Fig. 3: Tunable gene repression and precise base editing with crRNA toolbox.

a Genetic components for the validation of tunable CRISPRi facilitated by crRNA toolbox. DR-mutated crRNAs guided dCas12a to inhibit gfp transcription in diverse levels, indicating tunable expression repression. The expression of dCas12a was controlled by a P_BAD promoter. b Relative expression derived from seven crRNAs with no inducer (L-ara) added. A strong RBS (RBS0) and a weak RBS (RBS33) were used upstream of the dCas12a coding region. c Relative expression derived from seven crRNAs with various concentrations of inducer (L-ara: 0, 2, 5, 10 mM) added. d Relationship between gfp relative expression levels when crRNA mutants target different protospacers. Relative expression was calculated based on specific fluorescence levels (RFU/OD₆₀₀) and normalized with the non-targeted control set to 100%. CN indicates canonical crRNA. e Genetic components for precise base editing facilitated by crRNA toolbox. DR-mutated crRNAs guided APOBEC-dCas12a-UGI/evoCDA-dCas12a-UGI for base editing and achieved tunable editing window. BE indicates base editor. f,g C to T editing efficiency at multiple sites derived from APOBEC-dCas12a-UGI (f) and evoCDA-dCas12a-UGI (g) guided by crRNA mutants. h,i Average C to T editing efficiency across the 20-bp spacer derived from APOBEC-dCas12a-UGI (h) and evoCDA-dCas12a-UGI (i) guided by crRNA mutants. Editing window narrowed with the use of FL2 and L1, indicating precise editing. Data are shown as mean ± s.d. for n  =  3 biologically independent samples. Source data are provided as a Source Data file.