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Cronin T. Invited Session III: Diversity in chromatic processing across the animal kingdom: Color vision in stomatopod crustaceans. J Vis 2023; 23:12. [PMID: 38109636 DOI: 10.1167/jov.23.15.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023] Open
Abstract
Stomatopod crustaceans, commonly known as mantis shrimp, have perhaps the most unusual color-vision systems of any animals. The uniqueness is possible because stomatopods have compound eyes. Here, each unit, or ommatidium, acts as an independent visual detector, with its own corneal lens, internal optics, and set of photoreceptors. Ommatidia tuned to different wavelengths can be individually placed in the eye to build unusual color systems. In mantis shrimps, the receptors responsible for color vision are limited to six parallel rows of ommatidia that together form an equatorial belt, called the midband. Various receptors in these ommatidia are tuned to eight narrow-band spectral channels in the visible spectrum plus up to four additional ultraviolet channels. Thus, there is a total of twelve different color receptors for color vision. How these color channels are analyzed in the complex set of optic lobes existing behind the retina is only partly understood. It appears that stomatopods use both opponent and labelled-line color channels. Oddly, these animals appear to have limited ability to discriminate between spectral lights, but they have outstanding color constancy. Color vision, and color processing, in stomatopods is probably unlike that of any other animal group.
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Childers RAR, Bernard GD, Huang H, Tsai CC, Stoddard MC, Hogan BG, Greenwood JSF, Soucy ER, Cornwall M, Lim MLM, Liénard MA, Yu N, Pierce NE. A hypothesis for robust polarization vision: An example from the Australian Imperial Blue butterfly, Jalmenus evagoras. J Exp Biol 2023; 226:297475. [PMID: 36967715 PMCID: PMC10120070 DOI: 10.1242/jeb.244515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 03/08/2023] [Indexed: 03/29/2023]
Abstract
The Australian lycaenid butterfly, Jalmenus evagoras, has iridescent wings that are sexually dimorphic, spectrally and in their degree of polarization, suggesting that these properties are likely to be important in mate recognition. We first describe the results of a field experiment showing that free-flying individuals of J. evagoras discriminate between visual stimuli that vary in polarization content in blue wavelengths but not in others. We then present detailed reflectance spectrophotometry measurements of the polarization content of male and female wings, showing that female wings exhibit blue-shifted reflectance, with a lower degree of polarization relative to male wings. Finally, we describe a novel method for measuring alignment of ommatidial arrays: By measuring variation of depolarized eyeshine intensity from patches of ommatidia as a function of eye rotation, we show that a) individual rhabdoms contain mutually perpendicular microvilli; b) many rhabdoms in the array have their microvilli misaligned with respect to neighboring rhabdoms by as much as 45°; c) the misaligned ommatidia are useful for robust polarization detection. By mapping the distribution of the ommatidial misalignments in eye patches of J. evagoras, we show that males and females exhibit differences in the extent to which ommatidia are aligned. Both the number of misaligned ommatidia suitable for robust polarization-detection, and the number of aligned ommatidia suitable for edge-detection, vary with respect to both sex and eye-patch elevation. Thus, J. evagoras exhibits finely-tuned ommatidial arrays suitable for perception of polarized signals, likely to match sex-specific life history differences in the utility of polarized signals.
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Affiliation(s)
- Richard A. Rabideau Childers
- Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
- Authors for correspondence (; ; )
| | - Gary D. Bernard
- Department of Electrical & Computer Engineering, University of Washington, Seattle, WA 98195, USA
- Authors for correspondence (; ; )
| | - Heqing Huang
- Department of Applied Physics & Applied Mathematics, Columbia University, New York, NY 10027, USA
| | - Cheng-Chia Tsai
- Department of Applied Physics & Applied Mathematics, Columbia University, New York, NY 10027, USA
| | - Mary Caswell Stoddard
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Benedict G. Hogan
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Joel S. F. Greenwood
- Center for Brain Science, Harvard University, 52 Oxford St - room 331, Cambridge, MA 02138, USA
- Neurotechnology Core, Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Edward R. Soucy
- Center for Brain Science, Harvard University, 52 Oxford St - room 331, Cambridge, MA 02138, USA
| | - Mark Cornwall
- Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Matthew Lek Min Lim
- Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
- Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore117558
| | - Marjorie A. Liénard
- Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Department of Biology, Lund University, 22362 Lund, Sweden
| | - Nanfang Yu
- Department of Applied Physics & Applied Mathematics, Columbia University, New York, NY 10027, USA
| | - Naomi E. Pierce
- Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
- Authors for correspondence (; ; )
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Yeung K, Bollepogu Raja KK, Shim YK, Li Y, Chen R, Mardon G. Single cell RNA sequencing of the adult Drosophila eye reveals distinct clusters and novel marker genes for all major cell types. Commun Biol 2022; 5:1370. [PMID: 36517671 PMCID: PMC9751288 DOI: 10.1038/s42003-022-04337-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 12/02/2022] [Indexed: 12/16/2022] Open
Abstract
The adult Drosophila eye is a powerful model system for phototransduction and neurodegeneration research. However, single cell resolution transcriptomic data are lacking for this tissue. We present single cell RNA-seq data on 1-day male and female, 3-day and 7-day old male adult eyes, covering early to mature adult eyes. All major cell types, including photoreceptors, cone and pigment cells in the adult eye were captured and identified. Our data sets identified novel cell type specific marker genes, some of which were validated in vivo. R7 and R8 photoreceptors form clusters that reflect their specific Rhodopsin expression and the specific Rhodopsin expression by each R7 and R8 cluster is the major determinant to their clustering. The transcriptomic data presented in this report will facilitate a deeper mechanistic understanding of the adult fly eye as a model system.
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Affiliation(s)
- Kelvin Yeung
- Department of Pathology and Immunology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Komal Kumar Bollepogu Raja
- Department of Pathology and Immunology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Yoon-Kyung Shim
- Department of Pathology and Immunology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Yumei Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
- Structural and Computation Biology and Molecular Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Rui Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
- Human Genome Sequencing Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
- Structural and Computation Biology and Molecular Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Graeme Mardon
- Department of Pathology and Immunology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
- Program in Developmental Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
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Meglič A, Ilić M, Quero C, Arikawa K, Belušič G. Two chiral types of randomly rotated ommatidia are distributed across the retina of the flathead oak borer Coraebus undatus (Coleoptera: Buprestidae). J Exp Biol 2020; 223:jeb225920. [PMID: 32532862 DOI: 10.1242/jeb.225920] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 06/03/2020] [Indexed: 11/20/2022]
Abstract
Jewel beetles are colorful insects, which use vision to recognize their conspecifics and can be lured with colored traps. We investigated the retina and coloration of one member of this family, the flathead oak borer Coraebus undatus using microscopy, spectrometry, polarimetry, electroretinography and intracellular recordings of photoreceptor cell responses. The compound eyes are built of a highly unusual mosaic of mirror-symmetric or chiral ommatidia that are randomly rotated along the body axes. Each ommatidium has eight photoreceptors, two of them having rhabdomeres in tiers. The eyes contain six spectral classes of photoreceptors, peaking in the UV, blue, green and red. Most photoreceptors have moderate polarization sensitivity with randomly distributed angular maxima. The beetles have the necessary retinal substrate for complex color vision, required to recognize conspecifics and suitable for a targeted design of color traps. However, the jewel beetle array of freely rotated ommatidia is very different from the ordered mosaic in insects that have object-directed polarization vision. We propose that ommatidial rotation enables the cancelling out of polarization signals, thus allowing stable color vision, similar to the rhabdomeric twist in the eyes of flies and honeybees.
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Affiliation(s)
- Andrej Meglič
- Eye Hospital, University Medical Centre, Grablovičeva 46, 1000 Ljubljana, Slovenia
| | - Marko Ilić
- Laboratory of Neuroethology, Sokendai - The Graduate University for Advanced Studies, Hayama 240-0193, Japan
| | - Carmen Quero
- Department of Biological Chemistry and Molecular Modelling, IQAC (CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Kentaro Arikawa
- Laboratory of Neuroethology, Sokendai - The Graduate University for Advanced Studies, Hayama 240-0193, Japan
| | - Gregor Belušič
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
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Blake AJ, Hahn GS, Grey H, Kwok SA, McIntosh D, Gries G. Polarized light sensitivity in Pieris rapae is dependent on both color and intensity. J Exp Biol 2020; 223:jeb220350. [PMID: 32461306 DOI: 10.1242/jeb.220350] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 05/18/2020] [Indexed: 08/26/2023]
Abstract
There is an ever increasing number of arthropod taxa shown to have polarization sensitivity throughout their compound eyes. However, the downstream processing of polarized reflections from objects is not well understood. The small white butterfly, Pieris rapae, has been demonstrated to exploit foliar polarized reflections, specifically the degree of linear polarization (DoLP), to recognize host plants. The well-described visual system of P. rapae includes several photoreceptor types (red, green, blue) that are sensitive to polarized light. Yet, the roles and interaction among photoreceptors underlying the behavioral responses of P. rapae to stimuli with different DoLP remain unknown. To investigate potential neurological mechanisms, we designed several two-choice behavioral bioassays, displaying plant images on paired LCD monitors, which allowed for independent control of polarization, color and intensity. When we presented choices between stimuli that differed in either color or DoLP, both decreasing and increasing the intensity of the more attractive stimulus reduced the strength of preference. This result suggests that differences in color and DoLP are perceived in a similar manner. When we offered a DoLP choice between plant images manipulated to minimize the response of blue, red, or blue and red photoreceptors, P. rapae shifted its preference for DoLP, suggesting a role for all of these photoreceptors. Modeling of P. rapae photoreceptor responses to test stimuli suggests that differential DoLP is not perceived solely as a color difference. Our combined results suggest that Prapae females process and interpret polarization reflections in a way different from that described for other polarization-sensitive taxa.
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Affiliation(s)
- Adam J Blake
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Gina S Hahn
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Hayley Grey
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Shelby A Kwok
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Deby McIntosh
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Gerhard Gries
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
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Yamamoto H, Agata K. Optic chiasm formation in planarian I: Cooperative netrin- and robo-mediated signals are required for the early stage of optic chiasm formation. Dev Growth Differ 2011; 53:300-11. [PMID: 21428985 DOI: 10.1111/j.1440-169x.2010.01234.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Freshwater planarians can regenerate a brain, including eyes, from the anterior blastema, and coordinately form an optic chiasm during eye and brain regeneration. To investigate the role of the netrin- and slit-signaling systems during optic chiasm formation, we cloned three receptor genes (Djunc5A, Djdcc and DjroboA) expressed in visual neurons and their ligand genes (DjnetB and Djslit) and analyzed their functions by RNA interference (RNAi). Although each of DjroboA(RNAi), Djunc5A(RNAi) and DjnetB(RNAi) showed a weak phenotype and Djslit(RNAi) showed a severe defect of eye formation, we did not observe any defect of crossing of visual axons over the midline among single knockdown planarians. However, among double knockdown planarians, some of DjnetB(RNAi);DjroboA(RNAi) and Djunc5A(RNAi);DjroboA(RNAi) showed complete disconnection between the visual axons from the two sides, suggesting that some combination of netrin- and robo-mediated signals may be required for crossing over the midline. Finally, we carefully investigated the distribution patterns of cells expressing DjNetB protein, DjnetB, and Djslit at the early stage of regeneration, and found that visual axons projected along a path sandwiched between DjNetB protein and Djslit-positive cells. These results suggest that two different collaborative or combinatory signals may be required for midline crossing at the early stage of chiasm formation during eye and brain regeneration.
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Affiliation(s)
- Hiroshi Yamamoto
- Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan
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Berry B, Deddouche S, Kirschner D, Imler JL, Antoniewski C. Viral suppressors of RNA silencing hinder exogenous and endogenous small RNA pathways in Drosophila. PLoS One 2009; 4:e5866. [PMID: 19516905 PMCID: PMC2689938 DOI: 10.1371/journal.pone.0005866] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Accepted: 05/13/2009] [Indexed: 12/19/2022] Open
Abstract
Background In plants and insects, RNA interference (RNAi) is the main responder against viruses and shapes the basis of antiviral immunity. Viruses counter this defense by expressing viral suppressors of RNAi (VSRs). While VSRs in Drosophila melanogaster were shown to inhibit RNAi through different modes of action, whether they act on other silencing pathways remained unexplored. Methodology/Principal Findings Here we show that expression of various plant and insect VSRs in transgenic flies does not perturb the Drosophila microRNA (miRNA) pathway; but in contrast, inhibits antiviral RNAi and the RNA silencing response triggered by inverted repeat transcripts, and injection of dsRNA or siRNA. Strikingly, these VSRs also suppressed transposon silencing by endogenous siRNAs (endo-siRNAs). Conclusions/Significance Our findings identify VSRs as tools to unravel small RNA pathways in insects and suggest a cosuppression of antiviral RNAi and endo-siRNA silencing by viruses during fly infections.
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Affiliation(s)
- Bassam Berry
- Institut Pasteur, Drosophila Genetics and Epigenetics, CNRS-URA2578, Paris, France
| | | | - Doris Kirschner
- Institut Pasteur, Drosophila Genetics and Epigenetics, CNRS-URA2578, Paris, France
| | | | - Christophe Antoniewski
- Institut Pasteur, Drosophila Genetics and Epigenetics, CNRS-URA2578, Paris, France
- * E-mail:
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Sanil D, Shetty NJ. The genetics of green thorax, a new larval colour mutant, non-linked with ruby - eye locus in the malaria mosquito, Anopheles stephensi. J Vector Borne Dis 2009; 46:117-124. [PMID: 19502691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
BACKGROUND & OBJECTIVES Anopheles stephensi, an important vector of malaria continues to be distributed widely in the Indian subcontinent. The natural vigour of the species combined with its new tolerance, indeed resistance to insecticides has made it obligatory that we look for control methods involving genetic manipulation. Hence, there is an immediate need for greater understanding of the genetics of this vector species. One of the requirements for such genetic studies is the establishment of naturally occurring mutants, establishment of the genetic basis for the same and use of such mutants in the genetic transformation studies and other genetic control programme(s). This paper describes the isolation and genetic studies of a larval colour mutant, green thorax (gt), and linkage studies involving another autosomal recessive mutant ruby- eye (ru) in An. stephensi. METHODS After the initial discovery, the mutant green thorax was crossed inter se and pure homozygous stock of the mutant was established. The stock of the mutant ruby- eye, which has been maintained as a pure stock in the laboratory. Crosses were made between the wild type and mutant, green thorax to determine the mode of inheritance of green thorax. For linkage studies, crosses were made between the mutant green thorax and another autosomal recessive mutant ruby-eye. The percentage cross-over was calculated for the genes linkage relationship for gt and gt ru. RESULTS Results of crosses between mutant and wild type showed that the inheritance of green thorax (gt) in An. stephensi is monofactorial in nature. The gt allele is recessive to wild type and is autosomal. The linkage studies showed no linkage between ru and gt. INTERPRETATION & CONCLUSION The mutant gt represents an excellent marker for An. stephensi as it is expressed in late III instar stage of larvae and is prominent in IV instar and pupal stages with complete penetrance and high viability. The said mutant could be easily identified without the aid of a microscope. This mutant can be used extensively to conduct basic and applied research. The mutant has been maintained in two large cages in our laboratory.
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Affiliation(s)
- D Sanil
- Centre for Applied Genetics, Bangalore University, J.B. Campus, Bengaluru & Janardhana Foundation, Nagadevanahalli,Jnanabharathi Post, Bengaluru, India
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9
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Abstract
Most animals rely on circadian clocks to synchronize their physiology and behavior with the day/night cycle. Light and temperature are the major physical variables that can synchronize circadian rhythms. Although the effects of light on circadian behavior have been studied in detail in Drosophila, the neuronal mechanisms underlying temperature synchronization of circadian behavior have received less attention. Here, we show that temperature cycles synchronize and durably affect circadian behavior in Drosophila in the absence of light input. This synchronization depends on the well characterized and functionally coupled circadian neurons controlling the morning and evening activity under light/dark cycles: the M cells and E cells. However, circadian neurons distinct from the M and E cells are implicated in the control of rhythmic behavior specifically under temperature cycles. These additional neurons play a dual role: they promote evening activity and negatively regulate E cell function in the middle of the day. We also demonstrate that, although temperature synchronizes circadian behavior more slowly than light, this synchronization is considerably accelerated when the M cell oscillator is absent or genetically altered. Thus, whereas the E cells show great responsiveness to temperature input, the M cells and their robust self-sustained pacemaker act as a resistance to behavioral synchronization by temperature cycles. In conclusion, the behavioral responses to temperature input are determined by both the individual properties of specific groups of circadian neurons and their organization in a neural network.
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Affiliation(s)
- Ania Busza
- Department of Neurobiology and Program in Neuroscience and
- MD/PhD Program, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | | | - Patrick Emery
- Department of Neurobiology and Program in Neuroscience and
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del Alamo D, Mlodzik M. Frizzled/PCP-dependent asymmetric neuralized expression determines R3/R4 fates in the Drosophila eye. Dev Cell 2007; 11:887-94. [PMID: 17141162 DOI: 10.1016/j.devcel.2006.09.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Revised: 08/07/2006] [Accepted: 09/19/2006] [Indexed: 01/10/2023]
Abstract
Planar cell polarity (PCP) is a common feature in many epithelia, reflected in cellular organization within the plane of an epithelium. In the Drosophila eye, Frizzled (Fz)/PCP signaling induces cell-fate specification of the R3/R4 photoreceptors through regulation of Notch activation in R4. Except for Dl upregulation in R3, the mechanism of how Fz/PCP signaling regulates Notch in this context is not understood. We demonstrate that the E3-ubiquitin ligase Neuralized (Neur), required for Dl-N signaling, is asymmetrically expressed within the R3/R4 pair. It is required in R3, where it is also upregulated in a Fz/PCP-dependent manner. As is the case for Dl, N activity in R4 further represses neur expression, thus, reinforcing the asymmetry. We demonstrate that Neur asymmetry is instructive in correct R3/R4 specification. Our data indicate that Fz/PCP-dependent Neur expression in R3 ensures the proper directionality of Dl-N signaling during R3/R4 specification.
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Affiliation(s)
- David del Alamo
- Department of Molecular, Cell, and Developmental Biology, Mount Sinai School of Medicine, New York, New York 10029, USA
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11
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Ryoo HD, Domingos PM, Kang MJ, Steller H. Unfolded protein response in a Drosophila model for retinal degeneration. EMBO J 2007; 26:242-52. [PMID: 17170705 PMCID: PMC1782370 DOI: 10.1038/sj.emboj.7601477] [Citation(s) in RCA: 220] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Accepted: 11/06/2006] [Indexed: 12/15/2022] Open
Abstract
Stress in the endoplasmic reticulum (ER stress) and its cellular response, the unfolded protein response (UPR), are implicated in a wide variety of diseases, but its significance in many disorders remains to be validated in vivo. Here, we analyzed a branch of the UPR mediated by xbp1 in Drosophila to establish its role in neurodegenerative diseases. The Drosophila xbp1 mRNA undergoes ire-1-mediated unconventional splicing in response to ER stress, and this property was used to develop a specific UPR marker, xbp1-EGFP, in which EGFP is expressed in frame only after ER stress. xbp1-EGFP responds specifically to ER stress, but not to proteins that form cytoplasmic aggregates. The ire-1/xbp1 pathway regulates heat shock cognate protein 3 (hsc3), an ER chaperone. xbp1 splicing and hsc3 induction occur in the retina of ninaE(G69D)-/+, a Drosophila model for autosomal dominant retinitis pigmentosa (ADRP), and reduction of xbp1 gene dosage accelerates retinal degeneration of these animals. These results demonstrate the role of the UPR in the Drosophila ADRP model and open new opportunities for examining the UPR in other Drosophila disease models.
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Affiliation(s)
- Hyung Don Ryoo
- Department of Cell Biology, NYU School of Medicine, New York, NY, USA
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Pedro M Domingos
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Min-Ji Kang
- Department of Cell Biology, NYU School of Medicine, New York, NY, USA
| | - Hermann Steller
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
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12
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Colombetti G, Checcucci G, Lucia S, Usai C, Ramoino P, Bianchini P, Pesce M, Vicidomini G, Diaspro A. Evidence for ciliary pigment localization in colored ciliates and implications for their photosensory transduction chain: A confocal microscopy study. Microsc Res Tech 2007; 70:1028-33. [PMID: 17661390 DOI: 10.1002/jemt.20508] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In this study we report for the first time the localization of a photoreceptor pigment in the cilia of the colored heterotrich ciliates Blepharisma japonicum red and blue form, Fabrea salina, and Stentor coeruleus, as result of a confocal microscopy investigation. Optical sectioning confocal microscopy has been used for studying the spatial distribution of the pigment in the cell body, surprisingly showing that, besides its expected presence in the cortical region immediately below the cell membrane, it is located in the cilia too. In order to ascertain possible differences in the pigment fluorescence properties along the cell body, we have measured emission spectra from different parts of it (anterior, posterior, and cilia). Our results clearly indicate that in all cases the spectra are the same, within experimental errors. Finally, we have evaluated the pigment relative fluorescence efficiency of these ciliates. In an ordered scale from lower to greater efficiency, we have S. coeruleus, B. japonicum blue, B. japonicum red, and F. salina. The possible implications of our findings for the process of photosensory transduction are discussed.
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13
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Hummel T, Klämbt C. Eye development: random precision in color vision. Curr Biol 2006; 16:R361-3. [PMID: 16713942 DOI: 10.1016/j.cub.2006.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In insect and vertebrate eyes, different types of color-detecting photoreceptors are randomly distributed throughout the retina. A recent study has provided important new insights into the developmental mechanisms that generate the retinal mosaic required for color vision.
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Affiliation(s)
- Thomas Hummel
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, 48149 Münster, Germany.
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Abstract
This work presents the fabrication of biologically inspired artificial compound eyes. The artificial ommatidium, like that of an insect's compound eyes, consists of a refractive polymer microlens, a light-guiding polymer cone, and a self-aligned waveguide to collect light with a small angular acceptance. The ommatidia are omnidirectionally arranged along a hemispherical polymer dome such that they provide a wide field of view similar to that of a natural compound eye. The spherical configuration of the microlenses is accomplished by reconfigurable microtemplating, that is, polymer replication using the deformed elastomer membrane with microlens patterns. The formation of polymer waveguides self-aligned with microlenses is also realized by a self-writing process in a photosensitive polymer resin. The angular acceptance is directly measured by three-dimensional optical sectioning with a confocal microscope, and the detailed optical characteristics are studied in comparison with a natural compound eye.
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Affiliation(s)
- Ki-Hun Jeong
- Biomolecular Nanotechnology Center, Berkeley Sensor and Actuator Center, Department of Bioengineering, 485 Evans Hall No. 1762, University of California, Berkeley, CA 94720, USA
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15
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Abstract
The molecular mechanisms of circadian rhythms are well known, but how multiple clocks within one organism generate a structured rhythmic output remains a mystery. Many animals show bimodal activity rhythms with morning (M) and evening (E) activity bouts. One long-standing model assumes that two mutually coupled oscillators underlie these bouts and show different sensitivities to light. Three groups of lateral neurons (LN) and three groups of dorsal neurons govern behavioral rhythmicity of Drosophila. Recent data suggest that two groups of the LN (the ventral subset of the small LN cells and the dorsal subset of LN cells) are plausible candidates for the M and E oscillator, respectively. We provide evidence that these neuronal groups respond differently to light and can be completely desynchronized from one another by constant light, leading to two activity components that free-run with different periods. As expected, a long-period component started from the E activity bout. However, a short-period component originated not exclusively from the morning peak but more prominently from the evening peak. This reveals an interesting deviation from the original Pittendrigh and Daan (1976) model and suggests that a subgroup of the ventral subset of the small LN acts as "main" oscillator controlling M and E activity bouts in Drosophila.
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16
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Yamoah EN, Levic S, Redell JB, Crow T. Inhibition of conditioned stimulus pathway phosphoprotein 24 expression blocks the reduction in A-type transient K+ current produced by one-trial in vitro conditioning of Hermissenda. J Neurosci 2006; 25:4793-800. [PMID: 15888654 PMCID: PMC6724784 DOI: 10.1523/jneurosci.5256-04.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Long-term intrinsic enhanced excitability is a characteristic of cellular plasticity and learning-dependent modifications in the activity of neural networks. The regulation of voltage-dependent K+ channels by phosphorylation/dephosphorylation and their localization is proposed to be important in the control of cellular plasticity. One-trial conditioning in Hermissenda results in enhanced excitability in sensory neurons, type B photoreceptors, of the conditioned stimulus pathway. Conditioning also regulates the phosphorylation of conditioned stimulus pathway phosphoprotein 24 (Csp24), a cytoskeletal-related protein containing multiple beta-thymosin-like domains. Recently, it was shown that the downregulation of Csp24 expression mediated by an antisense oligonucleotide blocked the development of enhanced excitability in identified type B photoreceptors after one-trial conditioning without affecting short-term excitability. Here, we show using whole-cell patch recordings that one-trial in vitro conditioning applied to isolated photoreceptors produces a significant reduction in the amplitude of the A-type transient K+ current (I(A)) detected 1.5-16 h after conditioning. One-trial conditioning produced a depolarized shift in the steady-state activation curve of I(A) without altering the inactivation curve. The conditioning-dependent reduction in I(A) was blocked by preincubation of the photoreceptors with Csp antisense oligonucleotide. These results provide an important link between Csp24, a cytoskeletal protein, and regulation of voltage-gated ion channels associated with intrinsic enhanced excitability underlying pavlovian conditioning.
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Affiliation(s)
- Ebenezer N Yamoah
- Center for Neuroscience, Department of Otolaryngology, University of California, Davis, California 95616, USA
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17
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Abstract
When it is gliding, the unicellular euglenoid Peranema trichophorum uses activation of the photoreceptor rhodopsin to control the probability of its curling behavior. From the curled state, the cell takes off in a new direction. In a similar manner, archaea such as Halobacterium use light activation of bacterio- and sensory rhodopsins to control the probability of reversal of the rotation direction of flagella. Each reversal causes the cell to change its direction. In neither case does the cell track light, as known for the rhodopsin-dependent eukaryotic phototaxis of fungi, green algae, cryptomonads, dinoflagellates, and animal larvae. Rhodopsin was identified in Peranema by its native action spectrum (peak at 2.43 eV or 510 nm) and by the shifted spectrum (peak at 3.73 eV or 332 nm) upon replacement of the native chromophore with the retinal analog n-hexenal. The in vivo physiological activity of n-hexenal incorporated to become a chromophore also demonstrates that charge redistribution of a short asymmetric chromophore is sufficient for receptor activation and that the following isomerization step is probably not required when the rest of the native chromophore is missing. This property seems universal among the Euglenozoa, Plant, and Fungus kingdom rhodopsins. The rhodopsins of animals have yet to be studied in this respect. The photoresponse appears to be mediated by Ca2+ influx.
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Affiliation(s)
- Jureepan Saranak
- Physics Department, Syracuse University, 201 Physics Building, Syracuse, NY 13244-1130, USA
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18
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Wicher D, Agricola HJ, Schönherr R, Heinemann SH, Derst C. TRPgamma channels are inhibited by cAMP and contribute to pacemaking in neurosecretory insect neurons. J Biol Chem 2005; 281:3227-36. [PMID: 16319060 DOI: 10.1074/jbc.m511741200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
From a neuronal cDNA library of the cockroach Periplaneta americana we isolated a 3585-bp cDNA sequence encoding Periplaneta transient receptor potential gamma (pTRPgamma), a protein of 1194 amino acids showing 65% identity to the orthologous Drosophila channel protein dTRPgamma. Heterologous expression of pTRPgamma in HEK293 cells produced a constitutively active, non-selective cation channel with a Ca2+:Na+ permeability ratio of 2. In contrast to dTRPgamma-mediated currents, pTRPgamma currents were partially inhibited by 8-bromo-cAMP, and this effect was not mediated by protein kinase A (PKA) activation. pTRPgammab, a truncated pTRPgamma splice variant missing most of the C terminus, was insensitive to 8-bromo-cAMP. Thus, the critical cAMP-binding site seems to be located in the C-terminal part of pTRPgamma, although there is no common cAMP-binding consensus sequence. While dTRPgamma is only expressed in the photoreceptors, pTRPgamma is expressed throughout the nervous system. In particular it is expressed in dorsal unpaired median (DUM) neurons. In these octopamine-releasing, neurosecretory cells a Ca2+ background current contributing to pacemaker activity was found to be up-regulated by the reduction of cAMP level. In addition, the Ca2+ background current was inhibited by LOE-908, 2-APB, and La3+, which similarly affected the pTRPgamma current. We thus propose that the pTRPgamma protein is involved in forming the channel passing the Ca2+ pakemaking background current in DUM neurons.
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Affiliation(s)
- Dieter Wicher
- Department of Neurohormones, Saxon Academy of Sciences, 07743 Jena, Germany.
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19
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Mutsuddi M, Chaffee B, Cassidy J, Silver SJ, Tootle TL, Rebay I. Using Drosophila to decipher how mutations associated with human branchio-oto-renal syndrome and optical defects compromise the protein tyrosine phosphatase and transcriptional functions of eyes absent. Genetics 2005; 170:687-95. [PMID: 15802522 PMCID: PMC1450419 DOI: 10.1534/genetics.104.039156] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Eyes absent (EYA) proteins are defined by a conserved C-terminal EYA domain (ED) that both contributes to its function as a transcriptional coactivator by mediating protein-protein interactions and possesses intrinsic protein tyrosine phosphatase activity. Mutations in human EYA1 result in an autosomal dominant disorder called branchio-oto-renal (BOR) syndrome as well as congenital cataracts and ocular defects (OD). Both BOR- and OD-associated missense mutations alter residues in the conserved ED as do three missense mutations identified from Drosophila eya alleles. To investigate the molecular mechanisms whereby these mutations disrupt EYA function, we tested their activity in a series of assays that measured in vivo function, phosphatase activity, transcriptional capability, and protein-protein interactions. We find that the OD-associated mutations retain significant in vivo activity whereas those derived from BOR patients show a striking decrease or loss of in vivo functionality. Protein-protein interactions, either with its partner transcription factor Sine oculis or with EYA itself, were not significantly compromised. Finally, the results of the biochemical assays suggest that both loss of protein tyrosine phosphatase activity and reduced transcriptional capability contribute to the impaired EYA function associated with BOR/OD syndrome, thus shedding new light into the molecular mechanisms underlying this disease.
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Affiliation(s)
- Mousumi Mutsuddi
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA.
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20
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Abstract
Are bird-pollinated flowers red because bees - which might rob the flower of its nectar - cannot easily detect them, or might it be because of more subtle evolutionary trade-offs?
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Affiliation(s)
- Miguel A Rodríguez-Gironés
- Estación Experimental de Zonas Aridas, Consejo Superior de Investigaciones Científicas in Almería, Spain.
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21
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Masuda S, Hasegawa K, Ishii A, Ono TA. Light-induced structural changes in a putative blue-light receptor with a novel FAD binding fold sensor of blue-light using FAD (BLUF); Slr1694 of synechocystis sp. PCC6803. Biochemistry 2004; 43:5304-13. [PMID: 15122896 DOI: 10.1021/bi049836v] [Citation(s) in RCA: 173] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The sensor of blue-light using FAD (BLUF) domain is the flavin-binding fold categorized to a new class of blue-light sensing domain found in AppA from Rhodobacter sphaeroides and PAC from Euglena gracilis, but little is known concerning the mechanism of blue-light perception. An open reading frame slr1694 in a cyanobacterium Synechocystis sp. PCC6803 encodes a protein possessing the BLUF domain. Here, a full-length Slr1694 protein retaining FAD was expressed and purified and found to be present as an oligomeric form (trimer or tetramer). Using the purified Slr1694, spectroscopic properties of Slr1694 were characterized. Slr1694 was found to show the same red-shift of flavin absorption and quenching of flavin fluorescence by illumination as those of AppA. These changes reversed in the dark although the rate of dark state regeneration was much faster in Slr1694 than AppA, indicating that Slr1694 is a blue-light receptor based on BLUF with the similar photocycle to that of AppA. The dark decay in D(2)O was nearly four times slower than in H(2)O. Light-induced Fourier transform infrared (FTIR) difference spectroscopy was applied to examine the light-induced structure change of a chromophore and apo-protein with deuteration and universal (13)C and (15)N isotope labeling. The FTIR results indicate that light excitation induced distinct changes in the amide I modes of peptide backbone but relatively limited changes in flavin chromophore. Light excitation predominantly weakened the C(4)=O and C(2)=O bonding and strengthened the N1C10a and/or C4aN5 bonding, indicating formational changes of the isoalloxazine ring II and III of FAD but little formational change in the isoalloxazine ring I. The photocycle of the BLUF is unique in the sense that light excitation leads to the structural rearrangements of the protein moieties coupled with a minimum formational change of the chromophore.
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Affiliation(s)
- Shinji Masuda
- Laboratory for Photo-Biology (1), RIKEN Photodynamics Research Center, The Institute of Physical and Chemical Research, 519-1399 Aoba, Aramaki, Aoba, Sendai 980-0845, Japan
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22
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Naruse Y, Oh-hashi K, Iijima N, Naruse M, Yoshioka H, Tanaka M. Circadian and light-induced transcription of clock gene Per1 depends on histone acetylation and deacetylation. Mol Cell Biol 2004; 24:6278-87. [PMID: 15226430 PMCID: PMC434252 DOI: 10.1128/mcb.24.14.6278-6287.2004] [Citation(s) in RCA: 174] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Circadian clock genes are regulated through a transcriptional-translational feedback loop. Alterations of the chromatin structure by histone acetyltransferases and histone deacetylases (HDACs) are commonly implicated in the regulation of gene transcription. However, little is known about the transcriptional regulation of mammalian clock genes by chromatin modification. Here, we show that the state of acetylated histones fluctuated in parallel with the rhythm of mouse Per1 (mPer1) or mPer2 expression in fibroblast cells and liver. Mouse CRY1 (mCRY1) repressed transcription with HDACs and mSin3B, which was relieved by the HDAC inhibitor trichostatin A (TSA). In turn, TSA induced endogenous mPer1 expression as well as the acetylation of histones H3 and H4, which interacted with the mPer1 promoter region in fibroblast cells. Moreover, a light pulse stimulated rapid histone acetylation associated with the promoters of mPer1 or mPer2 in the suprachiasmatic nucleus (SCN) and the binding of phospho-CREB in the CRE of mPer1. We also showed that TSA administration into the lateral ventricle induced mPer1 and mPer2 expression in the SCN. Taken together, these data indicate that the rhythmic transcription and light induction of clock genes are regulated by histone acetylation and deacetylation.
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Affiliation(s)
- Yoshihisa Naruse
- Department of Anatomy, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamikyo-ku, Kyoto 602-0841, Japan
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23
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Abstract
The sea slug Hermissenda learns to associate light and hair cell stimulation, but not when the stimuli are temporally uncorrelated. Memory storage, which requires an elevation in calcium, occurs in the photoreceptors, which receive monosynaptic input from hair cells that sense acceleration stimuli such as turbulence. Both light and hair cell activity increase calcium concentration in the photoreceptor, but it is unknown whether paired calcium signals combine supralinearly to initiate memory storage. A correlate of memory storage is an enhancement of the long lasting depolarization (LLD) after light offset, which is attributed to a reduction in voltage dependent potassium currents; however, it is unclear what causes the LLD in the untrained animal. These issues were addressed using a multi-compartmental computer model of phototransduction, calcium dynamics, and ionic currents of the Hermissenda photoreceptor. Simulations of the interaction between light and hair cell activity show that paired stimuli do not produce a greater calcium increase than unpaired stimuli. This suggests that hair cell activity is acting via some other pathway to initiate memory storage. In addition, simulations show that a potassium leak channel, which closes with an increase in calcium, is required to produce both the untrained LLD and the enhanced LLD due to the decrease in voltage dependent potassium currents. Thus, the expression of this correlate of classical conditioning may depend on a leak potassium current.
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Affiliation(s)
- Kim T Blackwell
- School of Computational Sciences, and the Krasnow Institute for Advanced Study, George Mason University, MS 2A1, Fairfax, VA 22030, USA.
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24
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Abstract
Sunlight is a primary source of energy for life. However, its UV component causes DNA damage. We suggest that the strong UV component of sunlight contributed to the selective pressure for the evolution of the specialized photoreceptor cryptochrome from photolyases involved in DNA repair and propose that early metazoans avoided irradiation by descending in the oceans during the daytime. We suggest further that it is not coincidental that blue-light photoreception evolved in an aquatic environment, since only blue light can penetrate to substantial depths in water. These photoreceptors were then also critical for sensing the decreased luminescence that signals the coming of night and the time to return to the surface. The oceans and the 24-h light-dark cycle therefore provided an optimal setting for an early evolutionary relationship between blue-light photoreception and circadian rhythmicity.
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Affiliation(s)
- Walter Gehring
- Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland.
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25
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Hazlerigg DG, Andersson H, Johnston JD, Lincoln G. Molecular characterization of the long-day response in the Soay sheep, a seasonal mammal. Curr Biol 2004; 14:334-9. [PMID: 14972686 DOI: 10.1016/j.cub.2004.01.057] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Revised: 01/13/2004] [Accepted: 01/15/2004] [Indexed: 11/23/2022]
Abstract
In mammals, seasonal timekeeping depends on the generation of a nocturnal melatonin signal that reflects nightlength/daylength. To understand the mechanisms by which the melatonin signal is decoded, we studied the photoperiodic control of prolactin secretion in Soay sheep, which is mediated via melatonin responsive cells in the pars tuberalis of the pituitary. We demonstrate that the phases of peak expression of the clock genes Cryptochrome1 (Cry1), Period1 (Per1), and RevErbalpha respond acutely to altered melatonin secretion after a switch from short to long days. Cry1 is activated by melatonin onset, forming the dusk component of the molecular decoder, while Per1 expression at dawn reflects the offset of melatonin secretion. The Cry1-Per1 interval immediately adjusts to the melatonin signal on the first long day, and this is followed within 24 hr by an increase in prolactin secretion. The timing of peak RevErbalpha expression also responds to a switch to long days due to altered melatonin secretion but does not immediately reset to an entrained long-day state. These data suggest that effects of melatonin on clock gene expression are pivotal events in the neuroendocrine response and that pars tuberalis cells can act as molecular calendars, carrying a form of "photoperiodic memory."
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Affiliation(s)
- David G Hazlerigg
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen AB24 2TZ, Scotland.
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26
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Kennis JTM, van Stokkum IHM, Crosson S, Gauden M, Moffat K, van Grondelle R. The LOV2 domain of phototropin: a reversible photochromic switch. J Am Chem Soc 2004; 126:4512-3. [PMID: 15070357 DOI: 10.1021/ja031840r] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Light, oxygen, or voltage (LOV) domains constitute a new class of photoreceptor proteins that are sensitive to blue light through a noncovalently bound flavin chromophore. Blue-light absorption by the LOV2 domain initiates a photochemical reaction that results in formation of a long-lived covalent adduct between a cysteine and the flavin cofactor. We have applied ultrafast spectroscopy on the photoaccumulated covalent adduct state of LOV2 and find that, upon absorption of a near-UV photon by the adduct state, the covalent bond between the flavin and the cysteine is broken and the blue-light-sensitive ground state is regained on an ultrafast time scale of 100 ps. We thus demonstrate that the LOV2 domain is a reversible photochromic switch, which can be activated by blue light and deactivated by near-UV light.
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Affiliation(s)
- John T M Kennis
- Department of Biophysics, Faculty of Sciences, Vrije Universiteit, 1081HV Amsterdam, The Netherlands.
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27
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Johnston JD, Bashforth R, Diack A, Andersson H, Lincoln GA, Hazlerigg DG. Rhythmic melatonin secretion does not correlate with the expression of arylalkylamine N-acetyltransferase, inducible cyclic amp early repressor, period1 or cryptochrome1 mRNA in the sheep pineal. Neuroscience 2004; 124:789-95. [PMID: 15026119 DOI: 10.1016/j.neuroscience.2004.01.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2004] [Indexed: 11/26/2022]
Abstract
The pineal gland, through nocturnal melatonin, acts as a neuroendocrine transducer of daily and seasonal time. Melatonin synthesis is driven by rhythmic activation of the rate-limiting enzyme, arylalkylamine N-acetyltransferase (AA-NAT). In ungulates, AA-NAT mRNA is constitutively high throughout the 24-h cycle, and melatonin production is primarily controlled through effects on AA-NAT enzyme activity; this is in contrast to dominant transcriptional control in rodents. To determine whether there has been a selective loss of circadian control of AA-NAT mRNA expression in the sheep pineal, we measured the expression of other genes known to be rhythmic in rodents (inducible cAMP early repressor ICER, the circadian clock genes Period1 and Cryptochrome1, as well as AA-NAT). We first assayed gene expression in pineal glands collected from Soay sheep adapted to short days (Light: dark, 8-h: 16-h), and killed at 4-h intervals through 24-h. We found no evidence for rhythmic expression of ICER, AA-NAT or Cryptochrome1 under these conditions, whilst Period1 showed a low amplitude rhythm of expression, with higher values during the dark period. In a second group of animals, lights out was delayed by 8-h during the final 24-h sampling period, a manipulation that causes an immediate shortening of the period of melatonin secretion. This did not significantly affect the expression of ICER, AA-NAT or Cryptochrome1 in the pineal, whilst a slight suppressive effect on overall Per1 levels was observed. The attenuated response to photoperiod change appears to be specific to the ovine pineal, as the first long day induced rapid changes of Period1 and ICER expression in the hypothalamic suprachiasmatic nuclei and pituitary pars tuberalis, respectively. Overall, our data suggest a general reduction of circadian control of transcript abundance in the ovine pineal gland, consistent with a marked evolutionary divergence in the mechanism regulating melatonin production between terrestrial ruminants and fossorial rodents.
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Affiliation(s)
- J D Johnston
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen AB24 2TZ, UK.
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28
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Harper SM, Neil LC, Day IJ, Hore PJ, Gardner KH. Conformational changes in a photosensory LOV domain monitored by time-resolved NMR spectroscopy. J Am Chem Soc 2004; 126:3390-1. [PMID: 15025443 DOI: 10.1021/ja038224f] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phototropins are light-activated kinases from plants that utilize light-oxygen-voltage (LOV) domains as blue light photosensors. Illumination of these domains leads to the formation of a covalent linkage between the protein and an internally bound flavin chromophore, destabilizing the surrounding protein and displacing an alpha-helix from its surface. Here we use a combination of spectroscopic tools to monitor the kinetic processes that spontaneously occur in the dark as the protein returns to the noncovalent ground state. Using time-resolved two-dimensional (2D) NMR methods, we measured the rate of this process at over 100 independent sites throughout the protein, establishing that regeneration of the dark state occurs cooperatively within a 1.6-fold range of observed rates. These data agree with other spectroscopic measurements of the kinetics of protein/FMN bond cleavage and global conformational changes, consistent with these processes experiencing a common rate-limiting step. Arrhenius analyses of the temperature dependence of these rates suggest that the transition state visited during this regeneration has higher energy than the denatured form of this protein domain despite the fact that there is no global unfolding of the domain during this process.
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Affiliation(s)
- Shannon M Harper
- Departments of Biochemistry and Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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29
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Abstract
Experiments have shown that many phenylpropanoid genes are highly expressed in light-grown Arabidopsis roots. Studies employing reporter gene constructs have indicated that the expression of these genes is localized not only to the lignifying root vasculature, but also to non-lignifying tissues, such as the root cortex, suggesting that the proteins encoded by these genes may be involved in aspects of phenylpropanoid metabolism other than lignification. Consistent with this hypothesis, roots of etiolated and soil-grown plants contain almost no soluble phenylpropanoids, but exposure to light leads to the accumulation of flavonoids, as well as high levels of coniferin and syringin (coniferyl and sinapyl-4-O-glycosides), compounds not previously reported to be accumulated in Arabidopsis. To elucidate the mechanism by which light induces root secondary metabolism, extracts of mutants defective in light perception and light responses were analyzed for phenylpropanoid content. The results of these assays showed that phytochrome (PHY)B and cryptochrome (CRY)2 are the primary photoreceptors involved in light-dependent phenylpropanoid accumulation, and that the hypocotyl elongated (HY5) transcription factor is also required for this response. The presence of phenylpropanoids in etiolated roots of cop (constitutively photomorphogenic)1, cop9, and det (de-etiolated)1 mutants indicate that the corresponding wild-type genes are required to repress root phenylpropanoid biosynthesis in the absence of light. Biochemical analysis of root cell walls and analysis of phenylpropanoid gene expression suggest that coniferin and syringin accumulation may be the result of both increased biosynthesis and decreased conversion of these compounds into other phenylpropanoid end products. Finally, our data suggest that the accumulation of coniferin, syringin, and flavonoids in Arabidopsis roots is a high-irradiance response (HIR), and suggest that comparative analysis of light- and dark-grown Arabidopsis roots may provide new insights into both phenylpropanoid biosynthesis and light signaling in plants.
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Affiliation(s)
- Matthew R Hemm
- Department of Biochemistry, Purdue University, 1516 South University Dr, West Lafayette, IN 47907-1153, USA
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30
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Iwasaki T, Nakahama KI, Nagano M, Fujioka A, Ohyanagi H, Shigeyoshi Y. A partial hepatectomy results in altered expression of clock-related and cyclic glyceraldehyde 3-phosphate dehydrogenase (GAPDH) genes. Life Sci 2004; 74:3093-102. [PMID: 15081575 DOI: 10.1016/j.lfs.2003.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2003] [Accepted: 11/10/2003] [Indexed: 11/26/2022]
Abstract
The liver is among the peripheral organs that display a clear circadian rhythmicity. To investigate whether specific pathological conditions affect circadian rhythms in the liver, we examined the expression profiles of the clock-related and glyceraldehyde 3-phosphate dehydrogenase (GADPH) genes following a partial hepatectomy in the mouse. This surgical procedure causes dynamic proliferation of residual hepatocytes and within one day of the operation the hepatectomized mice demonstrated higher expression of both mPer1 and mPer2 genes in the remaining liver tissue when compared to control mice that had undergone a Sham-operation. In contrast, the mCry1 gene in hepatectomized mice displayed a circadian gene expression profile that was similar to the control group. In addition, GAPDH levels, that demonstrated no oscillations in Sham-hepatectomized mice, underwent daily alterations following a partial hepatectomy. These findings suggest that the regenerative state of the liver affects the expression not only of clock-related genes but also of genes that are constitutively expressed under steady state conditions.
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Affiliation(s)
- Takuya Iwasaki
- Department of Surgery, Kinki University, School of Medicine, Osakasayama City, 589-8511, Japan
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31
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Mühlbauer E, Wolgast S, Finckh U, Peschke D, Peschke E. Indication of circadian oscillations in the rat pancreas. FEBS Lett 2004; 564:91-6. [PMID: 15094047 DOI: 10.1016/s0014-5793(04)00322-9] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Revised: 03/11/2004] [Accepted: 03/15/2004] [Indexed: 12/11/2022]
Abstract
The central circadian oscillator of the suprachiasmatic nucleus controls diurnal rhythmicity of the body with light as its dominant zeitgeber. Recently, peripheral oscillators have been detected in liver and heart, which follow as yet unidentified cues. In this study real-time reverse transcription-polymerase chain reaction (RT-PCR) was used in analysis of the expression of the major clock genes Per1, Per2, Bmal1, Cry1, Tim (timeless) and Clock, as well as of the output genes Dbp and Rev-erbalpha in the pancreatic tissue of rats. The results presented here indicate a robust circadian expression of clock genes (e.g. Per1 and Bmal1) and the probable existence of a peripheral oscillator in the pancreas. Whether this oscillator regulates the diverse functions of the islets of Langerhans remains to be elucidated.
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Affiliation(s)
- E Mühlbauer
- Saxon Academy of Sciences Leipzig, Karl-Tauchnitz-Str. 1, D-04107 Leipzig, Germany.
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32
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Ohgishi M, Saji K, Okada K, Sakai T. Functional analysis of each blue light receptor, cry1, cry2, phot1, and phot2, by using combinatorial multiple mutants in Arabidopsis. Proc Natl Acad Sci U S A 2004; 101:2223-8. [PMID: 14982991 PMCID: PMC356932 DOI: 10.1073/pnas.0305984101] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Blue light receptors in Arabidopsis include two types of proteins, cryptochromes and phototropins. Previous studies have suggested that the cryptochromes cry1 and cry2 function mainly in photomorphogenic responses and that the phototropins phot1 and phot2 mainly regulate photo-induced movements. Receptors in the same family have redundant functions, although their responses to the fluence rate of blue light differ. To uncover functions of blue light receptors that may be concealed by their functional redundancy, we conducted analyses of combinatorial multiple mutants of blue light receptors. Comparison of the responses of the quadruple mutant cry1 cry2 phot1 phot2 to blue light with those of related triple mutants revealed that cryptochromes function in blue light-dependent, random hypocotyl-bending and that phototropins function in one photomorphogenic response, cotyledon expansion. Microarray analysis suggested that cry1 and cry2 independently function as key regulators of early blue light-induced genes, whereas phot1 and phot2 play subsidiary roles in transcriptional regulation by blue light.
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Affiliation(s)
- Maki Ohgishi
- Laboratory for Genetic Regulatory Systems, Genomic Function Research Group, RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Kanagawa 230-0045, Japan
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Reisdorph NA, Small GD. The CPH1 gene of Chlamydomonas reinhardtii encodes two forms of cryptochrome whose levels are controlled by light-induced proteolysis. Plant Physiol 2004; 134:1546-54. [PMID: 15064387 PMCID: PMC419830 DOI: 10.1104/pp.103.031930] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2003] [Revised: 10/26/2003] [Accepted: 01/21/2004] [Indexed: 05/19/2023]
Abstract
Cryptochromes are proteins related to DNA photolyases and have been shown to function as blue-light photoreceptors and to play important roles in circadian rhythms in both plants and animals. The CPH1 gene from Chlamydomonas reinhardtii was originally predicted to encode a putative cryptochrome protein of 867 amino acids with a predicted molecular mass of 91 kD (Small et al., 1995). However, western blotting with antibodies specific to the CPH1 protein revealed the presence of two proteins that migrate at apparent molecular mass of approximately 126 and 143 kD. A reexamination of the assigned intron-exon boundaries has shown that the previously assigned intron 7 is in fact part of exon 7 which leads to a predicted protein of 1,007 amino acids corresponding to a size of 104.6 kD. The two forms of CPH1 that migrate slower on SDS-PAGE presumably result from unknown posttranslational modifications. In C. reinhardtii cells synchronized by light to dark cycles, the two slow migrating forms of CPH1 protein accumulate in the dark and disappear rapidly in the light. Both red and blue light are effective at inducing the degradation of the CPH1 proteins. Proteasomes are implicated because degradation is inhibited by MG132, a proteasome inhibitor. Studies with deletion mutants indicate that the C-terminal region is important for both the posttranslational modification and the protein's stability under both light and dark conditions.
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Affiliation(s)
- Nichole A Reisdorph
- Cellular and Molecular Biology Group, University of South Dakota, Vermillion, South Dakota 57069, USA
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Yasuo S, Watanabe M, Tsukada A, Takagi T, Iigo M, Shimada K, Ebihara S, Yoshimura T. Photoinducible phase-specific light induction of Cry1 gene in the pars tuberalis of Japanese quail. Endocrinology 2004; 145:1612-6. [PMID: 14684603 DOI: 10.1210/en.2003-1285] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Prolactin (PRL) secretion is regulated by photoperiod in mammals and birds. In mammals, the pars tuberalis (PT) in the pituitary is involved in the regulation of photoperiodic regulation of PRL secretion. In birds, however, hypothalamic vasoactive intestinal peptide is implicated in PRL secretion, and physiological roles of the avian PT remain unknown. In the present study, we show that PRL secretion increases under long days and short days with a night interruptive schedule, both of which also cause gonadal growth in Japanese quail. We have also found Cry1 gene expression in the PT of Japanese quail. Cry1 expression was rhythmic under long and short photoperiods in the PT, and the peak was phase delayed under a lengthened photoperiod. Moreover, expression of Cry1 gene was induced by a light pulse but only when given during the photoinducible phase. In our previous study, we have shown rhythmic Per2 gene expression with a peak in the PT during the early day under various photoperiods. When taken together with the results from the present study, different phase relationships between Per2 and Cry1 in the Japanese quail PT under different photoperiods may decode photoperiodic information and regulate photoperiodic PRL secretion in a manner similar to that of mammals.
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Affiliation(s)
- Shinobu Yasuo
- Division of Biomodeling, Graduate School of Bioagricultural Sciences, Nagoya University, Japan
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35
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Inada S, Ohgishi M, Mayama T, Okada K, Sakai T. RPT2 is a signal transducer involved in phototropic response and stomatal opening by association with phototropin 1 in Arabidopsis thaliana. Plant Cell 2004; 16:887-96. [PMID: 15031408 PMCID: PMC412863 DOI: 10.1105/tpc.019901] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2003] [Accepted: 02/08/2004] [Indexed: 05/19/2023]
Abstract
Phototropin 1 (phot1) and phot2, which are blue light receptor kinases, function in blue light-induced hypocotyl phototropism, chloroplast relocation, and stomatal opening in Arabidopsis (Arabidopsis thaliana). Previous studies have shown that the proteins RPT2 (for ROOT PHOTOTROPISM2) and NPH3 (for NONPHOTOTROPIC HYPOCOTYL3) transduce signals downstream of phototropins to induce the phototropic response. However, the involvement of RPT2 and NPH3 in stomatal opening and in chloroplast relocation mediated by phot1 and phot2 was unknown. Genetic analysis of the rpt2 mutant and of a series of double mutants indicates that RPT2 is involved in the phot1-induced phototropic response and stomatal opening but not in chloroplast relocation or phot2-induced movements. Biochemical analyses indicate that RPT2 is purified in the crude microsomal fraction, as well as phot1 and NPH3, and that RPT2 makes a complex with phot1 in vivo. On the other hand, NPH3 is not necessary for stomatal opening or chloroplast relocation. Thus, these results suggest that phot1 and phot2 choose different signal transducers to induce three responses: phototropic response of hypocotyl, stomatal opening, and chloroplast relocation.
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Affiliation(s)
- Sayaka Inada
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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36
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Abstract
Circadian rhythms are driven by molecular clocks composed of interlocking transcription/translation feedback loops. CRYPTOCHROME (CRY) proteins are critical components of these clocks and repress the activity of the transcription factor heterodimer CLOCK/BMAL1. Unlike the homologous DNA repair enzyme 6-4 PHOTOLYASE, CRYs have extended carboxyl-terminal tails and cannot repair DNA damage (reviewed in ). Unlike mammals, Xenopus laevis contains both CRYs (xCRYs) and 6-4 PHOTOLYASE (xPHOTOLYASE), providing an excellent comparative tool to study CRY repressive function. We can extend findings to CRYs in general because xCRYs share high sequence homology with mammalian CRYs. We show here that deletion of xCRYs' C-terminal domain produces proteins that are, like xPHOTOLYASE, unable to suppress CLOCK/BMAL1 activation. However, these truncations also cause the proteins to be cytoplasmically localized. A heterologous nuclear localization signal (NLS) restores the truncation mutants' nuclear localization and repressive activity. Our results demonstrate that the CRYs' C termini are essential for nuclear localization but not necessary for the suppression of CLOCK/BMAL1 activation; this finding indicates that these two functions reside in separable domains. Furthermore, the functional differences between CRYs and PHOTOLYASE can be attributed to the few amino acid changes in the conserved portions of these proteins.
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Affiliation(s)
- Haisun Zhu
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
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Abstract
BACKGROUND The circadian clock of Drosophila is able to drive behavioral rhythms for many weeks in continuous darkness (DD). The endogenous rhythm generator is thought to be generated by interlocked molecular feedback loops involving circadian transcriptional and posttranscriptional regulation of several clock genes, including period. However, all attempts to demonstrate sustained rhythms of clock gene expression in DD have failed, making it difficult to link the molecular clock models with the circadian behavioral rhythms. Here we restricted expression of a novel period-luciferase transgene to certain clock neurons in the Drosophila brain, permitting us to monitor reporter gene activity in these cells in real-time. RESULTS We show that only a subset of the previously described pacemaker neurons is able to sustain PERIOD protein oscillations after 5 days in constant darkness. In addition, we identified a sustained and autonomous molecular oscillator in a group of clock neurons in the dorsal brain with heretofore unknown function. We found that these "dorsal neurons" (DNs) can synchronize behavioral rhythms and that light input into these cells involves the blue-light photoreceptor cryptochrome. CONCLUSIONS Our results suggest that the DNs play a prominent role in controlling locomotor behavior when flies are exposed to natural light-dark cycles. Analysis of similar "stable mosaic" transgenes should help to reveal the function of the other clock neuronal clusters within the fly brain.
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Affiliation(s)
- Shobi Veleri
- Universität Regensburg, Institut für Zoologie, Lehrstuhl für Entwicklungsbiologie, 93040, Regensburg, Germany.
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Abstract
Many plants flower in response to seasonal fluctuations in day length. The CONSTANS (CO) gene of Arabidopsis promotes flowering in long days. Flowering is induced when CO messenger RNA expression coincides with the exposure of plants to light. However, how this promotes CO activity is unknown. We show that light stabilizes nuclear CO protein in the evening, whereas in the morning or in darkness the protein is degraded by the proteasome. Photoreceptors regulate CO stability and act antagonistically to generate daily rhythms in CO abundance. This layer of regulation refines the circadian rhythm in CO messenger RNA and is central to the mechanism by which day length controls flowering.
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Affiliation(s)
- Federico Valverde
- Max Planck Institute for Plant Breeding, Carl-von-Linne Weg 10, D-50829 Cologne, Germany
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Affiliation(s)
- John Klejnot
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA
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40
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Abstract
Type 1 phototropin, one of the blue light receptors responsible for phototropism, is encoded in peas by at least two genes, PsPHOT1A and PsPHOT1B (formerly PsPK4 and PsPK5), both of which are more similar to Arabidopsis PHOT1 than to Arabidopsis PHOT2. We show here that PsPHOT1B encodes a full-length phototropin, whose expression pattern suggests that Psphot1b is the predominant phot1-type phototropin in etiolated seedlings. The gene encoding the other type 1 phototropin, PsPHOT1A, is expressed at low levels, with its highest levels in the leaves and stems of more mature, light-grown plants. Studies with phyA, phyB and the phyAphyB double mutants show that phyA and phyB have partially redundant roles in the reduction of PsPHOT1B expression under red light.
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Affiliation(s)
- Robert C Elliott
- School of Plant Science, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia.
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41
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Thompson CL, Selby CP, Partch CL, Plante DT, Thresher RJ, Araujo F, Sancar A. Further evidence for the role of cryptochromes in retinohypothalamic photoreception/phototransduction. ACTA ACUST UNITED AC 2004; 122:158-66. [PMID: 15010208 DOI: 10.1016/j.molbrainres.2003.12.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/08/2003] [Indexed: 11/20/2022]
Abstract
Cryptochrome is a blue-light absorbing photopigment that has been proposed to act as a photoreceptor for a variety of nonvisual light-responsive tasks. While mouse models have suggested an important role for cryptochrome in nonvisual photoreception, there are no biochemical data demonstrating the functional photoreceptive capability of cryptochrome in mice. There are two models that describe the effect of cryptochrome on light responsive events: (1) cryptochrome is a photoreceptor or (2) cryptochrome is required for either normal phototransduction from the retina to the brain or for normal transcriptional regulation in the brain, irrespective of light. To differentiate between these two models, we have examined the integrity of the regulatory mechanism of c-fos in cryptochromeless cell lines and in the suprachiasmatic nucleus (SCN) of cryptochromeless mice. Photoinduction of c-fos mRNA in the SCN can be used as a marker for circadian photoreception/phototransduction and it is drastically reduced in mice lacking cryptochromes. Our results indicate that light-independent transcription regulatory system of c-fos is normal in cryptochromeless mice and that the reduced c-fos light responsiveness in the absence of cryptochromes is due to a loss of photoreceptor function.
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Affiliation(s)
- Carol L Thompson
- Department of Biochemistry and Biophysics CB#7260, School of Medicine, University of North Carolina, Chapel Hill, NC 27599-7260, USA
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42
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Knieb E, Salomon M, Rüdiger W. Tissue-specific and subcellular localization of phototropin determined by immuno-blotting. Planta 2004; 218:843-51. [PMID: 14634818 DOI: 10.1007/s00425-003-1164-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2003] [Accepted: 10/20/2003] [Indexed: 05/05/2023]
Abstract
Phototropin (phot) is a UV/blue- light receptor mediating phototropic reactions of plants as a response to unilateral irradiation. Using an antiserum directed against the N-terminal part of Arabidopsis phot1, we show here cross-reaction with phototropin from Avena sativa, Eruca sativa, Glycine max, Lepidium sativum, Lycopersicon esculentum, Pisum sativum, Sinapis alba, and Zea mays. In all investigated plants, blue light irradiation led to a gel mobility shift of phototropin corresponding to an apparent increase in size of 2-3 kDa. This increase is transient: the apparent size of the phototropin band reverted back to the original size in the dark within 60-90 min. The capacity for in vitro phosphorylation increased to 350% ( A. sativa) and 200% ( L. sativum) at 90 min after a blue light pulse without an increase in the amount of phototropin protein. Starting from coleoptile tips of monocots that contained the highest concentration of phototropin, we found an exponential decrease in basipetal sections of equal size while a linear decrease was determined for dicots in basipetal sections starting from the section below the hypocotyl hook. We confirmed the membrane association of all phototropin in dark-grown seedlings; after a 2-min blue light pulse, however, 20% of phototropin was found in the cytosolic fraction and only 80% in the membrane fraction. Both fractions showed the gel mobility shift indicating light-dependent autophosphorylation. Detergent-free solubilization of phototropin with chaotropic reagents was investigated with etiolated A. sativa seedlings. Up to 95% of phototropin was solubilized with a mixture of sodium bromide and sodium diphosphate, and subsequently subjected to affinity purification using Cibachron Blue 3GA-agarose as a dinucleotide analogue. Immediately after solubilization, soluble phototropin still showed blue-light-dependent autophosphorylation but lost its activity within less than 1 h.
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Affiliation(s)
- Elke Knieb
- Department of Biology I (Botanik), Ludwig-Maximilians-Universität München, Menzingerstr. 67, 80638, München, Germany
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Tei H. [Genetic regulation of circadian rhythms]. Tanpakushitsu Kakusan Koso 2004; 49:456-62. [PMID: 14976772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
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Abstract
Earlier detailed studies of cnidarian planula larvae have revealed a simple nervous system but no eyes or identifiable light sensing structures. Here, we describe the planula of a box jellyfish, Tripedalia cystophora, and report that these larvae have an extremely simple organization with no nervous system at all. Their only advanced feature is the presence of 10-15 pigment-cup ocelli, evenly spaced across the posterior half of the larval ectoderm. The ocelli are single cell structures containing a cup of screening pigment filled with presumably photosensory microvilli. These rhabdomeric photoreceptors have no neural connections to any other cells, but each has a well-developed motor-cilium, appearing to be the only means by which light can control the behaviour of the larva. The ocelli are thus self-contained sensory-motor entities, making a nervous system superfluous.
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Affiliation(s)
- Karin Nordström
- Department of Cell and Organism Biology, Zoology, Lund University, Helgonav. 3, 223 62 Lund, Sweden
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45
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van der Horst MA, Hellingwerf KJ. Photoreceptor proteins, "star actors of modern times": a review of the functional dynamics in the structure of representative members of six different photoreceptor families. Acc Chem Res 2004; 37:13-20. [PMID: 14730990 DOI: 10.1021/ar020219d] [Citation(s) in RCA: 283] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Six well-characterized photoreceptor families function in Nature to mediate light-induced signal transduction: the rhodopsins, phytochromes, xanthopsins, cryptochromes, phototropins, and BLUF proteins. The first three catalyze E/Z isomerization of retinal, phytochromobilin, and p-coumaric acid, respectively, while the last three all have a different flavin-based photochemistry. For many of these photoreceptor proteins, (many of) the details of the conversion of the light-induced change in configuration of their chromophore into a signaling state and eventually a biological response have been resolved. Some members of the rhodopsins, the xanthopsins, and the phototropins are so well characterized that they function as model systems to study (receptor) protein dynamics and (un)folding.
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Affiliation(s)
- Michael A van der Horst
- Laboratory for Microbiology, Swammerdam Institute for Life Sciences, BioCentrum Amsterdam, University of Amsterdam, NL-1018 WV Amsterdam, The Netherlands
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46
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Abstract
Eukaryotes and some prokaryotes have adapted to the 24 h day/night cycle by evolving circadian clocks, which now control very many aspects of metabolism, physiology and behaviour. Circadian clocks in plants are entrained by light and temperature signals from the environment. The relative timing of internal and external events depends upon a complex interplay of interacting rhythmic controls and environmental signals, including changes in the period of the clock. Several of the phytochrome and cryptochrome photoreceptors responsible have been identified. This review concentrates on the resulting patterns of entrainment and on the multiple proposed mechanisms of light input to the circadian oscillator components.
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Affiliation(s)
- Andrew J Millar
- Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK.
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47
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Simonneaux V, Poirel VJ, Garidou ML, Nguyen D, Diaz-Rodriguez E, Pévet P. Daily rhythm and regulation of clock gene expression in the rat pineal gland. ACTA ACUST UNITED AC 2004; 120:164-72. [PMID: 14741406 DOI: 10.1016/j.molbrainres.2003.10.019] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Rhythms in pineal melatonin synthesis are controlled by the biological clock located in the suprachiasmatic nuclei. The endogenous clock oscillations rely upon genetic mechanisms involving clock genes coding for transcription factors working in negative and positive feedback loops. Most of these clock genes are expressed rhythmically in other tissues. Because of the peculiar role of the pineal gland in the photoneuroendocrine axis regulating biological rhythms, we studied whether clock genes are expressed in the rat pineal gland and how their expression is regulated.Per1, Per3, Cry2 and Cry1 clock genes are expressed in the pineal gland and their transcription is increased during the night. Analysis of the regulation of these pineal clock genes indicates that they may be categorized into two groups. Expression of Per1 and Cry2 genes shows the following features: (1) the 24 h rhythm persists, although damped, in constant darkness; (2) the nocturnal increase is abolished following light exposure or injection with a beta-adrenergic antagonist; and (3) the expression during daytime is stimulated by an injection with a beta-adrenergic agonist. In contrast, Per3 and Cry1 day and night mRNA levels are not responsive to adrenergic ligands (as previously reported for Per2) and daily expression of Per3 and Cry1 appears strongly damped or abolished in constant darkness. These data show that the expression of Per1 and Cry2 in the rat pineal gland is regulated by the clock-driven changes in norepinephrine, in a similar manner to the melatonin rhythm-generating enzyme arylalkylamine N-acetyltransferase. The expression of Per3 and Cry1 displays a daily rhythm not regulated by norepinephrine, suggesting the involvement of another day/night regulated transmitter(s).
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Affiliation(s)
- V Simonneaux
- Neurobiologie des Rythmes, UMR-CNRS 7518, Lab Zoology, Université Louis Pasteur, 12 rue de l'Université, 67000, Strasbourg, France.
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48
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Chappell PE, White RS, Mellon PL. Circadian gene expression regulates pulsatile gonadotropin-releasing hormone (GnRH) secretory patterns in the hypothalamic GnRH-secreting GT1-7 cell line. J Neurosci 2003; 23:11202-13. [PMID: 14657179 PMCID: PMC2932475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2003] [Revised: 09/03/2003] [Accepted: 10/08/2003] [Indexed: 04/27/2023] Open
Abstract
Although it has long been established that episodic secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus is required for normal gonadotropin release, the molecular and cellular mechanisms underlying the synchronous release of GnRH are primarily unknown. We used the GT1-7 mouse hypothalamic cell line as a model for GnRH secretion, because these cells release GnRH in a pulsatile pattern similar to that observed in vivo. To explore possible molecular mechanisms governing secretory timing, we investigated the role of the molecular circadian clock in regulation of GnRH secretion. GT1-7 cells express many known core circadian clock genes, and we demonstrate that oscillations of these components can be induced by stimuli such as serum and the adenylyl cyclase activator forskolin, similar to effects observed in fibroblasts. Strikingly, perturbation of circadian clock function in GT1-7 cells by transient expression of the dominant-negative Clock-Delta19 gene disrupts normal ultradian patterns of GnRH secretion, significantly decreasing mean pulse frequency. Additionally, overexpression of the negative limb clock gene mCry1 in GT1-7 cells substantially increases GnRH pulse amplitude without a commensurate change in pulse frequency, demonstrating that an endogenous biological clock is coupled to the mechanism of neurosecretion in these cells and can regulate multiple secretory parameters. Finally, mice harboring a somatic mutation in the Clock gene are subfertile and exhibit a substantial increase in estrous cycle duration as revealed by examination of vaginal cytology. This effect persists in normal light/dark (LD) cycles, suggesting that a suprachiasmatic nucleus-independent endogenous clock in GnRH neurons is required for eliciting normal pulsatile patterns of GnRH secretion.
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Affiliation(s)
- Patrick E Chappell
- Department of Reproductive Medicine, University of California, San Diego, School of Medicine, La Jolla, California 92093-0674, USA
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49
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Affiliation(s)
- M V Srinivasan
- Centre for Visual Science, Research School of Biological Sciences, Australian National University, PO Box 475, Canberra, ACT 2601, Australia.
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50
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El-Din El-Assal S, Alonso-Blanco C, Peeters AJM, Wagemaker C, Weller JL, Koornneef M. The role of cryptochrome 2 in flowering in Arabidopsis. Plant Physiol 2003; 133:1504-16. [PMID: 14605222 PMCID: PMC300707 DOI: 10.1104/pp.103.029819] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Revised: 08/13/2003] [Accepted: 09/15/2003] [Indexed: 05/18/2023]
Abstract
We have investigated the genetic interactions between cry2 and the various flowering pathways in relation to the regulation of flowering by photoperiod and vernalization. For this, we combined three alleles of CRY2, the wild-type CRY2-Landsberg erecta (Ler), a cry2 loss-of-function null allele, and the gain-of-function CRY2-Cape Verde Islands (Cvi), with mutants representing the various photoreceptors and flowering pathways. The analysis of CRY2 alleles combined with photoreceptor mutants showed that CRY2-Cvi could compensate the loss of phyA and cry1, also indicating that cry2 does not require functional phyA or cry1. The analysis of mutants of the photoperiod pathway showed epistasis of co and gi to the CRY2 alleles, indicating that cry2 needs the product of CO and GI genes to promote flowering. All double mutants of this pathway showed a photoperiod response very much reduced compared with Ler. In contrast, mutations in the autonomous pathway genes were additive to the CRY2 alleles, partially overcoming the effects of CRY2-Cvi and restoring day length responsiveness. The three CRY2 alleles were day length sensitive when combined with FRI-Sf2 and/or FLC-Sf2 genes, which could be reverted when the delay of flowering caused by FRI-Sf2 and FLC-Sf2 alleles was removed by vernalization. In addition, we looked at the expression of FLC and CRY2 genes and showed that CRY2 is negatively regulated by FLC. These results indicate an interaction between the photoperiod and the FLC-dependent pathways upstream to the common downstream targets of both pathways, SOC1 and FT.
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Affiliation(s)
- Salah El-Din El-Assal
- Laboratories of Genetics, Wageningen University, Arboretumlaan 4, NL-6703 BD Wageningen, The Netherlands
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