Regulation of Mesodermal Progenitors in Transgenic Zebrafish

转基因斑马鱼中胚层祖细胞的调控

基本信息

批准号：
8577068
负责人：
David Kimelman
金额：
$ 30.36万
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 2017-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): A hallmark of early vertebrate development is the progressive growth of the embryonic body from the anterior (A) to the posterior (P), which relies on a multipotent stem-like progenitor population located at the most posterior end of the embryo, in a region called the tailbud. This progenitor population gradually releases mesodermal cells that populate the somites (primarily muscle), as well as neural cells that form the spinal cord, until the complete A-P axis has been established. For the body to form normally, both the rate of release from the tailbud and cell proliferation must be carefully controlled so tht the correct proportion of cells is produced along the entire A-P axis. How these processes are regulated and integrated is poorly understood. The first aim of this proposal will examine the mechanisms by which cells leave the tailbud and enter the somites. Based on recent preliminary results with a new transgenic line, the role of Wnt signaling in regulating this process will be elucidated by testing two hypotheses for Wnt function. In addition, analysis of a small unique element within the tbx16/spadetail promoter, which is activated just as cells make the decision to leave the progenitor population, will provide key insight into the molecular mechanism that regulates the initial step in the commitment to the mesodermal fate as the body elongates. Identifying the mechanisms that control cell allocation will be a major step forward in understanding how the vertebrate embryo precisely regulates the release of cells from the tailbud. The second aim will determine why cell proliferation is tightly regulated in the post-gastrula embryo such that the progenitors are quiescent, and only divide when they first begin to differentiate. This aim will test the hypotheses that this regulation is essential to allow normal signaling and/or morphogenesis of the mesodermal progenitors and their derivatives using a novel transgenic line we have recently produced. Determining why the vertebrate embryo strictly controls proliferation is essential for understanding how the embryo regulates the competing needs to increase cell number yet maintain the complex signaling and morphogenetic processes necessary to establish the embryonic body plan. Studies, particularly in mammals, show that the posterior progenitors are a stem-cell like population, which contribute to a variety of cell types. With the ability to produce transgenic lines expressing temporally controlled regulators of signaling and cell proliferation, as well as the ability to easily knock down gene function, zebrafish provides an excellent model system for understanding how vertebrate stem cells are regulated in vivo. As stem cells have great promise for the treatment of many diseases, the studies described here will provide valuable information about the signaling networks and regulatory factors that control stem cell maintenance and tissue formation.

描述（由申请人提供）：早期脊椎动物发育的标志是胚胎体从前（a）到后（P）的胚胎逐渐生长，该胚胎依赖于胚胎最后端的多型茎状祖细胞种群，在一个名为尾巴的区域。该祖细胞逐渐释放出填充物体（主要是肌肉）的中胚层细胞，以及形成脊髓的神经细胞，直到建立完整的A-P轴为止。为了使身体正常形成，必须仔细控制尾梁和细胞增殖的释放速率，以便沿整个A-P轴产生正确的细胞比例。这些过程的调节和集成方式的理解很少。该提案的第一个目的是检查细胞离开尾舱并进入节点的机制。基于新的转基因线的最新初步结果，Wnt信号在调节此过程中的作用将通过测试两个假设Wnt功能来阐明。此外，对TBX16/Spadetail启动子中一个小唯一元素的分析（即在细胞决定离开祖细胞种群的决定）中被激活，它将对分子机制提供关键的见解，该分子机制调节了对中胚层命运的最初步骤，作为身体延长。识别控制细胞分配的机制将是了解脊椎动物胚胎如何精确调节细胞从尾扣中释放的重要一步。第二个目的将决定为什么细胞增殖在后腹部胚胎中受到严格的调节，使得祖细胞是静止的，并且只有在初次开始区分时才会分裂。该目标将检验以下假设：这种调节对于允许使用我们最近产生的新型转基因线对中胚层祖细胞及其衍生物的正常信号传导和/或形态发生至关重要。确定为什么脊椎动物的胚胎严格控制增殖对于理解胚胎如何调节竞争需要增加细胞数量，并保持复杂的信号传导和形态发生过程以建立胚胎身体计划所需的复杂信号传导和形态发生过程至关重要。研究，尤其是在哺乳动物中的研究表明，后祖细胞像干细胞一样，有助于各种细胞类型。 Zebrafish具有产生信号传导和细胞增殖的时间控制调节剂的转基因线的能力，以及能够轻松敲低基因功能的能力，提供了一个出色的模型系统，用于了解如何在体内调节脊椎动物干细胞。由于干细胞对许多疾病的治疗有很大的希望，因此此处描述的研究将提供有关控制干细胞维持和组织形成的信号网络和调节因素的宝贵信息。