Abstract
Cytidine base editors, composed of a cytidine deaminase fused to Cas9 nickase, enable efficient C-to-T conversion in various organisms. However, current base editors can induce unwanted bystander C-to-T conversions when more than one C is present in the activity window of cytidine deaminase, which negatively affects the precision. Here, we develop a new base editor with CC context-specificity using rationally engineered human APOBEC3G, thus significantly reduce unwanted bystander activities. In addition, efficient C-to-T conversion that can further recognize relaxed NG PAMs is achieved by combining an engineered SpCas9-NG variant. These novel base editors with improved precision and targeting scope will expand the toolset for precise gene modification in organisms.
List of abbreviations
- (CBE)
- (cytidine base editor);
- (DSBs)
- (double-strand breaks);
- (indels)
- (insertion/deletion mutations);
- (BE3)
- (base editor 3);
- (rA1)
- (rat APOBEC1);
- (SpCas9)
- (Streptococcus pyogenes Cas9);
- (UGI)
- (uracil glycosylase inhibitor);
- (eA3A)
- (engineered human APOBEC3A);
- (hA3G)
- (human APOBEC3G);
- (sgRNAs)
- (single guide RNAs);
- (OCA1)
- (oculocutaneous albinism type 1);
- (F0)
- (Founder);
- (AD)
- (Alzheimer’s disease);
- (H&E)
- Haematoxylin and eosin.