Regulation of neurodevelopmental cell behaviors in Ciona

项目摘要/摘要 瞬时细胞行为的调节和调节的“状态”是发育所不可缺少的 多细胞生物体。对这些基因结构和新特性的知识 过程也是开发先天性疾病和神经发育疗法的关键 基于细胞重新编程或基因组编辑的综合症。这项建议的目的是 描述控制极化神经元的潜在重要基因的调节和功能 脊索纳幼虫神经系统中的迁移和轴突生长，它有许多共同的解剖和 分子特征与其近亲脊椎动物的较大系统。中环 假设这些过程是由精确的基因发育调节控制的。 编码不同生化途径的限速成分，其可能根据不同的不同而不同 发育阶段和神经元亚型。这项拟议研究的基本原理是，通过 利用不断发育的Ciona胚胎所提供的基因组和细胞简单性，一种 可以在体内研究这些过程，具有更高的空间和时间分辨率。只有231个神经元 和一个完整的“连接体”，Ciona神经系统提供了一个独特的机会 了解脊索神经系统中的细胞行为和发育轨迹 决议。核心假设将通过追求三个具体目标来检验：1)检验 动态而恒定极化神经元内、外源性转化生长因子β通路成分 祖细胞；2)研究受体运输效应因子的调节与 细胞内极性和轴突生长方向的精确定时反转。3)调查 集体上皮片状迁移在牙周炎精确定位和形态发生中的作用 分化的神经元，并测试紧密连接蛋白参与调节这一不寻常的 集体迁徙的模式。将使用一种创新的方法来实现这些目标， 细胞谱系特异性、基于CRISPR/Cas9的体细胞基因敲除和实时荧光显微镜。 拟议工作的预期成果包括确定以前未认识到的 神经发育中保守但研究很少的基因，以及了解如何精确控制 过度神经元亚型特有的极化细胞行为可以通过转录 调节内在和外在效应基因。

PROJECT SUMMARY/ABSTRACT The regulation of transient cell behaviors and regulatory “states” is indispensable for the development of multicellular organisms. Knowledge of the genetic architecture and emergent properties of these processes is also key to developing therapies for congenital diseases and neurodevelopmental syndromes based on cellular reprogramming or genome editing. The objective of this proposal is to characterize the regulation and functions of potentially important genes that control polarized neuronal migration and axon outgrowth in the Ciona larval nervous system, which shares many anatomical and molecular features with the larger systems of their close relatives the vertebrates. The central hypothesis is that these processes are controlled by precise developmental regulation of genes encoding rate-limiting components of diverse biochemical pathways, which may vary according to developmental stage and neuronal subtype. The rationale underlying the proposed research is that, by exploiting the genomic and cellular simplicity afforded by invariantly developing Ciona embryos, one can study these processes in vivo, with greater spatial and temporal resolution. With only 231 neurons and a fully mapped “connectome”, the Ciona nervous system offers a singular opportunity to understand cell behaviors and developmental trajectories in a chordate nervous system at single-cell resolution. The central hypothesis will be tested by pursuing three specific aims: 1) Testing the role of instrinsic and extrinsic TGFβ pathway components in dynamically but invariantly polarizing neuronal progenitors; 2) Investigating the causal links between regulation of effectors of receptor trafficking and precisely timed inversion of intracellular polarity and axon outgrowth orientation. 3) Investigating the role of collective epithelial sheet-like migration in precise positioning and morphogenesis of differentiated neurons, and testing the involvement of tight junction proteins in regulating this unusual mode of collective migration. These aims will be pursued using an innovative approach that combines cell lineage-specific, CRISPR/Cas9-based somatic gene knockouts and live fluorescence microscopy. The expected outcomes of the proposed work include identifying previously unrecognized functions for conserved but poorly studied genes in neurodevelopment, and understanding how precise control over neuronal subtype-specific polarized cell behaviors can be achieved through transcriptional regulation of both intrinsic and extrinsic effector genes.