E2F deregulation compromises ER homeostasis by attenuating IRE1 activity
Bibliographic record
Abstract
Abstract The E2F family of transcription factors are key regulators of the cell cycle in all metazoans. While they are primarily known for their role in cell cycle progression, E2Fs also play broader roles in cellular physiology, including the maintenance of exocrine tissue homeostasis. However, the underlying mechanisms that render exocrine cells particularly sensitive to E2F deregulation remain poorly understood. The Drosophila larval salivary gland (SG), like its mammalian counterpart, is an exocrine tissue that produces large quantities of "glue proteins" in the endoplasmic reticulum (ER). Here, we show that E2F activity is important for the exocrine function of the Drosophila SG. The loss of de2f1b , an alternatively spliced isoform of Drosophila E2F1 , leads to elevated DNA damage and accumulation of cytoplasmic DNA (cytoDNA) in the SGs. Surprisingly, we found that IRE1, a key sensor of the unfolded protein response, is required not only for ER homeostasis but also for preventing cytoDNA accumulation in the SG. Importantly, we found evidence demonstrating that IRE1 activity is attenuated in de2f1b -deficient SGs, contributing to both ER dysfunction and cytoDNA accumulation. Together, these findings reveal an unanticipated link between ER homeostasis and cytoDNA processing and offer mechanistic insight into why exocrine tissues are particularly vulnerable to E2F deregulation. Author Summary We discovered an unexpected consequence of E2F deregulation in ER homeostasis. The loss of de2f1b in the Drosophila salivary gland impedes physiological activation of an ER-resident protein, IRE1, a central component of the unfolded protein response. We show that IRE1 is required not only for ER homeostasis but also for preventing DNA accumulation in the cytoplasm, a phenotype observed in de2f1b deficient salivary glands. Our study reveals a previously uncharacterized role of IRE1-dependent ER function and offers new perspectives on why exocrine tissues are particularly vulnerable to the loss of E2Fs.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".