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Evans JA, Schwartz WJ. On the origin and evolution of the dual oscillator model underlying the photoperiodic clockwork in the suprachiasmatic nucleus. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2024; 210:503-511. [PMID: 37481773 PMCID: PMC10924288 DOI: 10.1007/s00359-023-01659-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/07/2023] [Accepted: 07/13/2023] [Indexed: 07/25/2023]
Abstract
Decades have now passed since Colin Pittendrigh first proposed a model of a circadian clock composed of two coupled oscillators, individually responsive to the rising and setting sun, as a flexible solution to the challenge of behavioral and physiological adaptation to the changing seasons. The elegance and predictive power of this postulation has stimulated laboratories around the world in searches to identify and localize such hypothesized evening and morning oscillators, or sets of oscillators, in insects, rodents, and humans, with experimental designs and approaches keeping pace over the years with technological advances in biology and neuroscience. Here, we recount the conceptual origin and highlight the subsequent evolution of this dual oscillator model for the circadian clock in the mammalian suprachiasmatic nucleus; and how, despite our increasingly sophisticated view of this multicellular pacemaker, Pittendrigh's binary conception has remained influential in our clock models and metaphors.
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Affiliation(s)
- Jennifer A Evans
- Department of Biomedical Sciences, College of Health Sciences, Marquette University, Milwaukee, WI, USA.
| | - William J Schwartz
- Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
- Groningen Institute for Evolutionary Life Sciences, Faculty of Science and Engineering, University of Groningen, Groningen, The Netherlands
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2
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Brown MP, Verma S, Palmer I, Guerrero Zuniga A, Mehta A, Rosensweig C, Keles MF, Wu MN. A subclass of evening cells promotes the switch from arousal to sleep at dusk. Curr Biol 2024; 34:2186-2199.e3. [PMID: 38723636 PMCID: PMC11111347 DOI: 10.1016/j.cub.2024.04.039] [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: 08/25/2023] [Revised: 03/20/2024] [Accepted: 04/17/2024] [Indexed: 05/21/2024]
Abstract
Animals exhibit rhythmic patterns of behavior that are shaped by an internal circadian clock and the external environment. Although light intensity varies across the day, there are particularly robust differences at twilight (dawn/dusk). These periods are also associated with major changes in behavioral states, such as the transition from arousal to sleep. However, the neural mechanisms by which time and environmental conditions promote these behavioral transitions are poorly defined. Here, we show that the E1 subclass of Drosophila evening clock neurons promotes the transition from arousal to sleep at dusk. We first demonstrate that the cell-autonomous clocks of E2 neurons primarily drive and adjust the phase of evening anticipation, the canonical behavior associated with "evening" clock neurons. We next show that conditionally silencing E1 neurons causes a significant delay in sleep onset after dusk. However, rather than simply promoting sleep, activating E1 neurons produces time- and light-dependent effects on behavior. Activation of E1 neurons has no effect early in the day but then triggers arousal before dusk and induces sleep after dusk. Strikingly, these activation-induced phenotypes depend on the presence of light during the day. Despite their influence on behavior around dusk, in vivo voltage imaging of E1 neurons reveals that their spiking rate and pattern do not significantly change throughout the day. Moreover, E1-specific clock ablation has no effect on arousal or sleep. Thus, we suggest that, rather than specifying "evening" time, E1 neurons act, in concert with other rhythmic neurons, to promote behavioral transitions at dusk.
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Affiliation(s)
- Matthew P Brown
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Shubha Verma
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Isabelle Palmer
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | | | - Anuradha Mehta
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Clark Rosensweig
- Department of Neurobiology, Northwestern University, Evanston, IL 60201, USA
| | - Mehmet F Keles
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Mark N Wu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA.
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3
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Brown MP, Verma S, Palmer I, Zuniga AG, Rosensweig C, Keles MF, Wu MN. A subclass of evening cells promotes the switch from arousal to sleep at dusk. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.28.555147. [PMID: 37693540 PMCID: PMC10491161 DOI: 10.1101/2023.08.28.555147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Animals exhibit rhythmic patterns of behavior that are shaped by an internal circadian clock and the external environment. While light intensity varies across the day, there are particularly robust differences at twilight (dawn/dusk). These periods are also associated with major changes in behavioral states, such as the transition from arousal to sleep. However, the neural mechanisms by which time and environmental conditions promote these behavioral transitions are poorly defined. Here, we show that the E1 subclass of Drosophila evening clock neurons promotes the transition from arousal to sleep at dusk. We first demonstrate that the cell-autonomous clocks of E2 neurons alone are required to drive and adjust the phase of evening anticipation, the canonical behavior associated with "evening" clock neurons. We next show that conditionally silencing E1 neurons causes a significant delay in sleep onset after dusk. However, rather than simply promoting sleep, activating E1 neurons produces time- and light- dependent effects on behavior. Activation of E1 neurons has no effect early in the day, but then triggers arousal before dusk and induces sleep after dusk. Strikingly, these phenotypes critically depend on the presence of light during the day. Despite their influence on behavior around dusk, in vivo voltage imaging of E1 neurons reveals that their spiking rate does not vary between dawn and dusk. Moreover, E1-specific clock ablation has no effect on arousal or sleep. Thus, we suggest that, rather than specifying "evening" time, E1 neurons act, in concert with other rhythmic neurons, to promote behavioral transitions at dusk.
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Affiliation(s)
- Matthew P. Brown
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, U.S.A
| | - Shubha Verma
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, U.S.A
| | - Isabelle Palmer
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, U.S.A
| | | | - Clark Rosensweig
- Department of Neurobiology, Northwestern University, Evanston, IL 60201, U.S.A
| | - Mehmet F. Keles
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, U.S.A
| | - Mark N. Wu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, U.S.A
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, U.S.A
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4
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Kuwano R, Katsura M, Iwata M, Yokosako T, Yoshii T. Pigment-dispersing factor and CCHamide1 in the Drosophila circadian clock network. Chronobiol Int 2023; 40:284-299. [PMID: 36786215 DOI: 10.1080/07420528.2023.2166416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Animals possess a circadian central clock in the brain, where circadian behavioural rhythms are generated. In the fruit fly (Drosophila melanogaster), the central clock comprises a network of approximately 150 clock neurons, which is important for the maintenance of a coherent and robust rhythm. Several neuropeptides involved in the network have been identified, including Pigment-dispersing factor (PDF) and CCHamide1 (CCHa1) neuropeptides. PDF signals bidirectionally to CCHa1-positive clock neurons; thus, the clock neuron groups expressing PDF and CCHa1 interact reciprocally. However, the role of these interactions in molecular and behavioural rhythms remains elusive. In this study, we generated Pdf 01 and CCHa1SK8 double mutants and examined their locomotor activity-related rhythms. The single mutants of Pdf 01 or CCHa1SK8 displayed free-running rhythms under constant dark conditions, whereas approximately 98% of the double mutants were arrhythmic. In light-dark conditions, the evening activity of the double mutants was phase-advanced compared with that of the single mutants. In contrast, both the single and double mutants had diminished morning activity. These results suggest that the effects of the double mutation varied in behavioural parameters. The double and triple mutants of per 01, Pdf 01, and CCHa1SK8 further revealed that PDF signalling plays a role in the suppression of activity during the daytime under a clock-less background. Our results provide insights into the interactions between PDF and CCHa1 signalling and their roles in activity rhythms.
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Affiliation(s)
- Riko Kuwano
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Maki Katsura
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Mai Iwata
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Tatsuya Yokosako
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
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5
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Kim M, Son GI, Cho YH, Kim GH, Yun SE, Kim YJ, Chung J, Lee E, Park JJ. Reduced branched-chain aminotransferase activity alleviates metabolic vulnerability caused by dim light exposure at night in Drosophila. J Neurogenet 2022:1-11. [DOI: 10.1080/01677063.2022.2144292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Mari Kim
- Department of Preventive Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Gwang-Ic Son
- Department of Preventive Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Yun-Ho Cho
- Department of Physiology, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Gye-Hyeong Kim
- Department of Physiology, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Sung-Eun Yun
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Young-Joon Kim
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea
| | - Jongkyeong Chung
- SRC Center for Systems Geroscience, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Eunil Lee
- Department of Preventive Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Joong-Jean Park
- Department of Physiology, College of Medicine, Korea University, Seoul, Republic of Korea
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Dopamine and GPCR-mediated modulation of DN1 clock neurons gates the circadian timing of sleep. Proc Natl Acad Sci U S A 2022; 119:e2206066119. [PMID: 35969763 PMCID: PMC9407311 DOI: 10.1073/pnas.2206066119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neuromodulation is essential for adaptive animal behaviors among other physiological processes. It is essential to reliably manipulate neuromodulator pathways to understand their functions in animal physiology. In this study, we generated a CRISPR-Cas9-based guide library to target every G-Protein Coupled Receptor (GPCR) in the Drosophila genome and applied it to the well-studied clock neuron network. Notably, these GPCRs are highly enriched and differentially expressed in this small network, making it an ideal candidate to investigate their function. We cell-type specifically mutated GPCRs highly efficiently with no background gene editing detected. Applying this strategy to a specific node of the clock network revealed a role for dopamine in prolonging daytime sleep, suggesting network-specific functions of dopamine receptors in sleep-wake regulation. The metronome-like circadian regulation of sleep timing must still adapt to an uncertain environment. Recent studies in Drosophila indicate that neuromodulation not only plays a key role in clock neuron synchronization but also affects interactions between the clock network and brain sleep centers. We show here that the targets of neuromodulators, G Protein Coupled Receptors (GPCRs), are highly enriched in the fly brain circadian clock network. Single-cell sequencing indicates that they are not only enriched but also differentially expressed and contribute to clock neuron identity. We generated a comprehensive guide library to mutagenize individual GPCRs in specific neurons and verified the strategy by introducing a targeted sequencing approach. Combined with a behavioral screen, the mutagenesis strategy revealed a role of dopamine in sleep regulation by identifying two dopamine receptors and a clock neuron subpopulation that gate the timing of sleep.
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7
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Crespo-Flores SL, Barber AF. The Drosophila circadian clock circuit is a nonhierarchical network of peptidergic oscillators. CURRENT OPINION IN INSECT SCIENCE 2022; 52:100944. [PMID: 35709899 DOI: 10.1016/j.cois.2022.100944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/02/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
The relatively simple Drosophila circadian clock circuit consists of 150 clock neurons that coordinate rhythmic behavior and physiology, which are generally classified based on neuroanatomical location. Transcriptional and connectomic studies have identified novel subdivisions of these clock neuron populations, and identified neuropeptides not previously known to be expressed in the fly clock circuit. An additional feature of fly clock neurons is daily axonal remodeling, first noted in small ventrolateral neurons, but more recently also found in additional clock neuron groups. These findings raise new questions about the functional roles of clock neuron subpopulations and daily remodeling of network architecture in regulating circadian behavior and physiology.
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Affiliation(s)
- Sergio L Crespo-Flores
- Waksman Institute, Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, USA
| | - Annika F Barber
- Waksman Institute, Department of Molecular Biology and Biochemistry, Rutgers, the State University of New Jersey, USA.
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8
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Prakash P, Pradhan AK, Sheeba V. Hsp40 overexpression in pacemaker neurons delays circadian dysfunction in a Drosophila model of Huntington's disease. Dis Model Mech 2022; 15:275556. [PMID: 35645202 PMCID: PMC9254228 DOI: 10.1242/dmm.049447] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 05/24/2022] [Indexed: 12/13/2022] Open
Abstract
Circadian disturbances are early features of neurodegenerative diseases, including Huntington's disease (HD). Emerging evidence suggests that circadian decline feeds into neurodegenerative symptoms, exacerbating them. Therefore, we asked whether known neurotoxic modifiers can suppress circadian dysfunction. We performed a screen of neurotoxicity-modifier genes to suppress circadian behavioural arrhythmicity in a Drosophila circadian HD model. The molecular chaperones Hsp40 and HSP70 emerged as significant suppressors in the circadian context, with Hsp40 being the more potent mitigator. Upon Hsp40 overexpression in the Drosophila circadian ventrolateral neurons (LNv), the behavioural rescue was associated with neuronal rescue of loss of circadian proteins from small LNv soma. Specifically, there was a restoration of the molecular clock protein Period and its oscillations in young flies and a long-lasting rescue of the output neuropeptide Pigment dispersing factor. Significantly, there was a reduction in the expanded Huntingtin inclusion load, concomitant with the appearance of a spot-like Huntingtin form. Thus, we provide evidence implicating the neuroprotective chaperone Hsp40 in circadian rehabilitation. The involvement of molecular chaperones in circadian maintenance has broader therapeutic implications for neurodegenerative diseases. This article has an associated First Person interview with the first author of the paper. Summary: This study shows, for the first time, a neuroprotective role of chaperone Hsp40 in suppressing circadian dysfunction associated with Huntington's disease in a Drosophila model.
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Affiliation(s)
- Pavitra Prakash
- Evolutionary and Integrative Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Arpit Kumar Pradhan
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Vasu Sheeba
- Evolutionary and Integrative Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.,Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
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9
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Decapentaplegic Acutely Defines the Connectivity of Central Pacemaker Neurons in Drosophila. J Neurosci 2021; 41:8338-8350. [PMID: 34429376 DOI: 10.1523/jneurosci.0397-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 07/12/2021] [Accepted: 08/11/2021] [Indexed: 11/21/2022] Open
Abstract
Rhythmic rest-activity cycles are controlled by an endogenous clock. In Drosophila, this clock resides in ∼150 neurons organized in clusters whose hierarchy changes in response to environmental conditions. The concerted activity of the circadian network is necessary for the adaptive responses to synchronizing environmental stimuli. Thus far, work was devoted to unravel the logic of the coordination of different clusters focusing on neurotransmitters and neuropeptides. We further explored communication in the adult male brain through ligands belonging to the bone morphogenetic protein (BMP) pathway. Herein we show that the lateral ventral neurons (LNvs) express the small morphogen decapentaplegic (DPP). DPP expression in the large LNvs triggered a period lengthening phenotype, the downregulation of which caused reduced rhythmicity and affected anticipation at dawn and dusk, underscoring DPP per se conveys time-of-day relevant information. Surprisingly, DPP expression in the large LNvs impaired circadian remodeling of the small LNv axonal terminals, likely through local modulation of the guanine nucleotide exchange factor Trio. These findings open the provocative possibility that the BMP pathway is recruited to strengthen/reduce the connectivity among specific clusters along the day and thus modulate the contribution of the clusters to the circadian network.SIGNIFICANCE STATEMENT The circadian clock relies on the communication between groups of so-called clock neurons to coordinate physiology and behavior to the optimal times across the day, predicting and adapting to a changing environment. The circadian network relies on neurotransmitters and neuropeptides to fine-tune connectivity among clock neurons and thus give rise to a coherent output. Herein we show that decapentaplegic, a ligand belonging to the BMP retrograde signaling pathway required for coordinated growth during development, is recruited by a group of circadian neurons in the adult brain to trigger structural remodeling of terminals on a daily basis.
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Nettnin EA, Sallese TR, Nasseri A, Saurabh S, Cavanaugh DJ. Dorsal clock neurons in Drosophila sculpt locomotor outputs but are dispensable for circadian activity rhythms. iScience 2021; 24:103001. [PMID: 34505011 PMCID: PMC8413890 DOI: 10.1016/j.isci.2021.103001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 06/04/2021] [Accepted: 08/16/2021] [Indexed: 11/26/2022] Open
Abstract
The circadian system is comprised three components: a network of core clock cells in the brain that keeps time, input pathways that entrain clock cells to the environment, and output pathways that use this information to ensure appropriate timing of physiological and behavioral processes throughout the day. Core clock cells can be divided into molecularly distinct populations that likely make unique functional contributions. Here we clarify the role of the dorsal neuron 1 (DN1) population of clock neurons in the transmission of circadian information by the Drosophila core clock network. Using an intersectional genetic approach that allowed us to selectively and comprehensively target DN1 cells, we show that suppressing DN1 neuronal activity alters the magnitude of daily activity and sleep without affecting overt rhythmicity. This suggests that DN1 cells are dispensable for both the generation of circadian information and the propagation of this information across output circuits. Intersectional genetic approach targets DN1 cells comprehensively and selectively DN1p silencing alters distribution and amount of activity and sleep across the day DN1p cell firing is neither necessary nor sufficient for circadian activity rhythms DN1a silencing subtly alters total activity and sleep but leaves rhythmicity intact
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Affiliation(s)
- Ella A Nettnin
- Department of Biology, Loyola University Chicago, Chicago IL 60660, USA
| | - Thomas R Sallese
- Department of Biology, Loyola University Chicago, Chicago IL 60660, USA
| | - Anita Nasseri
- Department of Biology, Loyola University Chicago, Chicago IL 60660, USA
| | - Sumit Saurabh
- Department of Biology, Loyola University Chicago, Chicago IL 60660, USA
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11
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Abstract
Sleep is critical for diverse aspects of brain function in animals ranging from invertebrates to humans. Powerful genetic tools in the fruit fly Drosophila melanogaster have identified - at an unprecedented level of detail - genes and neural circuits that regulate sleep. This research has revealed that the functions and neural principles of sleep regulation are largely conserved from flies to mammals. Further, genetic approaches to studying sleep have uncovered mechanisms underlying the integration of sleep and many different biological processes, including circadian timekeeping, metabolism, social interactions, and aging. These findings show that in flies, as in mammals, sleep is not a single state, but instead consists of multiple physiological and behavioral states that change in response to the environment, and is shaped by life history. Here, we review advances in the study of sleep in Drosophila, discuss their implications for understanding the fundamental functions of sleep that are likely to be conserved among animal species, and identify important unanswered questions in the field.
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Affiliation(s)
- Orie T Shafer
- The Advanced Science Research Center, City University of New York, New York, NY 10031, USA.
| | - Alex C Keene
- Department of Biological Science, Florida Atlantic University, Jupiter, FL 33458, USA.
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12
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Klose MK, Shaw PJ. Sleep drive reconfigures wake-promoting clock circuitry to regulate adaptive behavior. PLoS Biol 2021; 19:e3001324. [PMID: 34191802 PMCID: PMC8277072 DOI: 10.1371/journal.pbio.3001324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 07/13/2021] [Accepted: 06/15/2021] [Indexed: 11/19/2022] Open
Abstract
Circadian rhythms help animals synchronize motivated behaviors to match environmental demands. Recent evidence indicates that clock neurons influence the timing of behavior by differentially altering the activity of a distributed network of downstream neurons. Downstream circuits can be remodeled by Hebbian plasticity, synaptic scaling, and, under some circumstances, activity-dependent addition of cell surface receptors; the role of this receptor respecification phenomena is not well studied. We demonstrate that high sleep pressure quickly reprograms the wake-promoting large ventrolateral clock neurons to express the pigment dispersing factor receptor (PDFR). The addition of this signaling input into the circuit is associated with increased waking and early mating success. The respecification of PDFR in both young and adult large ventrolateral neurons requires 2 dopamine (DA) receptors and activation of the transcriptional regulator nejire (cAMP response element-binding protein [CREBBP]). These data identify receptor respecification as an important mechanism to sculpt circuit function to match sleep levels with demand.
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Affiliation(s)
- Markus K. Klose
- Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Paul J. Shaw
- Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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13
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Kostadinov B, Lee Pettibone H, Bell EV, Zhou X, Pranevicius A, Shafer OT, Fernandez MP. Open-source computational framework for studying Drosophila behavioral phase. STAR Protoc 2021; 2:100285. [PMID: 33532734 PMCID: PMC7829270 DOI: 10.1016/j.xpro.2020.100285] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
This protocol describes a standardized method for analyzing Drosophila behavioral rhythmicity under light dark cycles, temperature ramps, and free running conditions. The protocol constitutes a step-by-step guide from generation of appropriate Drosophila genetic crosses to behavioral experiments. We also provide an open-source computational framework using R for the analysis of the phase of behavior using circular statistics. An extended method for complete use is also provided. For complete details on the use and execution of this protocol, please refer to Fernandez et al. (2020). R framework for analysis of Drosophila behavioral phase and circular statistics analysis Visualization of activity, phase of behavior, and rose plots
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Affiliation(s)
- Boyan Kostadinov
- Mathematics Department, NYC College of Technology, City University of New York, Brooklyn, NY 11201, USA
| | - Hannah Lee Pettibone
- Advanced Science Research Center, The Graduate Center, City University of New York, New York, NY 10031, USA
| | - Evardra Valerie Bell
- Department of Neuroscience and Behavior, Barnard College of Columbia University, New York, NY 10027, USA
| | - Xiaona Zhou
- Mathematics Department, NYC College of Technology, City University of New York, Brooklyn, NY 11201, USA
| | - Ausra Pranevicius
- Department of Neuroscience and Behavior, Barnard College of Columbia University, New York, NY 10027, USA
| | - Orie Thomas Shafer
- Advanced Science Research Center, The Graduate Center, City University of New York, New York, NY 10031, USA
| | - Maria Paz Fernandez
- Department of Neuroscience and Behavior, Barnard College of Columbia University, New York, NY 10027, USA
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14
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Duhart JM, Herrero A, de la Cruz G, Ispizua JI, Pírez N, Ceriani MF. Circadian Structural Plasticity Drives Remodeling of E Cell Output. Curr Biol 2020; 30:5040-5048.e5. [PMID: 33065014 DOI: 10.1016/j.cub.2020.09.057] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/21/2020] [Accepted: 09/17/2020] [Indexed: 12/15/2022]
Abstract
Behavioral outputs arise as a result of highly regulated yet flexible communication among neurons. The Drosophila circadian network includes 150 neurons that dictate the temporal organization of locomotor activity; under light-dark (LD) conditions, flies display a robust bimodal pattern. The pigment-dispersing factor (PDF)-positive small ventral lateral neurons (sLNv) have been linked to the generation of the morning activity peak (the "M cells"), whereas the Cryptochrome (CRY)-positive dorsal lateral neurons (LNds) and the PDF-negative sLNv are necessary for the evening activity peak (the "E cells") [1, 2]. While each group directly controls locomotor output pathways [3], an interplay between them along with a third dorsal cluster (the DN1ps) is necessary for the correct timing of each peak and for adjusting behavior to changes in the environment [4-7]. M cells set the phase of roughly half of the circadian neurons (including the E cells) through PDF [5, 8-10]. Here, we show the existence of synaptic input provided by the evening oscillator onto the M cells. Both structural and functional approaches revealed that E-to-M cell connectivity changes across the day, with higher excitatory input taking place before the day-to-night transition. We identified two different neurotransmitters, acetylcholine and glutamate, released by E cells that are relevant for robust circadian output. Indeed, we show that acetylcholine is responsible for the excitatory input from E cells to M cells, which show preferential responsiveness to acetylcholine during the evening. Our findings provide evidence of an excitatory feedback between circadian clusters and unveil an important plastic remodeling of the E cells' synaptic connections.
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Affiliation(s)
- José M Duhart
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires 1405-BWE, Argentina
| | - Anastasia Herrero
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires 1405-BWE, Argentina
| | - Gabriel de la Cruz
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires 1405-BWE, Argentina
| | - Juan I Ispizua
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires 1405-BWE, Argentina
| | - Nicolás Pírez
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires 1405-BWE, Argentina
| | - M Fernanda Ceriani
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires 1405-BWE, Argentina.
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15
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Breda C, Rosato E, Kyriacou CP. Norpa Signalling and the Seasonal Circadian Locomotor Phenotype in Drosophila. BIOLOGY 2020; 9:biology9060130. [PMID: 32560221 PMCID: PMC7345481 DOI: 10.3390/biology9060130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/04/2020] [Accepted: 06/09/2020] [Indexed: 01/22/2023]
Abstract
In this paper, we review the role of the norpA-encoded phospholipase C in light and thermal entrainment of the circadian clock in Drosophila melanogaster. We extend our discussion to the role of norpA in the thermo-sensitive splicing of the per 3′ UTR, which has significant implications for seasonal adaptations of circadian behaviour. We use the norpA mutant-generated enhancement of per splicing and the corresponding advance that it produces in the morning (M) and evening (E) locomotor component to dissect out the neurons that are contributing to this norpA phenotype using GAL4/UAS. We initially confirmed, by immunocytochemistry and in situ hybridisation in adult brains, that norpA expression is mostly concentrated in the eyes, but we were unable to unequivocally reveal norpA expression in the canonical clock cells using these methods. In larval brains, we did see some evidence for co-expression of NORPA with PDF in clock neurons. Nevertheless, downregulation of norpA in clock neurons did generate behavioural advances in adults, with the eyes playing a significant role in the norpA seasonal phenotype at high temperatures, whereas the more dorsally located CRYPTOCHROME-positive clock neurons are the likely candidates for generating the norpA behavioural effects in the cold. We further show that knockdown of the related plc21C encoded phospholipase in clock neurons does not alter per splicing nor generate any of the behavioural advances seen with norpA. Our results with downregulating norpA and plc21C implicate the rhodopsins Rh2/Rh3/Rh4 in the eyes as mediating per 3′ UTR splicing at higher temperatures and indicate that the CRY-positive LNds, also known as ‘evening’ cells are likely mediating the low-temperature seasonal effects on behaviour via altering per 3′UTR splicing.
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16
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Fernandez MP, Pettibone HL, Bogart JT, Roell CJ, Davey CE, Pranevicius A, Huynh KV, Lennox SM, Kostadinov BS, Shafer OT. Sites of Circadian Clock Neuron Plasticity Mediate Sensory Integration and Entrainment. Curr Biol 2020; 30:2225-2237.e5. [PMID: 32386535 DOI: 10.1016/j.cub.2020.04.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 03/09/2020] [Accepted: 04/09/2020] [Indexed: 01/22/2023]
Abstract
Networks of circadian timekeeping in the brain display marked daily changes in neuronal morphology. In Drosophila melanogaster, the striking daily structural remodeling of the dorsal medial termini of the small ventral lateral neurons has long been hypothesized to mediate endogenous circadian timekeeping. To test this model, we have specifically abrogated these sites of daily neuronal remodeling through the reprogramming of neural development and assessed the effects on circadian timekeeping and clock outputs. Remarkably, the loss of these sites has no measurable effects on endogenous circadian timekeeping or on any of the major output functions of the small ventral lateral neurons. Rather, their loss reduces sites of glutamatergic sensory neurotransmission that normally encodes naturalistic time cues from the environment. These results support an alternative model: structural plasticity in critical clock neurons is the basis for proper integration of light and temperature and gates sensory inputs into circadian clock neuron networks.
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Affiliation(s)
- Maria P Fernandez
- Advanced Science Research Center, The Graduate Center, City University of New York, New York City, NY 10031, USA; Department of Neuroscience and Behavior, Barnard College of Columbia University, New York City, NY 10027, USA.
| | - Hannah L Pettibone
- Advanced Science Research Center, The Graduate Center, City University of New York, New York City, NY 10031, USA; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Joseph T Bogart
- Advanced Science Research Center, The Graduate Center, City University of New York, New York City, NY 10031, USA
| | - Casey J Roell
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Charles E Davey
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ausra Pranevicius
- Department of Neuroscience and Behavior, Barnard College of Columbia University, New York City, NY 10027, USA
| | - Khang V Huynh
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sara M Lennox
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Boyan S Kostadinov
- Mathematics Department, NYC College of Technology, City University of New York, Brooklyn, NY 11201, USA
| | - Orie T Shafer
- Advanced Science Research Center, The Graduate Center, City University of New York, New York City, NY 10031, USA; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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17
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de Azevedo RVDM, Hansen C, Chen KF, Rosato E, Kyriacou CP. Disrupted Glutamate Signaling in Drosophila Generates Locomotor Rhythms in Constant Light. Front Physiol 2020; 11:145. [PMID: 32210832 PMCID: PMC7069353 DOI: 10.3389/fphys.2020.00145] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 02/11/2020] [Indexed: 01/23/2023] Open
Abstract
We have used the Cambridge Protein Trap resource (CPTI) to screen for flies whose locomotor rhythms are rhythmic in constant light (LL) as a means of identifying circadian photoreception genes. From the screen of ∼150 CPTI lines, we obtained seven hits, two of which targeted the glutamate pathway, Got1 (Glutamate oxaloacetate transaminase 1) and Gs2 (Glutamine synthetase 2). We focused on these by employing available mutants and observed that variants of these genes also showed high levels of LL rhythmicity compared with controls. It was also clear that the genetic background was important with a strong interaction observed with the common and naturally occurring timeless (tim) polymorphisms, ls-tim and s-tim. The less circadian photosensitive ls-tim allele generated high levels of LL rhythmicity in combination with Got1 or Gs2, even though ls-tim and s-tim alleles do not, by themselves, generate the LL phenotype. The use of dsRNAi for both genes as well as for Gad (Glutamic acid decarboxylase) and the metabotropic glutamate receptor DmGluRA driven by clock gene promoters also revealed high levels of LL rhythmicity compared to controls. It is clear that the glutamate pathway is heavily implicated in circadian photoreception. TIM levels in Got1 and Gs2 mutants cycled and were more abundant than in controls under LL. Got1 but not Gs2 mutants showed diminished phase shifts to 10 min light pulses. Neurogenetic dissection of the LL rhythmic phenotype using the gal4/gal80 UAS bipartite system suggested that the more dorsal CRY-negative clock neurons, DNs and LNds were responsible for the LL phenotype. Immunocytochemistry using the CPTI YFP tagged insertions for the two genes revealed that the DN1s but not the DN2 and DN3s expressed Got1 and Gs2, but expression was also observed in the lateral neurons, the LNds and s-LNvs. Expression of both genes was also found in neuroglia. However, downregulation of glial Gs2 and Got1 using repo-gal4 did not generate high levels of LL rhythmicity, so it is unlikely that this phenotype is mediated by glial expression. Our results suggest a model whereby the DN1s and possibly CRY-negative LNds use glutamate signaling to supress the pacemaker s-LNvs in LL.
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Affiliation(s)
| | - Celia Hansen
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Ko-Fan Chen
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Ezio Rosato
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Charalambos P Kyriacou
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
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18
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Schlichting M. Entrainment of the Drosophila clock by the visual system. Neurosci Insights 2020; 15:2633105520903708. [PMID: 35174330 PMCID: PMC8842342 DOI: 10.1177/2633105520903708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 01/08/2020] [Indexed: 12/27/2022] Open
Abstract
Circadian clocks evolved as an adaptation to the cyclic change of day and night. To precisely adapt to this environment, the endogenous period has to be adjusted every day to exactly 24 hours by a process called entrainment. Organisms can use several external cues, called zeitgebers, to adapt. These include changes in temperature, humidity, or light. The latter is the most powerful signal to synchronize the clock in animals. Research shows that a complex visual system and circadian photoreceptors work together to adjust animal physiology to the outside world. This review will focus on the importance of the visual system for clock synchronization in the fruit fly Drosophila melanogaster. It will cover behavioral and physiological evidence that supports the importance of the visual system in light entrainment.
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19
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Molecular mechanisms and physiological importance of circadian rhythms. Nat Rev Mol Cell Biol 2019; 21:67-84. [PMID: 31768006 DOI: 10.1038/s41580-019-0179-2] [Citation(s) in RCA: 566] [Impact Index Per Article: 113.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2019] [Indexed: 12/12/2022]
Abstract
To accommodate daily recurring environmental changes, animals show cyclic variations in behaviour and physiology, which include prominent behavioural states such as sleep-wake cycles but also a host of less conspicuous oscillations in neurological, metabolic, endocrine, cardiovascular and immune functions. Circadian rhythmicity is created endogenously by genetically encoded molecular clocks, whose components cooperate to generate cyclic changes in their own abundance and activity, with a periodicity of about a day. Throughout the body, such molecular clocks convey temporal control to the function of organs and tissues by regulating pertinent downstream programmes. Synchrony between the different circadian oscillators and resonance with the solar day is largely enabled by a neural pacemaker, which is directly responsive to certain environmental cues and able to transmit internal time-of-day representations to the entire body. In this Review, we discuss aspects of the circadian clock in Drosophila melanogaster and mammals, including the components of these molecular oscillators, the function and mechanisms of action of central and peripheral clocks, their synchronization and their relevance to human health.
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20
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Schlichting M, Díaz MM, Xin J, Rosbash M. Neuron-specific knockouts indicate the importance of network communication to Drosophila rhythmicity. eLife 2019; 8:e48301. [PMID: 31613223 PMCID: PMC6794074 DOI: 10.7554/elife.48301] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 09/24/2019] [Indexed: 12/16/2022] Open
Abstract
Animal circadian rhythms persist in constant darkness and are driven by intracellular transcription-translation feedback loops. Although these cellular oscillators communicate, isolated mammalian cellular clocks continue to tick away in darkness without intercellular communication. To investigate these issues in Drosophila, we assayed behavior as well as molecular rhythms within individual brain clock neurons while blocking communication within the ca. 150 neuron clock network. We also generated CRISPR-mediated neuron-specific circadian clock knockouts. The results point to two key clock neuron groups: loss of the clock within both regions but neither one alone has a strong behavioral phenotype in darkness; communication between these regions also contributes to circadian period determination. Under these dark conditions, the clock within one region persists without network communication. The clock within the famous PDF-expressing s-LNv neurons however was strongly dependent on network communication, likely because clock gene expression within these vulnerable sLNvs depends on neuronal firing or light.
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Affiliation(s)
- Matthias Schlichting
- Department of BiologyHoward Hughes Medical Institute, Brandeis UniversityWalthamUnited States
| | - Madelen M Díaz
- Department of BiologyHoward Hughes Medical Institute, Brandeis UniversityWalthamUnited States
| | - Jason Xin
- Department of BiologyHoward Hughes Medical Institute, Brandeis UniversityWalthamUnited States
| | - Michael Rosbash
- Department of BiologyHoward Hughes Medical Institute, Brandeis UniversityWalthamUnited States
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21
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Delventhal R, O'Connor RM, Pantalia MM, Ulgherait M, Kim HX, Basturk MK, Canman JC, Shirasu-Hiza M. Dissection of central clock function in Drosophila through cell-specific CRISPR-mediated clock gene disruption. eLife 2019; 8:48308. [PMID: 31613218 PMCID: PMC6794090 DOI: 10.7554/elife.48308] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 09/24/2019] [Indexed: 12/22/2022] Open
Abstract
In Drosophila, ~150 neurons expressing molecular clock proteins regulate circadian behavior. Sixteen of these neurons secrete the neuropeptide Pdf and have been called ‘master pacemakers’ because they are essential for circadian rhythms. A subset of Pdf+ neurons (the morning oscillator) regulates morning activity and communicates with other non-Pdf+ neurons, including a subset called the evening oscillator. It has been assumed that the molecular clock in Pdf+ neurons is required for these functions. To test this, we developed and validated Gal4-UAS based CRISPR tools for cell-specific disruption of key molecular clock components, period and timeless. While loss of the molecular clock in both the morning and evening oscillators eliminates circadian locomotor activity, the molecular clock in either oscillator alone is sufficient to rescue circadian locomotor activity in the absence of the other. This suggests that clock neurons do not act in a hierarchy but as a distributed network to regulate circadian activity.
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Affiliation(s)
- Rebecca Delventhal
- Department of Genetics and Development, Columbia University Medical Center, New York, United States
| | - Reed M O'Connor
- Department of Genetics and Development, Columbia University Medical Center, New York, United States
| | - Meghan M Pantalia
- Department of Genetics and Development, Columbia University Medical Center, New York, United States
| | - Matthew Ulgherait
- Department of Genetics and Development, Columbia University Medical Center, New York, United States
| | - Han X Kim
- Department of Genetics and Development, Columbia University Medical Center, New York, United States
| | - Maylis K Basturk
- Department of Genetics and Development, Columbia University Medical Center, New York, United States
| | - Julie C Canman
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, United States
| | - Mimi Shirasu-Hiza
- Department of Genetics and Development, Columbia University Medical Center, New York, United States
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22
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Roessingh S, Rosing M, Marunova M, Ogueta M, George R, Lamaze A, Stanewsky R. Temperature synchronization of the Drosophila circadian clock protein PERIOD is controlled by the TRPA channel PYREXIA. Commun Biol 2019; 2:246. [PMID: 31286063 PMCID: PMC6602953 DOI: 10.1038/s42003-019-0497-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 06/08/2019] [Indexed: 12/30/2022] Open
Abstract
Circadian clocks are endogenous molecular oscillators that temporally organize behavioral activity thereby contributing to the fitness of organisms. To synchronize the fly circadian clock with the daily fluctuations of light and temperature, these environmental cues are sensed both via brain clock neurons, and by light and temperature sensors located in the peripheral nervous system. Here we demonstrate that the TRPA channel PYREXIA (PYX) is required for temperature synchronization of the key circadian clock protein PERIOD. We observe a molecular synchronization defect explaining the previously reported defects of pyx mutants in behavioral temperature synchronization. Surprisingly, surgical ablation of pyx-mutant antennae partially rescues behavioral synchronization, indicating that antennal temperature signals are modulated by PYX function to synchronize clock neurons in the brain. Our results suggest that PYX protects antennal neurons from faulty signaling that would otherwise interfere with temperature synchronization of the circadian clock neurons in the brain.
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Affiliation(s)
- Sanne Roessingh
- Department of Cell and Developmental Biology, University College London, London, WC1E 6DE UK
| | - Mechthild Rosing
- Institute for Neuro and Behavioral Biology, Westfälische Wilhelms University, Münster, D-48149 Germany
| | - Martina Marunova
- Department of Cell and Developmental Biology, University College London, London, WC1E 6DE UK
| | - Maite Ogueta
- Institute for Neuro and Behavioral Biology, Westfälische Wilhelms University, Münster, D-48149 Germany
| | - Rebekah George
- Institute for Neuro and Behavioral Biology, Westfälische Wilhelms University, Münster, D-48149 Germany
| | - Angelique Lamaze
- Institute for Neuro and Behavioral Biology, Westfälische Wilhelms University, Münster, D-48149 Germany
| | - Ralf Stanewsky
- Department of Cell and Developmental Biology, University College London, London, WC1E 6DE UK
- Institute for Neuro and Behavioral Biology, Westfälische Wilhelms University, Münster, D-48149 Germany
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23
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A Symphony of Signals: Intercellular and Intracellular Signaling Mechanisms Underlying Circadian Timekeeping in Mice and Flies. Int J Mol Sci 2019; 20:ijms20092363. [PMID: 31086044 PMCID: PMC6540063 DOI: 10.3390/ijms20092363] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/10/2019] [Accepted: 05/10/2019] [Indexed: 12/11/2022] Open
Abstract
The central pacemakers of circadian timekeeping systems are highly robust yet adaptable, providing the temporal coordination of rhythms in behavior and physiological processes in accordance with the demands imposed by environmental cycles. These features of the central pacemaker are achieved by a multi-oscillator network in which individual cellular oscillators are tightly coupled to the environmental day-night cycle, and to one another via intercellular coupling. In this review, we will summarize the roles of various neurotransmitters and neuropeptides in the regulation of circadian entrainment and synchrony within the mammalian and Drosophila central pacemakers. We will also describe the diverse functions of protein kinases in the relay of input signals to the core oscillator or the direct regulation of the molecular clock machinery.
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24
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Bulthuis N, Spontak KR, Kleeman B, Cavanaugh DJ. Neuronal Activity in Non-LNv Clock Cells Is Required to Produce Free-Running Rest:Activity Rhythms in Drosophila. J Biol Rhythms 2019; 34:249-271. [PMID: 30994046 DOI: 10.1177/0748730419841468] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Circadian rhythms in behavior and physiology are produced by central brain clock neurons that can be divided into subpopulations based on molecular and functional characteristics. It has become clear that coherent behavioral rhythms result from the coordinated action of these clock neuron populations, but many questions remain regarding the organizational logic of the clock network. Here we used targeted genetic tools in Drosophila to eliminate either molecular clock function or neuronal activity in discrete clock neuron subsets. We find that neuronal firing is necessary across multiple clock cell populations to produce free-running rhythms of rest and activity. In contrast, such rhythms are much more subtly affected by molecular clock suppression in the same cells. These findings demonstrate that network connectivity can compensate for a lack of molecular oscillations within subsets of clock cells. We further show that small ventrolateral (sLNv) clock neurons, which have been characterized as master pacemakers under free-running conditions, cannot drive rhythms independent of communication between other cells of the clock network. In particular, we pinpoint an essential contribution of the dorsolateral (LNd) clock neurons, and show that manipulations that affect LNd function reduce circadian rhythm strength without affecting molecular cycling in sLNv cells. These results suggest a hierarchical organization in which circadian information is first consolidated among one or more clock cell populations before accessing output pathways that control locomotor activity.
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25
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Goda T, Umezaki Y, Alwattari F, Seo HW, Hamada FN. Neuropeptides PDF and DH31 hierarchically regulate free-running rhythmicity in Drosophila circadian locomotor activity. Sci Rep 2019; 9:838. [PMID: 30696873 PMCID: PMC6351594 DOI: 10.1038/s41598-018-37107-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 11/30/2018] [Indexed: 11/09/2022] Open
Abstract
Neuropeptides play pivotal roles in modulating circadian rhythms. Pigment-dispersing factor (PDF) is critical to the circadian rhythms in Drosophila locomotor activity. Here, we demonstrate that diuretic hormone 31 (DH31) complements PDF function in regulating free-running rhythmicity using male flies. We determined that Dh31 loss-of-function mutants (Dh31#51) showed normal rhythmicity, whereas Dh31#51;Pdf01 double mutants exhibited a severe arrhythmic phenotype compared to Pdf-null mutants (Pdf01). The expression of tethered-PDF or tethered-DH31 in clock cells, posterior dorsal neurons 1 (DN1ps), overcomes the severe arrhythmicity of Dh31#51;Pdf01 double mutants, suggesting that DH31 and PDF may act on DN1ps to regulate free-running rhythmicity in a hierarchical manner. Unexpectedly, the molecular oscillations in Dh31#51;Pdf01 mutants were similar to those in Pdf01 mutants in DN1ps, indicating that DH31 does not contribute to molecular oscillations. Furthermore, a reduction in Dh31 receptor (Dh31r) expression resulted in normal locomotor activity and did not enhance the arrhythmic phenotype caused by the Pdf receptor (Pdfr) mutation, suggesting that PDFR, but not DH31R, in DN1ps mainly regulates free-running rhythmicity. Taken together, we identify a novel role of DH31, in which DH31 and PDF hierarchically regulate free-running rhythmicity through DN1ps.
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Affiliation(s)
- Tadahiro Goda
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA
| | - Yujiro Umezaki
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA
| | - Fay Alwattari
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA
| | - Hanna W Seo
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA
| | - Fumika N Hamada
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA. .,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA. .,Department of Ophthalmology, College of Medicine, University of Cincinnati, Cincinnati, OH, 45229, USA.
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26
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Shakhmantsir I, Nayak S, Grant GR, Sehgal A. Spliceosome factors target timeless ( tim) mRNA to control clock protein accumulation and circadian behavior in Drosophila. eLife 2018; 7:39821. [PMID: 30516472 PMCID: PMC6281371 DOI: 10.7554/elife.39821] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 11/17/2018] [Indexed: 12/11/2022] Open
Abstract
Transcription-translation feedback loops that comprise eukaryotic circadian clocks rely upon temporal delays that separate the phase of active transcription of clock genes, such as Drosophila period (per) and timeless (tim), from negative feedback by the two proteins. However, our understanding of the mechanisms involved is incomplete. Through an RNA interference screen, we found that pre-mRNA processing 4 (PRP4) kinase, a component of the U4/U5.U6 triple small nuclear ribonucleoprotein (tri-snRNP) spliceosome, and other tri-snRNP components regulate cycling of the molecular clock as well as rest:activity rhythms. Unbiased RNA-Sequencing uncovered an alternatively spliced intron in tim whose increased retention upon prp4 downregulation leads to decreased TIM levels. We demonstrate that the splicing of tim is rhythmic with a phase that parallels delayed accumulation of the protein in a 24 hr cycle. We propose that alternative splicing constitutes an important clock mechanism for delaying the daily accumulation of clock proteins, and thereby negative feedback by them. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
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Affiliation(s)
- Iryna Shakhmantsir
- Chronobiology Program at Penn, Howard Hughes Medical Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
| | - Soumyashant Nayak
- The Institute for Translational Medicine and Therapeutics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
| | - Gregory R Grant
- The Institute for Translational Medicine and Therapeutics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
| | - Amita Sehgal
- Chronobiology Program at Penn, Howard Hughes Medical Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,The Institute for Translational Medicine and Therapeutics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
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27
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Somers J, Harper REF, Albert JT. How Many Clocks, How Many Times? On the Sensory Basis and Computational Challenges of Circadian Systems. Front Behav Neurosci 2018; 12:211. [PMID: 30258357 PMCID: PMC6143808 DOI: 10.3389/fnbeh.2018.00211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 08/21/2018] [Indexed: 11/13/2022] Open
Abstract
A vital task for every organism is not only to decide what to do but also when to do it. For this reason, "circadian clocks" have evolved in virtually all forms of life. Conceptually, circadian clocks can be divided into two functional domains; an autonomous oscillator creates a ~24 h self-sustained rhythm and sensory machinery interprets external information to alter the phase of the autonomous oscillation. It is through this simple design that variations in external stimuli (for example, daylight) can alter our sense of time. However, the clock's simplicity ends with its basic concept. In metazoan animals, multiple external and internal stimuli, from light to temperature and even metabolism have been shown to affect clock time. This raises the fundamental question of cue integration: how are the many, and potentially conflicting, sources of information combined to sense a single time of day? Moreover, individual stimuli, are often detected through various sensory pathways. Some sensory cells, such as insect chordotonal neurons, provide the clock with both temperature and mechanical information. Adding confusion to complexity, there seems to be not only one central clock in the animal's brain but numerous additional clocks in the body's periphery. It is currently not clear how (or if) these "peripheral clocks" are synchronized to their central counterparts or if both clocks "tick" independently from one another. In this review article, we would like to leave the comfort zones of conceptual simplicity and assume a more holistic perspective of circadian clock function. Focusing on recent results from Drosophila melanogaster we will discuss some of the sensory, and computational, challenges organisms face when keeping track of time.
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Affiliation(s)
- Jason Somers
- Ear Institute, University College LondonLondon, United Kingdom
- The Francis Crick InstituteLondon, United Kingdom
| | - Ross E. F. Harper
- Ear Institute, University College LondonLondon, United Kingdom
- Centre for Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College LondonLondon, United Kingdom
| | - Joerg T. Albert
- Ear Institute, University College LondonLondon, United Kingdom
- The Francis Crick InstituteLondon, United Kingdom
- Centre for Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College LondonLondon, United Kingdom
- Department of Cell and Developmental Biology, University College LondonLondon, United Kingdom
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28
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Franco DL, Frenkel L, Ceriani MF. The Underlying Genetics of Drosophila Circadian Behaviors. Physiology (Bethesda) 2018; 33:50-62. [PMID: 29212892 DOI: 10.1152/physiol.00020.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/20/2017] [Accepted: 09/25/2017] [Indexed: 01/22/2023] Open
Abstract
Life is shaped by circadian clocks. This review focuses on how behavioral genetics in the fruit fly unveiled what is known today about circadian physiology. We will briefly summarize basic properties of the clock and focus on some clock-controlled behaviors to highlight how communication between central and peripheral oscillators defines their properties.
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Affiliation(s)
- D Lorena Franco
- Departamento de Física Médica, Centro Atómico Bariloche and Instituto Balseiro, CONICET, San Carlos de Bariloche, Río Negro, Argentina; and
| | - Lia Frenkel
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir (FIL)-Instituto de Investigaciones Bioquímicas-IIBBA-CONICET, Buenos Aires, Argentina
| | - M Fernanda Ceriani
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir (FIL)-Instituto de Investigaciones Bioquímicas-IIBBA-CONICET, Buenos Aires, Argentina
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Chatterjee A, Lamaze A, De J, Mena W, Chélot E, Martin B, Hardin P, Kadener S, Emery P, Rouyer F. Reconfiguration of a Multi-oscillator Network by Light in the Drosophila Circadian Clock. Curr Biol 2018; 28:2007-2017.e4. [PMID: 29910074 PMCID: PMC6039274 DOI: 10.1016/j.cub.2018.04.064] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/28/2018] [Accepted: 04/18/2018] [Indexed: 01/02/2023]
Abstract
The brain clock that drives circadian rhythms of locomotor activity relies on a multi-oscillator neuronal network. In addition to synchronizing the clock with day-night cycles, light also reformats the clock-driven daily activity pattern. How changes in lighting conditions modify the contribution of the different oscillators to remodel the daily activity pattern remains largely unknown. Our data in Drosophila indicate that light readjusts the interactions between oscillators through two different modes. We show that a morning s-LNv > DN1p circuit works in series, whereas two parallel evening circuits are contributed by LNds and other DN1ps. Based on the photic context, the master pacemaker in the s-LNv neurons swaps its enslaved partner-oscillator-LNd in the presence of light or DN1p in the absence of light-to always link up with the most influential phase-determining oscillator. When exposure to light further increases, the light-activated LNd pacemaker becomes independent by decoupling from the s-LNvs. The calibration of coupling by light is layered on a clock-independent network interaction wherein light upregulates the expression of the PDF neuropeptide in the s-LNvs, which inhibits the behavioral output of the DN1p evening oscillator. Thus, light modifies inter-oscillator coupling and clock-independent output-gating to achieve flexibility in the network. It is likely that the light-induced changes in the Drosophila brain circadian network could reveal general principles of adapting to varying environmental cues in any neuronal multi-oscillator system.
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Affiliation(s)
- Abhishek Chatterjee
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Angélique Lamaze
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Joydeep De
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Wilson Mena
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Elisabeth Chélot
- 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
| | - Paul Hardin
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX 77845-3258, USA
| | | | - Patrick Emery
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - François Rouyer
- Institut des Neurosciences Paris-Saclay, Univ. Paris Sud, CNRS, Université Paris-Saclay, 91190 Gif-sur-Yvette, France.
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30
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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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31
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Yadlapalli S, Jiang C, Bahle A, Reddy P, Meyhofer E, Shafer OT. Circadian clock neurons constantly monitor environmental temperature to set sleep timing. Nature 2018; 555:98-102. [PMID: 29466329 DOI: 10.1038/nature25740] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 01/10/2018] [Indexed: 02/08/2023]
Abstract
Circadian clocks coordinate behaviour, physiology and metabolism with Earth's diurnal cycle. These clocks entrain to both light and temperature cycles, and daily environmental temperature oscillations probably contribute to human sleep patterns. However, the neural mechanisms through which circadian clocks monitor environmental temperature and modulate behaviour remain poorly understood. Here we elucidate how the circadian clock neuron network of Drosophila melanogaster processes changes in environmental temperature. In vivo calcium-imaging techniques demonstrate that the posterior dorsal neurons 1 (DN1ps), which are a discrete subset of sleep-promoting clock neurons, constantly monitor modest changes in environmental temperature. We find that these neurons are acutely inhibited by heating and excited by cooling; this is an unexpected result when considering the strong correlation between temperature and light, and the fact that light excites clock neurons. We demonstrate that the DN1ps rely on peripheral thermoreceptors located in the chordotonal organs and the aristae. We also show that the DN1ps and their thermosensory inputs are required for the normal timing of sleep in the presence of naturalistic temperature cycles. These results identify the DN1ps as a major gateway for temperature sensation into the circadian neural network, which continuously integrates temperature changes to coordinate the timing of sleep and activity.
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Affiliation(s)
- Swathi Yadlapalli
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Chang Jiang
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Andrew Bahle
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Pramod Reddy
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Edgar Meyhofer
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Orie T Shafer
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
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