Figure 1.

DSBs repair-mediated knock-in strategies

(A) HDR-mediated knock-in is based on homologous recombination (HR) between the long homology arms present in the target genome and donor vector (circular dsDNA, linearized dsDNA or ssDNA). Dashed lines refer to the HR event. (B) NHEJ-mediated knock-in relies on end-joining, either blunt end or sticky end, between donor DNA and target genome around DSBs. (C) MMEJ-mediated knock-in starts requires short microhomology, which starts resection of the microhomology and is followed by annealing of the sequences. (D) SSA-mediated knock-in leverages phage-encoded SSAPs to preform precise recombination which works in a sequence-independent manner. dsDNA, double-stranded DNA; GOI, gene of interest; HA, homology arms; MH, microhomology; ssDNA, single-stranded DNA.