1
|
Zhang L, Malkemper EP. Cryptochromes in mammals: a magnetoreception misconception? Front Physiol 2023; 14:1250798. [PMID: 37670767 PMCID: PMC10475740 DOI: 10.3389/fphys.2023.1250798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/01/2023] [Indexed: 09/07/2023] Open
Abstract
Cryptochromes are flavoproteins related to photolyases that are widespread throughout the plant and animal kingdom. They govern blue light-dependent growth in plants, control circadian rhythms in a light-dependent manner in invertebrates, and play a central part in the circadian clock in vertebrates. In addition, cryptochromes might function as receptors that allow animals to sense the Earth's magnetic field. As cryptochromes are also present in mammals including humans, the possibility of a magnetosensitive protein is exciting. Here we attempt to provide a concise overview of cryptochromes in mammals. We briefly review their canonical role in the circadian rhythm from the molecular level to physiology, behaviour and diseases. We then discuss their disputed light sensitivity and proposed role in the magnetic sense in mammals, providing three mechanistic hypotheses. Specifically, mammalian cryptochromes could form light-induced radical pairs in particular cellular milieus, act as magnetoreceptors in darkness, or as secondary players in a magnetoreception signalling cascade. Future research can test these hypotheses to investigate if the role of mammalian cryptochromes extends beyond the circadian clock.
Collapse
Affiliation(s)
| | - E. Pascal Malkemper
- Max Planck Research Group Neurobiology of Magnetoreception, Max Planck Institute for Neurobiology of Behavior—caesar, Bonn, Germany
| |
Collapse
|
2
|
Bhoi JD, Goel M, Ribelayga CP, Mangel SC. Circadian clock organization in the retina: From clock components to rod and cone pathways and visual function. Prog Retin Eye Res 2023; 94:101119. [PMID: 36503722 PMCID: PMC10164718 DOI: 10.1016/j.preteyeres.2022.101119] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 08/22/2022] [Accepted: 08/25/2022] [Indexed: 12/13/2022]
Abstract
Circadian (24-h) clocks are cell-autonomous biological oscillators that orchestrate many aspects of our physiology on a daily basis. Numerous circadian rhythms in mammalian and non-mammalian retinas have been observed and the presence of an endogenous circadian clock has been demonstrated. However, how the clock and associated rhythms assemble into pathways that support and control retina function remains largely unknown. Our goal here is to review the current status of our knowledge and evaluate recent advances. We describe many previously-observed retinal rhythms, including circadian rhythms of morphology, biochemistry, physiology, and gene expression. We evaluate evidence concerning the location and molecular machinery of the retinal circadian clock, as well as consider findings that suggest the presence of multiple clocks. Our primary focus though is to describe in depth circadian rhythms in the light responses of retinal neurons with an emphasis on clock control of rod and cone pathways. We examine evidence that specific biochemical mechanisms produce these daily light response changes. We also discuss evidence for the presence of multiple circadian retinal pathways involving rhythms in neurotransmitter activity, transmitter receptors, metabolism, and pH. We focus on distinct actions of two dopamine receptor systems in the outer retina, a dopamine D4 receptor system that mediates circadian control of rod/cone gap junction coupling and a dopamine D1 receptor system that mediates non-circadian, light/dark adaptive regulation of gap junction coupling between horizontal cells. Finally, we evaluate the role of circadian rhythmicity in retinal degeneration and suggest future directions for the field of retinal circadian biology.
Collapse
Affiliation(s)
- Jacob D Bhoi
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, UTHEALTH-The University of Texas Health Science Center at Houston, Houston, TX, USA; Neuroscience Honors Research Program, William Marsh Rice University, Houston, TX, USA
| | - Manvi Goel
- Department of Neuroscience, Wexner Medical Center, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Christophe P Ribelayga
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, UTHEALTH-The University of Texas Health Science Center at Houston, Houston, TX, USA; Neuroscience Honors Research Program, William Marsh Rice University, Houston, TX, USA.
| | - Stuart C Mangel
- Department of Neuroscience, Wexner Medical Center, College of Medicine, The Ohio State University, Columbus, OH, USA.
| |
Collapse
|
3
|
Kyriacou CP, Rosato E. Genetic analysis of cryptochrome in insect magnetosensitivity. Front Physiol 2022; 13:928416. [PMID: 36035470 PMCID: PMC9399412 DOI: 10.3389/fphys.2022.928416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 07/05/2022] [Indexed: 11/18/2022] Open
Abstract
The earth's magnetic field plays an important role in the spectacular migrations and navigational abilities of many higher animals, particularly birds. However, these organisms are not amenable to genetic analysis, unlike the model fruitfly, Drosophila melanogaster, which can respond to magnetic fields under laboratory conditions. We therefore review the field of insect magnetosensitivity focusing on the role of the Cryptochromes (CRYs) that were first identified in Arabidopsis and Drosophila as key molecular components of circadian photo-entrainment pathways. Physico-chemical studies suggest that photo-activation of flavin adenine dinucleotide (FAD) bound to CRY generates a FADo- Trpo+ radical pair as electrons skip along a chain of specific Trp residues and that the quantum spin chemistry of these radicals is sensitive to magnetic fields. The manipulation of CRY in several insect species has been performed using gene editing, replacement/rescue and knockdown methods. The effects of these various mutations on magnetosensitivity have revealed a number of surprises that are discussed in the light of recent developments from both in vivo and in vitro studies.
Collapse
Affiliation(s)
- Charalambos P. Kyriacou
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | | |
Collapse
|
4
|
Human magnetic sense is mediated by a light and magnetic field resonance-dependent mechanism. Sci Rep 2022; 12:8997. [PMID: 35637212 PMCID: PMC9151822 DOI: 10.1038/s41598-022-12460-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 05/10/2022] [Indexed: 11/13/2022] Open
Abstract
Numerous organisms use the Earth’s magnetic field as a sensory cue for migration, body alignment, or food search. Despite some contradictory reports, yet it is generally accepted that humans do not sense the geomagnetic field. Here, we demonstrate that a magnetic field resonance mechanism mediates light-dependent magnetic orientation in men, using a rotary chair experiment combined with a two-alternative forced choice paradigm. Two groups of subjects were classified with different magnetic orientation tendencies depending on the food context. Magnetic orientation of the subjects was sensitive to the wavelength of incident light and was critically dependent on blue light reaching the eyes. Importantly, it appears that a magnetic field resonance-dependent mechanism mediates these responses, as evidenced by disruption or augmentation of the ability to orient by radiofrequency magnetic fields at the Larmor frequency and the dependence of these effects on the angle between the radiofrequency and geomagnetic fields. Furthermore, inversion of the vertical component of the geomagnetic field revealed a non-canonical inclination compass effect on the magnetic orientation. These results establish the existence of a human magnetic sense and suggest an underlying quantum mechanical magnetoreception mechanism.
Collapse
|
5
|
Einwich A, Seth PK, Bartölke R, Bolte P, Feederle R, Dedek K, Mouritsen H. Localisation of cryptochrome 2 in the avian retina. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 208:69-81. [PMID: 34677638 PMCID: PMC8918457 DOI: 10.1007/s00359-021-01506-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 08/13/2021] [Accepted: 08/19/2021] [Indexed: 12/12/2022]
Abstract
Cryptochromes are photolyase-related blue-light receptors acting as core components of the mammalian circadian clock in the cell nuclei. One or more members of the cryptochrome protein family are also assumed to play a role in avian magnetoreception, but the primary sensory molecule in the retina of migratory birds that mediates light-dependent magnetic compass orientation has still not been identified. The mRNA of cryptochrome 2 (Cry2) has been reported to be located in the cell nuclei of the retina, but Cry2 localisation has not yet been demonstrated at the protein level. Here, we provide evidence that Cry2 protein is located in the photoreceptor inner segments, the outer nuclear layer, the inner nuclear layer and the ganglion cell layer in the retina of night-migratory European robins, homing pigeons and domestic chickens. At the subcellular level, we find Cry2 both in the cytoplasm and the nucleus of cells residing in these layers. This broad nucleic expression rather points to a role for avian Cry2 in the circadian clock and is consistent with a function as a transcription factor, analogous to mammalian Cry2, and speaks against an involvement in magnetoreception.
Collapse
Affiliation(s)
- Angelika Einwich
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Pranav Kumar Seth
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Rabea Bartölke
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Petra Bolte
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Regina Feederle
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility, Neuherberg, Germany
| | - Karin Dedek
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.,Research Centre for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Henrik Mouritsen
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany. .,Research Centre for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.
| |
Collapse
|
6
|
Brain-to-brain communication: the possible role of brain electromagnetic fields (As a Potential Hypothesis). Heliyon 2021; 7:e06363. [PMID: 33732922 PMCID: PMC7937662 DOI: 10.1016/j.heliyon.2021.e06363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 12/29/2020] [Accepted: 02/22/2021] [Indexed: 11/23/2022] Open
Abstract
Up now, the communication between brains of different humans or animals has been confirmed and confined by the sensory medium and motor facilities of body. Recently, direct brain-to-brain communication (DBBC) outside the conventional five senses has been verified between animals and humans. Nevertheless, no empirical studies or serious discussion have been performed to elucidate the mechanism behind this process. The validation of DBBC has been documented via recording similar pattern of action potentials occurring in the brain cortex of two animals. With regard to action potentials in brain neurons, the magnetic field resulting from the action potentials created in neurons is one of the tools where the brain of one animal can affect the brain of another. It has been shown that different animals, even humans, have the power to understand the magnetic field. Cryptochrome, which exists in the retina and in different regions of the brain, has been confirmed to be able to perceive magnetic fields and convert magnetic fields to action potentials. Recently, iron particles (Fe3O4) believed to be functioning as magnets have been found in various parts of the brain, and are postulated as magnetic field receptors. Newly developed supersensitive magnetic sensors made of iron magnets that can sense the brain's magnetic field have suggested the idea that these Fe3O4 particles or magnets may be capable of perceiving the brain's extremely weak magnetic field. The present study suggests that it is possible the extremely week magnetic field in one animal's brain to transmit vital and accurate information to another animal's brain.
Collapse
|
7
|
Vanderstraeten J, Gailly P, Malkemper EP. Light entrainment of retinal biorhythms: cryptochrome 2 as candidate photoreceptor in mammals. Cell Mol Life Sci 2020; 77:875-884. [PMID: 31982933 PMCID: PMC11104904 DOI: 10.1007/s00018-020-03463-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 01/08/2020] [Accepted: 01/14/2020] [Indexed: 12/31/2022]
Abstract
The mechanisms that synchronize the biorhythms of the mammalian retina with the light/dark cycle are independent of those synchronizing the rhythms in the central pacemaker, the suprachiasmatic nucleus. The identity of the photoreceptor(s) responsible for the light entrainment of the retina of mammals is still a matter of debate, and recent studies have reported contradictory results in this respect. Here, we suggest that cryptochromes (CRY), in particular CRY 2, are involved in that light entrainment. CRY are highly conserved proteins that are a key component of the cellular circadian clock machinery. In plants and insects, they are responsible for the light entrainment of these biorhythms, mediated by the light response of their flavin cofactor (FAD). In mammals, however, no light-dependent role is currently assumed for CRY in light-exposed tissues, including the retina. It has been reported that FAD influences the function of mammalian CRY 2 and that human CRY 2 responds to light in Drosophila, suggesting that mammalian CRY 2 keeps the ability to respond to light. Here, we hypothesize that CRY 2 plays a role in the light entrainment of retinal biorhythms, at least in diurnal mammals. Indeed, published data shows that the light intensity dependence and the wavelength sensitivity commonly reported for that light entrainment fits the light sensitivity and absorption spectrum of light-responsive CRY. We propose experiments to test our hypothesis and to further explore the still-pending question of the function of CRY 2 in the mammalian retina.
Collapse
Affiliation(s)
- Jacques Vanderstraeten
- Faculty of Medicine, School of Public Health, Environmental and Work Health Research Center, Université Libre de Bruxelles, CP593, Route de Lennik, 808, 1070, Brussels, Belgium.
- , Avenue Constant Montald, 11, 1200, Brussels, Belgium.
| | - Philippe Gailly
- Faculty of Medicine, Institute of Neuroscience (IONS), Cellular and Molecular Pole (CEMO), Catholic University of Louvain, Avenue Mounier 53/B1.53.17, 1200, Brussels, Belgium
| | - E Pascal Malkemper
- Center of Advanced European Studies and Research (CAESAR), Ludwig-Erhard-Allee 2, Bonn, 53175, Germany
| |
Collapse
|
8
|
Nitta Y, Matsui S, Kato Y, Kaga Y, Sugimoto K, Sugie A. Analysing the evolutional and functional differentiation of four types of Daphnia magna cryptochrome in Drosophila circadian clock. Sci Rep 2019; 9:8857. [PMID: 31222139 PMCID: PMC6586792 DOI: 10.1038/s41598-019-45410-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 06/06/2019] [Indexed: 12/02/2022] Open
Abstract
Cryptochrome (CRY) plays an important role in the input of circadian clocks in various species, but gene copies in each species are evolutionarily divergent. Type I CRYs function as a photoreceptor molecule in the central clock, whereas type II CRYs directly regulate the transcriptional activity of clock proteins. Functions of other types of animal CRYs in the molecular clock remain unknown. The water flea Daphnia magna contains four Cry genes. However, it is still difficult to analyse these four genes. In this study, we took advantage of powerful genetic resources available from Drosophila to investigate evolutionary and functional differentiation of CRY proteins between the two species. We report differences in subcellular localisation of each D. magna CRY protein when expressed in the Drosophila clock neuron. Circadian rhythm behavioural experiments revealed that D. magna CRYs are not functionally conserved in the Drosophila molecular clock. These findings provide a new perspective on the evolutionary conservation of CRY, as functions of the four D. magna CRY proteins have diverse subcellular localisation levels. Furthermore, molecular clocks of D. magna have been evolutionarily differentiated from those of Drosophila. This study highlights the extensive functional diversity existing among species in their complement of Cry genes.
Collapse
Affiliation(s)
- Yohei Nitta
- Center for Transdisciplinary Research, Niigata University, Niigata, Japan
- Brain Research Institute, Niigata University, Niigata, Japan
| | - Sayaka Matsui
- Department of Cell Science, Faculty of Graduate School of Science and Technology, Niigata University, Niigata, Japan
| | - Yukine Kato
- Department of Cell Science, Faculty of Graduate School of Science and Technology, Niigata University, Niigata, Japan
| | - Yosuke Kaga
- School of Medicine, Niigata University, Niigata, Japan
| | - Kenkichi Sugimoto
- Department of Cell Science, Faculty of Graduate School of Science and Technology, Niigata University, Niigata, Japan.
| | - Atsushi Sugie
- Center for Transdisciplinary Research, Niigata University, Niigata, Japan.
- Brain Research Institute, Niigata University, Niigata, Japan.
| |
Collapse
|
9
|
Abstract
Circadian oscillators are networks of biochemical feedback loops that generate 24-hour rhythms in organisms from bacteria to animals. These periodic rhythms result from a complex interplay among clock components that are specific to the organism, but share molecular mechanisms across kingdoms. A full understanding of these processes requires detailed knowledge, not only of the biochemical properties of clock proteins and their interactions, but also of the three-dimensional structure of clockwork components. Posttranslational modifications and protein–protein interactions have become a recent focus, in particular the complex interactions mediated by the phosphorylation of clock proteins and the formation of multimeric protein complexes that regulate clock genes at transcriptional and translational levels. This review covers the structural aspects of circadian oscillators, and serves as a primer for this exciting realm of structural biology.
Collapse
Affiliation(s)
- Reena Saini
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland.,Max-Planck-Institut für Pflanzenzüchtungsforschung, Cologne, Germany
| | - Mariusz Jaskolski
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland.,Department of Crystallography, Faculty of Chemistry, A. Mickiewicz University, Poznan, Poland
| | - Seth J Davis
- Max-Planck-Institut für Pflanzenzüchtungsforschung, Cologne, Germany. .,Department of Biology, University of York, York, UK.
| |
Collapse
|
10
|
Chae KS, Oh IT, Lee SH, Kim SC. Blue light-dependent human magnetoreception in geomagnetic food orientation. PLoS One 2019; 14:e0211826. [PMID: 30763322 PMCID: PMC6375564 DOI: 10.1371/journal.pone.0211826] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 01/22/2019] [Indexed: 02/03/2023] Open
Abstract
The Earth's geomagnetic field (GMF) is known to influence magnetoreceptive creatures, from bacteria to mammals as a sensory cue or a physiological modulator, despite it is largely thought that humans cannot sense the GMF. Here, we show that humans sense the GMF to orient their direction toward food in a self-rotatory chair experiment. Starved men, but not women, significantly oriented toward the ambient/modulated magnetic north or east, directions which had been previously food-associated, without any other helpful cues, including sight and sound. The orientation was reproduced under blue light but was abolished under a blindfold or a longer wavelength light (> 500 nm), indicating that blue light is necessary for magnetic orientation. Importantly, inversion of the vertical component of the GMF resulted in orientation toward the magnetic south and blood glucose levels resulting from food appeared to act as a motivator for sensing a magnetic field direction. The results demonstrate that male humans sense GMF in a blue light-dependent manner and suggest that the geomagnetic orientations are mediated by an inclination compass.
Collapse
Affiliation(s)
- Kwon-Seok Chae
- Department of Biology Education Kyungpook National University, Daegu, Republic of Korea
- Department of Nanoscience & Nanotechnology, Kyungpook National University, Daegu, Republic of Korea
- Brain Science and Engineering Institute, Kyungpook National University, Daegu, Republic of Korea
| | - In-Taek Oh
- Department of Biology Education Kyungpook National University, Daegu, Republic of Korea
| | - Sang-Hyup Lee
- Department of Biology Education Kyungpook National University, Daegu, Republic of Korea
| | - Soo-Chan Kim
- Department of Electrical and Electronic Engineering, Institute for IT Convergence, Hankyong National University, Anseong, Republic of Korea
| |
Collapse
|
11
|
Nikkola V, Miettinen ME, Karisola P, Grönroos M, Ylianttila L, Alenius H, Snellman E, Partonen T. Ultraviolet B radiation modifies circadian time in epidermal skin and in subcutaneous adipose tissue. PHOTODERMATOLOGY PHOTOIMMUNOLOGY & PHOTOMEDICINE 2018; 35:157-163. [PMID: 30472764 DOI: 10.1111/phpp.12440] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 11/01/2018] [Accepted: 11/20/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND Recent findings suggest that circadian time regulates cellular functions in the skin and may affect protection against ultraviolet radiation (UVR). It is not known, however, whether UVR through skin directly affects the expression of circadian genes. We investigated the effect of ultraviolet B (UVB) exposure on cryptochrome circadian clock 1 (CRY1), cryptochrome circadian clock 2 (CRY2), and circadian associated repressor of transcription (CIART) genes. METHODS Healthy volunteers (n = 12) were exposed to narrow-band UVB radiation of four standard erythemal dose (SED). Epidermal/dermal and subcutaneous adipose tissue samples were obtained by punch biopsies from irradiated and non-irradiated skin 10 cm away from the irradiated site 24 hours after UVB exposure. Gene expression of CRY1, CRY2, and CIART was measured using RT-PCR (TaqMan). RESULTS Ultraviolet B radiation affected mRNA expression in the epidermal/dermal skin and in the subcutaneous adipose tissue. It down-regulated expression of CRY2 gene in the epidermal/dermal skin, whereas it up-regulated expression of CRY1 and CIART genes in the subcutaneous adipose tissue. CONCLUSION We showed for the first time that UVB radiation affects expression of circadian genes in the subcutaneous adipose tissue. Further studies are warranted to understand the mechanisms in detail.
Collapse
Affiliation(s)
- Veera Nikkola
- Department of Dermatology and Venereology, Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland.,Department of Dermatology and Allergology, Tampere University Hospital, Tampere, Finland.,Department of Dermatology and Allergology, Päijät-Häme Social and Health Care Group, Lahti, Finland
| | - Maija E Miettinen
- Department of Public Health Solutions, National Institute for Health and Welfare, Helsinki, Finland
| | - Piia Karisola
- Department of Bacteriology and Immunology, Faculty of Medicine, Medicum, University of Helsinki, Helsinki, Finland
| | - Mari Grönroos
- Department of Dermatology and Allergology, Päijät-Häme Social and Health Care Group, Lahti, Finland
| | - Lasse Ylianttila
- STUK - Radiation and Nuclear Safety Authority, Helsinki, Finland
| | - Harri Alenius
- Department of Bacteriology and Immunology, Faculty of Medicine, Medicum, University of Helsinki, Helsinki, Finland.,Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Erna Snellman
- Department of Dermatology and Venereology, Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland.,Department of Dermatology and Allergology, Tampere University Hospital, Tampere, Finland
| | - Timo Partonen
- Department of Public Health Solutions, National Institute for Health and Welfare, Helsinki, Finland
| |
Collapse
|
12
|
Schlichting M, Rieger D, Cusumano P, Grebler R, Costa R, Mazzotta GM, Helfrich-Förster C. Cryptochrome Interacts With Actin and Enhances Eye-Mediated Light Sensitivity of the Circadian Clock in Drosophila melanogaster. Front Mol Neurosci 2018; 11:238. [PMID: 30072870 PMCID: PMC6058042 DOI: 10.3389/fnmol.2018.00238] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 06/19/2018] [Indexed: 11/13/2022] Open
Abstract
Cryptochromes (CRYs) are a class of flavoproteins that sense blue light. In animals, CRYs are expressed in the eyes and in the clock neurons that control sleep/wake cycles and are implied in the generation and/or entrainment of circadian rhythmicity. Moreover, CRYs are sensing magnetic fields in insects as well as in humans. Here, we show that in the fruit fly Drosophila melanogaster CRY plays a light-independent role as "assembling" protein in the rhabdomeres of the compound eyes. CRY interacts with actin and appears to increase light sensitivity of the eyes by keeping the "signalplex" of the phototransduction cascade close to the membrane. By this way, CRY also enhances light-responses of the circadian clock.
Collapse
Affiliation(s)
- Matthias Schlichting
- Neurobiology and Genetics, Biocenter, Theodor-Boveri-Institute, University of Würzburg, Würzburg, Germany
- Howard Hughes Medical Institute and National Center for Behavioral Genomics, Department of Biology, Brandeis University, Waltham, MA, United States
| | - Dirk Rieger
- Neurobiology and Genetics, Biocenter, Theodor-Boveri-Institute, University of Würzburg, Würzburg, Germany
| | - Paola Cusumano
- Department of Biology, University of Padova, Padova, Italy
| | - Rudi Grebler
- Neurobiology and Genetics, Biocenter, Theodor-Boveri-Institute, University of Würzburg, Würzburg, Germany
| | - Rodolfo Costa
- Department of Biology, University of Padova, Padova, Italy
| | | | - Charlotte Helfrich-Förster
- Neurobiology and Genetics, Biocenter, Theodor-Boveri-Institute, University of Würzburg, Würzburg, Germany
| |
Collapse
|
13
|
Thoss F, Bartsch B. A model of the FAD redox cycle describes the dynamics of the effect of the geomagnetic field on the human visual system. BIOLOGICAL CYBERNETICS 2017; 111:347-352. [PMID: 28776258 DOI: 10.1007/s00422-017-0725-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 07/27/2017] [Indexed: 06/07/2023]
Abstract
In experimental studies, we could show that the visual threshold of man is influenced by the geomagnetic field. One of the results was that the threshold shows periodic fluctuations when the vertical component of the field is reversed periodically. The maximum of these oscillations occurred at a period duration of 110 s. To explain this phenomenon, we chose the process that likely underlies the navigation of birds in the geomagnetic field: the light reaction of the FAD component of cryptochrome in the retina. The human retina contains cryptpochrome like the bird retina. Based on the investigations of Müller and Ahmad (J Biol Chem 286:21033-21040, 2011) and Solov'yov and Schulten (J Phys Chem B 116:1089-1099, 2012), we designed a model of the light-induced reduction and subsequent reoxidation of FAD. This model contains a radical pair, whose interconversion dynamics are affected by the geomagnetic field. The parameters of the model were partly calculated from the data of our experimental investigation and partly taken from the results of other authors. These parameters were then optimized by adjusting the model behaviour to the experimental results. The simulation of the finished model shows that the concentrations of all substances included show really oscillations with the frequency of the modelled magnetic field. After optimization of the parameters, the oscillations of FAD and FADH* show maximal amplitude at a period duration of 110 s, as was observed in the experiment. This makes it most likely that the signal, which influences the visual system, originates from FADH* (signalling state).
Collapse
Affiliation(s)
- Franz Thoss
- Carl-Ludwig-Institute of Physiology, University of Leipzig, Liebigstr. 27, 04103, Leipzig, Germany.
| | - Bengt Bartsch
- Carl-Ludwig-Institute of Physiology, University of Leipzig, Liebigstr. 27, 04103, Leipzig, Germany
| |
Collapse
|
14
|
Thompson CL, Selby CP, Van Gelder RN, Blaner WS, Lee J, Quadro L, Lai K, Gottesman ME, Sancar A. Effect of Vitamin A Depletion on Nonvisual Phototransduction Pathways in Cryptochromeless Mice. J Biol Rhythms 2016; 19:504-17. [PMID: 15523112 DOI: 10.1177/0748730404270519] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Mice exhibit multiple nonvisual responses to light, including 1) photoentrainment of circadian rhythm; 2) “masking,” which refers to the acute effect of light on behavior, either negative (activity suppressing) or positive (activity inducing); and 3) pupillary constriction. In mammals, the eye is the sole photosensory organ for these responses, and it contains only 2 known classes of pigments: opsins and cryptochromes. No individual opsin or cryptochrome gene is essential for circadian photoreception, gene photoinduction, or masking. Previously, the authors found that mice lacking retinol-binding protein, in which dietary depletion of ocular retinaldehyde can be achieved, had normal light signaling to the SCN, as determined by per gene photoinduction. In the present study, the authors analyzed phototransduction to the SCN in vitamin A-replete and vitamin A-depleted rbp-/- and rbp-/-cry1-/-cry2-/- mice using molecular and behavioral end points. They found that vitamin A-depleted rbp-/- mice exhibit either normal photoentrainment or become diurnal. In contrast, while vitamin A-replete rbp-/-cry1-/-cry2-/- mice are light responsive (with reduced sensitivity), vitamin A-depleted rbp-/-cry1-/-cry2-/- mice, which presumably lack functional opsins and cryptochromes, lose most behavioral and molecular responses to light. These data demonstrate that both cryptochromes and opsins regulate nonvisual photoresponses.
Collapse
Affiliation(s)
- Carol L Thompson
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Abstract
Retinas of all classes of vertebrates contain endogenous circadian clocks that control many aspects of retinal physiology, including retinal sensitivity to light, neurohormone synthesis, and cellular events such as rod disk shedding, intracellular signaling pathways, and gene expression. The vertebrate retina is an example of a “peripheral” oscillator that is particularly amenable to study because this tissue is well characterized, the relationships between the various cell types are extensively studied, and many local clock-controlled rhythms are known. Although the existence of a photoreceptor clock is well established in several species, emerging data are consistent with multiple or dual oscillators within the retina that interact to control local physiology. Aprominent example is the antiphasic regulation of melaton in and dopamine in photoreceptors and inner retina, respectively. This review focuses on the similarities and differences in the molecular mechanisms of the retinal versus the SCN oscillators, as well as on the expression of core components of the circadian clockwork in retina. Finally, the interactions between the retinal clock(s) and the master clock in the SCN are examined.
Collapse
Affiliation(s)
- Carla B Green
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA.
| | | |
Collapse
|
16
|
Sancar A. Mechanisms of DNA Repair by Photolyase and Excision Nuclease (Nobel Lecture). Angew Chem Int Ed Engl 2016; 55:8502-27. [PMID: 27337655 DOI: 10.1002/anie.201601524] [Citation(s) in RCA: 177] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Indexed: 01/27/2023]
Abstract
Ultraviolet light damages DNA by converting two adjacent thymines into a thymine dimer which is potentially mutagenic, carcinogenic, or lethal to the organism. This damage is repaired by photolyase and the nucleotide excision repair system in E. coli by nucleotide excision repair in humans. The work leading to these results is presented by Aziz Sancar in his Nobel Lecture.
Collapse
Affiliation(s)
- Aziz Sancar
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA.
| |
Collapse
|
17
|
Sancar A. Mechanismen der DNA-Reparatur durch Photolyasen und Exzisionsnukleasen (Nobel-Aufsatz). Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201601524] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Aziz Sancar
- Department of Biochemistry and Biophysics; University of North Carolina School of Medicine; Chapel Hill North Carolina USA
| |
Collapse
|
18
|
The Potential Role of Flavins and Retbindin in Retinal Function and Homeostasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 854:643-8. [PMID: 26427470 DOI: 10.1007/978-3-319-17121-0_85] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Flavins are highly concentrated in the retina; likely because they are involved as cofactors in energy metabolism and photoreceptors have an extremely high metabolic rate. How this concentration is established is currently unknown, but photoreceptor specific proteins may exist that shuttle flavins to flavoproteins, which may also function in retinal neuron specific processes. It has been suggested due to sequence homology to folate receptors that retbindin could be binding flavins in the retina. Here we present a brief overview of flavins in the retina and initial findings that suggest retbindin may be located in the photoreceptor layer where flavin acquisition from the RPE would occur.
Collapse
|
19
|
Is blue light, cryptochrome in the eye, and magnetite in the brain involved in the development of frontotemporal dementia and other diseases? Med Hypotheses 2015; 84:379-80. [PMID: 25678234 DOI: 10.1016/j.mehy.2015.01.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Revised: 12/01/2014] [Accepted: 01/21/2015] [Indexed: 11/22/2022]
Abstract
When cryptochrome in the retina is exposed to blue light, it undergo series of complicated chemical reactions. One of these intermediates has magnetic properties. It could be a link between the magnetic stage of cryptochrome in the retina and magnetite in the brain. A disturbance in this system could be involved in the development of frontotemporal dementia and other mental disturbances like Alzheimer's disease. There could also be a link between circadian rhythms and memory dysfunction connected to schizophrenia, type 2 diabetes, and blue light.
Collapse
|
20
|
Haug MF, Gesemann M, Lazović V, Neuhauss SCF. Eumetazoan cryptochrome phylogeny and evolution. Genome Biol Evol 2015; 7:601-19. [PMID: 25601102 PMCID: PMC4350181 DOI: 10.1093/gbe/evv010] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cryptochromes (Crys) are light sensing receptors that are present in all eukaryotes. They mainly absorb light in the UV/blue spectrum. The extant Crys consist of two subfamilies, which are descendants of photolyases but are now involved in the regulation of circadian rhythms. So far, knowledge about the evolution, phylogeny, and expression of cry genes is still scarce. The inclusion of cry sequences from a wide range of bilaterian species allowed us to analyze their phylogeny in detail, identifying six major Cry subgroups. Selective gene inactivations and stabilizations in multiple chordate as well as arthropod lineages suggest several sub- and/or neofunctionalization events. An expression study performed in zebrafish, the model organism harboring the largest amount of crys, showed indeed only partially overlapping expression of paralogous mRNA, supporting gene sub- and/or neofunctionalization. Moreover, the daily cry expression in the adult zebrafish retina indicated varying oscillation patterns in different cell types. Our extensive phylogenetic analysis provides for the first time an overview of cry evolutionary history. Although several, especially parasitic or blind species, have lost all cry genes, crustaceans have retained up to three crys, teleosts possess up to seven, and tetrapods up to four crys. The broad and cyclic expression pattern of all cry transcripts in zebrafish retinal layers implies an involvement in retinal circadian processes and supports the hypothesis of several autonomous circadian clocks present in the vertebrate retina.
Collapse
Affiliation(s)
- Marion F Haug
- Institute of Molecular Life Sciences, Neuroscience Center Zurich and Center for Integrative Human Physiology, University of Zurich, Switzerland
| | - Matthias Gesemann
- Institute of Molecular Life Sciences, Neuroscience Center Zurich and Center for Integrative Human Physiology, University of Zurich, Switzerland
| | - Viktor Lazović
- Institute of Molecular Life Sciences, Neuroscience Center Zurich and Center for Integrative Human Physiology, University of Zurich, Switzerland
| | - Stephan C F Neuhauss
- Institute of Molecular Life Sciences, Neuroscience Center Zurich and Center for Integrative Human Physiology, University of Zurich, Switzerland
| |
Collapse
|
21
|
Kelley RA, Al-Ubaidi MR, Naash MI. Retbindin is an extracellular riboflavin-binding protein found at the photoreceptor/retinal pigment epithelium interface. J Biol Chem 2014; 290:5041-5052. [PMID: 25542898 DOI: 10.1074/jbc.m114.624189] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Retbindin is a novel retina-specific protein of unknown function. In this study, we have used various approaches to evaluate protein expression, localization, biochemical properties, and function. We find that retbindin is secreted by the rod photoreceptors into the inter-photoreceptor matrix where it is maintained via electrostatic forces. Retbindin is predominantly localized at the interface between photoreceptors and retinal pigment epithelium microvilli, a region critical for retinal function and homeostasis. Interestingly, although it is associated with photoreceptor outer segments, retbindin's expression is not dependent on their presence. In vitro, retbindin is capable of binding riboflavin, thus implicating the protein as a metabolite carrier between the retina and the retinal pigment epithelium. Altogether, our data show that retbindin is a novel photoreceptor-specific protein with a unique localization and function. We hypothesize that retbindin is an excellent candidate for binding retinal flavins and possibly participating in their transport from the extracellular space to the photoreceptors. Further investigations are warranted to determine the exact function of retbindin in retinal homeostasis and disease.
Collapse
Affiliation(s)
- Ryan A Kelley
- From the Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Muayyad R Al-Ubaidi
- From the Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Muna I Naash
- From the Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104.
| |
Collapse
|
22
|
Avitabile D, Genovese L, Ponti D, Ranieri D, Raffa S, Calogero A, Torrisi MR. Nucleolar localization and circadian regulation of Per2S, a novel splicing variant of the Period 2 gene. Cell Mol Life Sci 2014; 71:2547-59. [PMID: 24202686 PMCID: PMC11113094 DOI: 10.1007/s00018-013-1503-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 09/26/2013] [Accepted: 10/17/2013] [Indexed: 12/14/2022]
Abstract
In this work, we show for the first time that a second splicing variant of the core clock gene Period 2 (Per2), Per2S, is expressed at both the mRNA and protein levels in human keratinocytes and that it localizes in the nucleoli. Moreover, we show that a reversible perturbation of the nucleolar structure acts as a resetting stimulus for the cellular clock. Per2S expression and periodic oscillation upon dexamethasone treatment were assessed by qRT-PCR using specific primers. Western blot (WB) analysis using an antibody against the recombinant human PER2 (abRc) displayed an intense band at a molecular weight of ~55 kDa, close to the predicted size of Per2S, and a weaker band at the expected size of Per2 (~140 kDa). The antibody raised against PER2 pS662 (abS662), an epitope absent in PER2S, detected only the higher band. Immunolocalization studies with abRc revealed a peculiar nucleolar signal colocalizing with the nucleolar marker nucleophosmin, whereas with abS662 the signal was predominantly diffuse all over the nucleus and partially colocalized with abRc in the nucleolus. The analysis of cell fractions by WB confirmed the enrichment of PER2S and the presence of PER2 in the nucleolar compartment. Finally, a pulse (1 h) of actinomycin D (0.01 μg/ml) induced reversible nucleolar disruption, PER2S de-localization and circadian synchronization of clock and Per2S genes. Our work represents the first evidence that the Per2S splicing isoform is a clock component expressed in human cells localizing in the nucleolus. These results suggest a critical role for the nucleolus in the process of circadian synchronization in human keratinocytes.
Collapse
Affiliation(s)
- Daniele Avitabile
- Department of Clinical and Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Via di Grottarossa 1035, 00189, Rome, Italy,
| | | | | | | | | | | | | |
Collapse
|
23
|
Abstract
Cryptochromes are flavoproteins, structurally and evolutionarily related to photolyases, that are involved in the development, magnetoreception, and temporal organization of a variety of organisms. Drosophila CRYPTOCHROME (dCRY) is involved in light synchronization of the master circadian clock, and its C terminus plays an important role in modulating light sensitivity and activity of the protein. The activation of dCRY by light requires a conformational change, but it has been suggested that activation could be mediated also by specific "regulators" that bind the C terminus of the protein. This C-terminal region harbors several protein-protein interaction motifs, likely relevant for signal transduction regulation. Here, we show that some functional linear motifs are evolutionarily conserved in the C terminus of cryptochromes and that class III PDZ-binding sites are selectively maintained in animals. A coimmunoprecipitation assay followed by mass spectrometry analysis revealed that dCRY interacts with Retinal Degeneration A (RDGA) and with Neither Inactivation Nor Afterpotential C (NINAC) proteins. Both proteins belong to a multiprotein complex (the Signalplex) that includes visual-signaling molecules. Using bioinformatic and molecular approaches, dCRY was found to interact with Neither Inactivation Nor Afterpotential C through Inactivation No Afterpotential D (INAD) in a light-dependent manner and that the CRY-Inactivation No Afterpotential D interaction is mediated by specific domains of the two proteins and involves the CRY C terminus. Moreover, an impairment of the visual behavior was observed in fly mutants for dCRY, indicative of a role, direct or indirect, for this photoreceptor in fly vision.
Collapse
|
24
|
Close J. Are stress responses to geomagnetic storms mediated by the cryptochrome compass system? Proc Biol Sci 2012; 279:2081-90. [PMID: 22418257 DOI: 10.1098/rspb.2012.0324] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
A controversial body of literature demonstrates associations of geomagnetic storms (GMS) with numerous cardiovascular, psychiatric and behavioural outcomes. Various melatonin hypotheses of GMS have suggested that temporal variation in the geomagnetic field (GMF) may be acting as an additional zeitgeber (a temporal synchronizer) for circadian rhythms, with GMS somehow interfering with the hypothesized system. The cryptochrome genes are known primarily as key components of the circadian pacemaker, ultimately involved in controlling the expression of the hormone melatonin. Cryptochrome is identified as a clear candidate for mediating the effect of GMS on humans, demonstrating the prior existence of several crucial pieces of evidence. A distinct scientific literature demonstrates the widespread use of geomagnetic information for navigation across a range of taxa. One mechanism of magnetoreception is thought to involve a light-dependent retinal molecular system mediated by cryptochrome, acting in a distinct functionality to its established role as a circadian oscillator. There is evidence suggesting that such a magnetosense--or at least the vestiges of it--may exist in humans. This paper argues that cryptochrome is not acting as secondary geomagnetic zeitgeber to influence melatonin synthesis. Instead, it is hypothesized that the cryptochrome compass system is mediating stress responses more broadly across the hypothalamic-pituitary-adrenal (HPA) axis (including alterations to circadian behaviour) in response to changes in the GMF. Two conceptual models are outlined for the existence of such responses--the first as a generalized migrational/dispersal strategy, the second as a stress response to unexpected signals to the magnetosense. It is therefore proposed that GMS lead to disorientation of hormonal systems in animals and humans, thus explaining the effects of GMS on human health and behaviour.
Collapse
|
25
|
Owens L, Buhr E, Tu DC, Lamprecht TL, Lee J, Van Gelder RN. Effect of circadian clock gene mutations on nonvisual photoreception in the mouse. Invest Ophthalmol Vis Sci 2012; 53:454-60. [PMID: 22159024 DOI: 10.1167/iovs.11-8717] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Mice lacking rods and cones retain pupillary light reflexes that are mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs). Melanopsin is necessary and sufficient for this nonvisual photoreception. The mammalian inner retina also expresses the potential blue light photopigments cryptochromes 1 and 2. Previous studies have shown that outer retinal degenerate mice lacking cryptochromes have lower nonvisual photic sensitivity than retinal degenerate mice, suggesting a role for cryptochrome in inner retinal photoreception. METHODS Nonvisual photoreception (pupillary light responses, circadian entrainment, and in vitro sensitivity of intrinsically photosensitive retinal ganglion cells) were studied in wild-type, rd/rd, and circadian clock-mutant mice with and without rd/rd mutation. RESULTS Loss of cryptochrome in retinal degenerate mice reduces the sensitivity of the pupillary light response at all wavelengths but does not alter the form of the action spectrum, suggesting that cryptochrome does not function as a photopigment in the inner retina. The authors compounded the rd/rd retinal degeneration mutation with mutations in other essential circadian clock genes, mPeriod and Bmal1. Both mPeriod1⁻/⁻; mPeriod2⁻/⁻;rd/rd and Bmal1⁻/⁻;rd/rd mice showed significantly lower pupillary light sensitivity than rd/rd mice alone. A moderate amplitude (0.5 log) circadian rhythm of pupillary light responsiveness was observed in rd/rd mice. Multielectrode array recordings of ipRGC responses of mCryptochrome1⁻/⁻;mCryptochrome2⁻/⁻ and mPeriod1⁻/⁻;mPeriod2⁻/⁻ mice showed minimal sensitivity decrement compared with wild-type animals. mCryptochrome1⁻/⁻;mCryptochrome2⁻/⁻;rd/rd, mPeriod1⁻/⁻;mPeriod2⁻/⁻;rd/rd and Bmal1⁻/⁻;rd/rd mice all showed comparable weak behavioral synchronization to a 12-hour light/12-hour dark cycle. CONCLUSIONS The effect of cryptochrome loss on nonvisual photoreception is due to loss of the circadian clock nonspecifically. The circadian clock modulates the sensitivity of nonvisual photoreception.
Collapse
Affiliation(s)
- Leah Owens
- Department of Ophthalmology and Visual Sciences, Washington University Medical School, St. Louis, Missouri, USA
| | | | | | | | | | | |
Collapse
|
26
|
Foley LE, Gegear RJ, Reppert SM. Human cryptochrome exhibits light-dependent magnetosensitivity. Nat Commun 2011; 2:356. [PMID: 21694704 PMCID: PMC3128388 DOI: 10.1038/ncomms1364] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 05/24/2011] [Indexed: 11/18/2022] Open
Abstract
Humans are not believed to have a magnetic sense, even though many animals use the Earth's magnetic field for orientation and navigation. One model of magnetosensing in animals proposes that geomagnetic fields are perceived by light-sensitive chemical reactions involving the flavoprotein cryptochrome (CRY). Here we show using a transgenic approach that human CRY2, which is heavily expressed in the retina, can function as a magnetosensor in the magnetoreception system of Drosophila and that it does so in a light-dependent manner. The results show that human CRY2 has the molecular capability to function as a light-sensitive magnetosensor and reopen an area of sensory biology that is ready for further exploration in humans.
Collapse
Affiliation(s)
- Lauren E. Foley
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Robert J. Gegear
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
- Present address: Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, USA
| | - Steven M. Reppert
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| |
Collapse
|
27
|
Abstract
Mammalian circadian rhythms are controlled by endogenous biological oscillators, including a master clock located in the hypothalamic suprachiasmatic nuclei (SCN). Since the period of this oscillation is of approximately 24 h, to keep synchrony with the environment, circadian rhythms need to be entrained daily by means of Zeitgeber ("time giver") signals, such as the light-dark cycle. Recent advances in the neurophysiology and molecular biology of circadian rhythmicity allow a better understanding of synchronization. In this review we cover several aspects of the mechanisms for photic entrainment of mammalian circadian rhythms, including retinal sensitivity to light by means of novel photopigments as well as circadian variations in the retina that contribute to the regulation of retinal physiology. Downstream from the retina, we examine retinohypothalamic communication through neurotransmitter (glutamate, aspartate, pituitary adenylate cyclase-activating polypeptide) interaction with SCN receptors and the resulting signal transduction pathways in suprachiasmatic neurons, as well as putative neuron-glia interactions. Finally, we describe and analyze clock gene expression and its importance in entrainment mechanisms, as well as circadian disorders or retinal diseases related to entrainment deficits, including experimental and clinical treatments.
Collapse
Affiliation(s)
- Diego A Golombek
- Laboratory of Chronobiology, Department of Science and Technology, University of Quilmes/Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Quilmes, Argentina.
| | | |
Collapse
|
28
|
Abstract
Rodents blind from outer retinal (rod and cone) degeneration still retain several light-dependent phenomena, including entrainment of the circadian clock and pupillary light responsiveness. This paradox is explained by the presence of intrinsically photosensitive retinal ganglion cells in the inner retina. These cells have unique properties, including a novel action spectrum, resistance to bleaching and adaptation under continuous light, and resistance to vitamin A depletion. Two candidate classes of photopigment have been proposed: melanopsin and cryptochromes. Physiologic analysis of circadian entrainment and pupillary light responsiveness in mice lacking these proteins leads to three conclusions: (1) outer and inner retinal photoreceptors provide partially redundant information to the inner retina, (2) melanopsin is required for inner retinal phototransduction in the absence of rod and cone signaling, and (3) cryptochromes contribute to the amplitude of inner retinal phototransduction but are not strictly required.
Collapse
Affiliation(s)
- Russell N Van Gelder
- Department of Ophthalmology and Visual Sciences, Washington University Medical School, St. Louis, Missouri 63110, USA
| |
Collapse
|
29
|
Oztürk N, Song SH, Ozgür S, Selby CP, Morrison L, Partch C, Zhong D, Sancar A. Structure and function of animal cryptochromes. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2008; 72:119-31. [PMID: 18419269 DOI: 10.1101/sqb.2007.72.015] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cryptochrome (CRY) is a photolyase-like flavoprotein with no DNA-repair activity but with known or presumed blue-light receptor function. Animal CRYs have DNA-binding and autokinase activities, and their flavin cofactor is reduced by photoinduced electron transfer. In Drosophila, CRY is a major circadian photoreceptor, and in mammals, the two CRY proteins are core components of the molecular clock and potential circadian photoreceptors. In mammals, CRYs participate in cell cycle regulation and the cellular response to DNA damage by controlling the expression of some cell cycle genes and by directly interacting with checkpoint proteins.
Collapse
Affiliation(s)
- N Oztürk
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Tsuji T, Hirota T, Takemori N, Komori N, Yoshitane H, Fukuda M, Matsumoto H, Fukada Y. Circadian proteomics of the mouse retina. Proteomics 2007; 7:3500-8. [PMID: 17726681 DOI: 10.1002/pmic.200700272] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The circadian clock in the retina regulates a variety of physiological phenomena such as disc shedding and melatonin release. Although these events are critical for retinal functions, it is almost unknown how the circadian clock controls the physiological rhythmicity. To gain insight into the processes, we performed a proteomic analysis using 2-DE to find proteins whose levels show circadian changes. Among 415 retinal protein spots, 11 protein spots showed circadian rhythmicity in their intensities. We performed MALDI-TOF MS and NanoLC-MS/MS analyses and identified proteins contained in the 11 spots. The proteins were related to vesicular transport, calcium-binding, protein degradation, metabolism, RNA-binding, and protein foldings, suggesting the clock-regulation of neurotransmitter release, transportation of the membrane proteins, calcium-binding capability, and so on. We also found a rhythmic phosphorylation of N-ethylmaleimide-sensitive fusion protein and identified one of the amino acid residues modified by phosphorylation. These findings provide a new perspective on the relationship between the physiological functions of the retina and the circadian clock system.
Collapse
Affiliation(s)
- Takahiro Tsuji
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Yu L, Kelly U, Ebright JN, Malek G, Saloupis P, Rickman D, McKay BS, Arshavsky VY, Rickman CB. Oxidative stress-induced expression and modulation of Phosphatase of Regenerating Liver-1 (PRL-1) in mammalian retina. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:1473-82. [PMID: 17673310 PMCID: PMC2118714 DOI: 10.1016/j.bbamcr.2007.06.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 06/06/2007] [Accepted: 06/18/2007] [Indexed: 11/18/2022]
Abstract
The phosphatase of regenerating liver-1, PRL-1, gene was detected in a screen for foveal cone photoreceptor-associated genes. It encodes a small protein tyrosine phosphatase that was previously immunolocalized to the photoreceptors in primate retina. Here we report that in cones and cone-derived cultured cells both PRL-1 activity and PRL-1 gene expression are modulated under oxidative stress. Oxidation reversibly inhibited the phosphatase activity of PRL-1 due to the formation of an intramolecular disulfide bridge between Cys104 within the active site and another conserved Cys, Cys49. This modulation was observed in vitro, in cell culture and in isolated retinas exposed to hydrogen peroxide. The same treatment caused a rapid increase in PRL-1 expression levels in cultured cells which could be blocked by the protein translation inhibitor, cycloheximide. Increased PRL-1 expression was also observed in living rats subjected to constant light exposure inducing photooxidative stress. We further demonstrated that both oxidation and overexpression of PRL-1 upon oxidative stress are greatly enhanced by inhibition of the glutathione system responsible for cellular redox regulation. These findings suggest that PRL-1 is a molecular component of the photoreceptor's response to oxidative stress acting upstream of the glutathione system.
Collapse
Affiliation(s)
- Ling Yu
- Departments of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Una Kelly
- Departments of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Jessica N. Ebright
- Departments of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Goldis Malek
- Departments of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Peter Saloupis
- Departments of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
| | - Dennis Rickman
- Departments of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Brian S. McKay
- Departments of Ophthalmology and Cell Biology and Anatomy, University of Arizona, Tucson, AZ 85711, USA
| | - Vadim Y. Arshavsky
- Departments of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Catherine Bowes Rickman
- Departments of Ophthalmology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
- Corresponding Author. Department of Ophthalmology, Duke University Medical Center, Albert Eye Research Institute Room 5010, Box 3802, Erwin Road, Durham, NC 27710, USA. Tel.: +1 (919) 668-0648; Fax: +1 (919) 684 3687. E-Mail: (Catherine Bowes Rickman, Ph.D.)
| |
Collapse
|
32
|
Yao G, Zhang K, Bellassai M, Chang B, Lei B. Ultraviolet light-induced and green light-induced transient pupillary light reflex in mice. Curr Eye Res 2007; 31:925-33. [PMID: 17114118 DOI: 10.1080/02713680600932308] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE To study UV light-induced and green light-induced pupillary light reflex (PLR) in mice and to measure the illumination thresholds of rod-mediated and cone-mediated PLR responses. METHODS We measured dark-adapted transient PLR- in C57BL/6 mice elicited with ultraviolet and green light over an intensity range of 9 log units. To assist in isolating the responses mediated by rods and cones, we studied the PLRs in mouse models presenting pure cone and pure rod functions. We also characterized ERG signals in these mice under the same experimental conditions. RESULTS The UV light-induced transient PLR has identical intensity-response curves as green light-induced PLR in all the three mice strains. The threshold (5% PLR) of rod-driven PLR is 107 approximately 108 photons cm2 s-1, which is 1 approximately 2 log units lower than the dark-adapted ERG b-wave. The threshold of cone-driven PLR is approximately 1012.5 photons cm-2 s-1 and is similar to that of the cone ERG. CONCLUSIONS We demonstrated that mice have PLR responses under UV stimulation. The cone-elicited PLRs have a threshold that is approximately 5 log units higher than that of rod-elicited PLR at both UV and green wavelengths. We observed a divergence between the spectra responses in PLR and ERG. However, the mechanism and implications of this phenomenon are yet to be identified.
Collapse
Affiliation(s)
- Gang Yao
- Department of Biological Engineering, University of Missouri Columbia, Columbia, MO 65211-0001, USA
| | | | | | | | | |
Collapse
|
33
|
Dinet V, Ansari N, Torres-Farfan C, Korf HW. Clock gene expression in the retina of melatonin-proficient (C3H) and melatonin-deficient (C57BL) mice. J Pineal Res 2007; 42:83-91. [PMID: 17198542 DOI: 10.1111/j.1600-079x.2006.00387.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In several mammalian species, the retina contains an autonomous circadian clock and is capable of synthesizing melatonin. The function of circadian clocks depends on interlocking transcriptional/translational feedback loops involving several clock genes. Here we investigated the expression of two clock genes (Per1, Cry2) and the level of phosphorylated (p) cyclic AMP response element binding protein (CREB) in retinae of melatonin-deficient (C57BL) with an intact retina and melatonin-proficient (C3H) mice with degenerated outer nuclear layer. RNase protection assay and in situ hybridization revealed in both strains a rhythm in transcript levels for Per1 with a peak at zeitgeber time (ZT) 08, but not for Cry2. Immunoreactions for PER1, CRY2 and pCREB were localized to the nuclei of cells in the inner nuclear layer (INL) and ganglion cell layer (GC) of both strains and to the outer nuclear layer of C57BL. In C3H, protein levels of PER1 and CRY2 followed a clear day/night rhythm in the INL and the GC with a peak at the end of the day (ZT14). pCREB levels peaked at the beginning of the day. Noteably, in melatonin-deficient C57BL mice, protein levels of PER1, CRY2 and pCREB did not show significant changes over a 16L/8D cycle. These data suggest that melatonin influences PER1 and CRY2 protein levels via post-transcriptional mechanisms and also plays a role in rhythmic regulation of pCREB levels in the mammalian retina.
Collapse
Affiliation(s)
- Virginie Dinet
- Dr Senckenbergische Anatomie, Institut für Anatomie II, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt am Main, Frankfurt, Germany
| | | | | | | |
Collapse
|
34
|
Peng ZW, Chen XG, Wei Z. Cryptochrome1 maybe a candidate gene of schizophrenia. Med Hypotheses 2007; 69:849-51. [PMID: 17376600 DOI: 10.1016/j.mehy.2007.02.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Accepted: 02/01/2007] [Indexed: 10/23/2022]
Abstract
During the last 10 years, we have witnessed major progress in the genetic study of schizophrenia, but gene-mapping efforts have been hampered by the complex mode of inheritance and the likelihood of multiple genes of small effect. In view of the complexity, it may be instructive to understand the biological bases for pathogenesis. Extensive disruption in circadian function is known to occur among schizophrenia patients. If circadian dysfunction can be established as an 'endophenotype' for schizophrenia, it may not only enable the identification of more homogenous sub-groups, but also facilitate the genetic analyses. Therefore, circadian dysfunction maybe underlies the pathogenesis of schizophrenia and would be logical to investigate polymorphisms of genes encoding key proteins that mediate circadian rhythms. Cryptochrome1 (Cry1), located in a chromosomal region 12q23-q24.1, performs predominantly regulatory function in circadian clock and which is close to a linkage hotspot (12q24) of schizophrenia. Recent studies also found that Cry1 gene interacted with antipsychotic drugs and dopamine system which played a core role in the pathophysiology of schizophrenia. Based on these findings, we speculate that Cry1 was the candidate gene of schizophrenia. The proposition may have new clues on the development of genetic study on complex diseases.
Collapse
Affiliation(s)
- Zi-wen Peng
- Mental Health Institute of The 2nd Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, 410011 Hunan Province, China
| | | | | |
Collapse
|
35
|
Bowes Rickman C, Ebright JN, Zavodni ZJ, Yu L, Wang T, Daiger SP, Wistow G, Boon K, Hauser MA. Defining the human macula transcriptome and candidate retinal disease genes using EyeSAGE. Invest Ophthalmol Vis Sci 2006; 47:2305-16. [PMID: 16723438 PMCID: PMC2813776 DOI: 10.1167/iovs.05-1437] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To develop large-scale, high-throughput annotation of the human macula transcriptome and to identify and prioritize candidate genes for inherited retinal dystrophies, based on ocular-expression profiles using serial analysis of gene expression (SAGE). METHODS Two human retina and two retinal pigment epithelium (RPE)/choroid SAGE libraries made from matched macula or midperipheral retina and adjacent RPE/choroid of morphologically normal 28- to 66-year-old donors and a human central retina longSAGE library made from 41- to 66-year-old donors were generated. Their transcription profiles were entered into a relational database, EyeSAGE, including microarray expression profiles of retina and publicly available normal human tissue SAGE libraries. EyeSAGE was used to identify retina- and RPE-specific and -associated genes, and candidate genes for retina and RPE disease loci. Differential and/or cell-type specific expression was validated by quantitative and single-cell RT-PCR. RESULTS Cone photoreceptor-associated gene expression was elevated in the macula transcription profiles. Analysis of the longSAGE retina tags enhanced tag-to-gene mapping and revealed alternatively spliced genes. Analysis of candidate gene expression tables for the identified Bardet-Biedl syndrome disease gene (BBS5) in the BBS5 disease region table yielded BBS5 as the top candidate. Compelling candidates for inherited retina diseases were identified. CONCLUSIONS The EyeSAGE database, combining three different gene-profiling platforms including the authors' multidonor-derived retina/RPE SAGE libraries and existing single-donor retina/RPE libraries, is a powerful resource for definition of the retina and RPE transcriptomes. It can be used to identify retina-specific genes, including alternatively spliced transcripts and to prioritize candidate genes within mapped retinal disease regions.
Collapse
|
36
|
Ruan GX, Zhang DQ, Zhou T, Yamazaki S, McMahon DG. Circadian organization of the mammalian retina. Proc Natl Acad Sci U S A 2006; 103:9703-8. [PMID: 16766660 PMCID: PMC1480470 DOI: 10.1073/pnas.0601940103] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mammalian retina contains an endogenous circadian pacemaker that broadly regulates retinal physiology and function, yet the cellular origin and organization of the mammalian retinal circadian clock remains unclear. Circadian clock neurons generate daily rhythms via cell-autonomous autoregulatory clock gene networks, and, thus, to localize circadian clock neurons within the mammalian retina, we have studied the cell type-specific expression of six core circadian clock genes in individual, identified mouse retinal neurons, as well as characterized the clock gene expression rhythms in photoreceptor degenerate rd mouse retinas. Individual photoreceptors, horizontal, bipolar, dopaminergic (DA) amacrines, catecholaminergic (CA) amacrines, and ganglion neurons were identified either by morphology or by a tyrosine hydroxylase (TH) promoter-driven red fluorescent protein (RFP) fluorescent reporter. Cells were collected, and their transcriptomes were subjected to multiplex single-cell RT-PCR for the core clock genes Period (Per) 1 and 2, Cryptochrome (Cry) 1 and 2, Clock, and Bmal1. Individual horizontal, bipolar, DA, CA, and ganglion neurons, but not photoreceptors, were found to coordinately express all six core clock genes, with the lowest proportion of putative clock cells in photoreceptors (0%) and the highest proportion in DA neurons (30%). In addition, clock gene rhythms were found to persist for >25 days in isolated, cultured rd mouse retinas in which photoreceptors had degenerated. Our results indicate that multiple types of retinal neurons are potential circadian clock neurons that express key elements of the circadian autoregulatory gene network and that the inner nuclear and ganglion cell layers of the mammalian retina contain functionally autonomous circadian clocks.
Collapse
Affiliation(s)
- Guo-Xiang Ruan
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Dao-Qi Zhang
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Tongrong Zhou
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Shin Yamazaki
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
| | - Douglas G. McMahon
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235
- *To whom correspondence should be addressed at:
Department of Biological Sciences, Vanderbilt University, VU Station B, Box 35-1634, Nashville, TN 37235-1634. E-mail:
| |
Collapse
|
37
|
Partch CL, Sancar A. Photochemistry and photobiology of cryptochrome blue-light photopigments: the search for a photocycle. Photochem Photobiol 2006; 81:1291-304. [PMID: 16164372 DOI: 10.1562/2005-07-08-ir-607] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cryptochromes are flavoproteins that exhibit high sequence and structural similarity to the light-dependent DNA-repair enzyme, photolyase. Cryptochromes have lost the ability to repair DNA; instead, they use the energy from near-UV/blue light to regulate a variety of growth and adaptive processes in organisms ranging from bacteria to humans. The photocycle of cryptochrome is not yet known, although it is hypothesized that it may share some similarity to that of photolyase, which utilizes light-driven electron transfer from the catalytic flavin chromophore. In this review, we present genetic evidence for the photoreceptive role of cryptochromes and discuss recent biochemical studies that have furthered our understanding of the cryptochrome photocycle. In particular, the role of the unique C-terminal domain in cryptochrome phototransduction is discussed.
Collapse
Affiliation(s)
- Carrie L Partch
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | | |
Collapse
|
38
|
von Schantz M, Jenkins A, Archer SN. Evolutionary History of the Vertebrate Period Genes. J Mol Evol 2006; 62:701-7. [PMID: 16752210 DOI: 10.1007/s00239-005-0185-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Accepted: 12/22/2005] [Indexed: 10/24/2022]
Abstract
Circadian clock genes are remarkably conserved between eucoelomates. Although Drosophila has one copy of each major component, vertebrates have two or (in the case of the Period genes) three paralogs (Per1-3). We investigated the possibility that the vertebrate Per genes arose through two genome duplications during the emergence of vertebrates. Phylogenetic trees have placed zebrafish and mammalian Per1 and 2 together in a separate branch from Per3. The positions of four coding region splice sites were conserved between Drosophila per and the human paralogs, the fifth one being unique to Drosophila. The human PER genes shared the positions of all coding region splice sites, except the first two in PER1 and PER2 (which PER3 lacks). The phases of all splice sites were conserved between all four genes with two exceptions. Analysis of all genes within 10 Mb of the human PER1-3 genes, which are located 7.8-8.8 Mb from the telomeres on chromosomes 17, 2, and 1, identified several orthologous neighbors shared by at least two PER genes. Two gene families, HES (hairy and Enhancer of Split) and KIF1 (kinesin-like protein 1), were represented in all three of these paralogons. Although no functional fourth human PER paralog exists, five representatives from the same gene families were found close to the telomer of chromosome 3. We conclude that the ancestral chordate Per gene underwent two duplication events, giving rise to Per1-3 and a lost fourth paralog.
Collapse
Affiliation(s)
- Malcolm von Schantz
- Centre for Chronobiology, School of Biomedical and Molecular Sciences, University of Surrey, Guildford, GU2 7XH, UK.
| | | | | |
Collapse
|
39
|
Kamphuis W, Cailotto C, Dijk F, Bergen A, Buijs RM. Circadian expression of clock genes and clock-controlled genes in the rat retina. Biochem Biophys Res Commun 2005; 330:18-26. [PMID: 15781226 DOI: 10.1016/j.bbrc.2005.02.118] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Indexed: 11/17/2022]
Abstract
The circadian expression patterns of genes encoding for proteins that make up the core of the circadian clock were measured in rat retina using real-time quantitative PCR (qPCR). Transcript levels of several genes previously used for normalization of qPCR assays were determined and the effect of ischemia-reperfusion on the expression of clock genes was studied. Statistically significant circadian changes in transcript levels were found for: Per2, Per3, Cry2, Bmal1, Rora, Rorb, and Rorc with changes ranging between 1.6- and 2.6-fold. No changes were found for Per1, Cry1, Clock, Rev-erb alpha, and Rev-erb beta. Significant differences in transcript levels were observed for several candidate reference genes: HPRT, GAPDH, rhodopsin, and Thy1 and, consequently, the use of these genes for normalization purposes in qPCR or Northern blots may lead to erroneous conclusions. Ischemia-reperfusion leads to a persistent decrease of Per1 and Cry2, which may be related to the selective degeneration of amacrine and ganglion cells. We conclude that while all clock genes are expressed in the retina, only a few show a clear circadian pattern.
Collapse
Affiliation(s)
- Willem Kamphuis
- Netherlands Ophthalmic Research Institute (NORI)-KNAW, Glaucoma Research Group, Department of Ophthalmogenetics, Graduate School for the Neurosciences Amsterdam, The Netherlands.
| | | | | | | | | |
Collapse
|
40
|
Abstract
Cryptochromes are photoreceptors that regulate entrainment by light of the circadian clock in plants and animals. They also act as integral parts of the central circadian oscillator in animal brains and as receptors controlling photomorphogenesis in response to blue or ultraviolet (UV-A) light in plants. Cryptochromes are probably the evolutionary descendents of DNA photolyases, which are light-activated DNA-repair enzymes, and are classified into three groups -- plant cryptochromes, animal cryptochromes, and CRY-DASH proteins. Cryptochromes and photolyases have similar three-dimensional structures, characterized by an alpha/beta domain and a helical domain. The structure also includes a chromophore, flavin adenine dinucleotide (FAD). The FAD-access cavity of the helical domain is the catalytic site of photolyases, and it is predicted also to be important in the mechanism of cryptochromes.
Collapse
Affiliation(s)
- Chentao Lin
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, 621 Charles Young Drive South, Los Angeles, CA 90095-1606, USA.
| | | |
Collapse
|
41
|
Abstract
Cryptochromes are photoreceptors that regulate entrainment of the circadian clock by light in plants and animals. They are related to DNA photolyases and have similar three-dimensional structures, characterized by a α/β domain and a helical domain and including a chromophore, flavin adenine dinucleotide. Cryptochromes are photoreceptors that regulate entrainment by light of the circadian clock in plants and animals. They also act as integral parts of the central circadian oscillator in animal brains and as receptors controlling photomorphogenesis in response to blue or ultraviolet (UV-A) light in plants. Cryptochromes are probably the evolutionary descendents of DNA photolyases, which are light-activated DNA-repair enzymes, and are classified into three groups - plant cryptochromes, animal cryptochromes, and CRY-DASH proteins. Cryptochromes and photolyases have similar three-dimensional structures, characterized by an α/β domain and a helical domain. The structure also includes a chromophore, flavin adenine dinucleotide (FAD). The FAD-access cavity of the helical domain is the catalytic site of photolyases, and it is predicted also to be important in the mechanism of cryptochromes.
Collapse
Affiliation(s)
- Chentao Lin
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, 621 Charles Young Drive South, Los Angeles, CA 90095-1606, USA.
| | | |
Collapse
|
42
|
Abstract
Cryptochromes are flavin- and folate-containing blue-light photoreceptors with a high degree of similarity to DNA photolyase, which repairs ultraviolet-induced DNA damage using blue light to initiate the repair reaction. Cryptochromes play essential roles in the maintenance of circadian rhythms in mice and Drosophila, and genetic data indicate that cryptochromes function as circadian photoreceptors in these and other animals. However, the photochemical reactions carried out by cryptochromes are not known at present.
Collapse
Affiliation(s)
- Carrie L Partch
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | | |
Collapse
|
43
|
Affiliation(s)
- Aziz Sancar
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.
| |
Collapse
|
44
|
Affiliation(s)
- Aziz Sancar
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
| |
Collapse
|