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Ehrlich A, Xu AA, Luminari S, Kidd S, Treiber CD, Russo J, Blau J. Tango-seq: overlaying transcriptomics on connectomics to identify neurons downstream of Drosophila clock neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.22.595372. [PMID: 38826334 PMCID: PMC11142192 DOI: 10.1101/2024.05.22.595372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Knowing how neural circuits change with neuronal plasticity and differ between individuals is important to fully understand behavior. Connectomes are typically assembled using electron microscopy, but this is low throughput and impractical for analyzing plasticity or mutations. Here, we modified the trans-Tango genetic circuit-tracing technique to identify neurons synaptically downstream of Drosophila s-LNv clock neurons, which show 24hr plasticity rhythms. s-LNv target neurons were labeled specifically in adult flies using a nuclear reporter gene, which facilitated their purification and then single cell sequencing. We call this Tango-seq, and it allows transcriptomic data - and thus cell identity - to be overlayed on top of anatomical data. We found that s-LNvs preferentially make synaptic connections with a subset of the CNMa+ DN1p clock neurons, and that these are likely plastic connections. We also identified synaptic connections between s-LNvs and mushroom body Kenyon cells. Tango-seq should be a useful addition to the connectomics toolkit.
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Affiliation(s)
- Alison Ehrlich
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - Angelina A Xu
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - Sofia Luminari
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - Simon Kidd
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - Christoph D Treiber
- Centre for Neural Circuits and Behaviour, University of Oxford, UK
- Current address: Department of Biology, University of Oxford, UK
| | - Jordan Russo
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - Justin Blau
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
- Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, Abu Dhabi, UAE
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2
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Jameson AT, Spera LK, Nguyen DL, Paul EM, Tabuchi M. Membrane-coated glass electrodes for stable, low-noise electrophysiology recordings in Drosophila central neurons. J Neurosci Methods 2024; 404:110079. [PMID: 38340901 PMCID: PMC11034715 DOI: 10.1016/j.jneumeth.2024.110079] [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: 11/20/2023] [Revised: 01/21/2024] [Accepted: 02/06/2024] [Indexed: 02/12/2024]
Abstract
BACKGROUND Electrophysiological recording with glass electrodes is one of the best techniques to measure membrane potential dynamics and ionic currents of voltage-gated channels in neurons. However, artifactual variability of the biophysical state variables that determine recording quality can be caused by insufficient affinity between the electrode and cell membrane during the recording. NEW METHOD We introduce a phospholipid membrane coating on glass electrodes to improve intracellular electrophysiology recording quality. Membrane-coated electrodes were prepared with a tip-dip protocol for perforated-patch, sharp-electrode current-clamp, and cell-attached patch-clamp recordings from specific circadian clock neurons in Drosophila. We perform quantitative comparisons based on the variability of functional biophysical parameters used in various electrophysiological methods, and advanced statistical comparisons based on the degree of stationariness and signal-to-noise ratio. RESULTS Results indicate a dramatic reduction in artifactual variabilities of functional parameters from enhanced stability. We also identify significant exclusions of a statistically estimated noise component in a time series of membrane voltage signals, improving signal-to-noise ratio. COMPARISON WITH EXISTING METHODS Compared to standard glass electrodes, using membrane-coated glass electrodes achieves improved recording quality in intracellular electrophysiology. CONCLUSIONS Electrophysiological recordings from Drosophila central neurons can be technically challenging, however, membrane-coated electrodes will possibly be beneficial for reliable data acquisition and improving the technical feasibility of axonal intracellular activities measurements and single-channel recordings. The improved electrical stability of the recordings should also contribute to increased mechanical stability, thus facilitating long-term stable measurements of neural activity. Therefore, it is possible that membrane-coated electrodes will be useful for any model system.
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Affiliation(s)
- Angelica T Jameson
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Lucia K Spera
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Dieu Linh Nguyen
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Elizabeth M Paul
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Masashi Tabuchi
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States.
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3
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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: 0] [Impact Index Per Article: 0] [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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4
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Reinhard N, Schubert FK, Bertolini E, Hagedorn N, Manoli G, Sekiguchi M, Yoshii T, Rieger D, Helfrich-Förster C. The Neuronal Circuit of the Dorsal Circadian Clock Neurons in Drosophila melanogaster. Front Physiol 2022; 13:886432. [PMID: 35574472 PMCID: PMC9100938 DOI: 10.3389/fphys.2022.886432] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 03/28/2022] [Indexed: 11/30/2022] Open
Abstract
Drosophila’s dorsal clock neurons (DNs) consist of four clusters (DN1as, DN1ps, DN2s, and DN3s) that largely differ in size. While the DN1as and the DN2s encompass only two neurons, the DN1ps consist of ∼15 neurons, and the DN3s comprise ∼40 neurons per brain hemisphere. In comparison to the well-characterized lateral clock neurons (LNs), the neuroanatomy and function of the DNs are still not clear. Over the past decade, numerous studies have addressed their role in the fly’s circadian system, leading to several sometimes divergent results. Nonetheless, these studies agreed that the DNs are important to fine-tune activity under light and temperature cycles and play essential roles in linking the output from the LNs to downstream neurons that control sleep and metabolism. Here, we used the Flybow system, specific split-GAL4 lines, trans-Tango, and the recently published fly connectome (called hemibrain) to describe the morphology of the DNs in greater detail, including their synaptic connections to other clock and non-clock neurons. We show that some DN groups are largely heterogenous. While certain DNs are strongly connected with the LNs, others are mainly output neurons that signal to circuits downstream of the clock. Among the latter are mushroom body neurons, central complex neurons, tubercle bulb neurons, neurosecretory cells in the pars intercerebralis, and other still unidentified partners. This heterogeneity of the DNs may explain some of the conflicting results previously found about their functionality. Most importantly, we identify two putative novel communication centers of the clock network: one fiber bundle in the superior lateral protocerebrum running toward the anterior optic tubercle and one fiber hub in the posterior lateral protocerebrum. Both are invaded by several DNs and LNs and might play an instrumental role in the clock network.
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Affiliation(s)
- Nils Reinhard
- Julius Maximilian University of Würzburg, Würzburg, Germany
| | | | - Enrico Bertolini
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Würzburg, Germany
| | | | - Giulia Manoli
- Julius Maximilian University of Würzburg, Würzburg, Germany
| | - Manabu Sekiguchi
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Dirk Rieger
- Julius Maximilian University of Würzburg, Würzburg, Germany
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5
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Chen SC, Tang X, Goda T, Umezaki Y, Riley AC, Sekiguchi M, Yoshii T, Hamada FN. Dorsal clock networks drive temperature preference rhythms in Drosophila. Cell Rep 2022; 39:110668. [PMID: 35417715 PMCID: PMC9109596 DOI: 10.1016/j.celrep.2022.110668] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 09/21/2021] [Accepted: 03/22/2022] [Indexed: 11/24/2022] Open
Abstract
Animals display a body temperature rhythm (BTR). Little is known about the mechanisms by which a rhythmic pattern of BTR is regulated and how body temperature is set at different times of the day. As small ectotherms, Drosophila exhibit a daily temperature preference rhythm (TPR), which generates BTR. Here, we demonstrate dorsal clock networks that play essential roles in TPR. Dorsal neurons 2 (DN2s) are the main clock for TPR. We find that DN2s and posterior DN1s (DN1ps) contact and the extent of contacts increases during the day and that the silencing of DN2s or DN1ps leads to a lower temperature preference. The data suggest that temporal control of the microcircuit from DN2s to DN1ps contributes to TPR regulation. We also identify anterior DN1s (DN1as) as another important clock for TPR. Thus, we show that the DN networks predominantly control TPR and determine both a rhythmic pattern and preferred temperatures. The body temperature rhythm (BTR) is vital for maintaining homeostasis. Drosophila exhibit a daily temperature preference rhythm (TPR), which generates BTR. Chen et al. show that dorsal clock neurons in the brain form a time-dependent network and govern TPR by regulating a rhythmic pattern and a temperature setpoint.
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Affiliation(s)
- Shyh-Chi Chen
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Xin Tang
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Tadahiro Goda
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA 95616, USA
| | - Yujiro Umezaki
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA 95616, USA
| | - Abigail C Riley
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Manabu Sekiguchi
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Taishi Yoshii
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Fumika N Hamada
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, CA 95616, USA.
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6
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Nguyen DL, Hutson AN, Zhang Y, Daniels SD, Peard AR, Tabuchi M. Age-Related Unstructured Spike Patterns and Molecular Localization in Drosophila Circadian Neurons. Front Physiol 2022; 13:845236. [PMID: 35356078 PMCID: PMC8959858 DOI: 10.3389/fphys.2022.845236] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 02/09/2022] [Indexed: 01/02/2023] Open
Abstract
Aging decreases sleep quality by disrupting the molecular machinery that regulates the circadian rhythm. However, we do not fully understand the mechanism that underlies this process. In Drosophila, sleep quality is regulated by precisely timed patterns of spontaneous firing activity in posterior DN1 (DN1p) circadian clock neurons. How aging affects the physiological function of DN1p neurons is unknown. In this study, we found that aging altered functional parameters related to neural excitability and disrupted patterned spike sequences in DN1p neurons during nighttime. We also characterized age-associated changes in intrinsic membrane properties related to spike frequency adaptations and synaptic properties, which may account for the unstructured spike patterns in aged DN1p neurons. Because Slowpoke binding protein (SLOB) and the Na+/K+ ATPase β subunit (NaKβ) regulate clock-dependent spiking patterns in circadian networks, we compared the subcellular organization of these factors between young and aged DN1p neurons. Young DN1p neurons showed circadian cycling of HA-tagged SLOB and myc-tagged NaKβ targeting the plasma membrane, whereas aged DN1p neurons showed significantly disrupted subcellular localization patterns of both factors. The distribution of SLOB and NaKβ signals also showed greater variability in young vs. aged DN1p neurons, suggesting aging leads to a loss of actively formed heterogeneity for these factors. These findings showed that aging disrupts precisely structured molecular patterns that regulate structured neural activity in the circadian network, leading to age-associated declines in sleep quality. Thus, it is possible to speculate that a recovery of unstructured neural activity in aging clock neurons could help to rescue age-related poor sleep quality.
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7
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Perception of Daily Time: Insights from the Fruit Flies. INSECTS 2021; 13:insects13010003. [PMID: 35055846 PMCID: PMC8780729 DOI: 10.3390/insects13010003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/21/2021] [Accepted: 12/07/2021] [Indexed: 11/17/2022]
Abstract
We create mental maps of the space that surrounds us; our brains also compute time—in particular, the time of day. Visual, thermal, social, and other cues tune the clock-like timekeeper. Consequently, the internal clock synchronizes with the external day-night cycles. In fact, daylength itself varies, causing the change of seasons and forcing our brain clock to accommodate layers of plasticity. However, the core of the clock, i.e., its molecular underpinnings, are highly resistant to perturbations, while the way animals adapt to the daily and annual time shows tremendous biological diversity. How can this be achieved? In this review, we will focus on 75 pairs of clock neurons in the Drosophila brain to understand how a small neural network perceives and responds to the time of the day, and the time of the year.
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8
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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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9
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Jaumouillé E, Koch R, Nagoshi E. Uncovering the Roles of Clocks and Neural Transmission in the Resilience of Drosophila Circadian Network. Front Physiol 2021; 12:663339. [PMID: 34122135 PMCID: PMC8188733 DOI: 10.3389/fphys.2021.663339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 05/03/2021] [Indexed: 11/22/2022] Open
Abstract
Studies of circadian locomotor rhythms in Drosophila melanogaster gave evidence to the preceding theoretical predictions on circadian rhythms. The molecular oscillator in flies, as in virtually all organisms, operates using transcriptional-translational feedback loops together with intricate post-transcriptional processes. Approximately150 pacemaker neurons, each equipped with a molecular oscillator, form a circuit that functions as the central pacemaker for locomotor rhythms. Input and output pathways to and from the pacemaker circuit are dissected to the level of individual neurons. Pacemaker neurons consist of functionally diverse subclasses, including those designated as the Morning/Master (M)-oscillator essential for driving free-running locomotor rhythms in constant darkness and the Evening (E)-oscillator that drives evening activity. However, accumulating evidence challenges this dual-oscillator model for the circadian circuit organization and propose the view that multiple oscillators are coordinated through network interactions. Here we attempt to provide further evidence to the revised model of the circadian network. We demonstrate that the disruption of molecular clocks or neural output of the M-oscillator during adulthood dampens free-running behavior surprisingly slowly, whereas the disruption of both functions results in an immediate arrhythmia. Therefore, clocks and neural communication of the M-oscillator act additively to sustain rhythmic locomotor output. This phenomenon also suggests that M-oscillator can be a pacemaker or a downstream path that passively receives rhythmic inputs from another pacemaker and convey output signals. Our results support the distributed network model and highlight the remarkable resilience of the Drosophila circadian pacemaker circuit, which can alter its topology to maintain locomotor rhythms.
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Affiliation(s)
| | | | - Emi Nagoshi
- Department of Genetics and Evolution, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland
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10
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Tabuchi M, Coates KE, Bautista OB, Zukowski LH. Light/Clock Influences Membrane Potential Dynamics to Regulate Sleep States. Front Neurol 2021; 12:625369. [PMID: 33854471 PMCID: PMC8039321 DOI: 10.3389/fneur.2021.625369] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/15/2021] [Indexed: 11/13/2022] Open
Abstract
The circadian rhythm is a fundamental process that regulates the sleep-wake cycle. This rhythm is regulated by core clock genes that oscillate to create a physiological rhythm of circadian neuronal activity. However, we do not know much about the mechanism by which circadian inputs influence neurons involved in sleep-wake architecture. One possible mechanism involves the photoreceptor cryptochrome (CRY). In Drosophila, CRY is receptive to blue light and resets the circadian rhythm. CRY also influences membrane potential dynamics that regulate neural activity of circadian clock neurons in Drosophila, including the temporal structure in sequences of spikes, by interacting with subunits of the voltage-dependent potassium channel. Moreover, several core clock molecules interact with voltage-dependent/independent channels, channel-binding protein, and subunits of the electrogenic ion pump. These components cooperatively regulate mechanisms that translate circadian photoreception and the timing of clock genes into changes in membrane excitability, such as neural firing activity and polarization sensitivity. In clock neurons expressing CRY, these mechanisms also influence synaptic plasticity. In this review, we propose that membrane potential dynamics created by circadian photoreception and core clock molecules are critical for generating the set point of synaptic plasticity that depend on neural coding. In this way, membrane potential dynamics drive formation of baseline sleep architecture, light-driven arousal, and memory processing. We also discuss the machinery that coordinates membrane excitability in circadian networks found in Drosophila, and we compare this machinery to that found in mammalian systems. Based on this body of work, we propose future studies that can better delineate how neural codes impact molecular/cellular signaling and contribute to sleep, memory processing, and neurological disorders.
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Affiliation(s)
- Masashi Tabuchi
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Kaylynn E Coates
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Oscar B Bautista
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Lauren H Zukowski
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, United States
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11
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George R, Stanewsky R. Peripheral Sensory Organs Contribute to Temperature Synchronization of the Circadian Clock in Drosophila melanogaster. Front Physiol 2021; 12:622545. [PMID: 33603678 PMCID: PMC7884628 DOI: 10.3389/fphys.2021.622545] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/08/2021] [Indexed: 02/06/2023] Open
Abstract
Circadian clocks are cell-autonomous endogenous oscillators, generated and maintained by self-sustained 24-h rhythms of clock gene expression. In the fruit fly Drosophila melanogaster, these daily rhythms of gene expression regulate the activity of approximately 150 clock neurons in the fly brain, which are responsible for driving the daily rest/activity cycles of these insects. Despite their endogenous character, circadian clocks communicate with the environment in order to synchronize their self-sustained molecular oscillations and neuronal activity rhythms (internal time) with the daily changes of light and temperature dictated by the Earth's rotation around its axis (external time). Light and temperature changes are reliable time cues (Zeitgeber) used by many organisms to synchronize their circadian clock to the external time. In Drosophila, both light and temperature fluctuations robustly synchronize the circadian clock in the absence of the other Zeitgeber. The complex mechanisms for synchronization to the daily light-dark cycles are understood with impressive detail. In contrast, our knowledge about how the daily temperature fluctuations synchronize the fly clock is rather limited. Whereas light synchronization relies on peripheral and clock-cell autonomous photoreceptors, temperature input to the clock appears to rely mainly on sensory cells located in the peripheral nervous system of the fly. Recent studies suggest that sensory structures located in body and head appendages are able to detect temperature fluctuations and to signal this information to the brain clock. This review will summarize these studies and their implications about the mechanisms underlying temperature synchronization.
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Affiliation(s)
| | - Ralf Stanewsky
- Institute of Neuro- and Behavioral Biology, Westfälische Wilhelms-Universität Münster, Münster, Germany
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12
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Beer K, Helfrich-Förster C. Model and Non-model Insects in Chronobiology. Front Behav Neurosci 2020; 14:601676. [PMID: 33328925 PMCID: PMC7732648 DOI: 10.3389/fnbeh.2020.601676] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 10/30/2020] [Indexed: 12/20/2022] Open
Abstract
The fruit fly Drosophila melanogaster is an established model organism in chronobiology, because genetic manipulation and breeding in the laboratory are easy. The circadian clock neuroanatomy in D. melanogaster is one of the best-known clock networks in insects and basic circadian behavior has been characterized in detail in this insect. Another model in chronobiology is the honey bee Apis mellifera, of which diurnal foraging behavior has been described already in the early twentieth century. A. mellifera hallmarks the research on the interplay between the clock and sociality and complex behaviors like sun compass navigation and time-place-learning. Nevertheless, there are aspects of clock structure and function, like for example the role of the clock in photoperiodism and diapause, which can be only insufficiently investigated in these two models. Unlike high-latitude flies such as Chymomyza costata or D. ezoana, cosmopolitan D. melanogaster flies do not display a photoperiodic diapause. Similarly, A. mellifera bees do not go into "real" diapause, but most solitary bee species exhibit an obligatory diapause. Furthermore, sociality evolved in different Hymenoptera independently, wherefore it might be misleading to study the social clock only in one social insect. Consequently, additional research on non-model insects is required to understand the circadian clock in Diptera and Hymenoptera. In this review, we introduce the two chronobiology model insects D. melanogaster and A. mellifera, compare them with other insects and show their advantages and limitations as general models for insect circadian clocks.
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Affiliation(s)
- Katharina Beer
- Neurobiology and Genetics, Theodor-Boveri Institute, Biocentre, Am Hubland, University of Würzburg, Würzburg, Germany
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13
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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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14
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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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Rouyer F, Chatterjee A. Circadian Clocks: Structural Plasticity on the Input Side. Curr Biol 2020; 30:R890-R893. [PMID: 32750352 DOI: 10.1016/j.cub.2020.06.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Key Drosophila clock neurons remodel their axonal arborization on a daily basis. The current view is that remodelling is part of the control of clock neuron output but new data support a major role in modulating sensory inputs.
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Affiliation(s)
- François Rouyer
- Institut des Neurosciences Paris-Saclay, Université Paris-Sud, Université Paris-Saclay, CNRS, 91190 Gif-sur-Yvette, France.
| | - Abhishek Chatterjee
- Institut des Neurosciences Paris-Saclay, Université Paris-Sud, Université Paris-Saclay, CNRS, 91190 Gif-sur-Yvette, France
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