NUCLEAR DYNAMICS IN RETINAL DEVELOPMENT AND HOMEOSTASIS

视网膜发育和稳态中的核动力学

• 批准号: 8502978
• 负责人: DIDIER HODZIC
• 金额: $ 38万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8502978
• 关键词: Address; Adult; Affect; Aging; Animal Model; Apical; Atrophic; Brain; Cell Cycle; Cell Nucleus; Cells; Central Nervous System Diseases; Complex; Cytoskeleton; Defect; Development; Disease; Etiology; Failure; Family; Genes; Genetic; Homeostasis; Human; Impairment; Knowledge; Lamin Type B; Link; Mammals; Microphthalmos; Mitotic; Modeling; Molecular; Molecular Analysis; Molecular Motors; Movement; Mus; Mutation; Nature; Neuroepithelial Cells; Neurons; Newborn Infant; Nuclear; Nuclear Envelope; Nuclear Translocation; Optic Nerve; Pathology; Pattern; Phase; Phenotype; Photoreceptors; Physiological; Population; Positioning Attribute; Protein Isoforms; Proteins; Retina; Retinal; Retinal Cone; Retinal Diseases; Retinal Dysplasia; Role; Side; System; Testing; Time; Tissues; Transcriptional Regulation; Transgenic Model; Transgenic Organisms; base; dystroglycanopathy; in vivo; macromolecular assembly; macula; migration; mouse model; nerve stem cell; nervous system disorder; neuroepithelium; neurogenesis; neurogenetics; novel; postnatal; prevent; progenitor; public health relevance; retinal neuron; retinal progenitor cell; retinogenesis; stem

DESCRIPTION (provided by applicant): Nuclear movements within neuronal progenitors and post-mitotic neurons underlie fundamental aspects of CNS development. Accordingly, failure of these nuclear movements are associated to severe neurodevelopmental defects such as abnormal cortical lamination, optic nerve hypoplasia and atrophy, retinal dysplasia, macular hypoplasia and microphthalmia. Our limited understanding of the physiological relevance of these nuclear movements stems, in part, from the current lack of appropriate animal models to interfere with nucleokinesis. We recently validated a novel transgenic strategy that interferes with nuclear movements within specific cells and/or tissues in vivo. This strategy is based on the inducible disruption of "Linkers of the Nucleoskeleton to the Cytoskeleton" (LINC complexes), a family of macromolecular assemblies that span the nuclear envelope and provide anchor points for molecular motors and cytoskeletal networks to the nucleus. Using this transgenic strategy, we will examine the role of LINC complexes in interkinetic nuclear migration that consists of oscillations of retinal progenitor nuclei in phase with the cell cycle. Because nuclear translocation is strictly required for the migration of cortical post-mitotic neurons, we will examine whether LINC complex disruption affects the migration of newborn retinal neurons towards their final laminar position. The phenotypical consequences resulting from induced alterations of nuclear movements during retinogenesis will be fully examined in adult retinas, a set of results that may provide new models of congenital retinal disorders. We recently observed that cone nuclei positioning are severely altered upon LINC complex disruption, a phenotype that is strikingly similar to the progressive mispositioning of cone nuclei within the aging human retina. Here, the morphological and physiological consequences of cone nuclei mispositioning will be carefully analyzed in our mouse model. Cone nuclei mispositioning phenotype in adult retina originates from the inability of cone precursor nuclei to migrate apically during postnatal retinal development. Because B-type lamins directly interact with nucleoplasmic interfaces of LINC complexes, their involvement in cone nuclei positioning will be examined. Cytoplasmic interfaces of LINC complex are represented by Nesprins, a group of structurally- related proteins encoded by four distinct genes whose transcriptional regulation leads to the synthesis of multiple isoforms. Currently, the identity of Nesprin isoform(s) expressed in the CNS remains unknown, a knowledge gap that prevents the examination of the molecular nature of LINC complex interactions with molecular motors. Here, we will identify Nesprin isoforms expressed in retinal neurons and their progenitors. Because mutations of Nesprin genes are genetically linked to an increasing number of neurological disorders, our results may further emphasize CNS-specific isoforms of Nesprins whose mutations underlie human neurological disorders.

描述(由申请人提供)：神经前体细胞和有丝分裂后神经元内的核运动是中枢神经系统发育的基本方面。因此，这些核运动的失败与严重的神经发育缺陷有关，如皮质板层异常、视神经发育不良和萎缩、视网膜发育不良、黄斑发育不良和小眼炎。我们对这些核运动的生理相关性的了解有限，部分原因是目前缺乏适当的动物模型来干扰核分裂。我们最近验证了一种新的转基因策略，该策略可以干扰体内特定细胞和/或组织内的核运动。这一策略是基于“核骨架到细胞骨架的连接物”(LINC复合体)的诱导破坏，LINC复合体是一类跨越核膜并为分子马达和细胞骨架网络提供到细胞核的锚点的大分子组装。利用这种转基因策略，我们将研究LINC复合体在动间核迁移中的作用，这种迁移包括视网膜前体细胞核与细胞周期同步的振荡。由于核移位是皮质有丝分裂后神经元迁移的严格要求，我们将研究LINC复合体的破坏是否影响新生视网膜神经元向其最终板层位置的迁移。将在成人视网膜上全面研究视网膜发生过程中诱导的核运动变化所造成的表型后果，这一结果可能会提供先天性视网膜疾病的新模型。我们最近观察到，随着LINC复合体的破坏，锥体核的位置发生了严重的变化，这一表型与锥体核在老化的人类视网膜内的进行性错误定位惊人地相似。在这里，我们将在我们的小鼠模型中仔细分析锥体核错位的形态和生理后果。视锥细胞核错位在成人视网膜中的表型起源于视锥前体核在出生后视网膜发育过程中不能顶端迁移。由于B-型层与LINC复合体的核质界面直接相互作用，因此我们将研究它们在锥核定位中的作用。LINC复合体的细胞质界面由Nesprs代表，它是一组结构相关的蛋白质，由四个不同的基因编码，其转录调控导致多种异构体的合成。目前，Nesprin异构体(S)在中枢神经系统中表达的身份尚不清楚，这一知识空白阻碍了对LINC复合体与分子马达相互作用的分子性质的研究。在这里，我们将确定在视网膜神经元及其前体细胞中表达的Nesprin亚型。因为Nesprin基因的突变与越来越多的神经疾病在基因上有关，我们的结果可能进一步强调Nesprs的中枢神经系统特异性亚型，其突变是人类神经疾病的基础。