A non-mammalian type opsin 5 functions dually in the photoreceptive and non-photoreceptive organs of birds.
A non-mammalian type opsin 5 functions dually in the photoreceptive and non-photoreceptive organs of birds.
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DOI：
10.1371/journal.pone.0031534
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Shichida Y
中科院分区：
文献类型：
--
作者：
Ohuchi H;Yamashita T;Tomonari S;Fujita-Yanagibayashi S;Sakai K;Noji S;Shichida Y
哺乳动物型视蛋白 5（神经视蛋白）是最近在鸟类视网膜和其他感光器官中发现的一种紫外线 (UV) 敏感色素。在非哺乳动物脊椎动物的基因组中还发现了另外两种视蛋白 5 相关分子。然而，它们的功能尚未得到检验。在这里，我们鉴定了第二种禽类视蛋白 5 cOpn5L2（鸡视蛋白 5 样 2）的分子特性及其在孵化后鸡中的定位。分光光度分析和放射性核苷酸结合测定表明，cOpn5L2 是一种紫外线敏感的双稳态色素，可与鸟嘌呤核苷酸结合蛋白（G 蛋白）的 Gi 亚型偶联。作为一种双稳态色素，它还表现出直接结合激动全反式视网膜以激活G蛋白的能力。紫外光吸收和可见光吸收形式的吸收最大值分别为350和521 nm。表达分析显示，cOpn5L2 mRNA 在肾上腺（非感光器官而是内分泌器官）中表达相对较高，而在大脑和视网膜中表达较低。在蛋白质水平上，cOpn5L2 免疫反应细胞存在于肾上腺的嗜铬细胞中。在大脑中，在下丘脑前部的室旁核和视上核中发现了 cOpn5L2 免疫反应细胞，这些细胞以感光深部脑区而闻名。在视网膜中，cOpn5L2 蛋白定位于神经节细胞层和内核层的细胞亚群。这些结果表明，非哺乳动物型视蛋白 5 (Opn5L2) 在感光器官中充当第二个紫外线传感器，同时它可能利用其直接结合能力在非感光器官（例如鸟类的肾上腺）中激动全反式视网膜，从而充当化学传感器。
A mammalian type opsin 5 (neuropsin) is a recently identified ultraviolet (UV)-sensitive pigment of the retina and other photosensitive organs in birds. Two other opsin 5-related molecules have been found in the genomes of non-mammalian vertebrates. However, their functions have not been examined as yet. Here, we identify the molecular properties of a second avian opsin 5, cOpn5L2 (chicken opsin 5-like 2), and its localization in the post-hatch chicken. Spectrophotometric analysis and radionucleotide-binding assay have revealed that cOpn5L2 is a UV-sensitive bistable pigment that couples with the Gi subtype of guanine nucleotide-binding protein (G protein). As a bistable pigment, it also shows the direct binding ability to agonist all-trans-retinal to activate G protein. The absorption maxima of UV-light-absorbing and visible light-absorbing forms were 350 and 521 nm, respectively. Expression analysis showed relatively high expression of cOpn5L2 mRNA in the adrenal gland, which is not photoreceptive but an endocrine organ, while lower expression was found in the brain and retina. At the protein level, cOpn5L2 immunoreactive cells were present in the chromaffin cells of the adrenal gland. In the brain, cOpn5L2 immunoreactive cells were found in the paraventricular and supraoptic nuclei of the anterior hypothalamus, known for photoreceptive deep brain areas. In the retina, cOpn5L2 protein was localized to subsets of cells in the ganglion cell layer and the inner nuclear layer. These results suggest that the non-mammalian type opsin 5 (Opn5L2) functions as a second UV sensor in the photoreceptive organs, while it might function as chemosensor using its direct binding ability to agonist all-trans-retinal in non-photoreceptive organs such as the adrenal gland of birds.
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DOI：
10.1073/pnas.1006393107
发表时间：
2010-08-24
影响因子：
11.1
作者：
Nakane, Yusuke;Ikegami, Keisuke;Yoshimura, Takashi
通讯作者：
Yoshimura, Takashi
影响因子：
64.8
作者：
Choe, Hui-Woog;Kim, Yong Ju;Ernst, Oliver P.
通讯作者：
Ernst, Oliver P.
影响因子：
3.6
作者：
FOSTER, RG;PANZICA, GC;VIGLIETTIPANZICA, C
通讯作者：
VIGLIETTIPANZICA, C
影响因子：
2.7
作者：
Chaturvedi, CM;Chowdhary, A;Cornett, LE
通讯作者：
Cornett, LE
影响因子：
2.5
作者：
MILLAR, T;ISHIMOTO, I;MORGAN, IG
通讯作者：
MORGAN, IG