A copper-responsive gene cluster is required for copper homeostasis and contributes to oxidative resistance in <i>Deinococcus radiodurans</i> R1
Bibliographic record
Abstract
Excess copper is toxic to organisms, and therefore, copper homeostasis is important for the limitation of its cellular levels. However, copper homeostasis has not been studied to date in the bacteria Deinococcus radiodurans R1, which exhibits extreme resistance to various environmental stresses. We have identified a copper-responsive gene cluster that encodes CopA, which is a copper-transporting P1-type ATPase, CopZ, which is a copper metallochaperone, and CsoR, which is a copper-sensing repressor. Copper induces the transcription of genes in this cluster. Mutants lacking copA exhibited reduced copper resistance and the overaccumulation of copper compared with the wild-type strain. Additionally, both in the absence and presence of copper, the copZ mutation increased the expression of copA and led to the accumulation of lower levels of copper compared with the wild type. The bioinformatic analysis showed that CsoR in D. radiodurans R1 shares high sequence similarity and identity with the CsoR of Mycobacterium tuberculosis and Bacillus subtilis. We also demonstrated through DNase I footprinting and electrophoretic mobility shift assays that CsoR binds to the promoter of the cluster and that copper ions eliminate this interaction. This implies that CsoR is the repressor of this cluster and that CopA, CopZ and CsoR participate in the regulation of copper homeostasis. Our data also indicate that after treatment with H2O2 and cumene hydroperoxide, the viability of the copA mutants was significantly reduced. This suggests that copper homeostasis plays an important role in oxidative resistance in D. radiodurans R1.
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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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".