小柯机器人

美国麻省理工和哈佛大学布罗德研究所David R. Liu研究小组，将腺嘌呤碱基编辑器（ABE）优化成具有低脱靶活性的小型高效胞嘧啶碱基编辑器（CBE）。相关论文于2022年11月10日发表于国际学术期刊《自然-生物技术》杂志。

为了开发与ABE大小相似且具有低脱靶活性和高编辑效率的CBE，研究人员优化出具有高活性的脱氧腺苷脱氨酶TadA-8e，以使用噬菌体辅助实现胞苷脱氨连续发生。进化的TadA胞苷脱氨酶含有与DNA结合的残基突变，这些突变改变了酶的选择性，有利于脱氧胞苷而不是脱氧腺苷脱氨活性。与常用的CBE相比，TadA衍生的胞嘧啶碱基编辑器（TadCBE）具有相似或更高的靶向活性、更小的尺寸以及更低的Cas非依赖性DNA和RNA脱靶编辑活性。

研究人员还发现了一种TadA双碱基编辑器（TadDE），它可以高效的进行胞嘧啶和腺嘌呤碱基编辑。TadCB可在人原代T细胞和原代造血干细胞和祖细胞中对治疗相关基因组位点进行单一或多重碱基编辑。TadCBEs扩展了CBEs在精准基因编辑中的实用性。

据悉，与ABE相比，CBE分子量更大并且可能具有更高的脱靶活性或更低的编辑效率。

附：英文原文

Title: Evolution of an adenine base editor into a small, efficient cytosine base editor with low off-target activity

Author: Neugebauer, Monica E., Hsu, Alvin, Arbab, Mandana, Krasnow, Nicholas A., McElroy, Amber N., Pandey, Smriti, Doman, Jordan L., Huang, Tony P., Raguram, Aditya, Banskota, Samagya, Newby, Gregory A., Tolar, Jakub, Osborn, Mark J., Liu, David R.

Issue&Volume: 2022-11-10

Abstract: Cytosine base editors (CBEs) are larger and can suffer from higher off-target activity or lower on-target editing efficiency than current adenine base editors (ABEs). To develop a CBE that retains the small size, low off-target activity and high on-target activity of current ABEs, we evolved the highly active deoxyadenosine deaminase TadA-8e to perform cytidine deamination using phage-assisted continuous evolution. Evolved TadA cytidine deaminases contain mutations at DNA-binding residues that alter enzyme selectivity to strongly favor deoxycytidine over deoxyadenosine deamination. Compared to commonly used CBEs, TadA-derived cytosine base editors (TadCBEs) offer similar or higher on-target activity, smaller size and substantially lower Cas-independent DNA and RNA off-target editing activity. We also identified a TadA dual base editor (TadDE) that performs equally efficient cytosine and adenine base editing. TadCBEs support single or multiplexed base editing at therapeutically relevant genomic loci in primary human T cells and primary human hematopoietic stem and progenitor cells. TadCBEs expand the utility of CBEs for precision gene editing.

DOI: 10.1038/s41587-022-01533-6

Source: https://www.nature.com/articles/s41587-022-01533-6

Nature Biotechnology：《自然—生物技术》，创刊于1996年。隶属于施普林格·自然出版集团，最新IF：68.164
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