Harnessing Coding Sequence Cleavage: Theophylline Aptazymes as Portable Gene Regulators in Bacteria
Bibliographic record
Abstract
Abstract Nucleic acid-based regulatory elements capable of modulating gene expression in response to specific molecular cues have gained increasing attention in synthetic biology. These systems, which include riboswitches, allosteric DNAzymes, and aptazymes, function as Gene Expression Nucleic Allosteric actuators (GENAs) by coupling molecular recognition with genetic regulation. Their versatility can enable applications in diagnostics, therapeutics, and metabolic engineering. This study presents a novel “semi-trans” aptazyme-based system for gene regulation in bacteria, expanding the range of GENAs. The system employs theophylline-responsive hammerhead ribozyme aptazymes positioned in the 5’ UnTranslated Region (UTR), designed to cleave within the coding sequence of the target gene, thereby modulating gene expression in a ligand-dependent manner. Using the tetA gene in Escherichia coli ( E. coli ) as a proof of concept, we demonstrate ligand-controlled regulation of tetracycline resistance and nickel sensitivity. The system′s effectiveness is validated through in vitro cleavage assays and in vivo phenotypic studies in two E. col i strains, highlighting its portability across genetic backgrounds. Furthermore, the ability to design multiple aptazymes targeting different coding regions enables complex and fine-tuned regulation. This work broadens the landscape of synthetic gene regulation tools, facilitating the development of new aptazymes based on this approach. Abstract Figure
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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) | 0.000 | 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".