Mutations in Su(var)205 and Su(var)3-7 Suppress P-Element-Dependent Silencing in Drosophila melanogaster
Bibliographic record
Abstract
In Drosophila melanogaster, the w(+) transgene in P[lacW]ci(Dplac) is uniformly expressed throughout the adult eye. However, when other P elements are present, this w(+) transgene is randomly silenced and this produces a variegated eye phenotype. This P-element-dependent silencing (PDS) is limited to w(+) transgenes inserted in a specific region on chromosome 4. In a screen for genetic modifiers of PDS, we isolated mutations in Su(var)205, Su(var)3-7, and two unidentified genes that suppress this variegated phenotype. Therefore, only a few of the genes encoding heterochromatic modifiers act dose dependently in PDS. In addition, we recovered two spontaneous mutations of P[lacW]ci(Dplac) that variegate in the absence of P elements. These P[lacW]i(Dplac) derivatives have a gypsy element inserted proximally to the P[lacW]ci(Dplac) insert. The same mutations that suppress PDS also suppress w(+) silencing from these P[lacW]ci(Dplac) derivative alleles. This indicates that both cis-acting changes in sequence and trans-acting P elements cause a similar change in chromatin structure that silences w(+) expression in P[lacW]ci(Dplac). Together, these results confirm that PDS occurs at P[lacW]ci(Dplac) because of the chromatin structure at this chromosomal position. Studying w(+) variegation from P[lacW]ci(Dplac) provides a model for the interactions that can enhance heterochromatic silencing at single P-element inserts.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".