Two Duplicated Genes DDI2 and DDI3 in Budding Yeast Encode a Cyanamide Hydratase and Are Induced by Cyanamide
Bibliographic record
Abstract
Two DNA damage-inducible genes in Saccharomyces cerevisiae, DDI2 and DDI3, are identical and encode putative HD domain-containing proteins, whose functions are currently unknown. Because Ddi2/3 also shows limited homology to a fungal cyanamide hydratase that converts cyanamide to urea, we tested the enzymatic activity of recombinant Ddi2. To this end, we developed a novel enzymatic assay and determined that the Km value of the recombinant Ddi2/3 for cyanamide is 17.3 ± 0.05 mm, and its activity requires conserved residues in the HD domain. Unlike most other DNA damage-inducible genes, DDI2/3 is only induced by a specific set of alkylating agents and surprisingly is strongly induced by cyanamide. To characterize the biological function of DDI2/3, we sequentially deleted both DDI genes and found that the double mutant was unable to metabolize cyanamide and became much more sensitive to growth inhibition by cyanamide, suggesting that the DDI2/3 genes protect host cells from cyanamide toxicity. Despite the physiological relevance of the cyanamide induction, DDI2/3 is not involved in its own transcriptional regulation. The significance of cyanamide hydratase activity and its induced expression is discussed.
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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 | 0.001 |
| 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 | 0.001 |
| 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".