Nuclear Export of <i>Drosophila</i> PERIOD contributes to temperature compensation of the circadian clock
Bibliographic record
Abstract
Abstract Circadian clocks are self-sustained molecular oscillators controlling daily changes of behavioral activity and physiology. For functional reliability and precision the frequency of these molecular oscillations must be stable at different environmental temperatures, known as ‘temperature compensation’. Despite being an intrinsic property of all circadian clocks, this phenomenon is not well understood at the molecular level. Here we use behavioral and molecular approaches to characterize a novel mutation in the period ( per ) clock gene of Drosophila melanogaster , which alters a predicted nuclear export sequence (NES) of the PER protein. We show that this new per I530A allele leads to progressively longer behavioral periods and clock oscillations with increasing temperature in both clock neurons and peripheral clock cells. While the mutant PER I530A protein shows normal circadian fluctuations and post-translational modifications at cool temperatures, increasing temperatures lead to both, severe amplitude dampening and hypophosphorylation of PER I530A . We further show that PER I530A displays reduced repressor activity at warmer temperatures, presumably because it cannot inactivate the transcription factor CLOCK (CLK). With increasing temperatures nuclear accumulation of PER I530A within clock neurons is increased, suggesting that PER is normally exported out of the nucleus at warm temperatures. Consequently, downregulating the nuclear export factor CRM1 also leads to temperature-dependent changes of behavioral rhythms. In summary, our results suggest that the PER NES and the nuclear export of clock proteins play an important role in temperature compensation of the Drosophila circadian clock.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".