Fig. 1: The CRISPR/Cas tools.
From: Gene editing in cancer therapy: overcoming drug resistance and enhancing precision medicine
A Cas nucleases introduce double-strand breaks (DSBs) in the genome, which are repaired via homology-directed repair (HDR) or non-homologous end joining (NHEJ). B Cytidine base editors (CBEs), composed of cytidine deaminase and uracil glycosylase inhibitor (UGI), deaminate cytosine (C), ultimately converting it into thymine (T). C Adenine base editors (ABEs) utilize adenosine deaminase to convert adenine (A) into inosine (I), which is interpreted as guanine (G) during DNA repair or replication. D Prime editors (PEs) consist of reverse transcriptase, nCas9, and a prime editing guide RNA (pegRNA) containing a primer binding site, reverse transcriptase template, and edit sequence. The pegRNA binds to the target DNA strand, enabling the precise modifications.
