Clock network in Drosophila

Hermann-Luibl, Christiane; Helfrich‐Förster, Charlotte

doi:10.1016/j.cois.2014.11.003

Cited by 52 publications

(48 citation statements)

References 80 publications

(43 reference statements)

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“…The Drosophila clock network consists of approximately 150 clock neurons, several orders of magnitude fewer than those of mammals, yet it shares both anatomical and functional similarities with the mammalian clock network (Nitabach and Taghert, 2008; Vansteensel et al, 2008). Studies of the Drosophila clock network suggest that it is organized into multiple oscillatory units that are differentially coupled to one another (Hermann-Luibl and Helfrich-Forster, 2015; Yao and Shafer, 2014). At the heart of the clock neuron network rest two critical groups of neurons: (i) the ventral lateral neurons (LN v s), consisting of four pairs of large LN v s (l-LN v s) and four pairs of small LN v s (s-LN v s), both of which express the neuropeptide pigment-dispersing factor (PDF) and (ii) six pairs of dorsal lateral neurons (LN d s) along with a pair of PDF-negative s-LN v s, also called 5 th s-LN v s. The LN v s are required for the fly’s morning peak of activity, which commences in anticipation of lights-on, and are therefore considered to be the “Morning Oscillator” (Grima et al, 2004; Stoleru et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

The Drosophila Clock Neuron Network Features Diverse Coupling Modes and Requires Network-wide Coherence for Robust Circadian Rhythms

et al. 2016

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Summary In animals, networks of clock neurons containing molecular clocks orchestrate daily rhythms in physiology and behavior. How various types of clock neurons communicate and coordinate with one another to produce coherent circadian rhythms is not well understood. Here, we investigate clock neuron coupling in the brain of Drosophila and demonstrate that the fly’s various groups of clock neurons display unique and complex coupling relationships to core pacemaker neurons. Furthermore, we find that coordinated free-running rhythms require molecular clock synchrony not only within the well-characterized lateral clock neuron classes, but also between lateral clock neurons and dorsal clock neurons. These results uncover unexpected patterns of coupling in the clock neuron network and reveal that robust free-running behavioral rhythms require a coherence of molecular oscillations across most of the fly’s clock neuron network.

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Section: Introductionmentioning

confidence: 99%

The Drosophila Clock Neuron Network Features Diverse Coupling Modes and Requires Network-wide Coherence for Robust Circadian Rhythms

et al. 2016

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“…As described above, it is now clear that the 'core' or 'central' pacemaker is actually composed of heterogeneous groups of networked cells that interact in complex ways to organize time. Cells in this central clock network and in many other tissues respond differentially to zeitgebers, which in turn are not limited to light [42,108,206] (figure 2). In order to understand basic questions in chronobiology, such as why there are so many oscillators and how they interact to organize the organism's internal clock time, chronobiologists need to know the many environmental cues that are important to their model organism and the ways they influence the circadian system ( figure 1).…”

Section: (C) Prospects Of a Wild Clock Approachmentioning

confidence: 99%

Two sides of a coin: ecological and chronobiological perspectives of timing in the wild

Helm

Visser

Schwartz

et al. 2017

Phil. Trans. R. Soc. B

135

199

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Most processes within organisms, and most interactions between organisms and their environment, have distinct time profiles. The temporal coordination of such processes is crucial across levels of biological organization, but disciplines differ widely in their approaches to study timing. Such differences are accentuated between ecologists, who are centrally concerned with a holistic view of an organism in relation to its external environment, and chronobiologists, who emphasize internal timekeeping within an organism and the mechanisms of its adjustment to the environment. We argue that ecological and chronobiological perspectives are complementary, and that studies at the intersection will enable both fields to jointly overcome obstacles that currently hinder progress. However, to achieve this integration, we first have to cross some conceptual barriers, clarifying prohibitively inaccessible terminologies. We critically assess main assumptions and concepts in either field, as well as their common interests. Both approaches intersect in their need to understand the extent and regulation of temporal plasticity, and in the concept of 'chronotype', i.e. the characteristic temporal properties of individuals which are the targets of natural and sexual selection. We then highlight promising developments, point out open questions, acknowledge difficulties and propose directions for further integration of ecological and chronobiological perspectives through Wild Clock research.

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“…Moreover, they also exhibited increased arrhythmicity in constant conditions (Figure 5B, 13 Table S1). The results show that visual system function in the absence of norpA and rdgA requires Gq and PLC21C for robust clock synchronization.…”

Section: Cry 02 Fliesmentioning

confidence: 94%

“…Locomotor activity rhythms in Drosophila are controlled by approximately 150 clock neurons in the fly brain, characterized by rhythmic clock gene expression described above [13].…”

Section: Introductionmentioning

confidence: 99%

Less is more: Light sampling via throttled visual phototransduction robustly synchronizes theDrosophilacircadian clock in the absence of Cryptochrome

Ogueta

Hardie

Stanewsky

2020

Preprint

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The daily changes of light and dark exemplify a prominent cue for the synchronization of internal circadian clocks to external time. The match between external and internal time is crucial for the fitness of organisms and desynchronization has been linked to numerous physical and mental health problems in humans. Organisms therefore developed complex and not fully understood mechanisms to synchronize their circadian clock to light. In mammals and in Drosophila both the visual system and dedicated non-image forming photoreceptors contribute to light resetting of the circadian clock. In the fruit fly, lightdependent degradation of the clock protein TIMELESS (TIM) by the blue light photoreceptor Cryptochrome is considered the main mechanism for clock synchronization, although the visual system also contributes. In order to understand the nature of the visual system contribution, we generated a genetic variant exhibiting extremely slow phototransduction kinetics, yet normal sensitivity. We show that in this variant the visual system is able to contribute its full share to circadian clock entrainment, both with regard to behavioral and molecular synchronization to light:dark cycles. This function depends on an alternative Phospholipase C-ß enzyme, encoded by PLC21C, presumably playing a dedicated role in clock resetting by light. We show that this pathway requires the ubiquitin ligase CULLIN-3, presumably mediating CRY-independent degradation of TIM during light:dark cycles. Our results suggest that visual system contribution to circadian clock entrainment operates on a drastically slower time scale compared with fast, visual and image forming phototransduction. Our findings are therefore consistent with the general idea that the visual system samples light over prolonged periods of time (hours) in order to reliably synchronize their internal clocks with the external time.

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Clock network in Drosophila

Cited by 52 publications

References 80 publications

The Drosophila Clock Neuron Network Features Diverse Coupling Modes and Requires Network-wide Coherence for Robust Circadian Rhythms

The Drosophila Clock Neuron Network Features Diverse Coupling Modes and Requires Network-wide Coherence for Robust Circadian Rhythms

Two sides of a coin: ecological and chronobiological perspectives of timing in the wild

Less is more: Light sampling via throttled visual phototransduction robustly synchronizes theDrosophilacircadian clock in the absence of Cryptochrome

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