Recent advances in CRISPR/Cas9-mediated knock-ins in mammalian cells

Since its inception, the CRISPR/Cas9 technology has been widely utilized for the targeted insertion of donor DNAs into mammalian genomes. A shortcoming with the earlier knock-in (KI) approaches, however, has been the low efficiency of targeted integrations—especially in primary cells and mouse embryos. Since, a variety of novel strategies have been developed towards improving the KI efficiencies in select target cells. In this review, the current applications of CRISPR/Cas9-mediated KIs in mammalian cells are described. Furthermore, the recent strategies which have been developed in order to augment the CRISPR/Cas9-mediated KI efficiencies are summarized.