Genetic Analyses of Dendrite Morphogenesis in Caenorhabditis Elegans

PI：Buelow，Hannes E. 项目摘要 多细胞生物的行为是由神经元整合的神经回路控制的 突触输入和计算输出。大多数神经元是双极的，包括树突和轴突， 它们分别介导信息的接收和传输。枝晶分枝是 正确的电路组装所必需的。我们使用的是一对PVD和FLP神经元， 线虫C.研究树突的基本遗传和分子机制 发展PVD和FLP神经元都精心制作了高度分支，非重叠的树突状细胞， 在树突形态发生过程中采用保守机制的乔木。此前，我们有 将我们的研究集中在PVD树突状细胞形成所需的基因上， FLP神经元，重点关注非自主作用因素。在本建议中，我们将重点关注两个 这些方面以前研究不足，无论是关于PVD的发展，而且在 一般关于枝晶图案化。在遗传筛选中，我们已经确定了几个基因座， 限制分支。在具体目标1中，我们将研究我们在遗传修饰筛选中鉴定的基因座， KPC-1/Furin前蛋白转化酶的亚纯型等位基因。我们以前发现科索沃保护团- 1/弗林蛋白酶在PVD神经元中自主发挥细胞功能，负调节树突分支。这 目的是阐明KPC-1/Furin限制分支的分子机制。在 此外，我们还将研究一个等位基因，该等位基因构成了一个转录因子结合位点的突变， 编码肌动蛋白调节蛋白的基因。在具体目标2中，我们将重点关注一个假定的与兔子有关的 我们发现它在表皮中起限制树突分支的作用。该目的是 重点是确定这种假定的GTcells控制分支非- 从皮肤上自动脱落。此外，我们将研究一个等位基因，显示相同的表型作为一个 突变体中的GT3获得更多的洞察如何分支的过程中受到限制。 最后，FLP和PVD神经元提供了一个独特的机会来研究异型性的过程， 平铺（即两种不同类型的神经元之间的感受野的平铺）和控制 分子细节中的树枝状场大小。在正向和候选基因筛选的组合中， 已经鉴定了许多调节FLP和PVD树突之间平铺的基因。因此在 具体目标3，我们将确定管理异型平铺的遗传和分子机制 以及字段大小的控制。总之，该建议旨在了解分子和 一方面是限制和控制树突分支的遗传机制， 其确保在不同类型之间建立限定尺寸的非重叠树突区域 的神经元。

PI: Buelow, Hannes E. Project Summary Behavior in multicellular organisms is controlled by neural circuits in which neurons integrate synaptic input and compute output. Most neurons are bipolar and comprise dendrites and axons, which mediate reception and transmission of information, respectively. Dendrite branching is necessary for correct circuit assembly. We are using the pair of PVD and FLP neurons in the small nematode C. elegans to investigate basic genetic and molecular mechanisms of dendrite development. Both PVD and FLP neurons elaborate highly branched, non-overlapping dendritic arbors that employ conserved mechanisms during dendrite morphogenesis. Previously, we have focused our studies on genes that are required for the formation of the dendritic arbors of PVD and FLP neurons, with a focus on non-autonomously acting factors. In this proposal, we will focus on two aspects that have been previously understudied, both with regard to PVD development, but also in general with regard to dendrite patterning. In genetic screens we have identified several loci that restrict branching. In Specific Aim 1, we will study loci we identified in genetic modifier screens of a hypomorphic allele of the KPC-1/Furin proprotein convertase. We had previously found that KPC- 1/Furin functions cell-autonomously in PVD neurons to negatively regulate dendritic branching. This aim is designed to elucidate the molecular mechanisms by which KPC-1/Furin restricts branching. In addition, we will study an allele that constitutes a mutation in a transcription factor binding site of a gene encoding an actin regulatory protein. In Specific Aim 2, we will focus on a putative rab-related GTPase, which we have found to function in the epidermis to restrict dendrite branching. This aim is focused on determining the mechanisms by which this putative GTPase controls branching non- autonomously from the skin. In addition, we will study an allele that displays the same phenotype as a mutant in the GTPase to gain additional insight into the process of how branching is restricted. Finally, The FLP and PVD neurons provide a unique opportunity to study the processes of heterotypic tiling (i.e. the tiling of receptive fields between two different types of neurons) and the control of dendritic field size in molecular detail. In a combination of forward and candidate genetic screens we have identified a number of genes that regulate tiling between FLP and PVD dendrites. Therefore, in Specific Aim 3, we will determine the genetic and molecular mechanisms that govern heterotypic tiling and the control of field size. In summary, this proposal is aimed at understanding the molecular and genetic mechanisms that restrict and control dendritic branching on the one hand and, the processes that ensure establishment of non-overlapping dendritic fields of defined size between different types of neurons.