Mechanisms of Morphogen Transport and Interpretation in Early Embryos

项目摘要 这个项目的长期目标是了解胚胎是如何准确地将指令传递给他们的 组成细胞。这一建议侧重于通过Nodal信号转导，Nodal是一种诱导内胚层和 脊椎动物早期胚胎中胚层的形成。遗传和生化研究表明，目标是 细胞根据自己的位置选择命运，这是节点信号活动的梯度。然而，它的作用机制 梯度的形成和信号解释仍不清楚。拟议中的实验将测试竞争性 来自内源节源的信号的空间传播机制(目标1)，并解释如何 相似的信号水平可以指定不止一个细胞的命运(目标2)。这些研究将在#年进行。 斑马鱼利用其独特的遗传和视觉处理能力。这项工作将解决争议 关于扩散在运输内源性节点配体(K99)中的作用，探索随机的 节状信号中的噪声影响脊椎动物胚胎(K99，R00)的生殖层规格并识别新的 节点依赖的基因表达程序(R00)。阐明Nodal信号在体内的功能也可能 对医学有影响，因为节点信号的错误调节可能导致出生缺陷和癌症 人类。最后，了解允许节点信号传输精确指令的机制将 告知组织工程学和再生生物学，因为Nodal用于控制体外细胞分化。 我的职业目标是管理一个学术实验室，研究发育中的胚胎如何实现精确的模式 面对意想不到的不安。拟议中的实验将给我提供胚胎学方面的经验， 斑马鱼遗传学和光遗传学是实现这一目标所必需的。我和我的同事制定了一份详细的培训计划 我的导师，亚历山大·希尔博士，帮助我过渡到独立。我将定期与Schier医生会面，以 讨论研究进展、助学金撰写策略、学生辅导和实验室管理。去实践 我的导师技能，我会监督研究生的工作。为了扩大我的科学关系网，我将 每年在两次国际会议上介绍我的工作，并参加与Megason的联合实验室会议， Zon和Ramanathan是哈佛大学的小组成员。为了寻求更多的指导，我收集了一份K99建议 委员会由亚当·科恩博士、阿隆·克莱因博士和肖恩·梅格森博士组成。他们在以下方面的专长 光遗传学、单细胞转录学和定量成像将帮助我执行我的研究计划 建议的附表。作为哈佛大学分子和细胞生物学系的一员，我将拥有 接触发育生物学、生物物理学和遗传学领域的领先者以及尖端核心设施。 独立之路奖将提供所需的时间和自由来启动雄心勃勃的 胚胎发育中强健图案形成机制的研究计划。

PROJECT ABSTRACT The long-term goal of this project is to understand how embryos accurately transmit instructions to their constituent cells. This proposal focuses on signaling by Nodal, a model morphogen that induces endoderm and mesoderm formation in early vertebrate embryos. Genetic and biochemical studies demonstrate that target cells select fates based on their position a gradient of Nodal signaling activity. However, the mechanisms of gradient formation and signal interpretation remain unclear. The proposed experiments will test competing mechanisms for the spatial spread of signaling from an endogenous Nodal source (Aim 1), and explain how similar signaling levels can specify more than one cell fate (Aim 2). These studies will be carried out in zebrafish to take advantage of its unique genetic and optical tractability. This work will resolve controversies concerning the role of diffusion in transporting endogenous Nodal ligands (K99), explore whether stochastic noise in Nodal signaling influences germ layer specification in a vertebrate embryo (K99, R00) and identify new Nodal-dependent gene expression programs (R00). Clarifying how Nodal signaling functions in vivo may also have implications for medicine, as misregulation of Nodal signaling can drive birth defects and cancer in humans. Finally, understanding the mechanisms that allow Nodal signals to transmit precise instructions will inform tissue engineering and regenerative biology, as Nodal is used to control cell differentiation in vitro. My career goal is to run an academic lab that studies how developing embryos achieve precise patterning in the face of unexpected perturbations. The proposed experiments will give me the experience in embryology, zebrafish genetics and optogenetics required for this goal. I have developed a detailed training plan with my mentor, Dr. Alexander Schier, to help me transition to independence. I will meet regularly with Dr. Schier to discuss research progress, strategies for grant writing, student mentorship and lab management. To practice my mentorship skills, I will oversee the work of a graduate student. To broaden my scientific network, I will present my work at two international meetings per year and participate in joint lab meetings with the Megason, Zon and Ramanathan groups at Harvard. To seek out additional mentorship, I assembled a K99 advisory committee consisting of Dr. Adam Cohen, Dr. Allon Klein, and Dr. Sean Megason. Their expertise in optogenetics, single-cell transcriptomics and quantitative imaging will help me to execute my research plan on the proposed schedule. As a member of the Harvard Department of Molecular and Cellular Biology, I will have access to leaders in developmental biology, biophysics and genetics, as well as cutting-edge core facilities. The Pathway to Independence Award will provide the time and freedom required to initiate an ambitious research program on the mechanisms of robust patterning in developing embryos.