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Vieira J, Jones AR, Danon A, Sakuma M, Hoang N, Robles D, Tait S, Heyes DJ, Picot M, Yoshii T, Helfrich-Förster C, Soubigou G, Coppee JY, Klarsfeld A, Rouyer F, Scrutton NS, Ahmad M. Human cryptochrome-1 confers light independent biological activity in transgenic Drosophila correlated with flavin radical stability. PLoS One 2012; 7:e31867. [PMID: 22427812 PMCID: PMC3299647 DOI: 10.1371/journal.pone.0031867] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 01/13/2012] [Indexed: 01/11/2023] Open
Abstract
Cryptochromes are conserved flavoprotein receptors found throughout the biological kingdom with diversified roles in plant development and entrainment of the circadian clock in animals. Light perception is proposed to occur through flavin radical formation that correlates with biological activity in vivo in both plants and Drosophila. By contrast, mammalian (Type II) cryptochromes regulate the circadian clock independently of light, raising the fundamental question of whether mammalian cryptochromes have evolved entirely distinct signaling mechanisms. Here we show by developmental and transcriptome analysis that Homo sapiens cryptochrome--1 (HsCRY1) confers biological activity in transgenic expressing Drosophila in darkness, that can in some cases be further stimulated by light. In contrast to all other cryptochromes, purified recombinant HsCRY1 protein was stably isolated in the anionic radical flavin state, containing only a small proportion of oxidized flavin which could be reduced by illumination. We conclude that animal Type I and Type II cryptochromes may both have signaling mechanisms involving formation of a flavin radical signaling state, and that light independent activity of Type II cryptochromes is a consequence of dark accumulation of this redox form in vivo rather than of a fundamental difference in signaling mechanism.
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Affiliation(s)
| | - Alex R. Jones
- Manchester Interdisciplinary Biocentre and Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | | | - Michiyo Sakuma
- Manchester Interdisciplinary Biocentre and Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | | | | | - Shirley Tait
- Manchester Interdisciplinary Biocentre and Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Derren J. Heyes
- Manchester Interdisciplinary Biocentre and Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Marie Picot
- Institut de Neurobiologie Alfred Fessard, CNRS UPR 2216 (NGI), Gif-sur-Yvette, France
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | | | - Guillaume Soubigou
- Institut Pasteur, Transcriptome and Epigenome Platform, Genomes and Genetics Department, Paris, France
| | - Jean-Yves Coppee
- Institut Pasteur, Transcriptome and Epigenome Platform, Genomes and Genetics Department, Paris, France
| | - André Klarsfeld
- Institut de Neurobiologie Alfred Fessard, CNRS UPR 2216 (NGI), Gif-sur-Yvette, France
| | - Francois Rouyer
- Institut de Neurobiologie Alfred Fessard, CNRS UPR 2216 (NGI), Gif-sur-Yvette, France
| | - Nigel S. Scrutton
- Manchester Interdisciplinary Biocentre and Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Margaret Ahmad
- Université Paris VI, Paris, France
- Penn State University, Media, Pennsylvania, United States of America
- * E-mail:
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Human and Drosophila cryptochromes are light activated by flavin photoreduction in living cells. PLoS Biol 2008; 6:e160. [PMID: 18597555 PMCID: PMC2443192 DOI: 10.1371/journal.pbio.0060160] [Citation(s) in RCA: 350] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Accepted: 05/19/2008] [Indexed: 11/19/2022] Open
Abstract
Cryptochromes are a class of flavoprotein blue-light signaling receptors found in plants, animals, and humans that control plant development and the entrainment of circadian rhythms. In plant cryptochromes, light activation is proposed to result from photoreduction of a protein-bound flavin chromophore through intramolecular electron transfer. However, although similar in structure to plant cryptochromes, the light-response mechanism of animal cryptochromes remains entirely unknown. To complicate matters further, there is currently a debate on whether mammalian cryptochromes respond to light at all or are instead activated by non–light-dependent mechanisms. To resolve these questions, we have expressed both human and Drosophila cryptochrome proteins to high levels in living Sf21 insect cells using a baculovirus-derived expression system. Intact cells are irradiated with blue light, and the resulting cryptochrome photoconversion is monitored by fluorescence and electron paramagnetic resonance spectroscopic techniques. We demonstrate that light induces a change in the redox state of flavin bound to the receptor in both human and Drosophila cryptochromes. Photoreduction from oxidized flavin and subsequent accumulation of a semiquinone intermediate signaling state occurs by a conserved mechanism that has been previously identified for plant cryptochromes. These results provide the first evidence of how animal-type cryptochromes are activated by light in living cells. Furthermore, human cryptochrome is also shown to undergo this light response. Therefore, human cryptochromes in exposed peripheral and/or visual tissues may have novel light-sensing roles that remain to be elucidated. Vision in animals is generally associated with light-sensitive rhodopsin pigments located in the eyes. However, animals ranging from flies to humans also possess ancient visual receptors known as cryptochromes in multiple cell types. In this work, we study the mechanism of light sensing in two representative animal cryptochromes: a light-sensitive Drosophila cryptochrome (Dmcry) and a presumed light-insensitive mammalian cryptochrome from humans (Hscry1). We expressed recombinant cryptochromes to high levels in living cells, irradiated the cells with blue light, and analyzed the proteins' response to irradiation with electron paramagnetic resonance and fluorescence spectroscopic techniques. Photoreduction of protein-bound oxidized FAD cofactor to its radical form emerged as the primary cryptochrome photoreaction in living cells, and was correlated with a light-sensitive biological response in whole organisms. These results indicate that both Dmcry and Hscry1 are capable of undergoing similar light-driven reactions and suggest the possibility of an as-yet unknown photo-perception role for human cryptochromes in tissues exposed to light. Cryptochromes are blue-light-absorbing receptors found in plants, animals, and humans. In mammals, they are not thought to respond to light, but this study demonstrates contrary evidence that indeed, human cryptochromes undergo a photochemical transformation in response to light.
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Zhang W, Ge W, Wang Z. A toolbox for light control of Drosophila behaviors through Channelrhodopsin 2-mediated photoactivation of targeted neurons. Eur J Neurosci 2007; 26:2405-16. [PMID: 17970730 DOI: 10.1111/j.1460-9568.2007.05862.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In order to study the function of specific neural circuits, we generated UAS-Channelrhodopsin2 (ChR2) transgenic Drosophila and established a ChR2-based system that enables specific activation of targeted neurons in larval and adult fruit flies with blue light illumination, under the control of a newly designed light source that provides fully programmable stimulation patterns. We showed that stimulating selectively the nociceptor of larvae expressing ChR2 elicited light-induced 'pain' response, confined freely behaving larvae in defined area and directed larva migration along a preset route. In freely behaving adult flies, rapid photoactivation of targeted gustatory sensory neurons, dopaminergic modulatory neurons and motor neurons triggered the proboscis extension response, escaping reflex and changes in the locomotion pattern, respectively, with precise temporal control. This non-invasive method for remote control of animal behaviors also provides a potential tool for conducting 'gain of function' studies toward understanding how animal behaviors are controlled by neural activity.
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Affiliation(s)
- Wei Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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Gottschling DE. Summary: epigenetics--from phenomenon to field. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2004; 69:507-19. [PMID: 16117688 DOI: 10.1101/sqb.2004.69.507] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Affiliation(s)
- D E Gottschling
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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Liu L, Leonard AS, Motto DG, Feller MA, Price MP, Johnson WA, Welsh MJ. Contribution of Drosophila DEG/ENaC genes to salt taste. Neuron 2003; 39:133-46. [PMID: 12848938 DOI: 10.1016/s0896-6273(03)00394-5] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ability to detect salt is critical for the survival of terrestrial animals. Based on amiloride-dependent inhibition, the receptors that detect salt have been postulated to be DEG/ENaC channels. We found the Drosophila DEG/ENaC genes Pickpocket11 (ppk11) and Pickpocket19 (ppk19) expressed in the larval taste-sensing terminal organ and in adults on the taste bristles of the labelum, the legs, and the wing margins. When we disrupted PPK11 or PPK19 function, larvae lost their ability to discriminate low concentrations of Na(+) or K(+) from water, and the electrophysiologic responses to low salt concentrations were attenuated. In both larvae and adults, disrupting PPK11 or PPK19 affected the behavioral response to high salt concentrations. In contrast, the response of larvae to sucrose, pH 3, and several odors remained intact. These results indicate that the DEG/ENaC channels PPK11 and PPK19 play a key role in detecting Na(+) and K(+) salts.
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Affiliation(s)
- Lei Liu
- Howard Hughes Medical Institute and Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City 52242, USA
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Liu L, Yermolaieva O, Johnson WA, Abboud FM, Welsh MJ. Identification and function of thermosensory neurons in Drosophila larvae. Nat Neurosci 2003; 6:267-73. [PMID: 12563263 DOI: 10.1038/nn1009] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2002] [Accepted: 01/06/2003] [Indexed: 11/09/2022]
Abstract
Although the ability to sense temperature is critical for many organisms, the underlying mechanisms are poorly understood. Using the calcium reporter yellow cameleon 2.1 and electrophysiological recordings, we identified thermosensitive neurons and examined their physiologic response in Drosophila melanogaster larvae. In the head, terminal sensory organ neurons showed increased activity in response to cooling by < or =1 degrees C, heating reduced their basal activity, and different units showed distinct response patterns. Neither cooling nor heating affected dorsal organ neurons. Body wall neurons showed a variety of distinct response patterns to both heating and cooling; the diverse thermal responses were strikingly similar to those described in mammals. These data establish a functional map of thermoresponsive neurons in Drosophila larvae and provide a foundation for understanding mechanisms of thermoreception in both insects and mammals.
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Affiliation(s)
- Lei Liu
- Department of Internal Medicine, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, 500 EMRB, Iowa City, Iowa 52242, USA
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Scott K, Brady R, Cravchik A, Morozov P, Rzhetsky A, Zuker C, Axel R. A chemosensory gene family encoding candidate gustatory and olfactory receptors in Drosophila. Cell 2001; 104:661-73. [PMID: 11257221 DOI: 10.1016/s0092-8674(01)00263-x] [Citation(s) in RCA: 481] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A novel family of candidate gustatory receptors (GRs) was recently identified in searches of the Drosophila genome. We have performed in situ hybridization and transgene experiments that reveal expression of these genes in both gustatory and olfactory neurons in adult flies and larvae. This gene family is likely to encode both odorant and taste receptors. We have visualized the projections of chemosensory neurons in the larval brain and observe that neurons expressing different GRs project to discrete loci in the antennal lobe and subesophageal ganglion. These data provide insight into the diversity of chemosensory recognition and an initial view of the representation of gustatory information in the fly brain.
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Affiliation(s)
- K Scott
- Department of Biochemistry and, Molecular Biophysics, Howard Hughes Medical Institute, 701 West 168th Street, New York, NY 10032, USA
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Rong YS, Golic KG. Dominant defects in Drosophila eye pigmentation resulting from a euchromatin-heterochromatin fusion gene. Genetics 1998; 150:1551-66. [PMID: 9832531 PMCID: PMC1460429 DOI: 10.1093/genetics/150.4.1551] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have isolated a dominant mutation, pugilistDominant (pugD), that causes variegated reductions in pteridine and ommochrome pigmentation of the Drosophila eye. The effect of pugD on pteridine pigmentation is most dramatic: the only remaining pigment consists of a thin ring of pigment around the periphery of the eye with a few scattered spots in the center. The pugD mutation disrupts a gene that encodes a Drosophila homolog of the trifunctional enzyme methylenetetrahydrofolate dehydrogenase (MTHFD; E.C.1.5.1.5, E.C.3.5. 4.9, E.C.6.3.4.3). This enzyme produces a cofactor that is utilized in purine biosynthesis. Because pteridines are derived from GTP, the pigment defect may result from an impairment in the production of purines. The mutant allele consists of a portion of the MTHFD coding region fused to approximately 1 kb of highly repetitive DNA. Transcription and translation of both parts are required for the phenotype. The repetitive DNA consists of approximately 140 nearly perfect repeats of the sequence AGAGAGA, a significant component of centric heterochromatin. The unusual nature of the protein produced by this gene may be responsible for its dominance. The repetitive DNA may also account for the variegated aspect of the phenotype. It may promote occasional association of the pugD locus with centric heterochromatin, accompanied by inactivation of pugD, in a manner similar to the proposed mode of action for brownDominant.
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Affiliation(s)
- Y S Rong
- Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA
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Zhimulev IF. Polytene chromosomes, heterochromatin, and position effect variegation. ADVANCES IN GENETICS 1997; 37:1-566. [PMID: 9352629 DOI: 10.1016/s0065-2660(08)60341-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- I F Zhimulev
- Institute of Cytology and Genetics, Siberian Division of the Russian Academy of Sciences, Novosibirsk, Russia
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