Characterization of the melanopsin photopigment.

描述（由申请人提供）：哺乳动物生物钟的光携带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。这种连接是由一小部分视网膜神经节细胞（RGCs）的轴突突起形成的。令人惊讶的是，杆状和锥状光感受器并不是必需的；相反，投射到SCN的RGCs似乎是作为自主的昼夜节律光感受器起作用，并表现出独立于杆状和锥状驱动的突触输入的光反应。这些投射scn的RGCs也表达黑视素，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。本研究的总体目标是表征黑视素的生化和光谱特性，以确定它是否介导scn投射RGCs的内在光响应。

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.