The role of mouse ARL13B in cell diversification during spinal cord development

描述（由申请人提供）：最近的研究通过显示纤毛在控制分化和细胞生长的信号事件中发挥作用，彻底改变了纤毛作为运动细胞器的看法。该提案结合了遗传，生物化学，分子和细胞生物学方法，以了解纤毛如何通过研究蛋白质ARL13B在发育中的脊髓中发出信号并指定细胞命运。由于ARL13 B在纤毛中的功能，ARL13 B缺陷的小鼠在脊髓中具有细胞特化缺陷。目标1中提出的实验将从遗传学上确定ARL13 B是否在最初指定神经细胞命运的既定信号通路中起作用。目的2将定义ARL13 B如何以及何时在发育为运动神经元并随后发育为少突胶质细胞的神经祖细胞中被需要。目的3的目标是通过定义调节ARL13 B定位的功能结构域和通过鉴定相互作用的蛋白质，将ARL13 B在细胞命运特化中的功能与其在纤毛中的功能联系起来。这些结果将为纤毛蛋白在细胞特化中的作用提供新的认识。睫状蛋白在基本细胞功能中发挥的基本作用通过这些蛋白缺陷的患者所表现出的表型的多样性谱来强调。肥胖、内脏逆位、不育、糖尿病、多指（趾）畸形、肾功能障碍、学习障碍、癫痫、耳聋、嗅觉丧失和失明都见于纤毛缺陷的患者，并且被认为是由纤毛的形成、运动和信号传导能力的失败引起的。通过建立ARL13 B在纤毛发生中发挥作用的机制，并将其与ARL13 B在信号传导中的作用联系起来，以指定脊髓细胞的命运，所提出的工作将更好地理解运动神经元和少突胶质细胞的发育，这可能影响髓鞘发育障碍疾病的治疗，如多发性硬化症以及脊髓损伤。考虑到控制细胞选择的信号通路与相同通路被破坏的人类疾病状态之间的直接联系，这项拟议的工作具有改善人类健康的高潜力。

DESCRIPTION (provided by applicant): Recent studies have revolutionized the perception of cilia as an organelle of motility by showing cilia play roles in signaling events that control differentiation and cell growth. This proposal combines genetic, biochemical, molecular and cell biological approaches in order to understand how cilia signal and specify cell fate in the developing spinal cord by studying a protein, ARL13B. Mice deficient for ARL13B have defects in cell specification in the spinal cord due to a function of ARL13B in cilia. The proposed experiments in Aim 1 will genetically determine if ARL13B acts in the established signaling pathways that initially specify neural cell fate. Aim 2 will define how and when ARL13B is required in the neural progenitor cells that develop as motor neurons and subsequently as oligodendrocytes. The goal of Aim 3 is to relate the function of ARL13B in cell fate specification to its function in cilia by defining the functional domains that regulate ARL13B localization and by identifying interacting proteins. Taken together these results will provide new understanding of the role of cilia proteins in cell specification. The fundamental role ciliary proteins play in basic cellular functions is underscored by the diverse spectrum of phenotypes exhibited by patients with defects in these proteins. Obesity, situs inversus, infertility, diabetes, polydactyly, renal dysfunction, learning disabilities, epilepsy, deafness, anosmia and blindness are all seen in patients with defective cilia and are thought to result from failures in the formation, motility and signaling ability of cilia. By establishing the mechanism through which ARL13B functions in ciliogenesis and connecting it to the role of ARL13B in signaling to specify spinal cord cell fates the proposed work will provide a better understanding of motor neuron and oligodendrocyte development that can impact the treatment of dysmyelinating diseases such as multiple sclerosis as well as spinal cord injury. Given the direct connections between the signaling pathways that govern cell choice and the human disease states in which the same pathways are disrupted, this proposed work has high potential to improve human health