Glossaire

Base editors are precision tools for editing DNA that directly rewrite letters, or nucleotides, in the DNA sequence. There are two key differences of base editors to the traditional CRISPR-Cas9 system (sometimes referred to as DNA scissors). Firstly, in base editors, the Cas9 protein is modified not to cut both of the DNA strands. Secondly, by the addition of a new element, deaminase, base editors can carry out the converting, and thus rewriting, of nucleotides. There are two types of base editors: cytosine base editors (CBE) and adenine base editors (ABE). In CBE, the deaminase converts the cytosine to uracil (letter C to U), whereas the ABE first converts adenine to guanosine (letter A to G) by a two-step process where adenine is converted to an inosine and then to a guanosine.