Fep1 represses expression of the fission yeast Schizosaccharomyces pombe siderophore-iron transport system
Bibliographic record
Abstract
When iron repletes, Schizosaccharomyces pombe cells repress transcription of genes encoding components involved in the reductive iron transport system. Fep1 mediates this transcriptional control by interacting specifically with GATA-type cis-acting elements. To further investigate the role that Fep1 plays in iron homeostasis, we searched for additional Fep1-regulated genes. We found that str1+ is subject to negative transcriptional regulation, which is exerted through binding of Fep1 to a single GATA element in the str1+ promoter. Introduction of str1+ into a Saccharomyces cerevisiae fet3Delta arn1-4Delta strain led to assimilation of iron from ferrichrome, revealing that Str1 functions as a siderophore-iron transporter in S.pombe. We also identified two additional target genes of Fep1, named str2+ and str3+. We demonstrate that the str1+, str2+ and str3+ genes share a common promoter element, 5'-(A/T)GATAA-3'. We found that the N-terminal 241 residue segment of Fep1 expressed in Escherichia coli specifically interacts with the 5'-(A/T)GATAA-3' element present in each of these promoters. Consistent with this, constitutive high level str1+, str2+ and str3+ gene expression was observed in a fep1Delta mutant strain. Taken together, these results demonstrate that Fep1 occupies a central role in coordinating transcriptional regulation of genes encoding components of the reductive and non-reductive iron transport systems in fission yeast.
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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 | 0.001 | 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 | 0.001 | 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".