Vitamin B2-based blue-light photoreceptors in the retinohypothalamic tract as the photoactive pigments for setting the circadian clock in mammals
Vitamin B2-based blue-light photoreceptors in the retinohypothalamic tract as the photoactive pigments for setting the circadian clock in mammals
复制标题
DOI：
10.1073/pnas.95.11.6097
复制
发表时间：
1998-05-26
影响因子：
11.1
通讯作者：
Sancar, A
中科院分区：
文献类型：
--
作者：
Miyamoto, Y;Sancar, A
在哺乳动物中，视网膜含有负责视觉和昼夜光反应系统的光敏分子。视蛋白位于视杆细胞和视锥细胞中，是视觉的色素，但尚不清楚它们是否在昼夜节律调节中发挥作用。直接投射到视交叉上核（SCN）的视网膜神经节细胞的亚群位于视网膜下丘脑束的起源处，所述视网膜下丘脑束将光信号传输到SCN中的主生物钟。然而，神经节细胞不知道含有视紫红质或其他视蛋白，可以作为光感受器。我们已经发现，最近在哺乳动物中发现的两种蓝光光感受器，隐花色素1和2（cryptochromes 1和cryptochromes 2），在小鼠视网膜的神经节细胞和内核层中特异性表达。此外，在SCN中高水平表达，并以昼夜节律的方式在该组织中振荡。这些数据，结合已确立的作用，在植物中的光周期，导致我们提出，哺乳动物有一个维生素A为基础的色素（视蛋白）的视觉和维生素B-2为基础的色素（隐花色素）的昼夜节律钟的夹带。
In mammals the retina contains photoactive molecules responsible for both vision and circadian photoresponse systems. Opsins, which are located in rods and cones, are the pigments for vision but it is not known whether they play a role in circadian regulation. A subset of retinal ganglion cells with direct projections to the suprachiasmatic nucleus (SCN) are at the origin of the retinohypothalamic tract that transmits the light signal to the master circadian clock in the SCN. However, the ganglion cells are not known to contain rhodopsin or other opsins that may function as photoreceptors. We have found that the two blue-light photoreceptors, cryptochromes 1 and 2 (CRY1 and CRY2), recently discovered in mammals are specifically expressed in the ganglion cell and inner nuclear layers of the mouse retina. In addition, CRY1 is expressed at high level in the SCN and oscillates in this tissue in a circadian manner. These data, in conjunction with the established role of CRY2 in photoperiodism in plants, lead us to propose that mammals have a vitamin A-based photopigment (opsin) for vision and a vitamin B-2-based pigment (cryptochrome) for entrainment of the circadian clock.