The Generation of Positional Identity in Mesendoderm; Mechanism(s) of Lineage Specification in Vertebrate Development

在胚胎发育早期，未来肠道的细胞沿着胚胎的中线移动，向神经系统发出信号。为了理解驱动这些细胞分化的分子指令，有必要将它们从胚胎中复杂和不断变化的环境中分离出来。能够打破这种体内谱系规范过程对于从人类胚胎干细胞中产生肠道相关细胞类型和器官也是必不可少的。在这项提议中，我们利用转基因小鼠胚胎干细胞，实时报告胚胎肠道的分化。我们已经使用这个系统来产生胚胎干细胞向胚胎肠分化的单层条件。我们有能力区分附着在塑料上的细胞，这意味着我们可以很容易地改变介质成分，并在视觉上跟踪分化。这个建议利用这个系统和胚胎模型来梳理分化的阶段。它包含了一个工作程序，既专注于识别新的决定因素，又了解这些决定因素如何驱动分化。这一提议将为发育生物学提供基本的机制见解，并为胚胎干细胞向肝脏和胰腺等器官的有效分化确定条件。

During early embryonic development, the cells of the future gut move along the midline of the embryo signalling to the nervous system. To understand the molecular instructions driving the differentiation of these cells it is necessary to isolate them from the complex and changing environments in the embryo. Being able to break down this in vivo process of lineage specification is also essential for the generation of gut associated cell types and organs from human ES cells. In this proposal, we utilise genetically modified mouse ES cells that report on differentiation towards the embryonic gut in real time. We have used this system to generate monolayer conditions for ES cell differentiation toward embryonic gut. Our ability to differentiate these cells attached to plastic means that we can easily change media components as well as following differentiation visually. This proposal exploits this system alongside embryonic models to tease apart the stages of differentiation. It contains a program of work that is both focused on identifying new determinants and understanding how these determinants drive differentiation. This proposal will provide basic mechanistic insight into developmental biology and define conditions for the efficient differentiation of ES cells towards organs like the liver and pancreas.