RUI: Use of Transgenic Xenopus Embryos to Study Cell Specification in Eye Development

脊椎动物的眼睛由前脑两个区域的细胞发育而来，这些细胞特化（或分化）产生多种细胞类型。细胞类型包括感光细胞（感光细胞）、多种神经细胞（整合来自感光细胞的信号并向大脑发送信号）和几种支持细胞。大脑中特定区域形成眼睛的机制，以及这些区域的细胞形成不同细胞类型的机制，目前还没有得到很好的理解。这项拟议的研究将检查一种模型实验室生物——非洲爪蟾（Xenopus laevis）青蛙的眼睛发育情况。发育中的眼睛内的细胞通过释放特定的信号蛋白进行交流；这些蛋白质与其他细胞上的受体结合，影响细胞的决定。一组被称为FGFs的信号蛋白在眼睛发育的几个过程中都有使用。fggf可以结合并激活四种不同的FGF受体（fgfr）中的任何一种，但目前尚不清楚特异性fgfr的激活是否会影响眼部细胞分化。将进行实验来验证不同fgfr的激活导致眼细胞以不同方式分化的假设。抑制性FGFRs将在发育中的眼睛中表达；这样就有可能比较通过FGFR-1阻断信号传导的效果与阻断其他fgfr的效果。这项分析将显示不同的fgfr是否在眼睛发育中发挥不同的作用。此次实验将利用最近在青蛙身上开发的转基因技术，将特定基因引入青蛙胚胎。引入的基因将由指导基因只在眼睛中表达的DNA和编码抑制FGFR的DNA组成。这些研究将有助于更好地理解脊椎动物眼睛发育的机制，以及当眼睛发育异常时，哪些过程可能会被破坏。最后，比较不同生物的眼睛发育将有助于更好地理解眼睛是如何进化的。本科生将积极参与拟议的研究。因此，这项研究将在一定程度上有助于培养下一代科学家。

Cell specification in eye developmentEyes in vertebrates develop from cells in two regions of the forebrain, and these cells specialize (or differentiate) to generate many cell types. The cell types include photoreceptor cells (which detect light), many types of neural cells (which integrate signals from photoreceptor cells and send signals to the brain), and several types of supporting cells. The mechanisms by which regions of the brain become specified to form eyes, and cells in these region become specified to form different cell types, are not well understood. The proposed research will examine eye development in a model laboratory organism, the frog Xenopus laevis. Cells within the developing eyes communicate by releasing specific signaling proteins; these proteins bind to receptors on other cells, influencing cell determination. One group of signaling proteins, called FGFs, is used in several processes during eye development. FGFs can bind to, and activate, any of four different FGF receptors (FGFRs), but it is not clear whether activation of specific FGFRs affects cell differentiation in the eye.Experiments will be conducted to test the hypothesis that activation of different FGFRs causes eye cells to differentiate in different ways. Inhibitory FGFRs will be expressed in the developing eye; it will then be possible to compare the effects of blocking signaling through, say, FGFR-1 with the effects of blocking other FGFRs. This analysis will show whether different FGFRs play distinct roles in eye development. The experiments will utilize recently developed transgenic technology in frogs, which makes it possible to introduce specific genes into frog embryos. The introduced genes will consist of DNA that directs the gene to be expressed only in the eye, coupled to DNA encoding an inhibitory FGFR. . These studies will lead to a better understanding of the mechanisms by which vertebrate eyes develop, and which processes may be disrupted when eyes develop abnormally. Finally, comparison of eye development in different organisms will contribute to a better understanding of how eyes have evolved.Undergraduate students will be strongly involved in the proposed research. This research will thus serve, in part, to train the next generation of scientists.