Melanophore Response to Light and Melatonin

9319344罗拉格 暴露于培养的非洲爪蟾尾鳍黑色素细胞的光引起细胞内色素颗粒迁移从一个均匀的细胞质分布到核周聚集。 这种直接的光反应，这是独立的视觉系统，提供了一个方便的模型系统的研究机制，光直接修改细胞功能。 拟议的研究将确定培养的黑色素细胞中光转导途径的分子组成部分，比较光和褪黑激素（一种引起类似形态变化的激素）引起的分子级联，并定义诱导光敏表型的实验范式。 将采用免疫细胞化学、分子生物学、放射免疫化学和视频显微镜技术。 本研究将为进一步了解脊椎动物细胞视网膜外光感受的分子机制提供重要的先例（一种生物反应，不仅用于伪装，而且用于调节各种脊椎动物物种的季节性繁殖现象），2）扩大两栖动物黑素细胞作为研究褪黑激素和光信号转导的分子机制的模型系统的用途，和3）提供在非光敏黑色素细胞中可靠地诱导光敏表型的方法（这是研究确定光敏诱导因子的化学特性及其作用机制的必要前提）。 ***

9319344 Rollag Exposure of cultured Xenopus tailfin melanophores to light causes intracellular pigment granules to migrate from a homogeneous cytoplasmic distribution to a perinuclear aggregate. This direct photic response, which is independent of the visual system, provides a convenient model system for study of the mechanisms by which light directly modifies cellular function. The proposed research will identify molecular components of the phototransduction pathway in cultured melanophores, compare the molecular cascades elicited by light and melatonin (a hormone which causes similar morphological changes), and define experimental paradigms that induce the photosensitive phenotype. Immunocytochemical, molecular biological, radioimmunochemical, and videomicroscopic techniques will be employed. It is expected that this research will 1) provide an important precedent for understanding the molecular mechanisms underlying extra-retinal photoreception in vertebrate cells (a biological response that is not only used during camouflage, but also for regulation of seasonal reproductive phenomena in a variety of vertebrate species), 2) expand upon the use of the amphibian melanophore as a model system for study of the molecular mechanism of both melatonin and light signal transduction, and 3) provide a method for reliably inducing the photosensitive phenotype in nonphotosensitive melanophores (a necessary preliminary to studies that seek to determine the chemical identity of photosensitizing inductive factors and their mechanisms of action). ***