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Study for the physiological characteristics of the pineal ultraviolet photoreceptor cells.

松果体紫外线感光细胞生理特性的研究。

基本信息

批准号：
15570063
负责人：
TAMOTSU Satoshi
金额：
$ 2.05万
依托单位：
Nara Women's University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

Lower vertebrates can detect UV light with the pineal complex independently of eyes. Electrophysiological studies, together with chromophore extraction analysis, have suggested that the underlying pigment in the lamprey pineal exhibits a bistable nature, that is, reversible photoreaction by UV and visible lights, which is never achieved by known UV pigments. Here we addressed the molecular identification of the pineal UV receptor. Our results showed that the long-hypothesized pigment is a lamprey homologue ofparapinopsin, which exhibits an absorption maximum at 370 nm. UV light causes cis-trans isomerization of its retinal_2 chromophore,.forming a stable photoproduct having an absorption maximum at 515 nm. The photoproduct reverts to the original pigment upon visible light absorption, showing photoregeneration of the pigment. In situ hybridization showed that parapinopsin is selectively expressed in the cells located at the dorsal region of the pineal organ. We successfully obtained the hyperpolarizing responses with a maximum sensitivity about 380 nm from the photoreceptor cells at the dorsal region, in which the outer segment was clearly stained with anti-parapinopsin antibody. These results demonstrated that parapinopsin is the pineal UV pigment having photo-interconvertible two stable states. The bistable nature of the parapinopsin can account for the photorecovery of the pineal UV-sensitivity by background green light in the lamprey. Furthermore, we isolated the parapinopsin homologues from fish and frog pineal complexes which exhibit UV-sensitivity, suggesting that parapinopsin is a common molecular basis for pineal UV reception in the vertebrate.

低等脊椎动物可以用松果体复合体独立于眼睛检测紫外线。电生理学研究和发色团提取分析表明七鳃鳗松果体中的潜在色素具有可逆性，即紫外光和可见光的可逆光反应，这是已知的紫外色素从未实现的。在这里，我们解决了松果体UV受体的分子鉴定。我们的研究结果表明，长期假设的色素是七鳃鳗同系物的parapinopsin，表现出最大吸收波长为370 nm。紫外光使其视黄醛_2发色团发生顺-反异构化，形成稳定的光产物，其最大吸收波长为515 nm。光产物在可见光吸收后恢复为原始色素，显示色素的光再生。原位杂交结果表明，视神经肽选择性地表达于松果体背侧区的细胞。我们成功地获得了超极化反应的最大灵敏度约380 nm的感光细胞在背侧区，其中的外节清楚地被抗视蛋白抗体染色。这些结果表明，副视蛋白是具有光可互变两种稳定状态的松果体紫外色素。视蛋白的光恢复特性可以解释七鳃鳗在背景绿色光下对松果体紫外线敏感性的光恢复。此外，我们分离出的parapinopsin同系物从鱼类和青蛙松果体复合物表现出紫外线敏感性，表明parapinopsin是一个共同的分子基础松果体紫外线接收脊椎动物。