Table 4. Dual and chimeric riboregulators.
| Application area (contribution) | RNA Unit Device | Function | Host | Description | Strategy | Reference |
|---|---|---|---|---|---|---|
| Synthetic Biology (RNA device) | A riboswitch-activated sRNA (chimera) | Transcriptional elongation and translational initiation control | E. coli | A natural theophylline aptamer activates transcriptional and translational regulators (sRNAs) | Natural sensor+adaptor coupled to a natural sRNA by engineering a kissing-loop2 –like interaction. | 75 |
| Synthetic Biology (Increased signal propagation speed for complex circuits) | A dual sRNA-like system | Transcription control | E. coli | Showed “composability” of these devices for a complex circuit by using variants of wt pT181 regulation system | Regulator and sensor interactions engineered by introducing rational mutations | 74 |
| Molecular Biology (robust gene expression regulation tool) Synthetic Biology(programmable kill switch) |
A dual sRNA-like system | Translational initiation control | E. coli | Engineered riboregulator system (cr-taRNA) with a broad dynamic range | Rationally designed a diverse pool of regulators and tested in vivo |
73 Potential applications ref. 139 |
| Synthetic Biology(addition to platform/tool box) | An anti-sense RNA responsive aptazyme | Translation initiation control | E. coli | Trans-acting responsive element engineered into a HHR for construction of more complex genetic circuits | Rationally designed regulator-sensing device coupled to a scissile adaptor and an actuator. | 76 |
1 tnaC: is a regulatory element that contains a Ribosomal Binding Site, short leader peptide code and a rho terminator.1It is based on the regulatory element from tna operon in E. coli.2Kissing-loop interaction: is a common coaxial stacking motif in which nucleotides in two loops of two different hairpins base-pair to form a stable tertiary structure.