A global pH sensor: <i>Agrobacterium</i> sensor protein ChvG regulates acid-inducible genes on its two chromosomes and Ti plasmid
Bibliographic record
Abstract
A sensor protein ChvG is part of a chromosomally encoded two-component regulatory system ChvG/ChvI that is important for the virulence of Agrobacterium tumefaciens. However, it is not clear what genes ChvG regulates or what signal(s) it senses. In this communication, we demonstrate that ChvG is involved in the regulation of acid-inducible genes, including aopB and katA, residing on the circular and linear chromosomes, respectively, and the tumor-inducing (Ti)-plasmid-harbored vir genes, virB and virE. ChvG was absolutely required for the expression of aopB and very important for the expression of virB and virE. However, it was responsible only for the responsiveness of katA and, to a limited extent, the vir genes to acidic pH. ChvG appears to play a role in katA expression by repressing katA at neutral pH. ChvG had no effect on the expression of two genes that were not acid-inducible. Because ChvG regulates unlinked acid-inducible genes encoding different functions in different ways, we hypothesize that ChvG is a global sensor protein that can directly or indirectly sense extracellular acidity. We also analyzed the re-sequenced chvG and found that ChvG is more homologous to its Sinorhizobium meliloti counterpart ExoS than was previously thought. Full-length ChvG is conserved in members of the alpha-proteobacteria, whereas only the C-terminal kinase domain is conserved in other bacteria. Sensing acidity appears to enable Agrobacterium to coordinate its coping with the environment of wounded plants to cause tumors.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| 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".