FIGURE 1.

Site-specific gRNA design and activity assay. A, the target sequences of five gRNAs of the mutated HBB gene CD41/42 site. B, schematic of the GFP reporter assay. C, top, fluorescence images of 293T cells co-transfected with Cas9 gRNA and GFP-REP-del-CTTT. Bottom, fluorescence images of the co-transfected cells 48 h later. D, T7 endonuclease 1 assay to assess Cas9 gRNA activity in β-iPS-41/42 cells. E, the alignment of the gRNA1 target sequence (seq), HBB CD41/42 mutation, HBB WT, HBD, HBG1, and HBG2 sequences.