Regulation of pancreatic islet location and size during embryonic development

描述(由申请人提供)： 这个项目的重点是脊椎动物胰腺的发育。我之前已经证明，在发育过程中，CDX4转录因子是限制β细胞数量所必需的。我还证明了内胚层中的CDX4是正确定位胰腺所必需的。在这里，我建议通过进一步描述CDX4在胰腺发育中的作用来扩展这项工作。我将使用斑马鱼作为活体模型。目的1将确定在早期胰腺器官发生过程中胰岛细胞数量受到限制的机制。我将使用cdx4突变的胚胎来测试在没有cdx4的情况下，β细胞或其前体细胞是否促进了增殖。这一目标将决定胰岛大小在正常胰腺发育过程中受到限制的机制。目标2将验证Wnt信号作用于CDX4上游以定位胰腺的假设。目的3将检验内皮HOX因子作用于CDX4下游形成胰腺前内胚层的假说。因此，AIMS 2和3将识别和表征在胰腺区域前后构型过程中发挥CDX4上游和下游作用的因子。这些目标的设计是为了将我目前的研究发展成一个更成熟的研究计划，使我作为一名独立的私人投资公司，在未来获得R01资金。我的近期目标是学习与完成和发布这些目标相关的新技术。我的长期职业目标包括致力于以斑马鱼为模型研究胰腺的发育和功能。我计划在一家学术机构获得一个终身教职的全职助理教授的职位，在那里我的主要工作将是研究。职业发展计划包括通过一个指导委员会进行培训，该委员会由两名发育生物学家维多利亚·普林斯博士和罗伯特·何博士组成，他们都研究斑马鱼的发育，以及一名糖尿病内科科学家。路易斯·菲利普森，医学博士，研究小鼠和人类胰腺生物学和糖尿病。我会定期与委员会会面，评估我的研究和职业发展进展。 公共卫生相关性：这些目标与基于干细胞的糖尿病研究相关。目前引导干细胞走向β细胞命运的方案得益于从体内发育研究中学到的见解。这项拟议的工作将扩展我们目前的知识，即未分化的内胚层是如何形成胰腺的，以及β细胞数量是如何受到胚胎的调节的。

DESCRIPTION (provided by applicant): This project is focused on vertebrate pancreas development. I have previously shown that Cdx4 transcription factor is required to limit beta-cell number during development. I have also shown that Cdx4 is required in the endoderm to correctly localize the pancreas. Here I propose to extend that work by further characterizing the role of Cdx4 in pancreas development. I will use zebrafish as an vivo model. Aim 1 will determine the mechanism whereby beta-cell number is limited during early pancreas organogenesis. I will use Cdx4 mutant embryos to test whether beta-cells, or their precursors, have increased proliferation in the absence of Cdx4. This aim will determine the mechanism whereby islet size is limited during normal pancreas development. Aim 2 will test the hypothesis that Wnt signals function upstream of Cdx4 to localize the pancreas. Aim 3 will test the hypothesis that endodermal Hox factors function downstream of Cdx4 to pattern the pre-pancreatic endoderm. Thus, Aims 2 & 3 will identify and characterize factors that function upstream and downstream of Cdx4 during anteroposterior patterning of the pancreatic domain. These aims were designed with the career goal of developing my current research into a more mature research program that will allow me to secure R01 funding in the future, as an independent PI. My immediate goals are to learn new techniques relevant to completing and publishing these aims. My long-term career goals include a commitment to studying pancreas development and function using zebrafish as a model. I plan to secure a tenure-track, full-time Assistant Professor position at an academic institution, where research would be my primary focus. The career development plan includes training via a mentoring committee composed of two developmental biologists, Victoria Prince, PhD and Robert Ho, PhD, both of whom study zebrafish development, and a diabetes physician scientist. Louis Philipson, MD, PhD, who studies mouse and human pancreas biology and diabetes. I will meet regularly with the committee for evaluation of my research and career development progress. PUBLIC HEALTH RELEVANCE: These aims have relevance for stem-cell based diabetes research. Current protocols for directing stem-cells to a beta-cell fate have benefited from insights learned from in vivo developmental studies. The proposed work will extend our current knowledge of how undifferentiated endoderm is patterned to become pancreas, and how beta-cell number is modulated by the embryo.