PT  - JOURNAL ARTICLE
AU  - Lee, Sangsin
AU  - Ding, Ning
AU  - Sun, Yidi
AU  - Yuan, Tanglong
AU  - Li, Jing
AU  - Yuan, Qichen
AU  - Liu, Lizhong
AU  - Yang, Jie
AU  - Wang, Qian
AU  - Kolomeisky, Anatoly B.
AU  - Hilton, Isaac B.
AU  - Zuo, Erwei
AU  - Gao, Xue
TI  - Single C-to-T substitution using engineered APOBEC3G-nCas9 base editors with minimum genome- and transcriptome-wide off-target effects
AID  - 10.1126/sciadv.aba1773
DP  - 2020 Jul 01
TA  - Science Advances
PG  - eaba1773
VI  - 6
IP  - 29
4099  - http://advances.sciencemag.org/content/6/29/eaba1773.short
4100  - http://advances.sciencemag.org/content/6/29/eaba1773.full
SO  - Sci Adv2020 Jul 01; 6
AB  - Cytosine base editors (CBEs) enable efficient cytidine-to-thymidine (C-to-T) substitutions at targeted loci without double-stranded breaks. However, current CBEs edit all Cs within their activity windows, generating undesired bystander mutations. In the most challenging circumstance, when a bystander C is adjacent to the targeted C, existing base editors fail to discriminate them and edit both Cs. To improve the precision of CBE, we identified and engineered the human APOBEC3G (A3G) deaminase; when fused to the Cas9 nickase, the resulting A3G-BEs exhibit selective editing of the second C in the 5′-CC-3′ motif in human cells. Our A3G-BEs could install a single disease-associated C-to-T substitution with high precision. The percentage of perfectly modified alleles is more than 6000-fold for disease correction and more than 600-fold for disease modeling compared with BE4max. On the basis of the two-cell embryo injection method and RNA sequencing analysis, our A3G-BEs showed minimum genome- and transcriptome-wide off-target effects, achieving high targeting fidelity.