Morphogenetic mechanisms regulating directed cell migration required to form the vertebrate posterior body

调节形成脊椎动物后体所需的定向细胞迁移的形态发生机制

基本信息

批准号：
9982378
负责人：
David Kimelman
金额：
$ 33.23万
依托单位：
UNIVERSITY OF WASHINGTON
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-07-01 至 2021-07-31
项目状态：
已结题

项目摘要

PROJECT SUMMARY Much of the vertebrate embryonic body forms from a recently discovered neuromesodermal progenitor cell population located at the most posterior end of the early embryo, in a region called the Progenitor Zone (PZ). The PZ gradually releases mesodermal cells that populate the somites (primarily muscle) as well as the neural cells that form the spinal cord, until the complete anterior-posterior axis of the embryo has been established. While the mechanisms controlling the differentiation of the neuromesodermal cells are increasingly understood, how these cells regulate the completion of the epithelial to mesenchymal transition (EMT) and directional migration from the PZ into the body largely remains a mystery, yet this process is essential for the embryo to form its anterior-posterior axis correctly. Based on our analysis of a zebrafish mutant that specifically disrupts the migration of mesodermal cells from the PZ, we have identified a unique set of PZ-expressed Progenitor Cytoskeletal Regulatory Genes (PCRGs) that we propose must be down-regulated for cells to complete the EMT and migrate from the PZ into the presomitic mesoderm (PSM). Using a novel explant assay we recently developed that allows in vivo imaging of the migrating cells at very high resolution, in Aim 1 we will determine how the PCRGs are used to regulate the directional movement of cells into the PSM using a combination of gain and loss of function studies, as well as examining how the PCRGs control Rho activity. In Aim 2 we will determine how the posterior hox genes, which through unknown mechanisms control the orderly movement of cells from the PZ into the embryonic body, specifically regulate cell movements using our novel explant system to examine directional cell migration and protrusive activity of the hox-expressing cells. We will test the hypothesis that the hox genes act to sustain the expression of the PCRGs, and thereby regulate the timing of cell entry into the PSM. Collectively, these studies will examine the premise that the migration of cells from the PZ into the PSM is regulated by the action of the PCRGs and posterior hox genes, which acting together control the orderly anteriorward migration of newly differentiating mesodermal cells, thus allowing the vertebrate embryonic body to form with remarkable fidelity. With the ease of making transgenic lines that allow temporally controlled expression of the PCRGs and hox genes as well as CRISPR mutant lines, combined with our innovative explant system for high resolution imaging, zebrafish is an excellent system for understanding the mechanisms that control the early formation of the vertebrate body.

项目概要大部分脊椎动物胚胎体是由最近发现的神经中胚层祖细胞形成的群体位于早期胚胎的最后端，位于称为祖细胞区（PZ）的区域。 PZ 逐渐释放中胚层细胞，这些细胞填充体节（主要是肌肉）以及神经细胞形成脊髓的细胞，直到胚胎完整的前后轴建立。虽然控制神经中胚层细胞分化的机制越来越多了解这些细胞如何调节上皮间质转化（EMT）的完成以及从 PZ 到体内的定向迁移在很大程度上仍然是一个谜，但这个过程对于胚胎正确形成其前后轴。基于我们对斑马鱼突变体的分析，该突变体特异性破坏中胚层细胞的迁移 PZ，我们鉴定了一组独特的 PZ 表达的祖细胞骨架调节基因 (PCRG)，我们建议必须下调细胞才能完成 EMT 并从 PZ 迁移到前体中胚层（PSM）。使用我们最近开发的一种新型外植体测定法，可以对以非常高分辨率观察迁移细胞，在目标 1 中，我们将确定如何使用 PCRG 来调节使用功能获得和丧失研究的组合，将细胞定向移动到 PSM 中，以及检查 PCRG 如何控制 Rho 活性。在目标 2 中，我们将确定后 hox 基因如何通过未知机制控制细胞从 PZ 有序运动到胚胎体内，通过以下方式特异性调节细胞运动我们的新型外植体系统用于检查定向细胞迁移和表达 hox 的突出活性细胞。我们将检验 hox 基因维持 PCRG 表达的假设，从而调节细胞进入 PSM 的时间。总的来说，这些研究将检验以下前提：细胞从 PZ 迁移到 PSM 的过程是受 PCRG 和后 hox 基因的作用调节，它们共同作用控制着有序的新分化的中胚层细胞向前迁移，从而允许脊椎动物胚胎身体以非凡的保真度成形。易于制作转基因品系，允许暂时 PCRGs 和 hox 基因以及 CRISPR 突变系的受控表达，结合我们的用于高分辨率成像的创新外植体系统，斑马鱼是了解控制脊椎动物体早期形成的机制。