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Torii M, Kojima D, Nishimura A, Itoh H, Fukada Y. Light-dependent activation of G proteins by two isoforms of chicken melanopsins. Photochem Photobiol Sci 2016; 14:1991-7. [PMID: 26411960 DOI: 10.1039/c5pp00153f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the chicken pineal gland, light stimuli trigger signaling pathways mediated by two different subtypes, Gt and G11. These G proteins may be activated by any of the three major pineal opsins, pinopsin, OPN4-1 and OPN4-2, but biochemical evidence for the coupling has been missing except for functional coupling between pinopsin and Gt. Here we investigated the relative expression levels and the functional difference among the three pineal opsins. In the chicken pineal gland, the pinopsin mRNA level was significantly more abundant than the others, of which the OPN4-2 mRNA level was higher than that of OPN4-1. In G protein activation assays, Gt was strongly activated by pinopsin in a light-dependent manner, being consistent with previous studies, and weakly activated by OPN4-2. Unexpectedly, illuminated OPN4-2 more efficiently activated G protein(s) that was endogenously expressed in HEK293T cells in culture. On the other hand, Gq, the closest analogue of G11, was activated only by OPN4-1 although the activity was relatively weak under these conditions. These results suggest that OPN4-1 and OPN4-2 couple with Gq and Gt, respectively. Two melanopsins, OPN4-1 and OPN4-2, appear to have acquired mutually different functions through the evolution.
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Affiliation(s)
- Masaki Torii
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
| | - Daisuke Kojima
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
| | - Akiyuki Nishimura
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Hiroshi Itoh
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Yoshitaka Fukada
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
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Shirzad-Wasei N, DeGrip WJ. Heterologous expression of melanopsin: Present, problems and prospects. Prog Retin Eye Res 2016; 52:1-21. [DOI: 10.1016/j.preteyeres.2016.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 01/25/2016] [Accepted: 02/01/2016] [Indexed: 12/12/2022]
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The Visual Cycle in the Inner Retina of Chicken and the Involvement of Retinal G-Protein-Coupled Receptor (RGR). Mol Neurobiol 2016; 54:2507-2517. [DOI: 10.1007/s12035-016-9830-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 03/04/2016] [Indexed: 11/27/2022]
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Vöcking O, Kourtesis I, Hausen H. Posterior eyespots in larval chitons have a molecular identity similar to anterior cerebral eyes in other bilaterians. EvoDevo 2015; 6:40. [PMID: 26702352 PMCID: PMC4689004 DOI: 10.1186/s13227-015-0036-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 11/19/2015] [Indexed: 11/17/2022] Open
Abstract
Background Development of cerebral eyes is generally based on fine-tuned networks and closely intertwined with the formation of brain and head. Consistently and best studied in insects and vertebrates, many signaling pathways relaying the activity of eye developmental factors to positional information in the head region are characterized. Though known from several organisms, photoreceptors developing outside the head region are much less studied and the course of their development, relation to cerebral eyes and evolutionary origin is in most cases unknown. To explore how position influences development of otherwise similar photoreceptors, we analyzed the molecular characteristics of photoreceptors we discovered at the very anterior, the posttrochal mid-body and posterior body region of larval Leptochiton asellus, a representative of the chiton subgroup of mollusks. Results Irrespective of their position, all found photoreceptors exhibit a molecular signature highly similar to cerebral eye photoreceptors of related animals. All photoreceptors employ the same subtype of visual pigments (r-opsin), and the same key elements for phototransduction such as GNAq, trpC and arrestin and intracellular r-opsin transport such as rip11 and myosinV as described from other protostome cerebral eyes. Several transcription factors commonly involved in cerebral eye and brain development such as six1/2, eya, dachshund, lhx2/9 and prox are also expressed by all found photoreceptor cells, only pax6 being restricted to the anterior most cells. Coexpression of pax6 and MITF in photoreceptor-associated shielding pigment cells present at the mid-body position matches the common situation in cerebral eye retinal pigment epithelium specification and differentiation. Notably, all photoreceptors, even the posterior ones, further express clear anterior markers such as foxq2, irx, otx, and six3/6 (only the latter absent in the most posterior photoreceptors), which play important roles in the early patterning of the anterior neurogenic area throughout the animal kingdom. Conclusions Our data suggest that anterior eyes with brain-associated development can indeed be subject to heterotopic replication to developmentally distinct and even posterior body regions. Retention of the transcriptional activity of a broad set of eye developmental factors and common anterior markers suggests a mode of eye development induction, which is largely independent of body regionalization. Electronic supplementary material The online version of this article (doi:10.1186/s13227-015-0036-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Oliver Vöcking
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway ; Department of Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
| | - Ioannis Kourtesis
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
| | - Harald Hausen
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway
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Díaz NM, Morera LP, Guido ME. Melanopsin and the Non-visual Photochemistry in the Inner Retina of Vertebrates. Photochem Photobiol 2015; 92:29-44. [DOI: 10.1111/php.12545] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 10/09/2015] [Indexed: 01/28/2023]
Affiliation(s)
- Nicolás M. Díaz
- Departamento de Química Biológica-CIQUIBIC (CONICET); Facultad de Ciencias Químicas; Universidad Nacional de Córdoba (UNC); Córdoba Argentina
| | - Luis P. Morera
- Departamento de Química Biológica-CIQUIBIC (CONICET); Facultad de Ciencias Químicas; Universidad Nacional de Córdoba (UNC); Córdoba Argentina
| | - Mario E. Guido
- Departamento de Química Biológica-CIQUIBIC (CONICET); Facultad de Ciencias Químicas; Universidad Nacional de Córdoba (UNC); Córdoba Argentina
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56
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Light and the evolution of vision. Eye (Lond) 2015; 30:173-8. [PMID: 26541087 DOI: 10.1038/eye.2015.220] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 09/22/2015] [Indexed: 01/09/2023] Open
Abstract
It might seem a little ridiculous to cover the period over which vision evolved, perhaps 1.5 billion years, in only 3000 words. Yet, if we examine the photoreceptor molecules of the most basic eukaryote protists and even before that, in those of prokaryote bacteria and cyanobacteria, we see how similar they are to those of mammalian rod and cone photoreceptor opsins and the photoreceptive molecules of light sensitive ganglion cells. This shows us much with regard the development of vision once these proteins existed, but there is much more to discover about the evolution of even more primitive vision systems.
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D'Aniello S, Delroisse J, Valero-Gracia A, Lowe EK, Byrne M, Cannon JT, Halanych KM, Elphick MR, Mallefet J, Kaul-Strehlow S, Lowe CJ, Flammang P, Ullrich-Lüter E, Wanninger A, Arnone MI. Opsin evolution in the Ambulacraria. Mar Genomics 2015; 24 Pt 2:177-83. [PMID: 26472700 DOI: 10.1016/j.margen.2015.10.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 10/02/2015] [Accepted: 10/02/2015] [Indexed: 11/16/2022]
Abstract
Opsins--G-protein coupled receptors involved in photoreception--have been extensively studied in the animal kingdom. The present work provides new insights into opsin-based photoreception and photoreceptor cell evolution with a first analysis of opsin sequence data for a major deuterostome clade, the Ambulacraria. Systematic data analysis, including for the first time hemichordate opsin sequences and an expanded echinoderm dataset, led to a robust opsin phylogeny for this cornerstone superphylum. Multiple genomic and transcriptomic resources were surveyed to cover each class of Hemichordata and Echinodermata. In total, 119 ambulacrarian opsin sequences were found, 22 new sequences in hemichordates and 97 in echinoderms (including 67 new sequences). We framed the ambulacrarian opsin repertoire within eumetazoan diversity by including selected reference opsins from non-ambulacrarians. Our findings corroborate the presence of all major ancestral bilaterian opsin groups in Ambulacraria. Furthermore, we identified two opsin groups specific to echinoderms. In conclusion, a molecular phylogenetic framework for investigating light-perception and photobiological behaviors in marine deuterostomes has been obtained.
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Affiliation(s)
- S D'Aniello
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy.
| | - J Delroisse
- Biology of Marine Organisms and Biomimetics, Research Institute for Biosciences, University of Mons, Avenue du Champs de Mars 6, 7000 Mons, Belgium; School of Biological & Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - A Valero-Gracia
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy
| | - E K Lowe
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy; BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, MI, USA
| | - M Byrne
- Schools of Medical and Biological Sciences, The University of Sydney, Sydney, NSW, Australia
| | - J T Cannon
- Department of Biological Sciences and Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University, Auburn, USA; Department of Zoology, Naturhistoriska Riksmuseet, Stockholm, Sweden; Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
| | - K M Halanych
- Department of Biological Sciences and Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University, Auburn, USA
| | - M R Elphick
- School of Biological & Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - J Mallefet
- Laboratory of Marine Biology, Earth and Life Institute, Université Catholique de Louvain, Louvain-La-Neuve, Place Croix du Sud 3, bt L7.06.04, 1348 Louvain-la-Neuve, Belgium
| | - S Kaul-Strehlow
- Department of Molecular Evolution and Development, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - C J Lowe
- Hopkins Marine Station of Stanford University, Pacific Grove, CA 93950, USA
| | - P Flammang
- Biology of Marine Organisms and Biomimetics, Research Institute for Biosciences, University of Mons, Avenue du Champs de Mars 6, 7000 Mons, Belgium
| | - E Ullrich-Lüter
- Museum fuer Naturkunde Berlin, Invalidenstr 43, 10115 Berlin, Germany
| | - A Wanninger
- Department of Integrative Zoology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - M I Arnone
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy
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Kawano-Yamashita E, Koyanagi M, Wada S, Tsukamoto H, Nagata T, Terakita A. Activation of Transducin by Bistable Pigment Parapinopsin in the Pineal Organ of Lower Vertebrates. PLoS One 2015; 10:e0141280. [PMID: 26492337 PMCID: PMC4619617 DOI: 10.1371/journal.pone.0141280] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 10/05/2015] [Indexed: 11/18/2022] Open
Abstract
Pineal organs of lower vertebrates contain several kinds of photosensitive molecules, opsins that are suggested to be involved in different light-regulated physiological functions. We previously reported that parapinopsin is an ultraviolet (UV)-sensitive opsin that underlies hyperpolarization of the pineal photoreceptor cells of lower vertebrates to achieve pineal wavelength discrimination. Although, parapinopsin is phylogenetically close to vertebrate visual opsins, it exhibits a property similar to invertebrate visual opsins and melanopsin: the photoproduct of parapinopsin is stable and reverts to the original dark states, demonstrating the nature of bistable pigments. Therefore, it is of evolutionary interest to identify a phototransduction cascade driven by parapinopsin and to compare it with that in vertebrate visual cells. Here, we showed that parapinopsin is coupled to vertebrate visual G protein transducin in the pufferfish, zebrafish, and lamprey pineal organs. Biochemical analyses demonstrated that parapinopsins activated transducin in vitro in a light-dependent manner, similar to vertebrate visual opsins. Interestingly, transducin activation by parapinopsin was provoked and terminated by UV- and subsequent orange-lights irradiations, respectively, due to the bistable nature of parapinopsin, which could contribute to a wavelength-dependent control of a second messenger level in the cell as a unique optogenetic tool. Immunohistochemical examination revealed that parapinopsin was colocalized with Gt2 in the teleost, which possesses rod and cone types of transducin, Gt1, and Gt2. On the other hand, in the lamprey, which does not possess the Gt2 gene, in situ hybridization suggested that parapinopsin-expressing photoreceptor cells contained Gt1 type transducin GtS, indicating that lamprey parapinopsin may use GtS in place of Gt2. Because it is widely accepted that vertebrate visual opsins having a bleaching nature have evolved from non-bleaching opsins similar to parapinopsin, these results implied that ancestral bistable opsins might acquire coupling to the transducin-mediated cascade and achieve light-dependent hyperpolarizing response of the photoreceptor cells.
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Affiliation(s)
- Emi Kawano-Yamashita
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka, 558–8585, Japan
| | - Mitsumasa Koyanagi
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka, 558–8585, Japan
- The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka, 558–8585, Japan
- Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Tokyo, Japan
| | - Seiji Wada
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka, 558–8585, Japan
| | - Hisao Tsukamoto
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka, 558–8585, Japan
| | - Takashi Nagata
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka, 558–8585, Japan
| | - Akihisa Terakita
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka, 558–8585, Japan
- The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka, 558–8585, Japan
- * E-mail:
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59
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Vartanian GV, Zhao X, Wong KY. Using Flickering Light to Enhance Nonimage-Forming Visual Stimulation in Humans. Invest Ophthalmol Vis Sci 2015. [PMID: 26207303 DOI: 10.1167/iovs.15-16468] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Intrinsically photosensitive retinal ganglion cells (ipRGCs) mediate nonimage-forming visual functions such as pupillary constriction and circadian photoentrainment. Optimizing daytime nonimage-forming photostimulation has health benefits. We aimed to enhance ipRGC excitation using flickering instead of steady light. METHODS Human subjects were tested with a three-dimensional matrix of flickering 463-nm stimuli: three photon counts (13.7, 14.7 and 15.7 log photons cm(-2)), three duty cycles (12%, 47%, and 93%) and seven flicker frequencies (0.1, 0.25, 0.5, 1, 2, 4, and 7 Hz). Steady-state pupil constrictions were measured. RESULTS Among stimuli containing 13.7 log photons cm-2, the one flickering at 2 Hz with a 12% duty cycle evoked the greatest pupil constriction of 48% ± 4%, 71% greater than that evoked by an equal-intensity (12.3 log photons cm(-2) s(-1)) continuous light. This frequency and duty cycle were also best for 14.7 log photons cm-2 stimuli, inducing a 58% ± 4% constriction which was 38% more than that caused by an equal-intensity (13.3 log photons cm(-2) s(-1)) constant light. For 15.7 log photons cm-2 stimuli, the 1-Hz, 47% duty cycle flicker was optimal although it evoked the same constriction as the best 14.7 log photons cm(-2) flicker. CONCLUSIONS Pupillary constriction depends on flicker frequency and duty cycle besides intensity. Among the stimuli tested, the one with the lowest photon count inducing a maximal response is 13.3 log photons cm(-2) s(-1) flickering at 2 Hz with 12% duty cycle. Our data could guide the design of healthier architectural lighting and better phototherapy devices for treating seasonal affective disorder and jet lag.
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Affiliation(s)
- Garen V Vartanian
- Department of Ophthalmology & Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States 2Graduate Program in Macromolecular Science & Engineering, University of Michigan, Ann Arbor, Michigan, United States
| | - Xiwu Zhao
- Department of Ophthalmology & Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States
| | - Kwoon Y Wong
- Department of Ophthalmology & Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States 3Department of Molecular, Cellular & Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States
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Tsukamoto H, Kubo Y, Farrens DL, Koyanagi M, Terakita A, Furutani Y. Retinal Attachment Instability Is Diversified among Mammalian Melanopsins. J Biol Chem 2015; 290:27176-27187. [PMID: 26416885 DOI: 10.1074/jbc.m115.666305] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Indexed: 01/12/2023] Open
Abstract
Melanopsins play a key role in non-visual photoreception in mammals. Their close phylogenetic relationship to the photopigments in invertebrate visual cells suggests they have evolved to acquire molecular characteristics that are more suited for their non-visual functions. Here we set out to identify such characteristics by comparing the molecular properties of mammalian melanopsin to those of invertebrate melanopsin and visual pigment. Our data show that the Schiff base linking the chromophore retinal to the protein is more susceptive to spontaneous cleavage in mammalian melanopsins. We also find this stability is highly diversified between mammalian species, being particularly unstable for human melanopsin. Through mutagenesis analyses, we find that this diversified stability is mainly due to parallel amino acid substitutions in extracellular regions. We propose that the different stability of the retinal attachment in melanopsins may contribute to functional tuning of non-visual photoreception in mammals.
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Affiliation(s)
- Hisao Tsukamoto
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, Okazaki, 444-8585, Japan,; Department of Structural Molecular Science, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan,.
| | - Yoshihiro Kubo
- Division of Biophysics and Neurobiology, Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan,; Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
| | - David L Farrens
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239-3098
| | - Mitsumasa Koyanagi
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
| | - Akihisa Terakita
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
| | - Yuji Furutani
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, Okazaki, 444-8585, Japan,; Department of Structural Molecular Science, SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
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Diversification of non-visual photopigment parapinopsin in spectral sensitivity for diverse pineal functions. BMC Biol 2015; 13:73. [PMID: 26370232 PMCID: PMC4570685 DOI: 10.1186/s12915-015-0174-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 07/27/2015] [Indexed: 02/08/2023] Open
Abstract
Background Recent genome projects of various animals have uncovered an unexpectedly large number of opsin genes, which encode protein moieties of photoreceptor molecules, in most animals. In visual systems, the biological meanings of this diversification are clear; multiple types of visual opsins with different spectral sensitivities are responsible for color vision. However, the significance of the diversification of non-visual opsins remains uncertain, in spite of the importance of understanding the molecular mechanism and evolution of varied non-visual photoreceptions. Results Here, we investigated the diversification of the pineal photopigment parapinopsin, which serves as the UV-sensitive photopigment for the pineal wavelength discrimination in the lamprey, linking it with other pineal photoreception. Spectroscopic analyses of the recombinant pigments of the two teleost parapinopsins PP1 and PP2 revealed that PP1 is a UV-sensitive pigment, similar to lamprey parapinopsin, but PP2 is a blue-sensitive pigment, with an absorption maximum at 460–480 nm, showing the diversification of non-visual pigment with respect to spectral sensitivity. We also found that PP1 and PP2 exhibit mutually exclusive expressions in the pineal organs of three teleost species. By using transgenic zebrafish in which these parapinopsin-expressing cells are labeled, we found that PP1-expressing cells basically possess neuronal processes, which is consistent with their involvement in wavelength discrimination. Interestingly, however, PP2-expressing cells rarely possess neuronal processes, raising the possibility that PP2 could be involved in non-neural responses rather than neural responses. Furthermore, we found that PP2-expressing cells contain serotonin and aanat2, the key enzyme involved in melatonin synthesis from serotonin, whereas PP1-expressing cells do not contain either, suggesting that blue-sensitive PP2 is instead involved in light-regulation of melatonin secretion. Conclusions In this paper, we have clearly shown the different molecular properties of duplicated non-visual opsins by demonstrating the diversification of parapinopsin with respect to spectral sensitivity. Moreover, we have shown a plausible link between the diversification and its physiological impact by discovering a strong candidate for the underlying pigment in light-regulated melatonin secretion in zebrafish; the diversification could generate a new contribution of parapinopsin to pineal photoreception. Current findings could also provide an opportunity to understand the “color” preference of non-visual photoreception. Electronic supplementary material The online version of this article (doi:10.1186/s12915-015-0174-9) contains supplementary material, which is available to authorized users.
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Liegertová M, Pergner J, Kozmiková I, Fabian P, Pombinho AR, Strnad H, Pačes J, Vlček Č, Bartůněk P, Kozmik Z. Cubozoan genome illuminates functional diversification of opsins and photoreceptor evolution. Sci Rep 2015; 5:11885. [PMID: 26154478 PMCID: PMC5155618 DOI: 10.1038/srep11885] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 06/05/2015] [Indexed: 11/09/2022] Open
Abstract
Animals sense light primarily by an opsin-based photopigment present in a photoreceptor cell. Cnidaria are arguably the most basal phylum containing a well-developed visual system. The evolutionary history of opsins in the animal kingdom has not yet been resolved. Here, we study the evolution of animal opsins by genome-wide analysis of the cubozoan jellyfish Tripedalia cystophora, a cnidarian possessing complex lens-containing eyes and minor photoreceptors. A large number of opsin genes with distinct tissue- and stage-specific expression were identified. Our phylogenetic analysis unequivocally classifies cubozoan opsins as a sister group to c-opsins and documents lineage-specific expansion of the opsin gene repertoire in the cubozoan genome. Functional analyses provided evidence for the use of the Gs-cAMP signaling pathway in a small set of cubozoan opsins, indicating the possibility that the majority of other cubozoan opsins signal via distinct pathways. Additionally, these tests uncovered subtle differences among individual opsins, suggesting possible fine-tuning for specific photoreceptor tasks. Based on phylogenetic, expression and biochemical analysis we propose that rapid lineage- and species-specific duplications of the intron-less opsin genes and their subsequent functional diversification promoted evolution of a large repertoire of both visual and extraocular photoreceptors in cubozoans.
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Affiliation(s)
- Michaela Liegertová
- Department of Transcriptional Regulation, Institute of Molecular Genetics, Videnska 1083, Prague, CZ-14220, Czech Republic
| | - Jiří Pergner
- Department of Transcriptional Regulation, Institute of Molecular Genetics, Videnska 1083, Prague, CZ-14220, Czech Republic
| | - Iryna Kozmiková
- Department of Transcriptional Regulation, Institute of Molecular Genetics, Videnska 1083, Prague, CZ-14220, Czech Republic
| | - Peter Fabian
- Department of Transcriptional Regulation, Institute of Molecular Genetics, Videnska 1083, Prague, CZ-14220, Czech Republic
| | - Antonio R Pombinho
- Department of Cell Differentiation, Institute of Molecular Genetics, Videnska 1083, Prague, CZ-14220, Czech Republic
| | - Hynek Strnad
- Department of Genomics and Bioinformatics, Institute of Molecular Genetics, Videnska 1083, Prague, CZ-14220, Czech Republic
| | - Jan Pačes
- Department of Genomics and Bioinformatics, Institute of Molecular Genetics, Videnska 1083, Prague, CZ-14220, Czech Republic
| | - Čestmír Vlček
- Department of Genomics and Bioinformatics, Institute of Molecular Genetics, Videnska 1083, Prague, CZ-14220, Czech Republic
| | - Petr Bartůněk
- Department of Cell Differentiation, Institute of Molecular Genetics, Videnska 1083, Prague, CZ-14220, Czech Republic
| | - Zbyněk Kozmik
- Department of Transcriptional Regulation, Institute of Molecular Genetics, Videnska 1083, Prague, CZ-14220, Czech Republic
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Calcium activates the light-dependent conductance in melanopsin-expressing photoreceptors of amphioxus. Proc Natl Acad Sci U S A 2015; 112:7845-50. [PMID: 26056310 DOI: 10.1073/pnas.1420265112] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Melanopsin, the photopigment of the "circadian" receptors that regulate the biological clock and the pupillary reflex in mammals, is homologous to invertebrate rhodopsins. Evidence supporting the involvement of phosphoinositides in light-signaling has been garnered, but the downstream effectors that control the light-dependent conductance remain unknown. Microvillar photoreceptors of the primitive chordate amphioxus also express melanopsin and transduce light via phospholipase-C, apparently not acting through diacylglycerol. We therefore examined the role of calcium in activating the photoconductance, using simultaneous, high time-resolution measurements of membrane current and Ca(2+) fluorescence. The light-induced calcium rise precedes the onset of the photocurrent, making it a candidate in the activation chain. Moreover, photolysis of caged Ca elicits an inward current of similar size, time course and pharmacology as the physiological photoresponse, but with a much shorter latency. Internally released calcium thus emerges as a key messenger to trigger the opening of light-dependent channels in melanopsin-expressing microvillar photoreceptors of early chordates.
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Castro A, Becerra M, Manso MJ, Anadón R. Neuronal organization of the brain in the adult amphioxus (Branchiostoma lanceolatum): A study with acetylated tubulin immunohistochemistry. J Comp Neurol 2015; 523:2211-32. [DOI: 10.1002/cne.23785] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 09/11/2014] [Accepted: 09/19/2014] [Indexed: 12/28/2022]
Affiliation(s)
- Antonio Castro
- Department of Cell and Molecular Biology; Faculty of Sciences; University of A Coruña; 15008 A Coruña Spain
| | - Manuela Becerra
- Department of Cell Biology and Ecology; CIBUS, University of Santiago de Compostela; 15706 Santiago de Compostela Spain
| | - María Jesús Manso
- Department of Cell and Molecular Biology; Faculty of Sciences; University of A Coruña; 15008 A Coruña Spain
| | - Ramón Anadón
- Department of Cell Biology and Ecology; CIBUS, University of Santiago de Compostela; 15706 Santiago de Compostela Spain
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Hiragaki S, Suzuki T, Mohamed AAM, Takeda M. Structures and functions of insect arylalkylamine N-acetyltransferase (iaaNAT); a key enzyme for physiological and behavioral switch in arthropods. Front Physiol 2015; 6:113. [PMID: 25918505 PMCID: PMC4394704 DOI: 10.3389/fphys.2015.00113] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 03/25/2015] [Indexed: 11/26/2022] Open
Abstract
The evolution of N-acetyltransfeases (NATs) seems complex. Vertebrate arylalkylamine N-acetyltransferase (aaNAT) has been extensively studied since it leads to the synthesis of melatonin, a multifunctional neurohormone prevalent in photoreceptor cells, and is known as a chemical token of the night. Melatonin also serves as a scavenger for reactive oxygen species. This is also true with invertebrates. NAT therefore has distinct functional implications in circadian function, as timezymes (aaNAT), and also xenobiotic reactions (arylamine NAT or simply NAT). NATs belong to a broader enzyme group, the GCN5-related N-acetyltransferase superfamily. Due to low sequence homology and a seemingly fast rate of structural differentiation, the nomenclature for NATs can be confusing. The advent of bioinformatics, however, has helped to classify this group of enzymes; vertebrates have two distinct subgroups, the timezyme type and the xenobiotic type, which has a wider substrate range including imidazolamine, pharmacological drugs, environmental toxicants and even histone. Insect aaNAT (iaaNAT) form their own clade in the phylogeny, distinct from vertebrate aaNATs. Arthropods are unique, since the phylum has exoskeleton in which quinones derived from N-acetylated monoamines function in coupling chitin and arthropodins. Monoamine oxidase (MAO) activity is limited in insects, but NAT-mediated degradation prevails. However, unexpectedly iaaNAT occurs not only among arthropods but also among basal deuterostomia, and is therefore more apomorphic. Our analyses illustrate that iaaNATs has unique physiological roles but at the same time it plays a role in a timezyme function, at least in photoperiodism. Photoperiodism has been considered as a function of circadian system but the detailed molecular mechanism is not well understood. We propose a molecular hypothesis for photoperiodism in Antheraea pernyi based on the transcription regulation of NAT interlocked by the circadian system. Therefore, the enzyme plays both unique and universal roles in insects. The unique role of iaaNATs in physiological regulation urges the targeting of this system for integrated pest management (IPM). We indeed showed a successful example of chemical compound screening with reconstituted enzyme and further attempts seem promising.
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Affiliation(s)
- Susumu Hiragaki
- Graduate School of Agricultural Science, Kobe UniversityKobe, Japan
| | - Takeshi Suzuki
- Department of Biology, The University of Western OntarioLondon, ON, Canada
| | | | - Makio Takeda
- Graduate School of Agricultural Science, Kobe UniversityKobe, Japan
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Terakita A, Nagata T. Functional properties of opsins and their contribution to light-sensing physiology. Zoolog Sci 2015; 31:653-9. [PMID: 25284384 DOI: 10.2108/zs140094] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Many animals have developed systems for sensing environmental conditions during evolution. In sensory cells, receptor molecules are responsible for their sensing abilities. In light sensing, most animals capture light information via rhodopsin-like photoreceptive proteins known as opsin-based pigments. A body of evidence from comparisons of amino acid sequences and in vitro experiments demonstrates that opsins have phylogenetically and functionally diversified during evolution and suggests that the phylogenetic diversity in opsins correlates with the variety of molecular properties of opsin-based pigments. In this review, we discuss the various molecular properties of opsin-based pigments and their contribution to light-sensing ability by providing two examples: i) contribution of photoregeneration ability and Chromophore retinal binding property of an Opn3 homolog to non-visual photoreception, and ii) contribution of an absorption characteristic of a visual pigment to depth perception in jumping spiders.
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Affiliation(s)
- Akihisa Terakita
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
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Emanuel AJ, Do MTH. Melanopsin tristability for sustained and broadband phototransduction. Neuron 2015; 85:1043-55. [PMID: 25741728 PMCID: PMC4351474 DOI: 10.1016/j.neuron.2015.02.011] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 01/20/2015] [Accepted: 01/29/2015] [Indexed: 10/23/2022]
Abstract
Mammals rely upon three ocular photoreceptors to sense light: rods, cones, and intrinsically photosensitive retinal ganglion cells (ipRGCs). Rods and cones resolve details in the visual scene. Conversely, ipRGCs integrate over time and space, primarily to support "non-image" vision. The integrative mechanisms of ipRGCs are enigmatic, particularly since these cells use a phototransduction motif that allows invertebrates like Drosophila to parse light with exceptional temporal resolution. Here, we provide evidence for a single mechanism that allows ipRGCs to integrate over both time and wavelength. Light distributes the visual pigment, melanopsin, across three states, two silent and one signaling. Photoequilibration among states maintains pigment availability for sustained signaling, stability of the signaling state permits minutes-long temporal summation, and modest spectral separation of the silent states promotes uniform activation across wavelengths. By broadening the tuning of ipRGCs in both temporal and chromatic domains, melanopsin tristability produces signal integration for physiology and behavior.
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Affiliation(s)
- Alan Joseph Emanuel
- F.M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital and Harvard Medical School, Center for Life Science 12061, 3 Blackfan Circle, Boston, MA 02115, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA; Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA.
| | - Michael Tri Hoang Do
- F.M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital and Harvard Medical School, Center for Life Science 12061, 3 Blackfan Circle, Boston, MA 02115, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA; Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA.
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68
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COLLIN SP, HART NS. Vision and photoentrainment in fishes: The effects of natural and anthropogenic perturbation. Integr Zool 2015; 10:15-28. [DOI: 10.1111/1749-4877.12093] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Shaun P. COLLIN
- School of Animal Biology and the Oceans Institute; University of Western Australia; Crawley Western Australia Australia
| | - Nathan S. HART
- School of Animal Biology and the Oceans Institute; University of Western Australia; Crawley Western Australia Australia
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Bonmati-Carrion MA, Arguelles-Prieto R, Martinez-Madrid MJ, Reiter R, Hardeland R, Rol MA, Madrid JA. Protecting the melatonin rhythm through circadian healthy light exposure. Int J Mol Sci 2014; 15:23448-500. [PMID: 25526564 PMCID: PMC4284776 DOI: 10.3390/ijms151223448] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/02/2014] [Accepted: 11/09/2014] [Indexed: 12/14/2022] Open
Abstract
Currently, in developed countries, nights are excessively illuminated (light at night), whereas daytime is mainly spent indoors, and thus people are exposed to much lower light intensities than under natural conditions. In spite of the positive impact of artificial light, we pay a price for the easy access to light during the night: disorganization of our circadian system or chronodisruption (CD), including perturbations in melatonin rhythm. Epidemiological studies show that CD is associated with an increased incidence of diabetes, obesity, heart disease, cognitive and affective impairment, premature aging and some types of cancer. Knowledge of retinal photoreceptors and the discovery of melanopsin in some ganglion cells demonstrate that light intensity, timing and spectrum must be considered to keep the biological clock properly entrained. Importantly, not all wavelengths of light are equally chronodisrupting. Blue light, which is particularly beneficial during the daytime, seems to be more disruptive at night, and induces the strongest melatonin inhibition. Nocturnal blue light exposure is currently increasing, due to the proliferation of energy-efficient lighting (LEDs) and electronic devices. Thus, the development of lighting systems that preserve the melatonin rhythm could reduce the health risks induced by chronodisruption. This review addresses the state of the art regarding the crosstalk between light and the circadian system.
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Affiliation(s)
| | | | | | - Russel Reiter
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA.
| | - Ruediger Hardeland
- Johann Friedrich Blumenbach Institute of Zoology and Anthropology, University of Göttingen, Göttingen 37073, Germany.
| | - Maria Angeles Rol
- Department of Physiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain.
| | - Juan Antonio Madrid
- Department of Physiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain.
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Sun L, Kawano-Yamashita E, Nagata T, Tsukamoto H, Furutani Y, Koyanagi M, Terakita A. Distribution of mammalian-like melanopsin in cyclostome retinas exhibiting a different extent of visual functions. PLoS One 2014; 9:e108209. [PMID: 25251771 PMCID: PMC4177573 DOI: 10.1371/journal.pone.0108209] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 08/20/2014] [Indexed: 11/18/2022] Open
Abstract
Mammals contain 1 melanopsin (Opn4) gene that is expressed in a subset of retinal ganglion cells to serve as a photopigment involved in non-image-forming vision such as photoentrainment of circadian rhythms. In contrast, most nonmammalian vertebrates possess multiple melanopsins that are distributed in various types of retinal cells; however, their functions remain unclear. We previously found that the lamprey has only 1 type of mammalian-like melanopsin gene, which is similar to that observed in mammals. Here we investigated the molecular properties and localization of melanopsin in the lamprey and other cyclostome hagfish retinas, which contribute to visual functions including image-forming vision and mainly to non-image-forming vision, respectively. We isolated 1 type of mammalian-like melanopsin cDNA from the eyes of each species. We showed that the recombinant lamprey melanopsin was a blue light-sensitive pigment and that both the lamprey and hagfish melanopsins caused light-dependent increases in calcium ion concentration in cultured cells in a manner that was similar to that observed for mammalian melanopsins. We observed that melanopsin was distributed in several types of retinal cells, including horizontal cells and ganglion cells, in the lamprey retina, despite the existence of only 1 melanopsin gene in the lamprey. In contrast, melanopsin was almost specifically distributed to retinal ganglion cells in the hagfish retina. Furthermore, we found that the melanopsin-expressing horizontal cells connected to the rhodopsin-containing short photoreceptor cells in the lamprey. Taken together, our findings suggest that in cyclostomes, the global distribution of melanopsin in retinal cells might not be related to the melanopsin gene number but to the extent of retinal contribution to visual function.
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Affiliation(s)
- Lanfang Sun
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Emi Kawano-Yamashita
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Takashi Nagata
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Hisao Tsukamoto
- Department of life and Coordination-Complex Molecular Science, Institute for Molecular Science, Okazaki, Japan
- Department of Structural Molecular Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
| | - Yuji Furutani
- Department of life and Coordination-Complex Molecular Science, Institute for Molecular Science, Okazaki, Japan
- Department of Structural Molecular Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
| | - Mitsumasa Koyanagi
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, Japan
- PRESTO, Japan Science and Technology Agency, Saitama, Japan
| | - Akihisa Terakita
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, Japan
- * E-mail:
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71
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Hering L, Mayer G. Analysis of the opsin repertoire in the tardigrade Hypsibius dujardini provides insights into the evolution of opsin genes in panarthropoda. Genome Biol Evol 2014; 6:2380-91. [PMID: 25193307 PMCID: PMC4202329 DOI: 10.1093/gbe/evu193] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2014] [Indexed: 01/17/2023] Open
Abstract
Screening of a deeply sequenced transcriptome using Illumina sequencing as well as the genome of the tardigrade Hypsibius dujardini revealed a set of five opsin genes. To clarify the phylogenetic position of these genes and to elucidate the evolutionary history of opsins in Panarthropoda (Onychophora + Tardigrada + Arthropoda), we reconstructed the phylogeny of broadly sampled metazoan opsin genes using maximum likelihood and Bayesian inference methods in conjunction with carefully selected substitution models. According to our findings, the opsin repertoire of H. dujardini comprises representatives of all three major bilaterian opsin clades, including one r-opsin, three c-opsins, and a Group 4 opsin (neuropsin/opsin-5). The identification of the tardigrade ortholog of neuropsin/opsin-5 is the first record of this opsin type in a protostome, but our screening of available metazoan genomes revealed that it is also present in other protostomes. Our opsin phylogeny further suggests that two r-opsins, including an "arthropsin," were present in the last common ancestor of Panarthropoda. Although both r-opsin lineages were retained in Onychophora and Arthropoda, the arthropsin was lost in Tardigrada. The single (most likely visual) r-opsin found in H. dujardini supports the hypothesis of monochromatic vision in the panarthropod ancestor, whereas two duplications of the ancestral panarthropod c-opsin have led to three c-opsins in tardigrades. Although the early-branching nodes are unstable within the metazoans, our findings suggest that the last common ancestor of Bilateria possessed six opsins: Two r-opsins, one c-opsin, and three Group 4 opsins, one of which (Go opsin) was lost in the ecdysozoan lineage.
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Affiliation(s)
- Lars Hering
- Animal Evolution and Development, Institute of Biology, University of Leipzig, Germany
| | - Georg Mayer
- Animal Evolution and Development, Institute of Biology, University of Leipzig, Germany
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Eilertsen M, Drivenes O, Edvardsen RB, Bradley CA, Ebbesson LOE, Helvik JV. Exorhodopsin and melanopsin systems in the pineal complex and brain at early developmental stages of Atlantic halibut (Hippoglossus hippoglossus). J Comp Neurol 2014; 522:4003-22. [PMID: 25044160 DOI: 10.1002/cne.23652] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 07/03/2014] [Accepted: 07/09/2014] [Indexed: 01/05/2023]
Abstract
The complexity of the nonvisual photoreception systems in teleosts has just started to be appreciated, with colocalization of multiple photoreceptor types with unresolved functions. Here we describe an intricate expression pattern of melanopsins in early life stages of the marine flat fish Atlantic halibut (Hippoglossus hippoglossus), a period when the unpigmented brain is directly exposed to environmental photons. We show a refined and extensive expression of melanopsins in the halibut brain already at the time of hatching, long before the eyes are functional. We detect melanopsin in the habenula, suprachiasmatic nucleus, dorsal thalamus, and lateral tubular nucleus of first feeding larvae, suggesting conserved functions of the melanopsins in marine teleosts. The complex expression of melanopsins already at larval stages indicates the importance of nonvisual photoreception early in development. Most strikingly, we detect expression of both exorhodopsin and melanopsin in the pineal complex of halibut larvae. Double-fluorescence labeling showed that two clusters of melanopsin-positive cells are located lateral to the central rosette of exorhodopsin-positive cells. The localization of different photopigments in the pineal complex suggests that two parallel photoreceptor systems may be active. Furthermore, the dispersed melanopsin-positive cells in the spinal cord of halibut larvae at the time of hatching may be primary sensory cells or interneurons representing the first example of dispersed high-order photoreceptor cells. The appearance of nonvisual opsins early in the development of halibut provides an alternative model for studying the evolution and functional significance of nonvisual opsins.
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Sodhi P, Hartwick ATE. Adenosine modulates light responses of rat retinal ganglion cell photoreceptors througha cAMP-mediated pathway. J Physiol 2014; 592:4201-20. [PMID: 25038240 DOI: 10.1113/jphysiol.2014.276220] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Adenosine is an established neuromodulator in the mammalian retina, with A1 adenosine receptors being especially prevalent in the innermost ganglion cell layer. Activation of A1 receptors causes inhibition of adenylate cyclase, decreases in intracellular cyclic AMP (cAMP) levels and inhibition of protein kinase A (PKA). In this work, our aim was to characterize the effects of adenosine on the light responses of intrinsically photosensitive retinal ganglion cells (ipRGCs) and to determine whether these photoreceptors are subject to neuromodulation through intracellular cAMP-related signalling pathways. Using multielectrode array recordings from postnatal and adult rat retinas, we demonstrated that adenosine significantly shortened the duration of ipRGC photoresponses and reduced the number of light-evoked spikes fired by these neurons. The effects were A1 adenosine receptor-mediated, and the expression of this receptor on melanopsin-containing ipRGCs was confirmed by calcium imaging experiments on isolated cells in purified cultures. While inhibition of the cAMP/PKA pathway by adenosine shortened ipRGC light responses, stimulation of this pathway with compounds such as forskolin had the opposite effect and lengthened the duration of ipRGC spiking. Our findings reveal that the modification of ipRGC photoresponses through a cAMP/PKA pathway is a general feature of rat ganglion cell photoreceptors, and this pathway can be inhibited through activation of A1 receptors by adenosine. As adenosine levels in the retina rise at night, adenosinergic modulation of ipRGCs may serve as an internal regulatory mechanism to limit transmission of nocturnal photic signals by ipRGCs to the brain. Targeting retinal A1 adenosine receptors for ipRGC inhibition represents a potential therapeutic target for sleep disorders and migraine-associated photophobia.
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Affiliation(s)
- Puneet Sodhi
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
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Bertolesi GE, Hehr CL, McFarlane S. Wiring the retinal circuits activated by light during early development. Neural Dev 2014; 9:3. [PMID: 24521229 PMCID: PMC3937046 DOI: 10.1186/1749-8104-9-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 01/23/2014] [Indexed: 01/26/2023] Open
Abstract
Background Light information is sorted by neuronal circuits to generate image-forming (IF) (interpretation and tracking of visual objects and patterns) and non-image-forming (NIF) tasks. Among the NIF tasks, photic entrainment of circadian rhythms, the pupillary light reflex, and sleep are all associated with physiological responses, mediated mainly by a small group of melanopsin-expressing retinal ganglion cells (mRGCs). Using Xenopus laevis as a model system, and analyzing the c-fos expression induced by light as a surrogate marker of neural activity, we aimed to establish the developmental time at which the cells participating in both systems come on-line in the retina. Results We found that the peripheral retina contains 80% of the two melanopsin-expressing cell types we identified in Xenopus: melanopsin-expressing horizontal cells (mHCs; opn4m+/opn4x+/Prox1+) and mRGCs (2.7% of the total RGCs; opn4m+/opn4x+/Pax6+/Isl1), in a ratio of 6:1. Only mRGCs induced c-fos expression in response to light. Dopaminergic (tyrosine hydroxylase-positive; TH+) amacrine cells (ACs) may be part of the melanopsin-mediated circuit, as shown by preferential c-fos induction by blue light. In the central retina, two cell types in the inner nuclear layer (INL) showed light-mediated induction of c-fos expression [(On-bipolar cells (Otx2+/Isl1+), and a sub-population of ACs (Pax6−/Isl1−)], as well as two RGC sub-populations (Isl1+/Pax6+ and Isl1+/Pax6−). Melanopsin and opsin expression turned on a day before the point at which c-fos expression could first be activated by light (Stage 37/38), in cells of both the classic vision circuit, and those that participate in the retinal component of the NIF circuit. Key to the classic vision circuit is that the component cells engage from the beginning as functional ‘unit circuits’ of two to three cells in the INL for every RGC, with subsequent growth of the vision circuit occurring by the wiring in of more units. Conclusions We identified melanopsin-expressing cells and specific cell types in the INL and the RGC layer which induce c-fos expression in response to light, and we determined the developmental time when they become active. We suggest an initial formulation of retinal circuits corresponding to the classic vision pathway and melanopsin-mediated circuits to which they may contribute.
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Affiliation(s)
| | | | - Sarah McFarlane
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Dr, NW, Health Sciences Building, Room 2164, Calgary AB T2N4N1, Canada.
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Najjar RP, Chiquet C, Teikari P, Cornut PL, Claustrat B, Denis P, Cooper HM, Gronfier C. Aging of non-visual spectral sensitivity to light in humans: compensatory mechanisms? PLoS One 2014; 9:e85837. [PMID: 24465738 PMCID: PMC3900444 DOI: 10.1371/journal.pone.0085837] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 12/02/2013] [Indexed: 11/30/2022] Open
Abstract
The deterioration of sleep in the older population is a prevalent feature that contributes to a decrease in quality of life. Inappropriate entrainment of the circadian clock by light is considered to contribute to the alteration of sleep structure and circadian rhythms in the elderly. The present study investigates the effects of aging on non-visual spectral sensitivity to light and tests the hypothesis that circadian disturbances are related to a decreased light transmittance. In a within-subject design, eight aged and five young subjects were exposed at night to 60 minute monochromatic light stimulations at 9 different wavelengths (420-620 nm). Individual sensitivity spectra were derived from measures of melatonin suppression. Lens density was assessed using a validated psychophysical technique. Although lens transmittance was decreased for short wavelength light in the older participants, melatonin suppression was not reduced. Peak of non-visual sensitivity was, however, shifted to longer wavelengths in the aged participants (494 nm) compared to young (484 nm). Our results indicate that increased lens filtering does not necessarily lead to a decreased non-visual sensitivity to light. The lack of age-related decrease in non-visual sensitivity to light may involve as yet undefined adaptive mechanisms.
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Affiliation(s)
- Raymond P. Najjar
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France
| | - Christophe Chiquet
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University Joseph Fourier Grenoble 1, Grenoble, France
- Department of Ophthalmology, CHU Grenoble, Grenoble, France
| | - Petteri Teikari
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France
| | - Pierre-Loïc Cornut
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- Department of Ophthalmology, CHU de Lyon Hôpital Edouard Herriot, Lyon, France
| | - Bruno Claustrat
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- Center of Biology, Hormone Laboratory, Bron, France
| | - Philippe Denis
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- Department of Ophtalmology, Hôpital de la Croix-Rousse, Lyon, France
| | - Howard M. Cooper
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France
| | - Claude Gronfier
- Department of Chronobiology, Inserm U846, Stem Cell and Brain Research Institute, Bron, France
- University of Lyon, Claude Bernard Lyon 1, Villeurbanne, France
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Lucas RJ, Peirson SN, Berson DM, Brown TM, Cooper HM, Czeisler CA, Figueiro MG, Gamlin PD, Lockley SW, O'Hagan JB, Price LLA, Provencio I, Skene DJ, Brainard GC. Measuring and using light in the melanopsin age. Trends Neurosci 2014; 37:1-9. [PMID: 24287308 PMCID: PMC4699304 DOI: 10.1016/j.tins.2013.10.004] [Citation(s) in RCA: 491] [Impact Index Per Article: 49.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 10/21/2013] [Accepted: 10/22/2013] [Indexed: 01/17/2023]
Abstract
Light is a potent stimulus for regulating circadian, hormonal, and behavioral systems. In addition, light therapy is effective for certain affective disorders, sleep problems, and circadian rhythm disruption. These biological and behavioral effects of light are influenced by a distinct photoreceptor in the eye, melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs), in addition to conventional rods and cones. We summarize the neurophysiology of this newly described sensory pathway and consider implications for the measurement, production, and application of light. A new light-measurement strategy taking account of the complex photoreceptive inputs to these non-visual responses is proposed for use by researchers, and simple suggestions for artificial/architectural lighting are provided for regulatory authorities, lighting manufacturers, designers, and engineers.
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Affiliation(s)
- Robert J Lucas
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK.
| | - Stuart N Peirson
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Headley Way, Oxford OX3 9DU, UK
| | - David M Berson
- Department of Neuroscience, Brown University, Box G-LN, Providence, RI, USA
| | - Timothy M Brown
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Howard M Cooper
- INSERM 846 Stem Cell and Brain Research Institute, Department of Chronobiology, 18 Avenue du Doyen Lépine, 69500 Bron, France
| | - Charles A Czeisler
- Division of Sleep Medicine, Harvard Medical School, and Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Mariana G Figueiro
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Paul D Gamlin
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Steven W Lockley
- Division of Sleep Medicine, Harvard Medical School, and Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | | | | | - Ignacio Provencio
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Debra J Skene
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - George C Brainard
- Department of Neurology, Thomas Jefferson University, Philidelphia, PA, USA.
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77
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Koyanagi M, Terakita A. Diversity of animal opsin-based pigments and their optogenetic potential. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:710-6. [PMID: 24041647 DOI: 10.1016/j.bbabio.2013.09.003] [Citation(s) in RCA: 331] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 08/30/2013] [Accepted: 09/06/2013] [Indexed: 10/26/2022]
Abstract
Most animal opsin-based pigments are typical G protein-coupled receptors (GPCR) and consist of a protein moiety, opsin, and 11-cis retinal as a chromophore. More than several thousand opsins have been identified from a wide variety of animals, which have multiple opsin genes. Accumulated evidence reveals the molecular property of opsin-based pigments, particularly non-conventional visual pigments including non-visual pigments. Opsin-based pigments are generally a bistable pigment having two stable and photointerconvertible states and therefore are bleach-resistant and reusable, unlike vertebrate visual pigments which become bleached. The opsin family contains Gt-coupled, Gq-coupled, Go-coupled, Gs-coupled, Gi-coupled, and Gi/Go-coupled opsins, indicating the existence of a large diversity of light-driven GPCR-signaling cascades. It is suggested that these molecular properties might contribute to different physiologies. In addition, various opsin based-pigments, especially nonconventional visual pigments having different molecular characteristics would facilitate the design and development of promising optogenetic tools for modulating GPCR-signaling, which is involved in a wide variety of physiological responses. We here introduce molecular and functional properties of various kinds of opsins and discuss their physiological function and also their potentials for optogenetic applications. This article is part of a Special Issue entitled: Retinal proteins - you can teach an old dog new tricks.
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Affiliation(s)
- Mitsumasa Koyanagi
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Akihisa Terakita
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
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78
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Döring C, Gosda J, Tessmar-Raible K, Hausen H, Arendt D, Purschke G. Evolution of clitellate phaosomes from rhabdomeric photoreceptor cells of polychaetes - a study in the leech Helobdella robusta (Annelida, Sedentaria, Clitellata). Front Zool 2013; 10:52. [PMID: 24007384 PMCID: PMC3846555 DOI: 10.1186/1742-9994-10-52] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 08/20/2013] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION In Annelida two types of photoreceptor cells (PRCs) are regarded as generally present, rhabdomeric and ciliary PRCs. In certain taxa, however, an additional type of PRC may occur, the so called phaosomal PRC. Whereas the former two types of PRCs are always organized as an epithelium with their sensory processes projecting into an extracellular cavity formed by the PRCs and (pigmented) supportive cells, phaosomes are seemingly intracellular vacuoles housing the sensory processes. Phaosomal PRCs are the only type of PRC found in one major annelid group, Clitellata. Several hypotheses have been put forward explaining the evolutionary origin of the clitellate phaosomes. To elucidate the evolution of clitellate PRC and eyes the leech Helobdella robusta, for which a sequenced genome is available, was chosen. RESULTS TEM observations showed that extraocular and ocular PRCs are structurally identical. Bioinformatic analyses revealed predictions for four opsin genes, three of which could be amplified. All belong to the rhabdomeric opsin family and phylogenetic analyses showed them in a derived position within annelid opsins. Gene expression studies showed two of them expressed in the eye and in the extraocular PRCs. Polychaete eye-typic key enzymes for ommochromme and pterin shading pigments synthesis are not expressed in leech eyes. CONCLUSIONS By comparative gene-expression studies we herein provide strong evidence that the phaosomal PRCs typical of Clitellata are derived from the rhabdomeric PRCs characteristic for polychaete adult eyes. Thus, they represent a highly derived type of PRC that evolved in the stem lineage of Clitellata rather than another, primitive type of PRC in Metazoa. Evolution of these PRCs in Clitellata is related to a loss of the primary eyes and most of their photoreceptive elements except for the rhabdomeric PRCs. Most likely this happened while changing to an endobenthic mode of life. This hypothesis of PRC evolution is in accordance with a recently published phylogeny of Annelida based on phylogenomic data. The data provide a nice example how morphologically highly divergent light sensitive structures emerged from a standard type of photoreceptor cell.
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Affiliation(s)
- Carmen Döring
- Universität Osnabrück, Zoologie, Osnabrück 49069, Germany
| | - Jasmin Gosda
- Universität Osnabrück, Zoologie, Osnabrück 49069, Germany
- Present address: Kopernikusstrasse 5, 48477 Hörstel, Germany
| | - Kristin Tessmar-Raible
- Max F. Perutz Laboratories, Universität Wien, Campus Vienna Biocenter, Austria Research Plattform “Marine Rhythms of Life”, Dr. Bohr–Gasse 9/4, 1030 Wien, Austria
| | - Harald Hausen
- Sars International Centre for Marine Molecular Biology, Thormøhlensgate 55, 5008 Bergen, Norway
| | - Detlev Arendt
- Developmental Biology Programme, European Molecular Biology Laboratory, Meyerhofstraße 1, D-69012 Heidelberg, Germany
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79
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Evolution of phototransduction, vertebrate photoreceptors and retina. Prog Retin Eye Res 2013; 36:52-119. [DOI: 10.1016/j.preteyeres.2013.06.001] [Citation(s) in RCA: 257] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 06/02/2013] [Indexed: 01/12/2023]
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80
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Large scale expression and purification of mouse melanopsin-L in the baculovirus expression system. Protein Expr Purif 2013; 91:134-46. [PMID: 23921072 DOI: 10.1016/j.pep.2013.07.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 07/14/2013] [Accepted: 07/17/2013] [Indexed: 11/22/2022]
Abstract
Melanopsin is the mammalian photopigment that primarily mediates non-visual photoregulated physiology. So far, this photopigment is poorly characterized with respect to structure and function. Here, we report large-scale production and purification of the intact long isoform of mouse melanopsin (melanopsin-L) using the baculovirus/insect cell expression system. Exploiting the baculoviral GP67 signal peptide, we obtained expression levels that varied between 10-30pmol/10(6)cells, equivalent to 2-5mg/L. This could be further enhanced using DMSO as a chemical chaperone. LC-MS analysis confirmed that full-length melanopsin-L was expressed and demonstrated that the majority of the expressed protein was N-glycosylated at Asn(30) and Asn(34). Other posttranslational modifications were not yet detected. Purification was achieved exploiting a C-terminal deca-histag, realizing a purification factor of several hundred-fold. The final recovery of purified melanopsin-L averaged 2.5% of the starting material. This was mainly due to low extraction yields, probably since most of the protein was present as the apoprotein. The spectral data we obtained agree with an absorbance maximum in the 460-500nm wavelength region and a significant red-shift upon illumination. This is the first report on expression and purification of full length melanopsin-L at a scale that can easily be further amplified.
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81
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Cascella M, Bärfuss S, Stocker A. Cis-retinoids and the chemistry of vision. Arch Biochem Biophys 2013; 539:187-95. [PMID: 23791723 DOI: 10.1016/j.abb.2013.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/04/2013] [Accepted: 06/10/2013] [Indexed: 11/17/2022]
Abstract
We discuss here principal biochemical transformations of retinoid molecules in the visual cycle. We focus our analysis on the accumulating evidence of alternate pathways and functional redundancies in the cycle. The efficiency of the visual cycle depends, on one hand, on fast regeneration of the photo-bleached chromophores. On the other hand, it is crucial that the cyclic process should be highly selective to avoid accumulation of byproducts. The state-of-the-art knowledge indicates that single enzymatically active components of the cycle are not strictly selective and may require chaperones to enhance their rates. It appears that protein-protein interactions significantly improve the biological stability of the visual cycle. In particular, synthesis of thermodynamically less stable 11-cis-retinoid conformers is favored by physical interactions of the isomerases present in the retina with cellular retinaldehyde binding protein.
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Affiliation(s)
- Michele Cascella
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
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82
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Passamaneck YJ, Martindale MQ. Evidence for a phototransduction cascade in an early brachiopod embryo. Integr Comp Biol 2013; 53:17-26. [PMID: 23630970 DOI: 10.1093/icb/ict037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Bilaterian photoreceptor cells are characterized by the expression of opsins, signal transduction genes, and ion channels, which together facilitate behavioral responses to light. We have previously identified a ciliary opsin gene from the brachiopod Terebratalia transversa, whose expression in gastrula stage embryos coincides with a photoresponse behavior, suggesting the presence of a functional phototransduction system in these early embryos. To further evaluate the potential for light reception in these embryos, we surveyed transcriptome data to identify phototransduction genes and evaluated their expression. In addition to the previously described ciliary opsin gene, we have identified two Go-class opsins that are also expressed in gastrula stage embryos. Representative members from all classes of Gα-protein genes were also expressed, with a Gα12-class gene being localized in the same anterior ectodermal domain as the opsin transcripts. Both CNG-class and TRP-class ion channels were expressed in the gastrula stage embryos, as were GRK and arrestin genes, which are associated with inhibition of rhodopsin activity. Taken together, these data support the presence of a functional phototransduction system in the early brachiopod embryo.
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Affiliation(s)
- Yale J Passamaneck
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA.
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83
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Ivashkin E, Adameyko I. Progenitors of the protochordate ocellus as an evolutionary origin of the neural crest. EvoDevo 2013; 4:12. [PMID: 23575111 PMCID: PMC3626940 DOI: 10.1186/2041-9139-4-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 12/28/2012] [Indexed: 01/01/2023] Open
Abstract
The neural crest represents a highly multipotent population of embryonic stem cells found only in vertebrate embryos. Acquisition of the neural crest during the evolution of vertebrates was a great advantage, providing Chordata animals with the first cellular cartilage, bone, dentition, advanced nervous system and other innovations. Today not much is known about the evolutionary origin of neural crest cells. Here we propose a novel scenario in which the neural crest originates from neuroectodermal progenitors of the pigmented ocelli in Amphioxus-like animals. We suggest that because of changes in photoreception needs, these multipotent progenitors of photoreceptors gained the ability to migrate outside of the central nervous system and subsequently started to give rise to neural, glial and pigmented progeny at the periphery.
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Affiliation(s)
- Evgeniy Ivashkin
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles vag 1 A1, Stockholm 17177, Sweden.
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84
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Bailes HJ, Lucas RJ. Human melanopsin forms a pigment maximally sensitive to blue light (λmax ≈ 479 nm) supporting activation of G(q/11) and G(i/o) signalling cascades. Proc Biol Sci 2013; 280:20122987. [PMID: 23554393 PMCID: PMC3619500 DOI: 10.1098/rspb.2012.2987] [Citation(s) in RCA: 426] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A subset of mammalian retinal ganglion cells expresses an opsin photopigment (melanopsin, Opn4) and is intrinsically photosensitive. The human retina contains melanopsin, but the literature lacks a direct investigation of its spectral sensitivity or G-protein selectivity. Here, we address this deficit by studying physiological responses driven by human melanopsin under heterologous expression in HEK293 cells. Luminescent reporters for common second messenger systems revealed that light induces a high amplitude increase in intracellular calcium and a modest reduction in cAMP in cells expressing human melanopsin, implying that this pigment is able to drive responses via both Gq and Gi/o class G-proteins. Melanopsins from mouse and amphioxus had a similar profile of G-protein coupling in HEK293 cells, but chicken Opn4m and Opn4x pigments exhibited some Gs activity in addition to a strong Gq/11 response. An action spectrum for the calcium response in cells expressing human melanopsin had the predicted form for an opsin : vitamin A1 pigment and peaked at 479 nm. The G-protein selectivity and spectral sensitivity of human melanopsin is similar to that previously described for rodents, supporting the utility of such laboratory animals for developing methods of manipulating this system using light or pharmacological agents.
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Affiliation(s)
- Helena J Bailes
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
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85
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Dissecting the determinants of light sensitivity in amphioxus microvillar photoreceptors: possible evolutionary implications for melanopsin signaling. J Neurosci 2013; 32:17977-87. [PMID: 23238714 DOI: 10.1523/jneurosci.3069-12.2012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Melanopsin, a photopigment related to the rhodopsin of microvillar photoreceptors of invertebrates, evolved in vertebrates to subserve nonvisual light-sensing functions, such as the pupillary reflex and entrainment of circadian rhythms. However, vertebrate circadian receptors display no hint of a microvillar specialization and show an extremely low light sensitivity and sluggish kinetics. Recently in amphioxus, the most basal chordate, melanopsin-expressing photoreceptors were characterized; these cells share salient properties with both rhabdomeric photoreceptors of invertebrates and circadian receptors of vertebrates. We used electrophysiology to dissect the gain of the light-transduction process in amphioxus and examine key features that help outline the evolutionary transition toward a sensor optimized to report mean ambient illumination rather than mediating spatial vision. By comparing the size of current fluctuations attributable to single photon melanopsin isomerizations with the size of single-channels activated by light, we concluded that the gain of the transduction cascade is lower than in rhabdomeric receptors. In contrast, the expression level of melanopsin (gauged by measuring charge displacements during photo-induced melanopsin isomerization) is comparable with that of canonical visual receptors. A modest amplification in melanopsin-using receptors is therefore apparent in early chordates; the decrease in photopigment expression-and loss of the anatomical correlates-observed in vertebrates subsequently enabled them to attain the low photosensitivity tailored to the role of circadian receptors.
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86
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The evolutionary relationship between microbial rhodopsins and metazoan rhodopsins. ScientificWorldJournal 2013; 2013:435651. [PMID: 23476135 PMCID: PMC3583139 DOI: 10.1155/2013/435651] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 12/16/2012] [Indexed: 01/29/2023] Open
Abstract
Rhodopsins are photoreceptive proteins with seven-transmembrane alpha-helices and a covalently bound retinal. Based on their protein sequences, rhodopsins can be classified into microbial rhodopsins and metazoan rhodopsins. Because there is no clearly detectable sequence identity between these two groups, their evolutionary relationship was difficult to decide. Through ancestral state inference, we found that microbial rhodopsins and metazoan rhodopsins are divergently related in their seven-transmembrane domains. Our result proposes that they are homologous proteins and metazoan rhodopsins originated from microbial rhodopsins. Structure alignment shows that microbial rhodopsins and metazoan rhodopsins share a remarkable structural homology while the position of retinal-binding lysine is different between them. It suggests that the function of photoreception was once lost during the evolution of rhodopsin genes. This result explains why there is no clearly detectable sequence similarity between the two rhodopsin groups: after losing the photoreception function, rhodopsin gene was freed from the functional constraint and the process of divergence could quickly change its original sequence beyond recognition.
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87
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Backfisch B, Veedin Rajan VB, Fischer RM, Lohs C, Arboleda E, Tessmar-Raible K, Raible F. Stable transgenesis in the marine annelid Platynereis dumerilii sheds new light on photoreceptor evolution. Proc Natl Acad Sci U S A 2013; 110:193-8. [PMID: 23284166 PMCID: PMC3538230 DOI: 10.1073/pnas.1209657109] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Research in eye evolution has mostly focused on eyes residing in the head. In contrast, noncephalic light sensors are far less understood and rather regarded as evolutionary innovations. We established stable transgenesis in the annelid Platynereis, a reference species for evolutionary and developmental comparisons. EGFP controlled by cis-regulatory elements of r-opsin, a characteristic marker for rhabdomeric photoreceptors, faithfully recapitulates known r-opsin expression in the adult eyes, and marks a pair of pigment-associated frontolateral eyelets in the brain. Unexpectedly, transgenic animals revealed an additional series of photoreceptors in the ventral nerve cord as well as photoreceptors that are located in each pair of the segmental dorsal appendages (notopodia) and project into the ventral nerve cord. Consistent with a photosensory function of these noncephalic cells, decapitated animals display a clear photoavoidance response. Molecular analysis of the receptors suggests that they differentiate independent of pax6, a gene involved in early eye development of many metazoans, and that the ventral cells may share origins with the Hesse organs in the amphioxus neural tube. Finally, expression analysis of opn4×-2 and opn4m-2, two zebrafish orthologs of Platynereis r-opsin, reveals that these genes share expression in the neuromasts, known mechanoreceptors of the lateral line peripheral nervous system. Together, this establishes that noncephalic photoreceptors are more widespread than assumed, and may even reflect more ancient aspects of sensory systems. Our study marks significant advance for the understanding of photoreceptor cell (PRC) evolution and development and for Platynereis as a functional lophotrochozoan model system.
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Affiliation(s)
| | | | - Ruth M. Fischer
- Max F. Perutz Laboratories, Department of Microbiology, Immunobiology, and Genetics, University of Vienna, A-1030 Vienna, Austria
| | | | | | - Kristin Tessmar-Raible
- Max F. Perutz Laboratories, Department of Microbiology, Immunobiology, and Genetics, University of Vienna, A-1030 Vienna, Austria
| | - Florian Raible
- Max F. Perutz Laboratories, Department of Microbiology, Immunobiology, and Genetics, University of Vienna, A-1030 Vienna, Austria
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Borges R, Johnson WE, O’Brien SJ, Vasconcelos V, Antunes A. The role of gene duplication and unconstrained selective pressures in the melanopsin gene family evolution and vertebrate circadian rhythm regulation. PLoS One 2012; 7:e52413. [PMID: 23285031 PMCID: PMC3528684 DOI: 10.1371/journal.pone.0052413] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 11/15/2012] [Indexed: 12/27/2022] Open
Abstract
Melanopsin is a photosensitive cell protein involved in regulating circadian rhythms and other non-visual responses to light. The melanopsin gene family is represented by two paralogs, OPN4x and OPN4m, which originated through gene duplication early in the emergence of vertebrates. Here we studied the melanopsin gene family using an integrated gene/protein evolutionary approach, which revealed that the rhabdomeric urbilaterian ancestor had the same amino acid patterns (DRY motif and the Y and E conterions) as extant vertebrate species, suggesting that the mechanism for light detection and regulation is similar to rhabdomeric rhodopsins. Both OPN4m and OPN4x paralogs are found in vertebrate genomic paralogons, suggesting that they diverged following this duplication event about 600 million years ago, when the complex eye emerged in the vertebrate ancestor. Melanopsins generally evolved under negative selection (ω = 0.171) with some minor episodes of positive selection (proportion of sites = 25%) and functional divergence (θ(I) = 0.349 and θ(II) = 0.126). The OPN4m and OPN4x melanopsin paralogs show evidence of spectral divergence at sites likely involved in melanopsin light absorbance (200F, 273S and 276A). Also, following the teleost lineage-specific whole genome duplication (3R) that prompted the teleost fish radiation, type I divergence (θ(I) = 0.181) and positive selection (affecting 11% of sites) contributed to amino acid variability that we related with the photo-activation stability of melanopsin. The melanopsin intracellular regions had unexpectedly high variability in their coupling specificity of G-proteins and we propose that Gq/11 and Gi/o are the two G-proteins most-likely to mediate the melanopsin phototransduction pathway. The selection signatures were mainly observed on retinal-related sites and the third and second intracellular loops, demonstrating the physiological plasticity of the melanopsin protein group. Our results provide new insights on the phototransduction process and additional tools for disentangling and understanding the links between melanopsin gene evolution and the specializations observed in vertebrates, especially in teleost fish.
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Affiliation(s)
- Rui Borges
- CIMAR/CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas, Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, Porto, Portugal
| | - Warren E. Johnson
- Laboratory of Genomic Diversity, National Cancer Institute, Frederick, Maryland, United States of America
| | - Stephen J. O’Brien
- Laboratory of Genomic Diversity, National Cancer Institute, Frederick, Maryland, United States of America
- Theodosius Dobzhansky Center for Genome Bioinformatics, St. Petersburg State University, St. Petersburg, Russia
| | - Vitor Vasconcelos
- CIMAR/CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas, Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, Porto, Portugal
| | - Agostinho Antunes
- CIMAR/CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas, Porto, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, Porto, Portugal
- Laboratory of Genomic Diversity, National Cancer Institute, Frederick, Maryland, United States of America
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Davies WIL, Tay BH, Zheng L, Danks JA, Brenner S, Foster RG, Collin SP, Hankins MW, Venkatesh B, Hunt DM. Evolution and functional characterisation of melanopsins in a deep-sea chimaera (elephant shark, Callorhinchus milii). PLoS One 2012; 7:e51276. [PMID: 23251480 PMCID: PMC3522658 DOI: 10.1371/journal.pone.0051276] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 10/31/2012] [Indexed: 01/29/2023] Open
Abstract
Non-visual photoreception in mammals is primarily mediated by two splice variants that derive from a single melanopsin (OPN4M) gene, whose expression is restricted to a subset of retinal ganglion cells. Physiologically, this sensory system regulates the photoentrainment of many biological rhythms, such as sleep via the melatonin endocrine system and pupil constriction. By contrast, melanopsin exists as two distinct lineages in non-mammals, opn4m and opn4x, and is broadly expressed in a wide range of tissue types, including the eye, brain, pineal gland and skin. Despite these findings, the evolution and function of melanopsin in early vertebrates are largely unknown. We, therefore, investigated the complement of opn4 classes present in the genome of a model deep-sea cartilaginous species, the elephant shark (Callorhinchus milii), as a representative vertebrate that resides at the base of the gnathostome (jawed vertebrate) lineage. We reveal that three melanopsin genes, opn4m1, opn4m2 and opn4x, are expressed in multiple tissues of the elephant shark. The two opn4m genes are likely to have arisen as a result of a lineage-specific duplication, whereas “long” and “short” splice variants are generated from a single opn4x gene. By using a heterologous expression system, we suggest that these genes encode functional photopigments that exhibit both “invertebrate-like” bistable and classical “vertebrate-like” monostable biochemical characteristics. We discuss the evolution and function of these melanopsin pigments within the context of the diverse photic and ecological environments inhabited by this chimaerid holocephalan, as well as the origin of non-visual sensory systems in early vertebrates.
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Affiliation(s)
- Wayne I. L. Davies
- School of Animal Biology, University of Western Australia Oceans Institute and Lions Eye Institute, University of Western Australia, Perth, Western Australia, Australia
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Boon-Hui Tay
- Comparative Genomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research, Biopolis, Singapore
| | - Lei Zheng
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Janine A. Danks
- Comparative Endocrinology and Biochemistry Laboratory, School of Medical Sciences, Health Innovations Research Institute, Royal Melbourne Institute of Technology University, Victoria, Australia
| | - Sydney Brenner
- Comparative Genomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research, Biopolis, Singapore
| | - Russell G. Foster
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Shaun P. Collin
- School of Animal Biology, University of Western Australia Oceans Institute and Lions Eye Institute, University of Western Australia, Perth, Western Australia, Australia
| | - Mark W. Hankins
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
- * E-mail: (DH); (BV); (MWH)
| | - Byrappa Venkatesh
- Comparative Genomics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research, Biopolis, Singapore
- * E-mail: (DH); (BV); (MWH)
| | - David M. Hunt
- School of Animal Biology, University of Western Australia Oceans Institute and Lions Eye Institute, University of Western Australia, Perth, Western Australia, Australia
- * E-mail: (DH); (BV); (MWH)
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90
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Sekharan S, Wei JN, Batista VS. The Active Site of Melanopsin: The Biological Clock Photoreceptor. J Am Chem Soc 2012; 134:19536-9. [DOI: 10.1021/ja308763b] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Sivakumar Sekharan
- Department
of Chemistry, Yale University, New Haven,
Connecticut 06520-8107, United States
| | - Jennifer N. Wei
- Department
of Chemistry, Yale University, New Haven,
Connecticut 06520-8107, United States
| | - Victor S. Batista
- Department
of Chemistry, Yale University, New Haven,
Connecticut 06520-8107, United States
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91
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Molecular analysis of the amphioxus frontal eye unravels the evolutionary origin of the retina and pigment cells of the vertebrate eye. Proc Natl Acad Sci U S A 2012; 109:15383-8. [PMID: 22949670 DOI: 10.1073/pnas.1207580109] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The origin of vertebrate eyes is still enigmatic. The "frontal eye" of amphioxus, our most primitive chordate relative, has long been recognized as a candidate precursor to the vertebrate eyes. However, the amphioxus frontal eye is composed of simple ciliated cells, unlike vertebrate rods and cones, which display more elaborate, surface-extended cilia. So far, the only evidence that the frontal eye indeed might be sensitive to light has been the presence of a ciliated putative sensory cell in the close vicinity of dark pigment cells. We set out to characterize the cell types of the amphioxus frontal eye molecularly, to test their possible relatedness to the cell types of vertebrate eyes. We show that the cells of the frontal eye specifically coexpress a combination of transcription factors and opsins typical of the vertebrate eye photoreceptors and an inhibitory Gi-type alpha subunit of the G protein, indicating an off-responding phototransductory cascade. Furthermore, the pigmented cells match the retinal pigmented epithelium in melanin content and regulatory signature. Finally, we reveal axonal projections of the frontal eye that resemble the basic photosensory-motor circuit of the vertebrate forebrain. These results support homology of the amphioxus frontal eye and the vertebrate eyes and yield insights into their evolutionary origin.
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92
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McCormick LR, Cohen JH. Pupil light reflex in the Atlantic brief squid, Lolliguncula brevis. J Exp Biol 2012; 215:2677-83. [DOI: 10.1242/jeb.068510] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Coleoid behavioral ecology is highly visual and requires an eye capable of forming images in a variety of photic conditions. A variable pupil aperture is one feature that contributes to this visual flexibility in most coleoids, although pupil responses have yet to be quantitatively documented for squid. The pupil light reflex (PLR) of the Atlantic brief squid, Lolliguncula brevis, was analyzed by directly exposing one eye of individual squid to light stimuli of varying irradiance and imaging the reflex, while simultaneously recording from the opposite, indirectly stimulated eye to determine whether the constriction was consensual between eyes. A PLR was measured in L. brevis, with an asymmetrical constriction observed under increasing irradiance levels that was not consensual between eyes, although a response of some level was observed in both eyes. Response thresholds ranged between 12.56 and 12.66 log photons cm–2 s–1. The PLR was rapid and dependent upon the stimulus irradiance, achieving half-maximum constriction within 0.49–1.2 s. The spectral responsivity of the PLR was analyzed by measuring the magnitude of the reflex in the eye directly stimulated by light of equal quantal intensity at wavelengths from 410 to 632 nm. The responsivity curve showed a maximum at 500 nm, indicating the eye is especially well suited for vision at twilight. These results, when considered in the context of the ambient light characteristics, show that the PLR of L. brevis contributes to a dynamic visual system capable of adjusting to the highly variable composition of light in its estuarine habitat.
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Affiliation(s)
- Lillian R. McCormick
- Department of Marine Science, Eckerd College, 4200 54th Avenue South, St Petersburg, FL 33711, USA
| | - Jonathan H. Cohen
- Department of Marine Science, Eckerd College, 4200 54th Avenue South, St Petersburg, FL 33711, USA
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93
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Matsuyama T, Yamashita T, Imamoto Y, Shichida Y. Photochemical properties of mammalian melanopsin. Biochemistry 2012; 51:5454-62. [PMID: 22670683 DOI: 10.1021/bi3004999] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Melanopsin is the photoreceptor molecule of intrinsically photosensitive retinal ganglion cells, which serve as the input for various nonvisual behavior and physiological functions fundamental to organisms. The retina, therefore, possess a melanopsin-based nonvisual system in addition to the visual system based on the classical visual photoreceptor molecules. To elucidate the molecular properties of melanopsin, we have exogenously expressed mouse melanopsin in cultured cells. We were able to obtain large amounts of purified mouse melanopsin and conducted a comprehensive spectroscopic study of its photochemical properties. Melanopsin has an absorption maximum at 467 nm, and it converts to a meta intermediate having an absorption maximum at 476 nm. The melanopsin photoreaction is similar to that of squid rhodopsin, exhibiting bistability that results in a photosteady mixture of a resting state (melanopsin containing 11-cis-retinal) and an excited state (metamelanopsin containing all-trans-retinal) upon sustained irradiation. The absorption coefficient of melanopsin is 33000 ± 1000 M(-1) cm(-1), and its quantum yield of isomerization is 0.52; these values are also typical of invertebrate bistable pigments. Thus, the nonvisual system in the retina relies on a type of photoreceptor molecule different from that of the visual system. Additionally, we found a new state of melanopsin, containing 7-cis-retinal (extramelanopsin), which forms readily upon long-wavelength irradiation (yellow to red light) and photoconverts to metamelanopsin with short-wavelength (blue light) irradiation. Although it is unclear whether extramelanopsin would have any physiological role, it could potentially allow wavelength-dependent regulation of melanopsin functions.
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Affiliation(s)
- Take Matsuyama
- Department of Biophysics, Graduate School of Science, Kyoto University, Japan
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94
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Pulido C, Malagón G, Ferrer C, Chen JK, Angueyra JM, Nasi E, Gomez MDP. The light-sensitive conductance of melanopsin-expressing Joseph and Hesse cells in amphioxus. ACTA ACUST UNITED AC 2012; 139:19-30. [PMID: 22200946 PMCID: PMC3250099 DOI: 10.1085/jgp.201110717] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Two types of microvillar photoreceptors in the neural tube of amphioxus, an early chordate, sense light via melanopsin, the same photopigment as in “circadian” light detectors of higher vertebrates. Because in amphioxus melanopsin activates a Gq/phospholipase C cascade, like phototransduction in arthropods and mollusks, possible commonalities in the photoconductance were investigated. Unlike other microvillar photoreceptors, reversal of the photocurrent can only be attained upon replacement of extracellular Na+. In addition to Na+, Ca2+ is also permeant, as indicated by the fact that (a) in normal ionic conditions the photocurrent remains inward at Vm > ENa; (b) in Na-free solution a small residual inward photocurrent persists at Vm near resting level, provided that Ca is present; and (c) Vrev exhibits a modest shift with [Ca]o manipulations. The unusual reversal is accounted for by an uncommonly low permeability of the light-dependent channels to K+, as [K]o only marginally affects the photocurrent amplitude and its reversal. Lanthanum and ruthenium red (RuR), two TRP channel antagonists, reversibly suppress the response to photostimulation of moderate intensity; therefore, the melanopsin-initiated cascade may recruit ion channels of the same family as those of rhabdomeric photoreceptors. With brighter lights, blockage declines, so that both La3+ and RuR induce a right shift in the sensitivity curve without a reduction of its asymptote. Nonetheless, an effect on the transduction cascade, rather than the channels, was ruled out on the basis of the voltage dependency of the blockade and the lack of effects of intracellular application of the same substances. The mechanisms of action of these antagonists thus entail a state-dependent blockade, with a higher affinity for the channel in the closed conformation. Collectively, the results indicate a kinship of the light-sensitive channels of amphioxus with those of invertebrate rhabdomeric visual cells and support the representation of this lineage of photoreceptors among chordates.
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Affiliation(s)
- Camila Pulido
- Departamento de Biología, Universidad Nacional de Colombia, Bogotá
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95
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Sexton TJ, Golczak M, Palczewski K, Van Gelder RN. Melanopsin is highly resistant to light and chemical bleaching in vivo. J Biol Chem 2012; 287:20888-97. [PMID: 22547062 DOI: 10.1074/jbc.m111.325969] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Melanopsin is the photopigment of mammalian intrinsically photosensitive retinal ganglion cells, where it contributes to light entrainment of circadian rhythms, and to the pupillary light response. Previous work has shown that the melanopsin photocycle is independent of that used by rhodopsin (Tu, D. C., Owens, L. A., Anderson, L., Golczak, M., Doyle, S. E., McCall, M., Menaker, M., Palczewski, K., and Van Gelder, R. N. (2006) Inner retinal photoreception independent of the visual retinoid cycle. Proc. Natl. Acad. Sci. U.S.A. 103, 10426-10431). Here we determined the ability of apo-melanopsin, formed by ex vivo UV light bleaching, to use selected chromophores. We found that 9-cis-retinal, but not all-trans-retinal or 9-cis-retinol, is able to restore light-dependent ipRGC activity after bleaching. Melanopsin was highly resistant to both visible-spectrum photic bleaching and chemical bleaching with hydroxylamine under conditions that fully bleach rod and cone photoreceptor cells. These results suggest that the melanopsin photocycle can function independently of both rod and cone photocycles, and that apo-melanopsin has a strong preference for binding cis-retinal to generate functional pigment. The data support a model in which retinal is continuously covalently bound to melanopsin and may function through a reversible, bistable mechanism.
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Affiliation(s)
- Timothy J Sexton
- Department of Ophthalmology, University of Washington, Seattle, Washington 98195, USA
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96
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Sand A, Schmidt TM, Kofuji P. Diverse types of ganglion cell photoreceptors in the mammalian retina. Prog Retin Eye Res 2012; 31:287-302. [PMID: 22480975 DOI: 10.1016/j.preteyeres.2012.03.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 03/16/2012] [Accepted: 03/19/2012] [Indexed: 01/01/2023]
Abstract
Photoreceptors carry out the first step in vision by capturing light and transducing it into electrical signals. Rod and cone photoreceptors efficiently translate photon capture into electrical signals by light activation of opsin-type photopigments. Until recently, the central dogma was that, for mammals, all phototransduction occurred in rods and cones. However, the recent discovery of a novel photoreceptor type in the inner retina has fundamentally challenged this view. These retinal ganglion cells are intrinsically photosensitive and mediate a broad range of physiological responses such as photoentrainment of the circadian clock, light regulation of sleep, pupillary light reflex, and light suppression of melatonin secretion. Intrinsically photosensitive retinal ganglion cells express melanopsin, a novel opsin-based signaling mechanism reminiscent of that found in invertebrate rhabdomeric photoreceptors. Melanopsin-expressing retinal ganglion cells convey environmental irradiance information directly to brain centers such as the hypothalamus, preoptic nucleus, and lateral geniculate nucleus. Initial studies suggested that these melanopsin-expressing photoreceptors were an anatomically and functionally homogeneous population. However, over the past decade or so, it has become apparent that these photoreceptors are distinguishable as individual subtypes on the basis of their morphology, molecular markers, functional properties, and efferent projections. These results have provided a novel classification scheme with five melanopsin photoreceptor subtypes in the mammalian retina, each presumably with differential input and output properties. In this review, we summarize the evidence for the structural and functional diversity of melanopsin photoreceptor subtypes and current controversies in the field.
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Affiliation(s)
- Andrea Sand
- Department of Neuroscience, University of Minnesota, 6-145 Jackson Hall, 321 Church St SE, Minneapolis, MN 55455, USA
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97
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Sakai K, Imamoto Y, Su CY, Tsukamoto H, Yamashita T, Terakita A, Yau KW, Shichida Y. Photochemical nature of parietopsin. Biochemistry 2012; 51:1933-41. [PMID: 22303823 DOI: 10.1021/bi2018283] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Parietopsin is a nonvisual green light-sensitive opsin closely related to vertebrate visual opsins and was originally identified in lizard parietal eye photoreceptor cells. To obtain insight into the functional diversity of opsins, we investigated by UV-visible absorption spectroscopy the molecular properties of parietopsin and its mutants exogenously expressed in cultured cells and compared the properties to those of vertebrate and invertebrate visual opsins. Our mutational analysis revealed that the counterion in parietopsin is the glutamic acid (Glu) in the second extracellular loop, corresponding to Glu181 in bovine rhodopsin. This arrangement is characteristic of invertebrate rather than vertebrate visual opsins. The photosensitivity and the molar extinction coefficient of parietopsin were also lower than those of vertebrate visual opsins, features likewise characteristic of invertebrate visual opsins. On the other hand, irradiation of parietopsin yielded meta-I, meta-II, and meta-III intermediates after batho and lumi intermediates, similar to vertebrate visual opsins. The pH-dependent equilibrium profile between meta-I and meta-II intermediates was, however, similar to that between acid and alkaline metarhodopsins in invertebrate visual opsins. Thus, parietopsin behaves as an "evolutionary intermediate" between invertebrate and vertebrate visual opsins.
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Affiliation(s)
- Kazumi Sakai
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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98
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Papamichael C, Skene DJ, Revell VL. Human Nonvisual Responses to Simultaneous Presentation of Blue and Red Monochromatic Light. J Biol Rhythms 2012; 27:70-8. [DOI: 10.1177/0748730411431447] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Blue light sensitivity of melatonin suppression and subjective mood and alertness responses in humans is recognized as being melanopsin based. Observations that long-wavelength (red) light can potentiate responses to subsequent short-wavelength (blue) light have been attributed to the bistable nature of melanopsin whereby it forms stable associations with both 11-cis and all-trans isoforms of retinaldehyde and uses light to transition between these states. The current study examined the effect of concurrent administration of blue and red monochromatic light, as would occur in real-world white light, on acute melatonin suppression and subjective mood and alertness responses in humans. Young healthy men (18-35 years; n = 21) were studied in highly controlled laboratory sessions that included an individually timed 30-min light stimulus of blue (λmax 479 nm) or red (λmax 627 nm) monochromatic light at varying intensities (1013-1014 photons/cm2/sec) presented, either alone or in combination, in a within-subject randomized design. Plasma melatonin levels and subjective mood and alertness were assessed at regular intervals relative to the light stimulus. Subjective alertness levels were elevated after light onset irrespective of light wavelength or irradiance. For melatonin suppression, a significant irradiance response was observed with blue light. Co-administration of red light, at any of the irradiances tested, did not significantly alter the response to blue light alone. Under the current experimental conditions, the primary determinant of the melatonin suppression response was the irradiance of blue 479 nm light, and this was unaffected by simultaneous red light administration.
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Affiliation(s)
- Christiana Papamichael
- Chronobiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK
| | - Debra J. Skene
- Chronobiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK
| | - Victoria L. Revell
- Chronobiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK
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99
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Nagata T, Koyanagi M, Tsukamoto H, Saeki S, Isono K, Shichida Y, Tokunaga F, Kinoshita M, Arikawa K, Terakita A. Depth Perception from Image Defocus in a Jumping Spider. Science 2012; 335:469-71. [DOI: 10.1126/science.1211667] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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100
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Siegert S, Cabuy E, Scherf BG, Kohler H, Panda S, Le YZ, Fehling HJ, Gaidatzis D, Stadler MB, Roska B. Transcriptional code and disease map for adult retinal cell types. Nat Neurosci 2012; 15:487-95, S1-2. [PMID: 22267162 DOI: 10.1038/nn.3032] [Citation(s) in RCA: 191] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 12/20/2011] [Indexed: 12/17/2022]
Abstract
Brain circuits are assembled from a large variety of morphologically and functionally diverse cell types. It is not known how the intermingled cell types of an individual adult brain region differ in their expressed genomes. Here we describe an atlas of cell type transcriptomes in one brain region, the mouse retina. We found that each adult cell type expressed a specific set of genes, including a unique set of transcription factors, forming a 'barcode' for cell identity. Cell type transcriptomes carried enough information to categorize cells into morphological classes and types. Several genes that were specifically expressed in particular retinal circuit elements, such as inhibitory neuron types, are associated with eye diseases. The resource described here allows gene expression to be compared across adult retinal cell types, experimenting with specific transcription factors to differentiate stem or somatic cells to retinal cell types, and predicting cellular targets of newly discovered disease-associated genes.
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Affiliation(s)
- Sandra Siegert
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
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