C-terminal processing of yeast Spt7 occurs in the absence of functional SAGA complex
Bibliographic record
Abstract
BACKGROUND: Spt7 is an integral component of the multi-subunit SAGA complex that is required for the expression of approximately 10% of yeast genes. Two forms of Spt7 have been identified, the second of which is truncated at its C-terminus and found in the SAGA-like (SLIK) complex. RESULTS: We have found that C-terminal processing of Spt7 to its SLIK form (Spt7SLIK) and to a distinct third form (Spt7Form3) occurs in the absence of the SAGA complex components Gcn5, Spt8, Ada1 and Spt20, the latter two of which are required for the integrity of the complex. In addition, N-terminally truncated derivatives of Spt7, including a derivative lacking the histone fold, are processed, indicating that the C-terminus of Spt7 is sufficient for processing and that processing does not require functional Spt7. Using galactose inducible Spt7 expression, we show that the three forms of Spt7 appear and disappear at approximately the same rate with full-length Spt7 not being chased into Spt7SLIK or Spt7Form3. Interestingly, reduced levels of Spt7SLIK and Spt7Form3 were observed in a strain lacking the SAGA component Ubp8, suggesting a regulatory role for Ubp8 in the truncation of Spt7. CONCLUSION: We conclude that truncation of Spt7 occurs early in the biosynthesis of distinct Spt7 containing complexes rather than being a dynamic process linked to the action of the SAGA complex in transcriptional regulation.
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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) | 0.001 | 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 | 0.001 |
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".