EditR: A novel base editing quantification software using Sanger sequencing

Abstract

CRISPR/Cas9-Cytidine deaminase fusion enzymes - termed Base Editors - allow targeted editing of genomic deoxcytidine to deoxthymidine (C[->]T) without the need for double stranded break induction. Base editors represent a paradigm-shift in gene editing technology, due to their unprecedented efficiency to mediate targeted, single-base conversion; however, current analysis of base editing outcomes rely on methods that are either imprecise or expensive and time consuming. To overcome these limitations, we developed a simple, cost effective, and accurate program to measure base editing efficiency from fluorescence-based Sanger sequencing, termed EditR. We provide EditR as a free online tool or downloadable desktop application requiring a single Sanger sequencing file and guide RNA sequence (baseeditr.com). EditR is more accurate than enzymatic assays, and provides added insight to the position, type and efficiency of base editing. Collectively, we demonstrate that EditR is a robust, inexpensive tool that will facilitate the broad application of base editing technology, thereby fostering further innovation in this burgeoning field.