Develop an ecDHFR-regulated RESCUE system, ecRESCUE, with reduced RNA off-targeting activity

Currently, RESCUE RNA base editor proposes great potential for treating genetic diseases at transcription level. The relatively high off-target events are one of the main constrains for precisely RNA base editing mediated by RESCUE system. Here, we developed a new RNA base editor, ecRESCUE, fusing by inducible stabilization protein ecDHFR DD at the C-terminal of RESCUE system, respectively. The ecRESCUE RNA base editors are used for endogenous mRNA editing and off-target analysis. The results showed that the ecRESCUE RNA base editor markedly reduced its off-target SNP numbers without affecting RNA A-to-I and C-to-U base editing efficiency. Taken together, we developed an ecDHFR DD-regulated RESCUE system, ecRESCUE, with reduced RNA off-targeting activity.