CRISPR-cas9: a powerful tool towards precision medicine in cancer treatment

摘要

The synthesized 20 nt sgRNA is complementary to the target sequence near the protospacer adjacent motif (PAM). The cas9 protein introduces double-strand break (DSB) through the endonuclease domains HNH and Ruvc and then mediates gene repair by nonhomologous end joining (NHEJ) and homology directed repair (HDR), which may lead to an indel mutation or gene knockout. Moreover, cas9 can also be transformed into dcas9 by inactivating the endonuclease domain, which could cause gene transcriptional repression or activation via fusion to a transcriptional activator or repressor.