PHOTORECEPTOR CELL FATE DETERMINATION IN THE RETINA

这项研究提案的总体目标是确定 决定感光细胞命运的分子机制。这 将通过结合使用分子生物学和 基因技术。该研究体系将成为 果蝇黑腹果蝇。 在最近出版的著作中，我们确定并描述了一部小说 苍蝇眼中视色素基因的表达模式。通过操纵 从基因上讲，我们已经证明了视觉色素的表达 一种光感受器细胞类型的基因。似乎每个单元格中都有一个单元 小眼(R7)采用随机的两种细胞命运之一 方式，然后将该决定(感应地)传达给相邻的 R8细胞。这些事件用于协调视觉的表达 颜料在这两个单元中，并在其中产生两种类型的光学单元 对光谱有明显敏感性的眼睛。 在这个提案中，我们提供了一系列实验来严格测试 这个模型，通过检查视蛋白基因表达的各个方面，研究了 调节其表达的启动子，并进行基因筛选 以确定需要哪些基因来指定 光感受器细胞命运与视蛋白基因表达的调控。 这些研究对于理解 复眼就形成了。光感受器分化为 具有不同光谱敏感度的种群是颜色的基础 歧视。整个紧张的内部信号贩运也是如此 依赖于不同神经元群体的世代 不同的敏感度和变送器表型。因为苍蝇眼 已经成为发育生物学的一个关键模型系统，阐明 该系统中新的信号和细胞命运决定通路 将作为一个框架来理解更复杂的发展事件 在其他生物体的神经系统内。

The overall objective of this research proposal is to determine the molecular mechanisms by which photoreceptor cell fate is specified. This will be accomplished by using a combination of molecular biological and genetic techniques. The system of study will be the compound eye of the fruit fly Drosophila melanogaster. In recently published work, we identified and characterized a novel pattern of visual pigment gene expression in the fly eye. By manipulating the eye genetically we have shown that the expression of visual pigment genes in one photoreceptor cell type. It appears that one cell in each ommatidium (R7) adopts one of two different cell fates in a stochastic manner, and then communicates this decision (inductively) to the adjacent R8 cell. These events serve to coordinate the expression of visual pigments in these two cells, and produce two type of optical units within the eye that have distinct spectral sensitivities. In this proposal, we present a series of experiments to rigorously test this model, by examining aspects of opsin gene expression, studying the promoters which regulate their expression, and conducting genetic screens to identify genes which are required for the specification of photoreceptor cell fate and the regulation of opsin gene expression. These studies are of fundamental importance in understanding how the compound eye is formed. The differentiation of photoreceptors into populations having different spectral sensitivities is the basis for color discrimination. Signal trafficking within the nervous as a whole is also dependent upon the generation f diverse neuronal populations having different sensitivities and transmitter phenotypes. Because the fly eye has become a key model system in Developmental Biology, the elucidation of novel signaling and cell-fate determination pathways within this system will serve as a framework to understand more complex developmental events within the nervous system of other organisms.