Fig. 3

Opportunities resulting from knockout escaping. A Combining knockout escaping and RNAi, distinct roles of Bub1 and RZZ on SAC can be dissected. RZZ concentrates Mad1 around Bub1 to enhance Bub1–Mad1 interaction, which is critical for SAC activation [21]. B Combining knockout escaping and RNAi reveals the biological significance of the separation of kinase activity and phosphatase activity within the Bub complex. Adapted from Ref. [94]. C Knockout escaping provides an opportunity to treat monogenic disease such as DMD. AB (actin binding domain) and DB (b-dystroglycan binding domain) are two essential domains on N-terminal and C-terminal ends. Rounded rectangles with numbers represent exons. Green ones indicate the exons that could be transcribed, and red ones exons that could not be transcribed. Purple lines represent introns. Broken lines indicate the joining sites during the alternative splicing. Scissor means genome editing by CRSPR–Cas. Deletion of exon 44 causes reading frame shift and PTC, resulting in dysfunctional truncated dystrophin. Targeting the splicing acceptor of exon 45 by CRISPR–Cas9 induces exon 45 skipping and restores the reading frame. An internal truncated functional dystrophin is produced and rescues severe DMD [97]