The inventors have created an RNA-editing sensor system termed RADAR that can express an effector protein in the presence of a target RNA species. The sensor system comprises a single-stranded RNA (ssRNA) sensor and an adenosine deaminase acting on RNA (ADAR) deaminase. The ssRNA sensor consists of a stop codon and a payload and is capable of binding to a ssRNA target to form a dsRNA substrate.
The method includes creating a dsRNA region via hybridization of the ssRNA sensor to an endogenous transcript, which generates an A-C mismatch within the dsRNA substrate. Upon binding to the endogenous target transcript by the ssRNA sensor, the stop codon (UAG) on the sensor is changed to a sense codon (UIG) by ADAR, which enables translation and allows the payload to be expressed.