Collaborative Research: Melanopsin - A Novel Deep Brain Opsin

在非哺乳动物的脊椎动物中，除了眼睛之外，其他系统也可以检测到环境光的水平。这些视网膜外的光感受器通常被非哺乳动物脊椎动物用来同步生物节律，并控制皮肤色素沉着的快速变化来伪装。脊椎动物眼睛视网膜中的光色素包括一种叫做视蛋白的蛋白质，但是这种视网膜外的光敏感性的光色素是未知的。最近在青蛙的大脑、皮肤和眼睛中发现了一种新的视蛋白分子，因为它是从皮肤中的黑色素细胞中分离出来的，所以被命名为黑视素。这个合作研究项目使用基因表达和分子生物学技术，以及显微镜和免疫化学来观察光如何与青蛙的黑视素表达相互作用。测试将显示黑视素的表达是否需要黑色素细胞中色素分散的伪装反应，以及黑视素的表达是否需要光来抑制大脑松果体中褪黑激素的输出，这对生物节律的光控制很重要。将对转基因组织进行测试，看看那些过度表达黑视素的组织是否对光过敏，而那些表达不足的组织是否对光不敏感。研究结果对于理解动物在不依赖眼睛的情况下如何对光做出反应非常重要，不仅对神经内分泌学和感觉生物学有广泛的影响，而且对细胞生理学和行为生物学也有广泛的影响，分子结构的比较对进化生物学也很重要。

Environmental light levels can be detected by systems other than the eye in non-mammalian vertebrates. These extra-retinal photoreceptors often are used by non-mammalian vertebrates to synchronize biological rhythms, and to control rapid changes in skin pigmentation for camouflage. The photopigment in the retina of the eye in vertebrates includes proteins called opsins, but the photopigments for this extra-retinal light sensitivity are unknown. Recently a new opsin protein molecule in the brain, skin and eye of frogs has been found, and is named melanopsin because it was isolated from the pigment cells in the skin called melanophores. This collaborative research project uses techniques of gene expression and molecular biology along with microscopy and immunochemistry to see how light interacts with the expression of the melanopsin in frogs. Tests will show whether melanopsin expression is required for the camouflage response of pigment dispersion in the melanophores, and whether melanopsin expression is required for light to suppress the output of the hormone melatonin from the pineal gland of the brain, which is important for photic control of biological rhythms. Transgenic tissues will be tested to see whether those that over-express melanopsin are hypersensitive to light while those with under-expression are insensitive to light. Results will be important for understanding how animals respond to light without relying only upon the eyes, and will have a broad impact not only on neuroendocrinology and sensory biology, but on cell phyisiology and behavioral biology, and comparisons of molecular structure could be important to evolutionary biology.