In Vitro Selection for Small-Molecule-Triggered Strand Displacement and Riboswitch Activity

Area of Science:

• Molecular Biology
• Synthetic Biology
• Biochemistry

Background:

• Ligand-responsive RNA sensors are crucial for detecting small molecules.
• Existing methods for selecting RNA sensors can be limited in scope and efficiency.
• The thiamine pyrophosphate (TPP) riboswitch serves as a model for ligand-binding RNA.

Purpose of the Study:

• To develop a novel in vitro selection method for engineering ligand-responsive RNA sensors.
• To identify RNA sequences that mediate strand displacement reactions regulated by TPP binding.
• To demonstrate the ability of selected RNA sensors to control nucleic acid circuitry.

Main Methods:

• An in vitro selection strategy was employed using a library of RNA sequences based on the TPP riboswitch.
• Strand displacement reactions were utilized as the selection mechanism.
• Three rounds of selection were performed to enrich for RNA molecules with desired TPP-dependent activity.

Main Results:

• RNA sequences capable of TPP-regulated hybridization to a target DNA duplex were identified.
• Enriched RNA molecules effectively mediated strand exchange reactions upon TPP binding.
• The selected RNA sequences exhibited functional riboswitch activity.

Conclusions:

• A robust in vitro selection method was established for generating ligand-responsive RNA sensors.
• Small-molecule-responsive nucleic acid sensors can be engineered to control nucleic acid circuitry.
• This approach holds promise for developing sophisticated molecular devices and diagnostic tools.