The Schizosaccharomyces pombe Corepressor Tup11 Interacts with the Iron-responsive Transcription Factor Fep1
Bibliographic record
Abstract
The Schizosaccharomyces pombe fep1(+) gene encodes a GATA transcription factor that represses the expression of iron transport genes in response to elevated iron concentrations. This transcriptional response is altered only in strains harboring a combined deletion of both tup11(+) and tup12(+) genes. This suggests that Tup11 is capable of negatively regulating iron transport gene expression in the absence of Tup12 and vice versa. The tup11(+)- and tup12(+)-encoded proteins resemble the Saccharomyces cerevisiae Tup1 corepressor. Using yeast two-hybrid analysis we show that Tup11 and Fep1 physically interact with each other. The C-terminal region from amino acids 242 to 564 of Fep1 is required for interaction with Tup11. Within this region, a minimal domain encompassing amino acids 405-541 was sufficient for Tup11-Fep1 association. Deletion mapping analysis revealed that the WD40-repeat sequence motifs of Tup11 are necessary for its interaction with Fep1. Analysis of Tup11 mutants with single amino acid substitutions in the WD40 repeats suggested that the Fep1 transcription factor interacts with a putative flat upper surface on the predicted beta-propeller structure of this motif. Further analysis by in vivo coimmunoprecipitation showed that Tup11 and Fep1 are physically associated. In vitro pull-down experiments further verified a direct interaction between the Fep1 C terminus and the Tup11 C-terminal WD40 repeat domain. Taken together, these results describe the first example of a physical interaction between a corepressor and an iron-sensing factor controlling the expression of iron uptake genes.
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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 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| 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".