Originally published Aug 16, 2016 and last updated Aug 6, 2020 by Jennifer Tsang.
When we talk about CRISPR applications, one negative often comes up: the low editing efficiency of homology-directed repair (HDR). Compared to non-homologous end joining, HDR occurs at a relatively low frequency, and in nondividing cells, this pathway is further downregulated. Rather than try to improve HDR, scientists have developed two classes of base editors: cytosine base editors (CBEs) and adenine base editors (ABEs).
(There are also RNA base editors, but we’ll just be covering DNA base editors here. To learn more about RNA base editors head over to this blog post: CRISPR 101: RNA Editing with Cas13)