Biology subjects

Ogueta, M.

Publications and source records attributed to Ogueta, M..

7 recordsLinked to original sources

bioRxiv2025

Hsp90 buffers behavioral plasticity by regulating Pdf transcription in clock neurons of Drosophila melanogaster

Circadian rhythms are prevalent on Earth and temporally organize behaviour and physiology of organisms to occur in species-specific temporal niches. However, species differ in how strictly individuals are controlled by their circadian clock, suggesting that it may offer a selective advantage for an individual to extend its temporal niche under certain circumstances, for example during stressful environmental conditions. A potential mechanism controlling temporal niche adherence involves the evolutionary capacitor and chaperon protein HSP90, known to assist the proper folding of important signalling molecules. If HSP90 becomes rate limiting (e.g., under environmental stress) hidden genetic variation will be expressed, producing novel and potentially beneficial phenotypes for the individual. While this role of HSP90 is well established for morphological traits, we show here that it extends to regulation of temporal behavioural patterns. We show that within a small subset of clock neurons in the fly brain, HSP83, the fly homologue of HSP90, mitigates inter-individual behavioural plasticity. We provide evidence for the requirement of HSP83 for efficient transcription of the gene encoding the circadian neuropeptide Pigment Dispersing Factor (PDF), and for correct PDF accumulation in central clock neurons. Strikingly, Hsp83 mutants affect synchronized oscillations of the clock protein PERIOD (PER) in subsets of circadian clock neurons in the same way as flies without PDF, further supporting a role of Hsp83 in regulating Pdf. Our findings therefore provide a mechanistic explanation for HSP83 function in regulation of behavioural plasticity, and offer an explanation for how to restrict temporal niche extension to stressful environmental conditions.

neuroscience↗

bioRxiv2025

Fruit flies actively restart their circadian clock by proactively shaping their environment

Circadian clocks are prevalent on Earth and are generally believed to provide adaptive advantage to organisms. Functional circadian clocks, and their synchronization with the outside world, has also been implicated to provide health benefits for humans. However, experimental evidence for the benefits of possessing a circadian clock is sparse and largely restricted to prokaryotic organisms. Here, we provide evidence for the benefits of circadian clocks and temporally organized life in the fruit fly Drosophila melanogaster. We demonstrate that flies prefer and actively choose to live under circadian clock regulation: Exposure to constant light breaks down the circadian clock and leads to arrhythmic locomotor activity patterns. When given the choice to move between dark and illuminated areas in a constant light environment, flies were able to maintain, or even re-gain, rhythmic behavioural patterns. These rhythms were mirrored by regular positional changes between the two areas, demonstrating that flies actively contribute to creating an environment allowing circadian clock function and temporal organisation. The self-inflicted rhythms were accompanied by molecular rhythms in the majority of the clock neurons known to drive behavioural rhythms in flies, showing that they are indeed controlled by the circadian clock. Finally, behavioural rhythmicity was correlated with restoration of rhythmic sleep patterns and less-fragmented sleep compared to arrhythmic flies. While life is possible without a circadian clock, we show that if given the choice, animals prefer to live in a temporally organized manner and actively contribute to make this possible. This provides strong arguments for the benefits of possessing and using a circadian clock, for example by ensuring a better quality of sleep.

neuroscience↗

bioRxiv2024

Deciphering a beetle clock: individual and sex-dependent variation in daily activity patterns

Circadian clocks are inherent to most organisms, including cryptozoic animals that seldom encounter direct light, and regulate their daily activity cycles. A conserved suite of clock genes underpins these rhythms. In this study, we explore the circadian behaviors of the red flour beetle Tribolium castaneum, a significant pest impacting stored grain globally. We report on how daily light and temperature cues synchronize distinct activity patterns in these beetles, characterized by reduced morning activity and increased evening activity, anticipating the respective environmental transitions. Although less robust, rhythmicity in locomotor activity is maintained in constant dark and constant light conditions. Notably, we observed more robust rhythmic behaviors in males than females with individual variations exceeding those previously reported for other insect species. RNA interference targeting the Clock gene disrupted locomotor activity rhythms. Our findings demonstrate the existence of a circadian clock and of clock-controlled behaviors in T. castaneum. Furthermore, they highlight substantial individual differences in circadian activity, laying the groundwork for future research on the relevance of individual variation in circadian rhythms in an ecological and evolutionary context.

animal behavior and cognition↗

bioRxiv2022

Real time, in vivo measurement of neuronal and peripheral clocks in Drosophila melanogaster

Circadian clocks are highly conserved transcriptional regulators that control 24-hour oscillations in gene expression, physiological function, and behavior. Circadian clocks exist in almost every tissue and are thought to control tissue-specific gene expression and function, synchronized by the brain clock. Many disease states are associated with loss of circadian regulation. How and when circadian clocks fail during pathogenesis remains largely unknown because it is currently difficult to monitor tissue-specific clock function in intact organisms. Here, we developed a method to directly measure the transcriptional oscillation of distinct neuronal and peripheral clocks in live, intact Drosophila, which we term Locally Activatable BioLuminescence or LABL. Using this method, we observed that specific neuronal and peripheral clocks exhibit distinct transcription properties. Loss of the receptor for PDF, a circadian neurotransmitter critical for the function of the brain clock, disrupts circadian locomotor activity but not all tissue-specific circadian clocks; we found that, while peripheral clocks in non-neuronal tissues were less stable after the loss of PDF signaling, they continued to oscillate. This result suggests that the presumed dominance of the brain clock in regulating peripheral clocks needs to be re-examined. This result further demonstrates that LABL allows rapid, affordable, and direct real-time monitoring of clocks in vivo.

genetics↗

bioRxiv2021

The opposing Chloride Cotransporters KCC and NKCC control locomotor activity inconstant light and during long days.

Cation Chloride Cotransporters (CCCs) regulate intracellular chloride ion concentration ([Cl-]i) within neurons, which can reverse the direction of the neuronal response to the neurotransmitter GABA. Na+ K+ Cl- (NKCC) and K+ Cl- (KCC) cotransporters transport Cl- into or out of the cell, respectively. When NKCC activity dominates, the resulting high [Cl-]i can lead to an excitatory and depolarizing response of the neuron upon GABAA receptor opening, while KCC dominance has the opposite effect. This inhibitory-to-excitatory GABA switch has been linked to seasonal adaption of circadian clock function to changing day length, and its dysregulation is associated with neurodevelopmental disorders such as epilepsy. Constant light normally disrupts circadian clock function and leads to arrhythmic behavior. Here, we demonstrate a function for KCC in regulating Drosophila locomotor activity and GABA responses in circadian clock neurons because alteration of KCC expression in circadian clock neurons elicits rhythmic behavior in constant light. We observed the same effects after downregulation of the Wnk and Fray kinases, which modulate CCC activity in a [Cl-]i-dependent manner. Patch-clamp recordings from clock neurons show that downregulation of KCC results in a more positive GABA reversal potential, while KCC overexpression has the opposite effect. Finally, KCC downregulation represses morning behavioral activity during long photoperiods, while downregulation of NKCC promotes morning activity. In summary, our results support a model in which the regulation of [Cl-]i by a KCC/NKCC/Wnk/Fray feedback loop determines the response of clock neurons to GABA, which is important for adjusting behavioral activity to constant light and long-day conditions.

neuroscience↗

bioRxiv2020

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

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, light-dependent 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-{beta} 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.

neuroscience↗

bioRxiv2017

Open Source LED controller for circadian experiments

Controlling the light conditions when performing a circadian experiment is a key factor. In this article a simple, affordable and open source LED controller is presented. Using commercial available solutions like and Arduino [1] and LED stripes the cost is dramatically reduced.

animal behavior and cognition↗