The Opsin 3/Teleost multiple tissue opsin system: mRNA localization in the retina and brain of medaka (Oryzias latipes)

The photoreceptor protein, opsin, is one of the major components for vision and photoreceptive function in animals. Although many opsins have been discovered from animal genomes, only a few nonimage‐forming functions mediated by opsins have been identified. Understanding the mRNA distribution of photoreceptor proteins is one crucial step in uncovering their photoreceptive function in animals. Here, we focus on the medaka fish (Oryzias latipes) Opsin 3 (Opn3)/Teleost multiple opsin (Tmt) system, which constitutes a separate phylogenetic group, having putative blue light photoreceptors for nonimage‐forming functions. In medaka, there is one opn3 and five tmt‐opsin orthologs. The expression pattern of the opn3/tmt‐opsins in the retina and brain was investigated by in situ hybridization. mRNAs for opn3/tmt‐opsins were distributed in the retinal ganglion cells as well as interneurons and specific brain nuclei. Specifically, hybridization signals were observed in the glutamate decarboxylase 1 (gad1)‐expressing amacrine cells for opn3, tmt1a, tmt1b, and tmt2, in the caudal lobe of the cerebellum for tmt1b and tmt2, in the cranial nerve nuclei for opn3, tmt1a, tmt1b, tmt2, and in the rostral pars distalis (adenohypophysis) for opn3. These expression patterns suggest that blue light sensing in the fish retina and brain may be involved in the integration of visual inputs, vestibular function, somatosensation, motor outputs, and pituitary endocrine regulation.

This is the peer reviewed version of the following article: [Sato, K,  , KNN, Ohuchi, H. The Opsin 3/Teleost multiple tissue opsin system: mRNA localization in the retina and brain of medaka (Oryzias latipes). J Comp Neurol. 2021; 529: 2484– 2516. https://doi.org/10.1002/cne.25106], which has been published in final form at [https://doi.org/10.1002/cne.25106]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages there of by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.