DORSAL MESODERM FORMATION IN XENOPUS LAEVIS

在发育过程中，多种信号通路和形态发生运动 是活跃的，以塑造胚胎。这个过程包括渐进的 细胞的特化产生细胞类型的多样性， 在成年生物体中。这一过程的第一步是建立 三个胚胎胚层，内胚层，中胚层和外胚层， 原肠胚形成这项研究的总体目标是了解细胞如何 逐渐趋向于特定的胚层。这些知识 将有助于从根本上理解细胞命运是如何 以及它是如何与胚胎的模式相结合的。 该提案研究了细胞的信号传导和反应机制 在导致体节形成的背中胚层诱导期间。 第一个具体目标将检查背侧信号的活动 它负责指导腹侧中胚层 分化为体节组织。体节的发育是一个漫长的过程 从原肠胚形成开始， 后轴发育。异时移植物将用于确定 这个信号在发育过程中活跃的长度。这将 揭示了这个信号是否在整个渐进地层中都是活跃的 或者这个信号是否只在体节开始时才活跃 形成启动过程。为了了解细胞是如何被指示 为了形成体节，第二个特定的目的是检查细胞的行为， 移植细胞和相邻细胞的时间推移视频显微摄影。的 第三个具体的目的是检查细胞对这种反应的能力， 背侧信号初步结果表明，来自神经系统的细胞 外胚层直到最后仍能形成中胚层细胞类型 原肠胚形成为了进一步研究这一观察结果，我们将执行 前、后神经细胞的异时移植 外胚层、表皮和腹外侧中胚层。我们会研究如何 细胞能力的变化与基因表达的变化有关， 这一起导致脊椎动物胚胎的图案化。最后一个目标 是为那些代表性不足的本科生和研究生提供 团体有机会获得基本技能， 未来在生物医学研究中的职业生涯。

During development multiple signaling pathways and morphogenetic movements are active to pattern the embryo. This process consists of the progressive specialization of cells to give rise to the diversity of cell types fond in the adult organism. The first step in this process is the establishment of the three embryonic germ layers, endoderm, mesoderm and ectoderm during gastrulation. The overall goal of this research is to understand how cells become progressively committed to a specific germ layer. This knowledge will contribute to the fundamental understanding of how cell fates are established and how it integrates with patterning of the embryo. This proposal examines the signaling and response mechanism of cells during dorsal mesoderm induction which leads to the formation of somites. The first specific aim will examine the activity of the dorsalizing signal which is responsible for instructing ventral-lateral mesoderm to differentiate as somitic tissue. Somite development is a lengthy process that begins at gastrulation and continues into neuralation as the posterior axis develops. Heterochronic grafts will be used to determine the length to which this signal is active during development. This will reveal whether this signal is active throughout the progressive formation of somites or whether this signal is active only at the onset of somite formation to initiate the process. To understand how cells are instructed to form somites, the second specific aim examines the cell behaviors of grafted cells and neighboring cells by time-lapse video micrography. The third specific aim examines the competence of cells to respond to this dorsalizing signal. Preliminary results suggest that cells from the neural ectoderm remain competent to form mesodermal cell types as late as the end of gastrulation. To further examine this observation, we will perform heterochronic grafts of cells from the anterior and posterior neural ectoderm, epidermis and ventral-lateral mesoderm. We will examine how changes in cell competence relate to changes in gene expression and how together this leads to patterning of the vertebrate embryo. The last aim is to provide undergraduate and graduate students from under-represented groups an opportunity to acquire essential skills that will prepare them for future careers in biomedical research.