Morphogenesis and patterning of the vertebrate gut tube.

项目摘要/摘要 生命功能或呼吸和消化是由胚胎产生的器官来执行的。 被称为肠管的结构。尽管肠管的基本重要性，但它的形态发生一直是 研究明显不足，特别是当考虑到神经管、心脏、 四肢和发育中的胚胎的其他组织。这项工作的目的是研究这种结构是如何 通过生物物理和分子方法的整合形成，目的是揭示 内胚层上皮中的祖细胞运动与分化相协调，以构建 前肠、中肠和后肠通过分子控制机械力。 肠管一旦形成，就是一个简单的上皮圆柱体，但它是通过时空上不同的方式出现的。 分别引起管的前肠、中肠和后肠节段的事件。这些过程是 鲜为人知，尤其是这三个部分的形成是如何协调形成一个 单一的连续管道在很大程度上仍未得到解决。最近，我们转向了对鸡胚的研究 肠管形态发生，采用活体成像，基于电穿孔的基因错误表达，以及 生物力学/数学方法研究后肠的形成。这些研究揭示了许多 之前关于肠管形成的命运映射研究假设可能是不完整的，如果不是这样的话 不正确。本申请扩展了这些方法以研究集体细胞的生物物理作用 前肠形态发生的运动，并阐明假定中肠的细胞如何贡献细胞 形成的前肠和后肠。我们将对细胞运动和物理行为进行高度量化的分析 推定前肠和中肠内胚层的力，并研究前后部的出现 使用单分子荧光原位检测在细胞沿该轴移动的背景下的图案化 已建立的标记基因。 了解脊椎动物发育的这一关键步骤将为我们提供宝贵的见解 一系列胃肠道出生缺陷的根本原因。归根结底，源自 这项工作将对以细胞为基础的疗法的发展具有重要的意义 祖细胞需要分化为不同的胃肠道和呼吸系统谱系。

PROJECT SUMMARY/ABSTRACT The vital functions or respiration and digestion are carried out by organs that arise from an embryonic structure known as the gut tube. Despite its fundamental importance, morphogenesis of the gut tube has been remarkably understudied, particularly when considered alongside concurrent events in the neural tube, heart, limbs, and other tissues of the developing embryo. The purpose of this work is to study how this structure is formed through an integration of biophysical and molecular approaches, with the goal of revealing how progenitor cell movements in the endodermal epithelium are coordinated with differentiation to construct the foregut, midgut, and hindgut through molecular control of mechanical forces. The gut tube, once formed, is a simple epithelial cylinder, yet it arises through spatiotemporally distinct events that separately give rise to the foregut, midgut, and hindgut segments of the tube. These processes are poorly understood, and in particular, how the formation of these three segments are coordinated to form a single continuous tube remains largely unaddressed. Recently, we have turned to the chick embryo to study gut tube morphogenesis, employing live in vivo imaging, electroporation-based gene misexpression, and biomechanical/mathematical approaches to study formation of the hindgut. These studies revealed that much of what was previously assumed from fate mapping studies about gut tube formation may be incomplete, if not incorrect. The present application extends these approaches to study the biophysical role of collective cell movements in foregut morphogenesis, and to elucidate how cells of the presumptive midgut contribute cells to the forming foregut and hindgut. We will perform highly quantitative analyses of cell movements and physical forces in the presumptive foregut and midgut endoderm, and study the emergence of antero-posterior patterning in the context of cell movements along this axis, using single molecule fluorescent in situ detection of established marker genes. Understanding of this critical step in vertebrate development will provide valuable insight into the underlying causes of a broad range of gastrointestinal birth defects. Ultimately, the projects emanating from this work will have important implications for the development of cell-based therapies where directed the differentiation of progenitor cells toward distinct gastrointestinal and respiratory lineages is needed.