层表型， 将测试品系的致死年龄，并对脑、内耳、脊髓 和身体发育。第2层表型分析将包括脑、内耳和胎盘的组织病理学， 因为这些器官中的许多结构缺陷在不切片和染色的情况下不能确定。我们将 检查增殖、分层和轴突束缺陷。第3层表型将集中在少数 同时具有异常脑表型和胞质分裂中的基因功能的突变体，以解决我们的假设： 皮质神经干细胞胞质分裂的不同缺陷是各种脑畸形的基础。我们 将利用我们已经建立的定量分析细胞动力学开沟和分离的方法 发育中的小鼠皮层缺陷。在表型分型的所有阶段中，杂合子和纯合子将被 与对照组进行定量和统计学上的严格比较。数据将与IMPC共享，以便 社会各界我们的三名研究人员团队拥有超过50年的细胞研究专业知识， 小鼠模型中器官发育的基础，以及正向和反向遗传学。通过这个项目，我们 将发现大脑、内耳和胎盘发育障碍的新小鼠模型， 为神经干细胞分裂和细胞缺陷的机制提供了重要的新见解 潜在的大脑畸形

Abstract: The mechanisms by which neural stem cells build the brain from a simple epithelial tube is a compelling mystery of biology. Mouse genetics has been one of the most powerful tools to discover the genes and processes involved in building a healthy brain, or in neurodevelopmental disorders that affect brain structure or function. The library of targeted mutations created by the International Mouse Phenotyping Consortium (IMPC) provides a highly valuable resource for understanding those genes and processes. Many mutations that cause neurodevelopmental phenotypes are lethal, either due to the brain defect or to pleiotropic functions of the gene in other organs essential for viability. Thus, the bank of lethal mutants at IMPC provides an enriched set of candidate genes required for brain development. However, changes in brain structure or wiring are difficult to detect without the right tools and expertise. We propose to apply our expertise to phenotype selected knockout lines that are likely to have neurodevelopment defects, based on gene expression, function, and/or known mutation in a human developmental disorder. This is in response to an FOA to characterize developmental defects in lethal IMPC mutants. We will combine non-hypothesis driven gross phenotyping with hypothesis-driven analysis of a few selected brain development mutants. To add value and efficiency to this screen, subsets of mutants will also be tested by co-investigators for inner ear development phenotypes, and placenta, gastrulation, or neural tube defects. For the first tier of phenotyping, lines will be tested for age of lethality and phenotyped for gross abnormalities of brain, inner ear, spinal cord, and body development. Tier 2 phenotyping will incorporate histopathology of brain, inner ear, and placenta, since many structural defects in these organs cannot be ascertained without sectioning and staining. We will test for proliferation, layering, and axon tract defects. Tier 3 phenotyping will focus on a small number of mutants with both abnormal brain phenotypes and gene functions in cytokinesis, to address our hypothesis: that different defects in cytokinesis of cortical neural stem cells underlie a variety of brain malformations. We will make use of methods we have established for quantitative analysis of cytokinetic furrowing and abscission defects in developing mouse cortex. In all stages of phenotyping, heterozygotes and homozygotes will be compared to controls quantitatively and with statistical rigor. Data will be shared with IMPC for the benefit of the community. Our team of three investigators has a combined >50 years of expertise working on cellular bases of organ development in the mouse model, and forward and reverse genetics. Through this project , we will discover new mouse models for developmental disorders of the brain, inner ear, and placenta, and will provide important new insights into the mechanisms of neural stem cell divisions and cellular defects underlying brain malformations.