Fluoride-Controlled Riboswitch-Based Dampening of Gene Expression for Cloning Potent Promoters
Bibliographic record
Abstract
Bioreporter systems based on detectable enzyme activity, such as that of beta-galactosidase or luciferase, are key in novel bacterial promoter discovery and study. While these systems permit quantification of gene expression, their use is limited by the toxicity of the expressed reporter enzymes in a given host. Indeed, the most potent promoters may be overlooked if their activity causes a lethal overproduction of the reporter genes when screening for transcriptional activity of potential promoter sequences with the luxCDABE cassette. To overcome this limitation, a variation of the mini-CTX-lux plasmid has been designed which allows reduction of promoter activity via the addition of an adjacent fluoride riboswitch. The riboswitch adds a layer of regulation between the promoter and the reporter gene, allowing cloning of stronger promoters by weakening expression, while giving the potential to induce with fluoride to provide a good signal for weaker promoters, thus circumventing limitations associated with reporter toxicity. We noticed the riboswitch potential portability issues between species, suggesting caution when using riboswitches non-native to the species where it is being used. This study introduces a new molecular biology tool which will allow for the identification of previously unverifiable or uncharacterized potent promoters and also provides a cloning vector for translational fusion with luciferase in a plasmid compatible with many species such as from the genera Burkholderia and Pseudomonas.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".