Genome-wide, as opposed to local, antisilencing is mediated redundantly by the euchromatic factors Set1 and H2A.Z
Bibliographic record
Abstract
In Saccharomyces cerevisiae, several nonessential mechanisms including histone variant H2A.Z deposition and transcription-associated histone H3 methylation antagonize the local spread of Sir-dependent silent chromatin into adjacent euchromatic regions. However, it is unclear how and where these factors cooperate. To probe this question, we performed systematic genetic array screens for gene deletions that cause a synthetic growth defect in an htz1Delta mutant but not in an htz1Delta sir3Delta double mutant. Of the four genes identified, three, SET1, SWD1, and SWD3, encode components of the Set1 complex, which catalyzes the methylation of histone H3 on lysine 4 (H3-K4), a highly conserved modification that occurs in the coding sequences of transcribed genes. Using microarray-based transcriptional profiling, we find that H2A.Z and Set1 cooperate to prevent Sir-dependent repression of a large number of genes located across the genome, rather than the local effects reported previously for the individual mechanisms. This global, redundant function appears to be direct: using a DamID chromatin profiling method, we demonstrate ectopic association of Sir3 and Sir4 in htz1Delta set1Delta mutants at loci distant from silent chromatin domains. Antisilencing mechanisms may therefore cooperate to play a considerably broader role in regulating genome-wide transcription than previously thought.
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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".