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Bidell D, Feige ND, Triphan T, Müller C, Pauls D, Helfrich-Förster C, Selcho M. Photoreceptors for immediate effects of light on circadian behavior. iScience 2024; 27:109819. [PMID: 38770135 PMCID: PMC11103378 DOI: 10.1016/j.isci.2024.109819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 03/12/2024] [Accepted: 04/24/2024] [Indexed: 05/22/2024] Open
Abstract
Animals need to sharpen their behavioral output in order to adapt to a variable environment. Hereby, light is one of the most pivotal environmental signals and thus behavioral plasticity in response to light can be observed in diurnal animals, including humans. Furthermore, light is the main entraining signal of the clock, yet immediate effects of light enhance or overwrite circadian output and thereby mask circadian behavior. In Drosophila, such masking effects are most evident as a lights-on response in two behavioral rhythms - the emergence of the adult insect from the pupa, called eclosion, and the diurnal rhythm of locomotor activity. Here, we show that the immediate effect of light on eclosion depends solely on R8 photoreceptors of the eyes. In contrast, the increase in activity by light at night is triggered by different cells and organs that seem to compensate for the loss of each other, potentially to ensure behavioral plasticity.
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Affiliation(s)
- Daniel Bidell
- Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
| | - Natalie-Danielle Feige
- Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
| | - Tilman Triphan
- Department of Genetics, Institute of Biology, Leipzig University, Leipzig, Germany
| | - Claudia Müller
- Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
| | - Dennis Pauls
- Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
| | | | - Mareike Selcho
- Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
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2
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Xiao N, Xu S, Li ZK, Tang M, Mao R, Yang T, Ma SX, Wang PH, Li MT, Sunilkumar A, Rouyer F, Cao LH, Luo DG. A single photoreceptor splits perception and entrainment by cotransmission. Nature 2023; 623:562-570. [PMID: 37880372 PMCID: PMC10651484 DOI: 10.1038/s41586-023-06681-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 09/26/2023] [Indexed: 10/27/2023]
Abstract
Vision enables both image-forming perception, driven by a contrast-based pathway, and unconscious non-image-forming circadian photoentrainment, driven by an irradiance-based pathway1,2. Although two distinct photoreceptor populations are specialized for each visual task3-6, image-forming photoreceptors can additionally contribute to photoentrainment of the circadian clock in different species7-15. However, it is unknown how the image-forming photoreceptor pathway can functionally implement the segregation of irradiance signals required for circadian photoentrainment from contrast signals required for image perception. Here we report that the Drosophila R8 photoreceptor separates image-forming and irradiance signals by co-transmitting two neurotransmitters, histamine and acetylcholine. This segregation is further established postsynaptically by histamine-receptor-expressing unicolumnar retinotopic neurons and acetylcholine-receptor-expressing multicolumnar integration neurons. The acetylcholine transmission from R8 photoreceptors is sustained by an autocrine negative feedback of the cotransmitted histamine during the light phase of light-dark cycles. At the behavioural level, elimination of histamine and acetylcholine transmission impairs R8-driven motion detection and circadian photoentrainment, respectively. Thus, a single type of photoreceptor can achieve the dichotomy of visual perception and circadian photoentrainment as early as the first visual synapses, revealing a simple yet robust mechanism to segregate and translate distinct sensory features into different animal behaviours.
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Affiliation(s)
- Na Xiao
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Shuang Xu
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
| | - Ze-Kai Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
| | - Min Tang
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Renbo Mao
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
| | - Tian Yang
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
| | - Si-Xing Ma
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
| | - Peng-Hao Wang
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
| | - Meng-Tong Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
- Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY, USA
| | - Ajay Sunilkumar
- Institut des Neurosciences Paris-Saclay, Université Paris-Sud, Université Paris-Saclay, CNRS, Gif-sur-Yvette, France
| | - François Rouyer
- Institut des Neurosciences Paris-Saclay, Université Paris-Sud, Université Paris-Saclay, CNRS, Gif-sur-Yvette, France
| | - Li-Hui Cao
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
| | - Dong-Gen Luo
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China.
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China.
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
- School of Life Sciences, Peking University, Beijing, China.
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
- Chinese Institute for Brain Research, Beijing, China.
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3
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Hirata K, Shiga S. Bolwig Organ and Its Role in the Photoperiodic Response of Sarcophaga similis Larvae. INSECTS 2023; 14:115. [PMID: 36835683 PMCID: PMC9959995 DOI: 10.3390/insects14020115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/18/2023] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
Flesh-fly Sarcophaga similis larvae exhibit a photoperiodic response, in which short days induce pupal diapause for seasonal adaptation. Although the spectral sensitivity of photoperiodic photoreception is known, the photoreceptor organ remains unclear. We morphologically identified the Bolwig organ, a larval-photoreceptor identified in several other fly species, and examined the effects of its removal on the photoperiodic response in S. similis. Backfill-staining and embryonic-lethal-abnormal-vision (ELAV) immunohistochemical-staining identified ~34 and 38 cells, respectively, in a spherical body at the ocular depression of the cephalopharyngeal skeleton, suggesting that the spherical body is the Bolwig organ in S. similis. Forward-fill and immunohistochemistry revealed that Bolwig-organ neurons terminate in the vicinity of the dendritic fibres of pigment-dispersing factor-immunoreactive and potential circadian-clock neurons in the brain. After surgical removal of the Bolwig-organ regions, diapause incidence was not significantly different between short and long days, and was similar to that in the insects with an intact organ, under constant darkness. However, diapause incidence was not significantly different between the control and Bolwig-organ-removed insects for each photoperiod. These results suggest that the Bolwig organ contributes partially to photoperiodic photoreception, and that other photoreceptors may also be involved.
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Affiliation(s)
- Kazuné Hirata
- Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka 560-0043, Osaka, Japan
- Center for Ecological Research, Kyoto University, Otsu 520-2133, Shiga, Japan
| | - Sakiko Shiga
- Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka 560-0043, Osaka, Japan
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4
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Damulewicz M, Tyszka A, Pyza E. Light exposure during development affects physiology of adults in Drosophila melanogaster. Front Physiol 2022; 13:1008154. [PMID: 36505068 PMCID: PMC9732085 DOI: 10.3389/fphys.2022.1008154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 11/14/2022] [Indexed: 11/27/2022] Open
Abstract
Light is one of most important factors synchronizing organisms to day/night cycles in the environment. In Drosophila it is received through compound eyes, Hofbauer-Buchner eyelet, ocelli, using phospholipase C-dependent phototransduction and by deep brain photoreceptors, like Cryptochrome. Even a single light pulse during early life induces larval-time memory, which synchronizes the circadian clock and maintains daily rhythms in adult flies. In this study we investigated several processes in adult flies after maintaining their embryos, larvae and pupae in constant darkness (DD) until eclosion. We found that the lack of external light during development affects sleep time, by reduction of night sleep, and in effect shift to the daytime. However, disruption of internal CRY- dependent photoreception annuls this effect. We also observed changes in the expression of genes encoding neurotransmitters and their receptors between flies kept in different light regime. In addition, the lack of light during development results in decreasing size of mushroom bodies, involved in sleep regulation. Taking together, our results show that presence of light during early life plays a key role in brain development and affects adult behavior.
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Ikeda K, Kataoka M, Tanaka NK. Nonsynaptic Transmission Mediates Light Context-Dependent Odor Responses in Drosophila melanogaster. J Neurosci 2022; 42:8621-8628. [PMID: 36180227 PMCID: PMC9671575 DOI: 10.1523/jneurosci.1106-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 11/21/2022] Open
Abstract
Recent connectome analyses of the entire synaptic circuit in the nervous system have provided tremendous insights into how neural processing occurs through the synaptic relay of neural information. Conversely, the extent to which ephaptic transmission which does not depend on the synapses contributes to the relay of neural information, especially beyond a distance between adjacent neurons and to neural processing remains unclear. We show that ephaptic transmission mediated by extracellular potential changes in female Drosophila melanogaster can reach >200 µm, equivalent to the depth of its brain. Furthermore, ephaptic transmission driven by retinal photoreceptor cells mediates light-evoked firing rate increases in olfactory sensory neurons. These results indicate that ephaptic transmission contributes to sensory responses that can change momentarily in a context-dependent manner.SIGNIFICANCE STATEMENT Although extracellular field potential activities are commonly observed in many nervous systems, this activity has been generally considered as a side effect of synchronized spiking of neurons. This study, however, shows that field potential changes in retinae evoked by a sensory stimulus can control the excitability of distant neurons in vivo and mediates multimodal sensory integration in Drosophila melanogaster As such ephaptic transmission is more effective at a short distance, the ephaptic transmission from the retinae may contribute significantly to firing rate changes in downstream neurons of the photoreceptor cells in the optic lobe.
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Affiliation(s)
- Kazuaki Ikeda
- Division of Biology, Department of Biological Sciences, School of Science, Hokkaido University, Sapporo, 060-0810, Japan
- Graduate School of Life Sciences, Hokkaido University, Sapporo, 060-0810, Japan
| | - Masaki Kataoka
- Division of Biology, Department of Biological Sciences, School of Science, Hokkaido University, Sapporo, 060-0810, Japan
- Graduate School of Life Sciences, Hokkaido University, Sapporo, 060-0810, Japan
| | - Nobuaki K Tanaka
- Division of Biology, Department of Biological Sciences, School of Science, Hokkaido University, Sapporo, 060-0810, Japan
- Graduate School of Life Sciences, Hokkaido University, Sapporo, 060-0810, Japan
- Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
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6
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Kaladchibachi S, Negelspach DC, Zeitzer JM, Fernandez FX. Investigation of the aging clock's intermittent-light responses uncovers selective deficits to green millisecond flashes. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2022; 228:112389. [PMID: 35086027 DOI: 10.1016/j.jphotobiol.2022.112389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
The central pacemaker of flies, rodents, and humans generates less robust circadian output signals across normative aging. It is not well understood how changes in light sensitivity might contribute to this phenomenon. In the present study, we summarize results from an extended data series (n = 5681) showing that the locomotor activity rhythm of aged Drosophila can phase-shift normally to intermittently spaced episodes of bright polychromatic light exposure (600 lx) but that deficits emerge in response to 8, 16, and 120-millisecond flashes of narrowband blue (λm, 452 nm) and green (λm, 525 nm) LED light. For blue, phase-resetting of the activity rhythm of older flies is not as energy efficient as it is in younger flies at the fastest flash-exposures tested (8 milliseconds), suggesting there might be different floors of light duration necessary to incur photohabituation in each age group. For green, the responses of older flies are universally crippled relative to those of younger flies across the slate of protocols we tested. The difference in green flash photosensitivity is one of the most salient age-related phenotypes that has been documented in the circadian phase-shifting literature thus far. These data provide further impetus for investigations on pacemaker aging and how it might relate to changes in the circadian system's responses to particular sequences of light exposure tuned for wavelength, intensity, duration, and tempo.
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Affiliation(s)
| | | | - Jamie M Zeitzer
- Department of Psychiatry and Behavioral Sciences and Stanford Center for Sleep Sciences and Medicine, Stanford University, Stanford, CA, USA; Mental Illness Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Fabian-Xosé Fernandez
- Department of Psychology, University of Arizona, Tucson, AZ, USA; Department of Neurology, University of Arizona, Tucson, AZ, USA; BIO5 and McKnight Brain Research Institutes, University of Arizona, Tucson, AZ, USA.
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7
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Beer K, Härtel S, Helfrich-Förster C. The pigment-dispersing factor neuronal network systematically grows in developing honey bees. J Comp Neurol 2021; 530:1321-1340. [PMID: 34802154 DOI: 10.1002/cne.25278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 10/25/2021] [Accepted: 11/11/2021] [Indexed: 11/08/2022]
Abstract
The neuropeptide pigment-dispersing factor (PDF) plays a prominent role in the circadian clock of many insects including honey bees. In the honey bee brain, PDF is expressed in about 15 clock neurons per hemisphere that lie between the central brain and the optic lobes. As in other insects, the bee PDF neurons form wide arborizations in the brain, but certain differences are evident. For example, they arborize only sparsely in the accessory medulla (AME), which serves as important communication center of the circadian clock in cockroaches and flies. Furthermore, all bee PDF neurons cluster together, which makes it impossible to distinguish individual projections. Here, we investigated the developing bee PDF network and found that the first three PDF neurons arise in the third larval instar and form a dense network of varicose fibers at the base of the developing medulla that strongly resembles the AME of hemimetabolous insects. In addition, they send faint fibers toward the lateral superior protocerebrum. In last larval instar, PDF cells with larger somata appear and send fibers toward the distal medulla and the medial protocerebrum. In the dorsal part of the medulla serpentine layer, a small PDF knot evolves from which PDF fibers extend ventrally. This knot disappears during metamorphosis and the varicose arborizations in the putative AME become fainter. Instead, a new strongly stained PDF fiber hub appears in front of the lobula. Simultaneously, the number of PDF neurons increases and the PDF neuronal network in the brain gets continuously more complex.
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Affiliation(s)
- Katharina Beer
- Department of Neurobiology and Genetics, Biocenter, University of Würzburg, Würzburg, Germany
| | - Stephan Härtel
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Würzburg, Germany
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8
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Montell C. Drosophila sensory receptors-a set of molecular Swiss Army Knives. Genetics 2021; 217:1-34. [PMID: 33683373 DOI: 10.1093/genetics/iyaa011] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 11/17/2020] [Indexed: 01/01/2023] Open
Abstract
Genetic approaches in the fruit fly, Drosophila melanogaster, have led to a major triumph in the field of sensory biology-the discovery of multiple large families of sensory receptors and channels. Some of these families, such as transient receptor potential channels, are conserved from animals ranging from worms to humans, while others, such as "gustatory receptors," "olfactory receptors," and "ionotropic receptors," are restricted to invertebrates. Prior to the identification of sensory receptors in flies, it was widely assumed that these proteins function in just one modality such as vision, smell, taste, hearing, and somatosensation, which includes thermosensation, light, and noxious mechanical touch. By employing a vast combination of genetic, behavioral, electrophysiological, and other approaches in flies, a major concept to emerge is that many sensory receptors are multitaskers. The earliest example of this idea was the discovery that individual transient receptor potential channels function in multiple senses. It is now clear that multitasking is exhibited by other large receptor families including gustatory receptors, ionotropic receptors, epithelial Na+ channels (also referred to as Pickpockets), and even opsins, which were formerly thought to function exclusively as light sensors. Genetic characterizations of these Drosophila receptors and the neurons that express them also reveal the mechanisms through which flies can accurately differentiate between different stimuli even when they activate the same receptor, as well as mechanisms of adaptation, amplification, and sensory integration. The insights gleaned from studies in flies have been highly influential in directing investigations in many other animal models.
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Affiliation(s)
- Craig Montell
- Department of Molecular, Cellular, and Developmental Biology, The Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA
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9
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Pagni M, Haikala V, Oberhauser V, Meyer PB, Reiff DF, Schnaitmann C. Interaction of “chromatic” and “achromatic” circuits in Drosophila color opponent processing. Curr Biol 2021; 31:1687-1698.e4. [DOI: 10.1016/j.cub.2021.01.105] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 02/07/2023]
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10
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Mazzotta GM, Damulewicz M, Cusumano P. Better Sleep at Night: How Light Influences Sleep in Drosophila. Front Physiol 2020; 11:997. [PMID: 33013437 PMCID: PMC7498665 DOI: 10.3389/fphys.2020.00997] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 07/22/2020] [Indexed: 01/25/2023] Open
Abstract
Sleep-like states have been described in Drosophila and the mechanisms and factors that generate and define sleep-wake profiles in this model organism are being thoroughly investigated. Sleep is controlled by both circadian and homeostatic mechanisms, and environmental factors such as light, temperature, and social stimuli are fundamental in shaping and confining sleep episodes into the correct time of the day. Among environmental cues, light seems to have a prominent function in modulating the timing of sleep during the 24 h and, in this review, we will discuss the role of light inputs in modulating the distribution of the fly sleep-wake cycles. This phenomenon is of growing interest in the modern society, where artificial light exposure during the night is a common trait, opening the possibility to study Drosophila as a model organism for investigating shift-work disorders.
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Affiliation(s)
| | - Milena Damulewicz
- Department of Cell Biology and Imaging, Jagiellonian University, Kraków, Poland
| | - Paola Cusumano
- Department of Biology, University of Padova, Padua, Italy
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11
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Damulewicz M, Ispizua JI, Ceriani MF, Pyza EM. Communication Among Photoreceptors and the Central Clock Affects Sleep Profile. Front Physiol 2020; 11:993. [PMID: 32848895 PMCID: PMC7431659 DOI: 10.3389/fphys.2020.00993] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/22/2020] [Indexed: 12/17/2022] Open
Abstract
Light is one of the most important factors regulating rhythmical behavior of Drosophila melanogaster. It is received by different photoreceptors and entrains the circadian clock, which controls sleep. The retina is known to be essential for light perception, as it is composed of specialized light-sensitive cells which transmit signal to deeper parts of the brain. In this study we examined the role of specific photoreceptor types and peripheral oscillators located in these cells in the regulation of sleep pattern. We showed that sleep is controlled by the visual system in a very complex way. Photoreceptors expressing Rh1, Rh3 are involved in night-time sleep regulation, while cells expressing Rh5 and Rh6 affect sleep both during the day and night. Moreover, Hofbauer-Buchner (HB) eyelets which can directly contact with s-LN v s and l-LN v s play a wake-promoting function during the day. In addition, we showed that L2 interneurons, which receive signal from R1-6, form direct synaptic contacts with l-LN v s, which provides new light input to the clock network.
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Affiliation(s)
- Milena Damulewicz
- Department of Cell Biology and Imaging, Jagiellonian University, Kraków, Poland
| | - Juan I. Ispizua
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | - Maria F. Ceriani
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | - Elzbieta M. Pyza
- Department of Cell Biology and Imaging, Jagiellonian University, Kraków, Poland
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12
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Davis FP, Nern A, Picard S, Reiser MB, Rubin GM, Eddy SR, Henry GL. A genetic, genomic, and computational resource for exploring neural circuit function. eLife 2020; 9:e50901. [PMID: 31939737 PMCID: PMC7034979 DOI: 10.7554/elife.50901] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 01/14/2020] [Indexed: 12/11/2022] Open
Abstract
The anatomy of many neural circuits is being characterized with increasing resolution, but their molecular properties remain mostly unknown. Here, we characterize gene expression patterns in distinct neural cell types of the Drosophila visual system using genetic lines to access individual cell types, the TAPIN-seq method to measure their transcriptomes, and a probabilistic method to interpret these measurements. We used these tools to build a resource of high-resolution transcriptomes for 100 driver lines covering 67 cell types, available at http://www.opticlobe.com. Combining these transcriptomes with recently reported connectomes helps characterize how information is transmitted and processed across a range of scales, from individual synapses to circuit pathways. We describe examples that include identifying neurotransmitters, including cases of apparent co-release, generating functional hypotheses based on receptor expression, as well as identifying strong commonalities between different cell types.
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Affiliation(s)
- Fred P Davis
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
- Molecular Immunology and Inflammation BranchNational Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of HealthBethesdaUnited States
| | - Aljoscha Nern
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Serge Picard
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Michael B Reiser
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Sean R Eddy
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
- Howard Hughes Medical Institute and Department of Molecular and Cellular BiologyHarvard UniversityCambridgeUnited States
- John A. Paulson School of Engineering and Applied SciencesHarvard UniversityCambridgeUnited States
| | - Gilbert L Henry
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
- Cold Spring Harbor LaboratoryCold Spring HarborUnited States
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13
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Floessner TSE, Boekelman FE, Druiven SJM, de Jong M, Rigter PMF, Beersma DGM, Hut RA. Lifespan is unaffected by size and direction of daily phase shifts in Nasonia, a hymenopteran insect with strong circadian light resetting. JOURNAL OF INSECT PHYSIOLOGY 2019; 117:103896. [PMID: 31194973 DOI: 10.1016/j.jinsphys.2019.103896] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 06/07/2019] [Accepted: 06/08/2019] [Indexed: 06/09/2023]
Abstract
Most organisms have an endogenous circadian clock with a period length of approximately 24 h that enables adaptation, synchronization and anticipation to environmental cycles. The circadian system (circa = about or around, diem = a day) may provide evolutionary benefits when entrained to the 24-h light-dark cycle. The more the internal circadian period (τ) deviates from the external light-dark cycle, the larger the daily phase shifts need to be to synchronize to the environment. In some species, large daily phase shifts reduce survival rate. Here we tested this 'resonance fitness hypothesis' on the diurnal wasp Nasonia vitripennis, which exhibits a large latitudinal cline in free-running period with longer circadian period lengths in the north than in the south. Longevity was measured in northern and southern wasps placed into light-dark cycles (T-cycles) with periods ranging from 20 h to 28 h. Further, locomotor activity was recorded to estimate range and phase angle of entrainment under these various T-cycles. A light pulse induced phase response curve (PRC) was measured in both lines to understand entrainment results. We expected a concave survival curve with highest longevity at T = τ and a reduction in longevity the further τ deviates from T (τ/T<>1). Our results do not support this resonance fitness hypothesis. We did not observe a reduction in longevity when τ deviates from T. Our results may be understood by the strong circadian light resetting mechanism (type 0 PRC) to single light pulses that we measured in Nasonia, resulting in: (1) the broad range of entrainment, (2) the wide natural variation in circadian free-running period, and (3) the lack of reduced survival when τ/T ratio's deviates from 1. Together this indicates that circadian adaption to latitude may lead to changes in circadian period and light response, without negative influences on survival.
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Affiliation(s)
- Theresa S E Floessner
- Chronobiology Unit, Neurobiology Expertise Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, the Netherlands
| | - Floor E Boekelman
- Chronobiology Unit, Neurobiology Expertise Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, the Netherlands
| | - Stella J M Druiven
- Chronobiology Unit, Neurobiology Expertise Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, the Netherlands
| | - Maartje de Jong
- Chronobiology Unit, Neurobiology Expertise Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, the Netherlands
| | - Pomme M F Rigter
- Chronobiology Unit, Neurobiology Expertise Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, the Netherlands
| | - Domien G M Beersma
- Chronobiology Unit, Neurobiology Expertise Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, the Netherlands
| | - Roelof A Hut
- Chronobiology Unit, Neurobiology Expertise Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, the Netherlands.
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14
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Alejevski F, Saint-Charles A, Michard-Vanhée C, Martin B, Galant S, Vasiliauskas D, Rouyer F. The HisCl1 histamine receptor acts in photoreceptors to synchronize Drosophila behavioral rhythms with light-dark cycles. Nat Commun 2019; 10:252. [PMID: 30651542 PMCID: PMC6335465 DOI: 10.1038/s41467-018-08116-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 12/19/2018] [Indexed: 01/09/2023] Open
Abstract
In Drosophila, the clock that controls rest-activity rhythms synchronizes with light-dark cycles through either the blue-light sensitive cryptochrome (Cry) located in most clock neurons, or rhodopsin-expressing histaminergic photoreceptors. Here we show that, in the absence of Cry, each of the two histamine receptors Ort and HisCl1 contribute to entrain the clock whereas no entrainment occurs in the absence of the two receptors. In contrast to Ort, HisCl1 does not restore entrainment when expressed in the optic lobe interneurons. Indeed, HisCl1 is expressed in wild-type photoreceptors and entrainment is strongly impaired in flies with photoreceptors mutant for HisCl1. Rescuing HisCl1 expression in the Rh6-expressing photoreceptors restores entrainment but it does not in other photoreceptors, which send histaminergic inputs to Rh6-expressing photoreceptors. Our results thus show that Rh6-expressing neurons contribute to circadian entrainment as both photoreceptors and interneurons, recalling the dual function of melanopsin-expressing ganglion cells in the mammalian retina.
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Affiliation(s)
- Faredin Alejevski
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Alexandra Saint-Charles
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
- Institut de la Vision, Univ. P. & M. Curie, INSERM, CNRS, Sorbonne Université, Paris, 75012, France
| | - Christine Michard-Vanhée
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Béatrice Martin
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Sonya Galant
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Daniel Vasiliauskas
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - François Rouyer
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190, Gif-sur-Yvette, France.
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15
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Li MT, Cao LH, Xiao N, Tang M, Deng B, Yang T, Yoshii T, Luo DG. Hub-organized parallel circuits of central circadian pacemaker neurons for visual photoentrainment in Drosophila. Nat Commun 2018; 9:4247. [PMID: 30315165 PMCID: PMC6185921 DOI: 10.1038/s41467-018-06506-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 08/20/2018] [Indexed: 12/20/2022] Open
Abstract
Circadian rhythms are orchestrated by a master clock that emerges from a network of circadian pacemaker neurons. The master clock is synchronized to external light/dark cycles through photoentrainment, but the circuit mechanisms underlying visual photoentrainment remain largely unknown. Here, we report that Drosophila has eye-mediated photoentrainment via a parallel pacemaker neuron organization. Patch-clamp recordings of central circadian pacemaker neurons reveal that light excites most of them independently of one another. We also show that light-responding pacemaker neurons send their dendrites to a neuropil called accessary medulla (aMe), where they make monosynaptic connections with Hofbauer–Buchner eyelet photoreceptors and interneurons that transmit compound-eye signals. Laser ablation of aMe and eye removal both abolish light responses of circadian pacemaker neurons, revealing aMe as a hub to channel eye inputs to central circadian clock. Taken together, we demonstrate that the central clock receives eye inputs via hub-organized parallel circuits in Drosophila. The central circadian clock in Drosophila is made up of ~ 150 anatomically distributed neurons; the circuits underlying photoentrainment is unclear. This study describes ex vivo patch-clamp recording of the eye-mediated light response of all known circadian clock neurons, and shows that they are organized in parallel circuits centered around a hub.
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Affiliation(s)
- Meng-Tong Li
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, 100871, Beijing, China.,IDG/McGovern Institute for Brain Research, Peking University, 100871, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China.,PTN Graduate Program, College of Life Sciences, Peking University, 100871, Beijing, China
| | - Li-Hui Cao
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, 100871, Beijing, China.,IDG/McGovern Institute for Brain Research, Peking University, 100871, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China.,Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Na Xiao
- IDG/McGovern Institute for Brain Research, Peking University, 100871, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China.,Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Min Tang
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, 100871, Beijing, China.,IDG/McGovern Institute for Brain Research, Peking University, 100871, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China.,PTN Graduate Program, College of Life Sciences, Peking University, 100871, Beijing, China
| | - Bowen Deng
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, 100871, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Tian Yang
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, 100871, Beijing, China.,IDG/McGovern Institute for Brain Research, Peking University, 100871, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Dong-Gen Luo
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, 100871, Beijing, China. .,IDG/McGovern Institute for Brain Research, Peking University, 100871, Beijing, China. .,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China. .,Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China.
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16
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Top D, Young MW. Coordination between Differentially Regulated Circadian Clocks Generates Rhythmic Behavior. Cold Spring Harb Perspect Biol 2018; 10:a033589. [PMID: 28893860 PMCID: PMC6028074 DOI: 10.1101/cshperspect.a033589] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Specialized groups of neurons in the brain are key mediators of circadian rhythms, receiving daily environmental cues and communicating those signals to other tissues in the organism for entrainment and to organize circadian physiology. In Drosophila, the "circadian clock" is housed in seven neuronal clusters, which are defined by their expression of the main circadian proteins, Period, Timeless, Clock, and Cycle. These clusters are distributed across the fly brain and are thereby subject to the respective environments associated with their anatomical locations. While these core components are universally expressed in all neurons of the circadian network, additional regulatory proteins that act on these components are differentially expressed, giving rise to "local clocks" within the network that nonetheless converge to regulate coherent behavioral rhythms. In this review, we describe the communication between the neurons of the circadian network and the molecular differences within neurons of this network. We focus on differences in protein-expression patterns and discuss how such variation can impart functional differences in each local clock. Finally, we summarize our current understanding of how communication within the circadian network intersects with intracellular biochemical mechanisms to ultimately specify behavioral rhythms. We propose that additional efforts are required to identify regulatory mechanisms within each neuronal cluster to understand the molecular basis of circadian behavior.
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Affiliation(s)
- Deniz Top
- Laboratory of Genetics, The Rockefeller University, New York, New York 10065
| | - Michael W Young
- Laboratory of Genetics, The Rockefeller University, New York, New York 10065
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17
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A Neural Network Underlying Circadian Entrainment and Photoperiodic Adjustment of Sleep and Activity in Drosophila. J Neurosci 2017; 36:9084-96. [PMID: 27581451 DOI: 10.1523/jneurosci.0992-16.2016] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 07/09/2016] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED A sensitivity of the circadian clock to light/dark cycles ensures that biological rhythms maintain optimal phase relationships with the external day. In animals, the circadian clock neuron network (CCNN) driving sleep/activity rhythms receives light input from multiple photoreceptors, but how these photoreceptors modulate CCNN components is not well understood. Here we show that the Hofbauer-Buchner eyelets differentially modulate two classes of ventral lateral neurons (LNvs) within the Drosophila CCNN. The eyelets antagonize Cryptochrome (CRY)- and compound-eye-based photoreception in the large LNvs while synergizing CRY-mediated photoreception in the small LNvs. Furthermore, we show that the large LNvs interact with subsets of "evening cells" to adjust the timing of the evening peak of activity in a day length-dependent manner. Our work identifies a peptidergic connection between the large LNvs and a group of evening cells that is critical for the seasonal adjustment of circadian rhythms. SIGNIFICANCE STATEMENT In animals, circadian clocks have evolved to orchestrate the timing of behavior and metabolism. Consistent timing requires the entrainment these clocks to the solar day, a process that is critical for an organism's health. Light cycles are the most important external cue for the entrainment of circadian clocks, and the circadian system uses multiple photoreceptors to link timekeeping to the light/dark cycle. How light information from these photorecptors is integrated into the circadian clock neuron network to support entrainment is not understood. Our results establish that input from the HB eyelets differentially impacts the physiology of neuronal subgroups. This input pathway, together with input from the compound eyes, precisely times the activity of flies under long summer days. Our results provide a mechanistic model of light transduction and integration into the circadian system, identifying new and unexpected network motifs within the circadian clock neuron network.
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18
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Senthilan PR, Helfrich-Förster C. Rhodopsin 7-The unusual Rhodopsin in Drosophila. PeerJ 2016; 4:e2427. [PMID: 27651995 PMCID: PMC5018682 DOI: 10.7717/peerj.2427] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 08/11/2016] [Indexed: 12/17/2022] Open
Abstract
Rhodopsins are the major photopigments in the fruit fly Drosophila melanogaster. Drosophila express six well-characterized Rhodopsins (Rh1–Rh6) with distinct absorption maxima and expression pattern. In 2000, when the Drosophila genome was published, a novel Rhodopsin gene was discovered: Rhodopsin 7 (Rh7). Rh7 is highly conserved among the Drosophila genus and is also found in other arthropods. Phylogenetic trees based on protein sequences suggest that the seven Drosophila Rhodopsins cluster in three different groups. While Rh1, Rh2 and Rh6 form a “vertebrate-melanopsin-type”–cluster, and Rh3, Rh4 and Rh5 form an “insect-type”-Rhodopsin cluster, Rh7 seem to form its own cluster. Although Rh7 has nearly all important features of a functional Rhodopsin, it differs from other Rhodopsins in its genomic and structural properties, suggesting it might have an overall different role than other known Rhodopsins.
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19
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Rieger D, Stanewsky R, Helfrich-Förster C. Cryptochrome, Compound Eyes, Hofbauer-Buchner Eyelets, and Ocelli Play Different Roles in the Entrainment and Masking Pathway of the Locomotor Activity Rhythm in the Fruit Fly Drosophila Melanogaster. J Biol Rhythms 2016; 18:377-91. [PMID: 14582854 DOI: 10.1177/0748730403256997] [Citation(s) in RCA: 156] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The fly Drosophila melanogaster possesses five photoreceptors and/or photopigments that appear to be involved in light reception and synchronization of the circadian clock: (1) the compound eyes, (2) the ocelli, (3) the Hofbauer-Buchner eyelets, (4) the blue-light photopigment cryptochrome, and (5) unknown photopigments in the clock-gene-expressing dorsal neurons. To understand the contributions of these photoreceptors and photopigments to synchronization, the authors monitored the flies' activity rhythms under artificial long and short days. They found that all the different photoreceptors and photo-pigments contribute significantly to entrainment under each photoperiod, but the compound eyes are especially important for entrainment to extreme photoperiods. The compound eyes are, furthermore, necessary for adjusting the phase of the activity rhythm, for distinguishing long days from constant light, and for the normal masking effects of light—namely, promotion of activity by lights-on and inhibition of activity by darkness. Cryptochrome is important for period lengthening under long days, although it is more important for entrainment to short days than to long days and is, furthermore, important for after effects of the photoperiod on the internal clock. The specific roles of the remaining photoreceptors are more difficult to assess.
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Affiliation(s)
- Dirk Rieger
- University of Regensburg, Institute of Zoology, 93040 Regensburg, Germany
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20
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Veleri S, Rieger D, Helfrich-Förster C, Stanewsky R. Hofbauer-Buchner Eyelet Affects Circadian Photosensitivity and Coordinates TIM and PER Expression inDrosophilaClock Neurons. J Biol Rhythms 2016; 22:29-42. [PMID: 17229923 DOI: 10.1177/0748730406295754] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Extraretinal photoreception is a common input route for light resetting signals into the circadian clock of animals. In Drosophila melanogaster, substantial circadian light inputs are mediated via the blue light photoreceptor CRYPTOCHROME (CRY) expressed in clock neurons within the brain. The current model predicts that, upon light activation, CRY interacts with the clock proteins TIMELESS (TIM) and PERIOD (PER), thereby inducing their degradation, which in turn leads to a resetting of the molecular oscillations within the circadian clock. Here the authors investigate the function of another putative extraretinal circadian photoreceptor, the Hofbauer-Buchner eyelet (H-B eyelet), located between the retina and the medulla in the fly optic lobes. Blocking synaptic transmission between the H-B eyelet and its potential target cells, the ventral circadian pacemaker neurons, impaired the flies' ability to resynchronize their behavior under jet-lag conditions in the context of nonfunctional retinal photoreception and a mutation in the CRY-encoding gene. The same manipulation also affected synchronized expression of the clock proteins TIM and PER in different subsets of the clock neurons. This shows that synaptic communication between the H-B eyelet and clock neurons contributes to synchronization of molecular and behavioral rhythms and confirms that the H-B eyelet functions as a circadian photoreceptor. Blockage of synaptic transmission from the H-B eyelet in the presence of functional compound eyes and the absence of CRY also results in increased numbers of flies that are unable to synchronize to extreme photoperiods, supplying independent proof for the role of the H-B eyelet as a circadian photoreceptor.
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21
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Saint-Charles A, Michard-Vanhée C, Alejevski F, Chélot E, Boivin A, Rouyer F. Four of the six Drosophila rhodopsin-expressing photoreceptors can mediate circadian entrainment in low light. J Comp Neurol 2016; 524:2828-44. [PMID: 26972685 DOI: 10.1002/cne.23994] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 02/23/2016] [Accepted: 02/25/2016] [Indexed: 12/30/2022]
Abstract
Light is the major stimulus for the synchronization of circadian clocks with day-night cycles. The light-driven entrainment of the clock that controls rest-activity rhythms in Drosophila relies on different photoreceptive molecules. Cryptochrome (CRY) is expressed in most brain clock neurons, whereas six different rhodopsins (RH) are present in the light-sensing organs. The compound eye includes outer photoreceptors that express RH1 and inner photoreceptors that each express one of the four rhodopsins RH3-RH6. RH6 is also expressed in the extraretinal Hofbauer-Buchner eyelet, whereas RH2 is only found in the ocelli. In low light, the synchronization of behavioral rhythms relies on either CRY or the canonical rhodopsin phototransduction pathway, which requires the phospholipase C-β encoded by norpA (no receptor potential A). We used norpA(P24) cry(02) double mutants that are circadianly blind in low light and restored NORPA function in each of the six types of photoreceptors, defined as expressing a particular rhodopsin. We first show that the NORPA pathway is less efficient than CRY for synchronizing rest-activity rhythms with delayed light-dark cycles but is important for proper phasing, whereas the two light-sensing pathways can mediate efficient adjustments to phase advances. Four of the six rhodopsin-expressing photoreceptors can mediate circadian entrainment, and all are more efficient for advancing than for delaying the behavioral clock. In contrast, neither RH5-expressing retinal photoreceptors nor RH2-expressing ocellar photoreceptors are sufficient to mediate synchronization through the NORPA pathway. Our results thus reveal different contributions of rhodopsin-expressing photoreceptors and suggest the existence of several circuits for rhodopsin-dependent circadian entrainment. J. Comp. Neurol. 524:2828-2844, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Alexandra Saint-Charles
- Paris-Saclay Institute of Neuroscience, Université Paris Sud, Centre National de la Recherche Scientifque, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Christine Michard-Vanhée
- Paris-Saclay Institute of Neuroscience, Université Paris Sud, Centre National de la Recherche Scientifque, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Faredin Alejevski
- Paris-Saclay Institute of Neuroscience, Université Paris Sud, Centre National de la Recherche Scientifque, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Elisabeth Chélot
- Paris-Saclay Institute of Neuroscience, Université Paris Sud, Centre National de la Recherche Scientifque, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Antoine Boivin
- Paris-Saclay Institute of Neuroscience, Université Paris Sud, Centre National de la Recherche Scientifque, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - François Rouyer
- Paris-Saclay Institute of Neuroscience, Université Paris Sud, Centre National de la Recherche Scientifque, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
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22
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Yoshii T, Hermann-Luibl C, Helfrich-Förster C. Circadian light-input pathways in Drosophila. Commun Integr Biol 2016; 9:e1102805. [PMID: 27066180 PMCID: PMC4802797 DOI: 10.1080/19420889.2015.1102805] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 09/25/2015] [Accepted: 09/25/2015] [Indexed: 12/02/2022] Open
Abstract
Light is the most important environmental cue to entrain the circadian clock in most animals. In the fruit fly Drosophila melanogaster, the light entrainment mechanisms of the clock have been well-studied. The Drosophila brain contains approximately 150 neurons that rhythmically express circadian clock genes. These neurons are called "clock neurons" and control behavioral activity rhythms. Many clock neurons express the Cryptochrome (CRY) protein, which is sensitive to UV and blue light, and thus enables clock neurons deep in the brain to directly perceive light. In addition to the CRY protein, external photoreceptors in the Drosophila eyes play an important role in circadian light-input pathways. Recent studies have provided new insights into the mechanisms that integrate these light inputs into the circadian network of the brain. In this review, we will summarize the current knowledge on the light entrainment pathways in the Drosophila circadian clock.
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Affiliation(s)
- Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Christiane Hermann-Luibl
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Charlotte Helfrich-Förster
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Am Hubland, Würzburg, Germany
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23
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Katagiri N, Katagiri Y, Wada M, Okano D, Shigematsu Y, Yoshioka T. Three-dimensional reconstruction of the axon extending from the dermal photoreceptor cell in the extraocular photoreception system of a marine gastropod, onchidium. Zoolog Sci 2014; 31:810-9. [PMID: 25483793 DOI: 10.2108/zs140085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The marine gastropod Onchidium has a multiple photoreceptive system consisting of stalk eyes, dorsal eyes, photosensitive neurons, and extraocular dermal photoreceptor cells (DPCs). The DPCs were widespread all over the dorsal mantle and distributed singly or in groups in the dermis, but were not discernible by the naked eye. The DPC was oval in shape and large in size, and characterized by features specific to gastropod photoreceptor cells such as massive microvilli, photic vesicles, and a depolarized response. DPC-17, one of a group of 19 DPCs, was examined on serial semi-thin sections of 0.4 µm in thickness with a high-voltage transmission electron microscope (HVTEM). The axon emerged specifically from the lateral side between the distal microvillous portion and proximal cytoplasm, travelled through the connective tissue, and joined a small nerve bundle (NB). Two types of supportive cells were found along the length of the axon. The first type was a covering cell (CC) surrounding the surface of the DPC body and continuing onward to the axon sheath. DPC-17 was covered by 11 CCs, while the larger DPC-6 was only covered by four CCs. The second type was a sheath cell (ShC) wrapping the surface of the small NB where the axon of the DPC merged with undefined nerve fibers. The axon extending directly from DPC-17 was reconstructed three-dimensionally (3D) using DeltaViewer software. The 3D-reconstructed image of the sheath of the axon and the CC demonstrated the continuity between the two structures, especially when the image was rotated using DeltaViewer.
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Affiliation(s)
- Nobuko Katagiri
- 1 Faculty of Nursing, Hirosaki Gakuin University, 20-7 Minori-cho, Hirosaki, Aomori 036-8231, Japan
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24
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Chin AL, Lin CY, Fu TF, Dickson BJ, Chiang AS. Diversity and wiring variability of visual local neurons in the Drosophila medulla M6 stratum. J Comp Neurol 2014; 522:3795-816. [PMID: 24782245 PMCID: PMC4265792 DOI: 10.1002/cne.23622] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 04/21/2014] [Accepted: 04/22/2014] [Indexed: 11/09/2022]
Abstract
Local neurons in the vertebrate retina are instrumental in transforming visual inputs to extract contrast, motion, and color information and in shaping bipolar-to-ganglion cell transmission to the brain. In Drosophila, UV vision is represented by R7 inner photoreceptor neurons that project to the medulla M6 stratum, with relatively little known of this downstream substrate. Here, using R7 terminals as references, we generated a 3D volume model of the M6 stratum, which revealed a retinotopic map for UV representations. Using this volume model as a common 3D framework, we compiled and analyzed the spatial distributions of more than 200 single M6-specific local neurons (M6-LNs). Based on the segregation of putative dendrites and axons, these local neurons were classified into two families, directional and nondirectional. Neurotransmitter immunostaining suggested a signal routing model in which some visual information is relayed by directional M6-LNs from the anterior to the posterior M6 and all visual information is inhibited by a diverse population of nondirectional M6-LNs covering the entire M6 stratum. Our findings suggest that the Drosophila medulla M6 stratum contains diverse LNs that form repeating functional modules similar to those found in the vertebrate inner plexiform layer.
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Affiliation(s)
- An-Lun Chin
- Institute of Biotechnology and Department of Life Science, National Tsing Hua University, Hsinchu, 30013, Taiwan
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25
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Helfrich-Förster C. From neurogenetic studies in the fly brain to a concept in circadian biology. J Neurogenet 2014; 28:329-47. [PMID: 24655073 DOI: 10.3109/01677063.2014.905556] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This paper is dedicated to Karl-Friedrich Fischbach, who has always shared with me the interest in the function of the fly brain, especially that of its optic lobes. He has accompanied me during my first steps in scientific research. The paper tells the story how our first common attempts to localize the circadian clock in the fly brain finally helped in phrasing the two-oscillator principle of circadian clocks that seems to be valid far beyond the fly circadian system. I hope that Karl-Friedrich will take this story as praise for his generosity in supporting younger scientists outside his own lab, even without the reward of a common paper.
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Affiliation(s)
- Charlotte Helfrich-Förster
- Neurobiology and Genetics, Biocenter, Theodor-Boveri Institute, University of Würzburg , Würzburg , Germany
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26
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Bohbot JD, Sparks JT, Dickens JC. The maxillary palp of Aedes aegypti, a model of multisensory integration. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2014; 48:29-39. [PMID: 24613607 DOI: 10.1016/j.ibmb.2014.02.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 02/19/2014] [Accepted: 02/24/2014] [Indexed: 06/03/2023]
Abstract
Female yellow-fever mosquitoes, Aedes aegypti, are obligate blood-feeders and vectors of the pathogens that cause dengue fever, yellow fever and Chikungunya. This feeding behavior concludes a series of multisensory events guiding the mosquito to its host from a distance. The antennae and maxillary palps play a major role in host detection and other sensory-mediated behaviors. Compared to the antennae, the maxillary palps are a relatively simple organ and thus an attractive model for exploration of the neuromolecular networks underlying chemo- and mechanosensation. In this study, we surveyed the expressed genetic components and examined their potential involvement with these sensory modalities. Using Illumina sequencing, we identified the transcriptome of the maxillary palps of physiologically mature female Ae. aegypti. Genes expressed in the maxillary palps included those involved in sensory reception, signal transduction and neuromodulation. In addition to previously reported chemosensory genes, we identified candidate transcripts potentially involved in mechanosensation and thermosensation. This survey lays the groundwork to explore sensory networks in an insect appendage. The identification of genes involved in thermosensation provides prospective molecular targets for the development of chemicals aimed at disrupting the behavior of this medically important insect.
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Affiliation(s)
- Jonathan D Bohbot
- United States Department of Agriculture, Agricultural Research Service, Henry A. Wallace Beltsville Agricultural Research Center, Invasive Insect Biocontrol and Behavior Laboratory, Beltsville, MD, USA
| | - Jackson T Sparks
- United States Department of Agriculture, Agricultural Research Service, Henry A. Wallace Beltsville Agricultural Research Center, Invasive Insect Biocontrol and Behavior Laboratory, Beltsville, MD, USA
| | - Joseph C Dickens
- United States Department of Agriculture, Agricultural Research Service, Henry A. Wallace Beltsville Agricultural Research Center, Invasive Insect Biocontrol and Behavior Laboratory, Beltsville, MD, USA.
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27
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Schlichting M, Grebler R, Peschel N, Yoshii T, Helfrich-Förster C. Moonlight Detection by Drosophila’s Endogenous Clock Depends on Multiple Photopigments in the Compound Eyes. J Biol Rhythms 2014; 29:75-86. [DOI: 10.1177/0748730413520428] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Many organisms change their activity on moonlit nights. Even the fruit fly Drosophila melanogaster responds to moonlight with a shift of activity into the night, at least under laboratory conditions. The compound eyes have been shown to be essential for the perception of moonlight, but it is unknown which of the 5 rhodopsins in the eyes are responsible for the observed moonlight effects. Here, we show that the outer (R1-R6) and inner (R7 and R8) photoreceptor cells in a fly’s ommatidium interact in a complex manner to provoke the moonlight effects on locomotor activity. The shift of the evening activity peak into the night depends on several rhodopsins in the inner and outer photoreceptor cells. The increase in relative nocturnal activity in response to moonlight is mainly mediated by the rhodopsin 6–expressing inner photoreceptor cell R8 together with the rhodopsin 1–expressing outer receptor cells (R1-R6), whereas just rhodopsin 1 of R1 to R6 seems necessary for increasing nocturnal activity in response to increasing daylight intensity.
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Affiliation(s)
- Matthias Schlichting
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Rudi Grebler
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Nicolai Peschel
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Charlotte Helfrich-Förster
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
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28
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Szular J, Sehadova H, Gentile C, Szabo G, Chou WH, Britt SG, Stanewsky R. Rhodopsin 5- and Rhodopsin 6-mediated clock synchronization in Drosophila melanogaster is independent of retinal phospholipase C-β signaling. J Biol Rhythms 2012; 27:25-36. [PMID: 22306971 DOI: 10.1177/0748730411431673] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Circadian clocks of most organisms are synchronized with the 24-hour solar day by the changes of light and dark. In Drosophila, both the visual photoreceptors in the compound eyes as well as the blue-light photoreceptor Cryptochrome expressed within the brain clock neurons contribute to this clock synchronization. A specialized photoreceptive structure located between the retina and the optic lobes, the Hofbauer-Buchner (H-B) eyelet, projects to the clock neurons in the brain and also participates in light synchronization. The compound eye photoreceptors and the H-B eyelet contain Rhodopsin photopigments, which activate the canonical invertebrate phototransduction cascade after being excited by light. We show here that 2 of the photopigments present in these photoreceptors, Rhodopsin 5 (Rh5) and Rhodopsin 6 (Rh6), contribute to light synchronization in a mutant (norpA(P41) ) that disrupts canonical phototransduction due to the absence of Phospholipase C-β (PLC-β). We reveal that norpA(P41) is a true loss-of-function allele, resulting in a truncated PLC-β protein that lacks the catalytic domain. Light reception mediated by Rh5 and Rh6 must therefore utilize either a different (nonretinal) PLC-β enzyme or alternative signaling mechanisms, at least in terms of clock-relevant photoreception. This novel signaling mode may distinguish Rhodopsin-mediated irradiance detection from image-forming vision in Drosophila.
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Affiliation(s)
- Joanna Szular
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom
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29
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Identifying specific light inputs for each subgroup of brain clock neurons in Drosophila larvae. J Neurosci 2012; 31:17406-15. [PMID: 22131402 DOI: 10.1523/jneurosci.5159-10.2011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In Drosophila, opsin visual photopigments as well as blue-light-sensitive cryptochrome (CRY) contribute to the synchronization of circadian clocks. We focused on the relatively simple larval brain, with nine clock neurons per hemisphere: five lateral neurons (LNs), four of which express the pigment-dispersing factor (PDF) neuropeptide, and two pairs of dorsal neurons (DN1s and DN2s). CRY is present only in the PDF-expressing LNs and the DN1s. The larval visual organ expresses only two rhodopsins (RH5 and RH6) and projects onto the LNs. We recently showed that PDF signaling is required for light to synchronize the CRY(-) larval DN2s. We now show that, in the absence of functional CRY, synchronization of the DN1s also requires PDF, suggesting that these neurons have no direct connection with the visual system. In contrast, the fifth (PDF(-)) LN does not require the PDF-expressing cells to receive visual system inputs. All clock neurons are light-entrained by light-dark cycles in the rh5(2);cry(b), rh6(1) cry(b), and rh5(2);rh6(1) double mutants, whereas the triple mutant is circadianly blind. Thus, any one of the three photosensitive molecules is sufficient, and there is no other light input for the larval clock. Finally, we show that constant activation of the visual system can suppress molecular oscillations in the four PDF-expressing LNs, whereas, in the adult, this effect of constant light requires CRY. A surprising diversity and specificity of light input combinations thus exists even for this simple clock network.
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30
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Lelito KR, Shafer OT. Reciprocal cholinergic and GABAergic modulation of the small ventrolateral pacemaker neurons of Drosophila's circadian clock neuron network. J Neurophysiol 2012; 107:2096-108. [PMID: 22279191 DOI: 10.1152/jn.00931.2011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The relatively simple clock neuron network of Drosophila is a valuable model system for the neuronal basis of circadian timekeeping. Unfortunately, many key neuronal classes of this network are inaccessible to electrophysiological analysis. We have therefore adopted the use of genetically encoded sensors to address the physiology of the fly's circadian clock network. Using genetically encoded Ca(2+) and cAMP sensors, we have investigated the physiological responses of two specific classes of clock neuron, the large and small ventrolateral neurons (l- and s-LN(v)s), to two neurotransmitters implicated in their modulation: acetylcholine (ACh) and γ-aminobutyric acid (GABA). Live imaging of l-LN(v) cAMP and Ca(2+) dynamics in response to cholinergic agonist and GABA application were well aligned with published electrophysiological data, indicating that our sensors were capable of faithfully reporting acute physiological responses to these transmitters within single adult clock neuron soma. We extended these live imaging methods to s-LN(v)s, critical neuronal pacemakers whose physiological properties in the adult brain are largely unknown. Our s-LN(v) experiments revealed the predicted excitatory responses to bath-applied cholinergic agonists and the predicted inhibitory effects of GABA and established that the antagonism of ACh and GABA extends to their effects on cAMP signaling. These data support recently published but physiologically untested models of s-LN(v) modulation and lead to the prediction that cholinergic and GABAergic inputs to s-LN(v)s will have opposing effects on the phase and/or period of the molecular clock within these critical pacemaker neurons.
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Affiliation(s)
- Katherine R Lelito
- Dept. of Molecular, Cellular, and Developmental Biology, Univ. of Michigan, Ann Arbor, MI 48109-1048, USA
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31
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Vasiliauskas D, Mazzoni EO, Sprecher SG, Brodetskiy K, Johnston RJ, Lidder P, Vogt N, Celik A, Desplan C. Feedback from rhodopsin controls rhodopsin exclusion in Drosophila photoreceptors. Nature 2011; 479:108-12. [PMID: 21983964 PMCID: PMC3208777 DOI: 10.1038/nature10451] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Accepted: 08/15/2011] [Indexed: 11/09/2022]
Abstract
Sensory systems with high discriminatory power use neurons that express only one of several alternative sensory receptor proteins. This exclusive receptor gene expression restricts the sensitivity spectrum of neurons and is coordinated with the choice of their synaptic targets. However, little is known about how it is maintained throughout the life of a neuron. Here we show that the green-light sensing receptor rhodopsin 6 (Rh6) acts to exclude an alternative blue-sensitive rhodopsin 5 (Rh5) from a subset of Drosophila R8 photoreceptor neurons. Loss of Rh6 leads to a gradual expansion of Rh5 expression into all R8 photoreceptors of the ageing adult retina. The Rh6 feedback signal results in repression of the rh5 promoter and can be mimicked by other Drosophila rhodopsins; it is partly dependent on activation of rhodopsin by light, and relies on G(αq) activity, but not on the subsequent steps of the phototransduction cascade. Our observations reveal a thus far unappreciated spectral plasticity of R8 photoreceptors, and identify rhodopsin feedback as an exclusion mechanism.
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Affiliation(s)
- Daniel Vasiliauskas
- Center for Developmental Genetics, Department of Biology, New York University, New York, New York 10003, USA
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32
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Tsachaki M, Sprecher SG. Genetic and developmental mechanisms underlying the formation of theDrosophilacompound eye. Dev Dyn 2011; 241:40-56. [DOI: 10.1002/dvdy.22738] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2011] [Indexed: 01/15/2023] Open
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33
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Dahdal D, Reeves DC, Ruben M, Akabas MH, Blau J. Drosophila pacemaker neurons require g protein signaling and GABAergic inputs to generate twenty-four hour behavioral rhythms. Neuron 2011; 68:964-77. [PMID: 21145008 DOI: 10.1016/j.neuron.2010.11.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2010] [Indexed: 01/30/2023]
Abstract
Intercellular signaling is important for accurate circadian rhythms. In Drosophila, the small ventral lateral neurons (s-LN(v)s) are the dominant pacemaker neurons and set the pace of most other clock neurons in constant darkness. Here we show that two distinct G protein signaling pathways are required in LN(v)s for 24 hr rhythms. Reducing signaling in LN(v)s via the G alpha subunit Gs, which signals via cAMP, or via the G alpha subunit Go, which we show signals via Phospholipase 21c, lengthens the period of behavioral rhythms. In contrast, constitutive Gs or Go signaling makes most flies arrhythmic. Using dissociated LN(v)s in culture, we found that Go and the metabotropic GABA(B)-R3 receptor are required for the inhibitory effects of GABA on LN(v)s and that reduced GABA(B)-R3 expression in vivo lengthens period. Although no clock neurons produce GABA, hyperexciting GABAergic neurons disrupts behavioral rhythms and s-LN(v) molecular clocks. Therefore, s-LN(v)s require GABAergic inputs for 24 hr rhythms.
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Affiliation(s)
- David Dahdal
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
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34
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Abstract
There has been considerable progress in elucidating the molecular mechanisms that contribute to memory formation and the generation of circadian rhythms. However, it is not well understood how these two processes interact to generate long-term memory. Recent studies in both vertebrate and invertebrate models have shown time-of-day effects on neurophysiology and memory formation, and have revealed a possible role for cycling molecules in memory persistence. Together, these studies suggest that common mechanisms underlie circadian rhythmicity and long-term memory formation.
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Affiliation(s)
- Jason R Gerstner
- Department of Genetics, University of Wisconsin-Madison, 3476 Genetics and Biotechnology, 425 Henry Mall, Madison, Wisconsin 53706, USA.
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35
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Mishra M, Oke A, Lebel C, McDonald EC, Plummer Z, Cook TA, Zelhof AC. Pph13 and orthodenticle define a dual regulatory pathway for photoreceptor cell morphogenesis and function. Development 2010; 137:2895-904. [PMID: 20667913 DOI: 10.1242/dev.051722] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The function and integrity of photoreceptor cells are dependent upon the creation and maintenance of specialized apical structures: membrane discs/outer segments in vertebrates and rhabdomeres in insects. We performed a molecular and morphological comparison of Drosophila Pph13 and orthodenticle (otd) mutants to investigate the transcriptional network controlling the late stages of rhabdomeric photoreceptor cell development and function. Although Otd and Pph13 have been implicated in rhabdomere morphogenesis, we demonstrate that it is necessary to remove both factors to completely eliminate rhabdomere formation. Rhabdomere absence is not the result of degeneration or a failure of initiation, but rather the inability of the apical membrane to transform and elaborate into a rhabdomere. Transcriptional profiling revealed that Pph13 plays an integral role in promoting rhabdomeric photoreceptor cell function. Pph13 regulates Rh2 and Rh6, and other phototransduction genes, demonstrating that Pph13 and Otd control a distinct subset of Rhodopsin-encoding genes in adult visual systems. Bioinformatic, DNA binding and transcriptional reporter assays showed that Pph13 can bind and activate transcription via a perfect Pax6 homeodomain palindromic binding site and the Rhodopsin core sequence I (RCSI) found upstream of Drosophila Rhodopsin genes. In vivo studies indicate that Pph13 is necessary and sufficient to mediate the expression of a multimerized RCSI reporter, a marker of photoreceptor cell specificity previously suggested to be regulated by Pax6. Our studies define a key transcriptional regulatory pathway that is necessary for late Drosophila photoreceptor development and will serve as a basis for better understanding rhabdomeric photoreceptor cell development and function.
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Affiliation(s)
- Monalisa Mishra
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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36
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Sullivan JM, Genco MC, Marlow ED, Benton JL, Beltz BS, Sandeman DC. Brain photoreceptor pathways contributing to circadian rhythmicity in crayfish. Chronobiol Int 2009; 26:1136-68. [PMID: 19731110 DOI: 10.3109/07420520903217960] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Freshwater crayfish have three known photoreceptive systems: the compound eyes, extraretinal brain photoreceptors, and caudal photoreceptors. The primary goal of the work described here was to explore the contribution of the brain photoreceptors to circadian locomotory activity and define some of the underlying neural pathways. Immunocytochemical studies of the brain photoreceptors in the parastacid (southern hemisphere) crayfish Cherax destructor reveal their expression of the blue light-sensitive photopigment cryptochrome and the neurotransmitter histamine. The brain photoreceptors project to two small protocerebral neuropils, the brain photoreceptor neuropils (BPNs), where they terminate among fibers expressing the neuropeptide pigment-dispersing hormone (PDH), a signaling molecule in arthropod circadian systems. Comparable pathways are also described in the astacid (northern hemisphere) crayfish Procambarus clarkii. Despite exhibiting markedly different diurnal locomotor activity rhythms, removal of the compound eyes and caudal photoreceptors in both C. destructor and P. clarkii (leaving the brain photoreceptors intact) does not abolish the normal light/dark activity cycle in either species, nor prevent the entrainment of their activity cycles to phase shifts of the light/dark period. These results suggest, therefore, that crayfish brain photoreceptors are sufficient for the entrainment of locomotor activity rhythms to photic stimuli, and that they can act in the absence of the compound eyes and caudal photoreceptors. We also demonstrate that the intensity of PDH expression in the BPNs varies in phase with the locomotor activity rhythm of both crayfish species. Together, these findings suggest that the brain photoreceptor cells can function as extraretinal circadian photoreceptors and that the BPN represents part of an entrainment pathway synchronizing locomotor activity to environmental light/dark cycles, and implicating the neuropeptide PDH in these functions.
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Affiliation(s)
- Jeremy M Sullivan
- Neuroscience Program, Wellesley College, Wellesley, Massachusetts 02481, USA
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37
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MEALEY-FERRARA MARIONL, MONTALVO ALEXANDRAG, HALL JEFFREYC. EFFECTS OF COMBINING A CRYPTOCHROME MUTATION WITH OTHER VISUAL-SYSTEM VARIANTS ON ENTRAINMENT OF LOCOMOTOR AND ADULT-EMERGENCE RHYTHMS INDROSOPHILA. J Neurogenet 2009. [DOI: 10.1080/neg.17.2-3.171.221] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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38
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Sprecher SG, Desplan C. Switch of rhodopsin expression in terminally differentiated Drosophila sensory neurons. Nature 2008; 454:533-7. [PMID: 18594514 DOI: 10.1038/nature07062] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Accepted: 05/09/2008] [Indexed: 11/09/2022]
Abstract
Specificity of sensory neurons requires restricted expression of one sensory receptor gene and the exclusion of all others within a given cell. In the Drosophila retina, functional identity of photoreceptors depends on light-sensitive Rhodopsins (Rhs). The much simpler larval eye (Bolwig organ) is composed of about 12 photoreceptors, eight of which are green-sensitive (Rh6) and four blue-sensitive (Rh5). The larval eye becomes the adult extraretinal 'eyelet' composed of four green-sensitive (Rh6) photoreceptors. Here we show that, during metamorphosis, all Rh6 photoreceptors die, whereas the Rh5 photoreceptors switch fate by turning off Rh5 and then turning on Rh6 expression. This switch occurs without apparent changes in the programme of transcription factors that specify larval photoreceptor subtypes. We also show that the transcription factor Senseless (Sens) mediates the very different cellular behaviours of Rh5 and Rh6 photoreceptors. Sens is restricted to Rh5 photoreceptors and must be excluded from Rh6 photoreceptors to allow them to die at metamorphosis. Finally, we show that Ecdysone receptor (EcR) functions autonomously both for the death of larval Rh6 photoreceptors and for the sensory switch of Rh5 photoreceptors to express Rh6. This fate switch of functioning, terminally differentiated neurons provides a novel, unexpected example of hard-wired sensory plasticity.
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Affiliation(s)
- Simon G Sprecher
- Center for Developmental Genetics, Department of Biology, New York University, 1090 Silver Center, 100 Washington Square East, New York, New York 10003-6688, USA
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39
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Abstract
Molecular genetics has revealed the identities of several components of the fundamental circadian molecular oscillator - an evolutionarily conserved molecular mechanism of transcription and translation that can operate in a cell-autonomous manner. Therefore, it was surprising when studies of circadian rhythmic behavior in the fruit fly Drosophila suggested that the normal operations of circadian clock cells, which house the molecular oscillator, in fact depend on non-cell-autonomous effects - interactions between the clock cells themselves. Here we review several genetic analyses that broadly extend that viewpoint. They support a model whereby the approximately 150 circadian clock cells in the brain of the fly are sub-divided into functionally discrete rhythmic centers. These centers alternatively cooperate or compete to control the different episodes of rhythmic behavior that define the fly's daily activity profile.
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Affiliation(s)
- Michael N Nitabach
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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40
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Ranade SS, Yang-Zhou D, Kong SW, McDonald EC, Cook TA, Pignoni F. Analysis of the Otd-dependent transcriptome supports the evolutionary conservation of CRX/OTX/OTD functions in flies and vertebrates. Dev Biol 2008; 315:521-34. [PMID: 18241855 PMCID: PMC2329912 DOI: 10.1016/j.ydbio.2007.12.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Revised: 12/04/2007] [Accepted: 12/11/2007] [Indexed: 11/18/2022]
Abstract
Homeobox transcription factors of the vertebrate CRX/OTX family play critical roles in photoreceptor neurons, the rostral brain and circadian processes. In mouse, the three related proteins, CRX, OTX1, and OTX2, fulfill these functions. In Drosophila, the single founding member of this gene family, called orthodenticle (otd), is required during embryonic brain and photoreceptor neuron development. We have used global gene expression analysis in late pupal heads to better characterize the post-embryonic functions of Otd in Drosophila. We have identified 61 genes that are differentially expressed between wild type and a viable eye-specific otd mutant allele. Among them, about one-third represent potentially direct targets of Otd based on their association with evolutionarily conserved Otd-binding sequences. The spectrum of biological functions associated with these gene targets establishes Otd as a critical regulator of photoreceptor morphology and phototransduction, as well as suggests its involvement in circadian processes. Together with the well-documented role of otd in embryonic patterning, this evidence shows that vertebrate and fly genes contribute to analogous biological processes, notwithstanding the significant divergence of the underlying genetic pathways. Our findings underscore the common evolutionary history of photoperception-based functions in vertebrates and invertebrates and support the view that a complex nervous system was already present in the last common ancestor of all bilateria.
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Affiliation(s)
- Swati S. Ranade
- Department of Ophthalmology, Harvard Medical School and the Massachusetts Eye and Ear Infirmary, Boston, MA
| | - Donghui Yang-Zhou
- Department of Ophthalmology, Harvard Medical School and the Massachusetts Eye and Ear Infirmary, Boston, MA
| | - Sek Won Kong
- Bauer Center for Genomic Research, Harvard University, Cambridge, MA
| | - Elizabeth C. McDonald
- Division of Developmental Biology and Department of Pediatric Ophthalmology, Cincinnati Children’s Hospital Medical Center, University of Cincinnati School of Medicine, Cincinnati, OH
| | - Tiffany A. Cook
- Division of Developmental Biology and Department of Pediatric Ophthalmology, Cincinnati Children’s Hospital Medical Center, University of Cincinnati School of Medicine, Cincinnati, OH
| | - Francesca Pignoni
- Department of Ophthalmology, Harvard Medical School and the Massachusetts Eye and Ear Infirmary, Boston, MA
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41
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Stuart AE, Borycz J, Meinertzhagen IA. The dynamics of signaling at the histaminergic photoreceptor synapse of arthropods. Prog Neurobiol 2007; 82:202-27. [PMID: 17531368 DOI: 10.1016/j.pneurobio.2007.03.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 03/08/2007] [Accepted: 03/29/2007] [Indexed: 10/23/2022]
Abstract
Histamine, a ubiquitous aminergic messenger throughout the body, also serves as a neurotransmitter in both vertebrates and invertebrates. In particular, the photoreceptors of adult arthropods use histamine, modulating its release to signal increases and decreases in light intensity. Strong evidence from various arthropod species indicates that histamine is synthesized and stored in photoreceptors, undergoes Ca-dependent release, inhibits postsynaptic interneurons by gating Cl channels, and is then recycled. In Drosophila, the synthetic enzyme, histidine decarboxylase, and the subunits of the histamine-gated chloride channel have been cloned. Possible histamine transporters at synaptic vesicles and for reuptake remain elusive. Indeed, the mechanisms that remove histamine from the synaptic cleft, and that help terminate histamine's action, are unexpectedly complex, their details remaining unresolved. A major pathway in Drosophila, and possibly other arthropod species, is by conjugation of histamine to beta-alanine to form carcinine in adjacent glia. This conjugate then returns to the photoreceptors where it is hydrolysed to liberate histamine, which is then loaded into synaptic vesicles. Evidence from other species suggests that direct reuptake of histamine into the photoreceptors may also occur. Light depolarizes the photoreceptors, causing histamine release and postsynaptic inhibition; dimming hyperpolarizes the photoreceptors, causing a decrease in histamine release and an "off" response in the postsynaptic cell. Further pursuit of histamine's action at these highly specialized synapses should lead to an understanding of how they signal minute changes in presynaptic membrane potential, how they reliably extract signals from noise, and how they adapt to a wide range of presynaptic membrane potentials.
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Affiliation(s)
- Ann E Stuart
- University of North Carolina, Department of Cell and Molecular Physiology, MBRB Campus Box 7545, 103 Mason Farm Road, Chapel Hill, NC 27599-7545, USA.
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42
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Friedrich M. Continuity versus split and reconstitution: exploring the molecular developmental corollaries of insect eye primordium evolution. Dev Biol 2006; 299:310-29. [PMID: 16973149 DOI: 10.1016/j.ydbio.2006.08.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Revised: 07/31/2006] [Accepted: 08/12/2006] [Indexed: 10/24/2022]
Abstract
Holometabolous insects like Drosophila proceed through two phases of visual system development. The embryonic phase generates simple eyes of the larva. The postembryonic phase produces the adult specific compound eyes during late larval development and pupation. In primitive insects, by contrast, eye development persists seemingly continuously from embryogenesis through the end of postembryogenesis. Comparative literature suggests that the evolutionary transition from continuous to biphasic eye development occurred via transient developmental arrest. This review investigates how the developmental arrest model relates to the gene networks regulating larval and adult eye development in Drosophila, and embryonic compound eye development in primitive insects. Consistent with the developmental arrest model, the available data suggest that the determination of the anlage of the rudimentary Drosophila larval eye is homologous to the embryonic specification of the juvenile compound eye in directly developing insects while the Drosophila compound eye primordium is evolutionarily related to the yet little studied stem cell based postembryonic eye primordium of primitive insects.
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Affiliation(s)
- Markus Friedrich
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA.
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Hess MW, Pfaller K, Hampölz B, Longato S, Teis D, Flörl A, Gutleben K, Huber LA. Microscopy of the Drosophila facet eye: vademecum for standardized fixation, embedding, and sectioning. Microsc Res Tech 2006; 69:93-8. [PMID: 16456832 DOI: 10.1002/jemt.20268] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We describe here a standardized method for histological processing of the Drosophila compound eye. Primary fixation with 2.5% glutaraldehyde, obligatorily supplemented with 0.1% household detergent regularly yielded the best structural preservation, as compared with that of other, more complicated fixation protocols tested. Notably, it proved indispensable not only to cut off the fly's head to facilitate the penetration of the reagents but also to open the chitinous head capsule. For this, we locally pierced the cuticle between the eyes, leaving the head structurally almost intact, a prerequisite for precisely aligning the head for microtomy. We developed a two-step re-embedding procedure allowing for exact and reproducible orientation of the fly heads. Thus, highly comparable series of cross sections through a representative number of ommatidia were obtained. The feasibility of our embedding and sectioning approach is finally demonstrated by three-dimensional reconstructions of the middle segments of the R1, R7, and R8 photoreceptor cells. We present reconstructions from structurally modified ommatidia, as seen after RNAi-mediated depletion of the endosomal adaptor protein p14, and from normal ommatidia corresponding to the wildtype.
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Affiliation(s)
- Michael W Hess
- Division of Histology and Embryology, Innsbruck Medical University, Innsbruck, Austria.
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Hamasaka Y, Nässel DR. Mapping of serotonin, dopamine, and histamine in relation to different clock neurons in the brain of Drosophila. J Comp Neurol 2006; 494:314-30. [PMID: 16320241 DOI: 10.1002/cne.20807] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Several sets of clock neurons cooperate to generate circadian activity rhythms in Drosophila melanogaster. To extend the knowledge on neurotransmitters in the clock circuitry, we analyzed the distribution of some biogenic amines in relation to identified clock neurons. This was accomplished by employing clock neuron-specific GAL4 lines driving green fluorescent protein (GFP) expression, combined with immunocytochemistry with antisera against serotonin, histamine, and tyrosine hydroxylase (for dopamine). In the larval and adult brain, serotonin-immunoreactive (-IR) neuron processes are in close proximity of both the dendrites and the dorsal terminals of the major clock neurons, the s-LN(v)s. Additionally, the terminals of the l-LN(v) clock neurons and serotonergic processes converge in the distal medulla. No histamine (HA)-IR processes contact the s-LN(v)s in the larval brain, but possibly impinge on the dorsal clock neurons, DN2. In the adult brain, HA-IR axons of the extraocular eyelet photoreceptors terminate on the dendritic branches of the LN(v)s. A few tyrosine hydroxylase (TH)-IR processes were seen close to the dorsal terminals of the s-LN(v)s, but not their dendrites, in the larval and adult brain. TH-IR processes also converge with the distal medulla branches of the l-LN(v)s in adults. None of the monoamines was detectable in the different clock neurons. By using an imaging system to monitor intracellular Ca(2+) levels in dissociated GFP-labeled larval s-LN(v)s, loaded with Fura-2, we demonstrated that application of serotonin induced dose-dependent decreases in Ca(2+). Thus, serotonergic neurons form functional inputs on the s-LN(v)s in the larval brain and possibly also in adults.
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Helfrich-Förster C. The circadian system of Drosophila melanogaster and its light input pathways. ZOOLOGY 2006; 105:297-312. [PMID: 16351879 DOI: 10.1078/0944-2006-00074] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The fruit fly Drosophila melanogaster has been a grateful object for circadian rhythm researchers over several decades. Behavioral, genetic, and molecular studies in the little fly have aided in understanding the bases of circadian time keeping and rhythmic behaviors not only in Drosophila, but also in other organisms, including mammals. This review summarizes our present knowledge about the fruit fly's circadian system at the molecular and neurobiological level, with special emphasis on its entrainment by environmental light-dark cycles. The results obtained for Drosophila are discussed with respect to parallel findings in mammals.
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Douglass JK, Strausfeld NJ. Sign-conserving amacrine neurons in the fly's external plexiform layer. Vis Neurosci 2005; 22:345-58. [PMID: 16079009 DOI: 10.1017/s095252380522309x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2004] [Accepted: 02/16/2005] [Indexed: 11/07/2022]
Abstract
Amacrine cells in the external plexiform layer of the fly's lamina have been intracellulary recorded and dye-filled for the first time. The recordings demonstrate that like the lamina's short photoreceptors R1-R6, type 1 lamina amacrine neurons exhibit nonspiking, "sign-conserving" sustained depolarizations in response to illumination. This contrasts with the sign-inverting responses that typify first-order retinotopic relay neurons: monopolar cells L1-L5 and the T1 efferent neuron. The contrast frequency tuning of amacrine neurons is similar to that of photoreceptors and large lamina monopolar cells. Initial observations indicate that lamina amacrine receptive fields are also photoreceptor-like, suggesting either that their inputs originate from a small number of neighboring visual sampling units (VSUs), or that locally generated potentials decay rapidly with displacement. Lamina amacrines also respond to motion, and in one recording these responses were selective for the orientation of moving edges. This functional organization corresponds to the anatomy of amacrine cells, in which postsynaptic inputs from several neighboring photoreceptor endings are linked by a network of very thin distal processes. In this way, each VSU can receive convergent inputs from a surround of amacrine processes. This arrangement is well suited for relaying responses to local intensity fluctuations from neighboring VSUs to a central VSU where amacrines are known to be presynaptic to the dendrites of the T1 efferent. The T1 terminal converges at a deeper level with that of the L2 monopolar cell relaying from the same optic cartridge. Thus, the localized spatial responses and receptor-like temporal response properties of amacrines are consistent with possible roles in lateral inhibition, motion processing, or orientation processing.
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Affiliation(s)
- John K Douglass
- Arizona Research Laboratories, Division of Neurobiology, University of Arizona, Tucson, 85721, USA.
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Spaethe J, Briscoe AD. Molecular characterization and expression of the UV opsin in bumblebees: three ommatidial subtypes in the retina and a new photoreceptor organ in the lamina. ACTA ACUST UNITED AC 2005; 208:2347-61. [PMID: 15939775 DOI: 10.1242/jeb.01634] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Ultraviolet-sensitive photoreceptors have been shown to be important for a variety of visual tasks performed by bees, such as orientation, color and polarization vision, yet little is known about their spatial distribution in the compound eye or optic lobe. We cloned and sequenced a UV opsin mRNA transcript from Bombus impatiens head-specific cDNA and, using western blot analysis, detected an eye protein band of approximately 41 kDa, corresponding to the predicted molecular mass of the encoded opsin. We then characterized UV opsin expression in the retina, ocelli and brain using immunocytochemistry. In the main retina, we found three different ommatidial types with respect to the number of UV opsin-expressing photoreceptor cells, namely ommatidia containing two, one or no UV opsin-immunoreactive cells. We also observed UV opsin expression in the ocelli. These results indicate that the cloned opsin probably encodes the P350 nm pigment, which was previously characterized by physiological recordings. Surprisingly, in addition to expression in the retina and ocelli, we found opsin expression in different parts of the brain. UV opsin immunoreactivity was detected in the proximal rim of the lamina adjacent to the first optic chiasm, which is where studies in other insects have found expression of proteins involved in the circadian clock, period and cryptochrome. We also found UV opsin immunoreactivity in the core region of the antennal lobe glomeruli and different clusters of perikarya within the protocerebrum, indicating a putative function of these brain regions, together with the lamina organ, in the entrainment of circadian rhythms. In order to test for a possible overlap of clock protein and UV opsin spatial expression, we also examined the expression of the period protein in these regions.
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Affiliation(s)
- Johannes Spaethe
- Comparative and Evolutionary Physiology Group, Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA
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Lampel J, Briscoe AD, Wasserthal LT. Expression of UV-, blue-, long-wavelength-sensitive opsins and melatonin in extraretinal photoreceptors of the optic lobes of hawk moths. Cell Tissue Res 2005; 321:443-58. [PMID: 16034628 DOI: 10.1007/s00441-004-1069-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2004] [Accepted: 12/03/2004] [Indexed: 10/25/2022]
Abstract
Lepidopterans display biological rhythms associated with egg laying, eclosion and flight activity but the photoreceptors that mediate these behavioural patterns are largely unknown. To further our progress in identifying candidate light-input channels for the lepidopteran circadian system, we have developed polyclonal antibodies against ultraviolet (UV)-, blue- and extraretinal long-wavelength (LW)-sensitive opsins and examined opsin immunoreactivity in the adult optic lobes of four hawk moths, Manduca sexta, Acherontia atropos, Agrius convolvuli and Hippotion celerio. Outside the retina, UV and blue opsin protein expression is restricted to the adult stemmata, with no apparent expression elsewhere in the brain. Melatonin, which is known to have a seasonal influence on reproduction and behaviour, is expressed with opsins in adult stemmata together with visual arrestin and chaoptin. By contrast, the LW opsin protein is not expressed in the retina or stemmata but rather exhibits a distinct and widespread distribution in dorsal and ventral neurons of the optic lobes. The lamina, medulla, lobula and lobula plate, accessory medulla and adjacent neurons innervating this structure also exhibit strong LW opsin immunoreactivity. Together with the adult stemmata, these neurons appear to be functional photoreceptors, as visual arrestin, chaoptin and melatonin are also co-expressed with LW opsin. These findings are the first to suggest a role for three spectrally distinct classes of opsin in the extraretinal detection of changes in ambient light and to show melatonin-mediated neuroendocrine output in the entrainment of sphingid moth circadian and/or photoperiodic rhythms.
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Affiliation(s)
- Jochen Lampel
- Institut für Zoologie 1, Universität Erlangen-Nürnberg, Staudtstr. 5, 91058 Erlangen, Germany.
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Borycz JA, Borycz J, Kubów A, Kostyleva R, Meinertzhagen IA. Histamine compartments of the Drosophila brain with an estimate of the quantum content at the photoreceptor synapse. J Neurophysiol 2005; 93:1611-9. [PMID: 15738275 DOI: 10.1152/jn.00894.2004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Reliable estimates of the quantum size in histaminergic neurons are not available. We have exploited two unusual opportunities in the fly's (Drosophila melanogaster) visual system to make such determinations for histaminergic photoreceptor synapses: 1) the possibility to microdissect successively from whole fly heads freeze-dried in acetone: the compound eyes; the first optic neuropils, or lamina; and the rest of the brain; and 2) the uniform sheaves of lamina synaptic terminals of photoreceptors R1-R6. We used this organization to count scrupulously the numbers of 30-nm synaptic vesicles from electron micrographs of R1-R6 profiles, and from microdissections we determined the regional contents of histamine in the compound eye, lamina, and central brain. Total head histamine averages 1.98 ng of which 9% was lost after freeze-drying in acetone and a further 28% after the brain was microdissected. Of the remainder, 71% was in the eye and lamina. Assuming that histamine loss from the tissue occurred mostly by diffusion evenly distributed among all regions, the overall lamina content of the head would be 0.1935 ng before dissection. From published values for the volumes of the brain's compartments, the computed regional concentrations of histamine are highest in the lamina (4.35 mM) because of the terminals of R1-R6. The concentration in the retina is approximately 13% that in the lamina, suggesting that most histamine is vesicular. There are approximately 43,500 +/- 7,400 (SD) synaptic vesicles per terminal and, if all histamine is allocated equally and exclusively among these, the vesicle contents would be 858 +/- 304 x 10(-21) moles or approximately 5,000 +/- 1,800 (SD) molecules at an approximate concentration of 670 mM. These values are compared with the vesicle contents at synapses using acetylcholine and catecholamines.
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Affiliation(s)
- J A Borycz
- Life Sciences Centre, Dalhousie University, 1355 Oxford St., Halifax, Nova Scotia, Canada B3H 4J1
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Oakley TH, Huber DR. Differential expression of duplicated opsin genes in two eyetypes of ostracod crustaceans. J Mol Evol 2005; 59:239-49. [PMID: 15486697 DOI: 10.1007/s00239-004-2618-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2003] [Accepted: 02/18/2004] [Indexed: 10/26/2022]
Abstract
In the first molecular study of ostracod (Crustacea) vision, we present partial cDNA sequences of ostracod visual pigment genes (opsins). We found strong support for differential expression of opsins in ostracod median and compound eyes and suggest that photoreceptor specific expression may be a general phenomenon in organisms with multiple receptors. We infer that eye-specific expression predates the divergence of the two species examined, Skogsbergia lerneri and Vargula hilgendorfii, because eye-specific opsin orthologs are present in both species. We found multiple opsin loci in ostracods, estimating that at least eight are present in Skogsbergia lerneri. All opsins from both ostracod species examined are more closely related to each other than to any other known opsin sequences. Because we find no evidence for gene conversion or alternative splicing, we suggest the occurrence of many recent gene duplications. Why ostracods may have retained multiple recent opsin gene duplicates is unknown, but we discuss several possible hypotheses.
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Affiliation(s)
- Todd H Oakley
- Biology Department, Duke University, Durham, NC 27706, USA.
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