Cytosine base editors and adenine base editors (ABEs) can correct point mutations predictably and independent of Cas9-induced double-stranded DNA breaks (which causes substantial indel formation) and homology-directed repair (which typically leads to low editing efficiency). Here, we show, in adult mice, that a subretinal injection of an adeno-associated virus expressing an ABE and a single-guide RNA targeting a de novo nonsense mutation in the Rpe65 gene corrects the pathogenic mutation with up to 29% efficiency and with minimal formation of indel and off-target mutations, despite the absence of the canonical NGG sequence as a protospacer-adjacent motif. The ABE-treated mice displayed restored RPE65 expression and retinoid isomerase activity, and near-normal levels of retinal and visual functions. Our findings motivate the further testing of ABEs for the treatment of inherited retinal diseases and for the correction of pathological mutations with non-canonical protospacer-adjacent motifs.

胞嘧啶碱基编辑器和腺嘌呤碱基编辑器 (ABE) 可以可预测地纠正点突变，并且与 Cas9 诱导的双链 DNA 断裂（导致大量插入缺失）和同源定向修复（通常导致编辑效率低）无关。在这里，我们在成年小鼠中显示，视网膜下注射表达 ABE 的腺相关病毒和靶向Rpe65中从头无义突变的单向导 RNA基因纠正致病突变的效率高达 29%，并且插入缺失和脱靶突变的形成最少，尽管没有典型的 NGG 序列作为原型间隔区相邻基序。ABE 治疗的小鼠显示出恢复的 RPE65 表达和类视黄醇异构酶活性，以及​​接近正常水平的视网膜和视觉功能。我们的研究结果促使进一步测试 ABE 治疗遗传性视网膜疾病和纠正具有非规范原型间隔区相邻基序的病理突变。