Table 1.
Comparison of the Main Features of the Novel Programmable RNA-Editing Platforms
| CIRTS30 | RESCUE32 | RESTORE33 | LEAPER36 | |
|---|---|---|---|---|
| Targeted base motifs on the transcripts evaluated | G-to-A mutation in the coding region of firefly luciferase gene | simultaneous targeting of an A and a C in the transcripts | 5′-UAG-3′ triplet in the 3′ UTRs; 5′-UAU-3′ and CAA motifs in the ORF regions | 5′-UAG-3′, 5′-UAC-3′, 5′-AAG-3′, 5′-CAG-3′ motifs |
| Guide RNA (gRNA) | 20–40 nt | 30 nt | short single-stranded sequence (63–95 nt) | ∼111–151 nt long for high editing efficiency |
| Deaminase | ADAR2 | ADAR2 | endogenous ADARs | endogenous ADARs |
| RNA-editing strategy | a gRNA with an engineered hairpin interacts with the hairpin RNA binding domain to drive a ribonucleoprotein complex formation | dRanCas13b-ADAR2 fusion | synthetic ASO with 2′-O-methyl, phosphorothioate modifications | short engineered ADAR-recruiting RNAs (arRNAs) |
| Efficiency | higher gRNA-dependent editing efficiency | RNA-editing rates up to 42% | editing efficiency up to 75%–85% (ADAR1 p150)a | editing efficiencies of up to 80% (arRNA151) |
| Delivery of editing system | viral delivery (AAV) | plasmid transfection | ASOs transfection | plasmid or lentiviral vector, or as a synthetic oligonucleotide |
| Clinically relevant mutation | KRAS4b transcript fused to the luciferase reporter | β-catenin transcript (CTNNB1) | phosphotyrosine 701 in STAT1; PiZZ mutation causing α1-antitrypsin deficiency (E342K in SERPINA1) | α-l-iduronidase catalytic activity (Hurler syndrome); TP53, COL3A1, BMPR2, AHI1, FANCC, MYBPC3, and IL2RG |
| Cellular model | HEK293T cells | HEK293FT and human umbilical vein endothelial cells (HUVECs) | human cell lines and different human primary cells | different human and mouse cell types, including various primary cell types and Hurler patient’s primary fibroblasts |
| Multiplexing approach | target multiple effectors to different transcripts | multiplexed C-to-U and A-to-I editing through the use of tailored guide RNAs | co-transfection of two ASOs | multiplex editing by co-expression of two arRNAs |
ASO, antisense oligonucleotide; ORF, open reading frame; UTR, untranslated region.
a
One of the two distinct isoforms of ADAR1 (p110 and p150).