Genetic editing and interrogation with Cpf1 and caged truncated pre-tRNA-like crRNA in mammalian cells

a Structures of conventional crRNA, caged crRNA (caRNA), and caged truncated pre-tRNA-like crRNA (catRNA) transcribed by Pol III and Pol II polymerases. Red, crRNA spacer sequence. Oligo-T (Pol III) or oligo-T-Poly A (Pol II) are incorporated into crRNA but not caRNA or catRNA. b Structures of pre-tRNA and truncated pre-tRNA. Pre-tRNA is matured by RNase P by removal of the leader sequence and subsequently modified and processed by RNase Z. RNase P processing is blocked by disrupting the 7-base pair stem structure of pre-tRNA, which is critical for RNase P recognition and cleavage. Subsequent RNase Z cleavage is also abolished due to RNase P processing failure. c Illustration of the RNase-resistant property of catRN