1. Gene editing by CRISPR/Cas9 for gene inactivation and targeted sequence replacement.
Gene editing by CRISPR/Cas9 for gene inactivation and targeted sequence replacement. During gene editing by CRISPR/Cas 9, the endonuclease Cas9 (green) is led by the guide RNA (gRNA) to the genomic target site, where it cleaves the double-stranded DNA (dsDNA) at a point 3-5 bp upstream of the protospacer adjacent motif (PAM). The resulting double-strand break (DSB) can then be repaired by nonhomologous end joining (NHEJ, left) or by homology-directed repair (HDR, right). NHEJ is an error-prone mechanism that can lead to sequence deletion, insertion or both, which can disrupt gene function. The HDR pathway is more precise and uses template DNA to repair the DSB via homologous recombination. The introduction of an exogenous DNA template, as dsDNA or as single-stranded oligodeoxynucleotide (ssODN), allows desired sequence changes to be engineered.
Carolin Perleberg et al. Dis. Model. Mech. 2018;11:dmm030783
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