Plasticity and Regulation in Xenopus Anterior-Posterior Patterning

描述（由申请人提供）：功能性器官系统的发育不仅需要导致细胞类型特异性和适当模式的决定性事件 这些细胞类型，但也有能力保持这种身份和模式，面对整个胚胎发生的基因和环境扰动。这种补偿发育中潜在破坏性变化的能力，通常被称为调节，是胚胎的一个几乎普遍的特征，是确保正常发育所必需的。然而，一直有相对较少的重点阐明的机制管理的过程中，监管后的发展扰动，尽管其明确的重要性，一个完整的了解发展，以及其对再生医学的影响。在这里，我们采用经典的两栖动物胚胎学系统的非洲爪蟾检查早期胚胎发育过程中的调节能力。我们实验室以前的实验已经证明，当假定的神经板从原肠胚阶段的胚胎中取出，旋转180 °，并移植回宿主胚胎中，从宿主胚胎中取出相应的区域，有一个几乎完全的调节，由此产生的胚胎产生了一个具有适当区域基因表达和功能能力的神经系统。这个建议的总体目标是检查管理这种深刻的调节能力的机制。第一个具体目标是评估对调控过程重要的候选基因的时间和空间表达谱，目的是获得基线信息以精确确定何时以及如何发生这种调控过程。这些基因包括：区域标记（XCG-1、Otx-2、En-2、Krox-20、HoxB 9）;后期分化基因（GAD、xvGlut 1）;在神经决定途径中较早表达的基因（FoxD 5、Geminin、Sox 2）;以及编码关键前后信号分子的基因（Frzb-1、xWnt 8和FGF 8）。第二个目标将确定特定的信号级联是否通过使用靶向吗啉代敲低方法扰乱其功能来介导调节过程。最后，无偏的全局基因表达方法，特别是微阵列分析和RNA-seq方法，将确定调控过程的其他分子组分。总的来说，这三个目标中提出的实验将吸引各级渴望的本科生，以解决发育生物学中一个基础性且研究不足的问题，该问题对再生医学具有更广泛的影响。

DESCRIPTION (provided by applicant): The development of a functional organ system not only entails the determinative events that lead to cell type specificity and appropriate patterning of those cell types, but also the ability to maintain this identity and pattern in the face of geneic and environmental perturbations that occur throughout embryogenesis. This ability to compensate for potentially disruptive alterations in development, which is often referred to regulation, is a near-universal characteristic of embryos, one that is required to ensure normal development. However, there has been relatively little focus on elucidating the mechanisms governing the process of regulation following a developmental perturbation, despite its clear importance for a complete understanding of development as well as its implications for regenerative medicine. Here we employ the classic amphibian embryological system of Xenopus laevis to examine regulative ability during early embryogenesis. Previous experiments from our lab have demonstrated that when the presumptive neural plate is removed from a gastrula-stage embryo, rotated 180o, and transplanted back into a host embryo from which the equivalent region was removed, there is a near total regulation, with the resulting embryo giving rise to a nervous system with appropriate regional gene expression and functional capabilities. The overall goal of this proposal is to examine the mechanisms governing this profound regulative ability. The first specific aim will assess the temporal and spatial expression profile f candidate genes important for the process of regulation, with the goal of obtaining baseline information to determine precisely when and how this regulative process occurs. These genes include: regional markers (XCG-1, Otx-2, En-2, Krox-20, HoxB9); later differentiation genes (GAD, xvGlut1); genes expressed earlier in the neural determination pathway (FoxD5, Geminin, Sox2); and genes encoding key anterior-posterior signaling molecules (Frzb-1, xWnt8, and FGF8). The second aim will determine if specific signaling cascades mediate the process of regulation by perturbing their function using a targeted morpholino knockdown approach. Finally, unbiased global gene expression approaches, specifically microarray analysis and an RNA-seq approach, will identify additional molecular components of the regulation process. Taken together, the experiments proposed in these three aims will engage an eager cadre of undergraduate students at all levels in an effort to address a fundamental and poorly studied problem in developmental biology that has broader implications for regenerative medicine.