Characterization of the melanopsin photopigment.

描述(申请人提供)：哺乳动物生物钟的光捕获需要来自视网膜的输入，视网膜通过视网膜下丘脑束(RHT)与视交叉上核(SCN)通信。这种联系是由一小部分视网膜神经节细胞(RGC)的轴突投射形成的。令人惊讶的是，视杆和视锥感受器并不是必需的；相反，投射到SCN的视网膜节细胞似乎作为自主的昼夜节光感受器发挥功能，并表现出独立于视杆和视锥驱动的突触输入的光反应。这些投射SCN的视网膜节细胞也表达黑素，这是一种新的视蛋白样蛋白，被认为是昼夜节律系统中难以捉摸的光色素。这项研究的总体目标是表征黑素的生化和光谱特性，以确定它是否介导了SCN投射的视网膜节细胞的内在光反应。

DESCRIPTION (provided by applicant): Light entrainment of the mammalian circadian clock requires input from the retina, which communicates with the suprachiasmatic nucleus (SCN) via the retinohypo-thalamic tract (RHT). This connection is formed by the axonal projections of a small subset of retinal ganglion cells (RGCs). Surprisingly, rod and cone photoreceptors are not required; instead, RGCs that project to the SCN seem to function as autonomous circadian photoreceptors, and exhibit light responses independent of rod- and cone-driven synaptic input. These SCN-projecting RGCs also express melanopsin, a novel opsin-like protein, which has been proposed to be the elusive photopigment of the circadian system. The overall goal of this research is to characterize the biochemical and spectral properties of melanopsin to determine if it mediates the intrinsic light responses of SCN-projecting RGCs.