BE-PLUS: a new base editing tool with broadened editing window and enhanced fidelity

Abstract

<p class="first" id="Par1">Base editor (BE), containing a cytidine deaminase and catalytically defective Cas9, has been widely used to perform base editing. However, the narrow editing window of BE limits its utility. Here, we developed a new editing technology named as <span style="text-decoration: underline">b</span>ase <span style="text-decoration: underline">e</span>ditor for <span style="text-decoration: underline">p</span>rogramming <span style="text-decoration: underline">l</span>arger C to <span style="text-decoration: underline">U</span> (T) <span style="text-decoration: underline">s</span>cope (BE-PLUS) by fusing 10 copies of GCN4 peptide to nCas9(D10A) for recruiting scFv-APOBEC-UGI-GB1 to the target sites. The new system achieves base editing with a broadened window, resulting in an increased genome-targeting scope. Interestingly, the new system yielded much fewer unwanted indels and non-C-to-T conversions. We also demonstrated its potential use in gene disruption across the whole genome through induction of stop codons (iSTOP). Taken together, the BE-PLUS system offers a new editing tool with increased editing window and enhanced fidelity. </p>