Base editing in Streptomyces with Cas9-deaminase fusions

Zhiyu Zhong, Junhong Guo, Liang Deng, Li Chen, Jian Wang, Sicong Li, Wei Xu, Zixin Deng and Yuhui Sun

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May 15, 2019

Received Date: 6th May 19

Conventional CRISPR/Cas genetic manipulation has been profitably applied to the genus Streptomyces, the most prolific bacterial producers of antibiotics. However, its reliance on DNA double-strand break (DSB) formation leads to unacceptably low yields of desired recombinants. We have adapted for Streptomyces recently-introduced cytidine base editors (CBEs) and adenine base editors (ABEs) which enable targeted C-to-T or A-to-G nucleotide substitutions, respectively, bypassing DSB and the need for a repair template. We report successful genome editing in Streptomyces at frequencies of around 50% using defective Cas9-guided base editors and up to 100% by using nicked Cas9-guided base editors. Furthermore, we demonstrate the multiplex genome editing potential of the nicked Cas9-guided base editor BE3 by programmed mutation of nine target genes simultaneously. Use of the high-fidelity version of BE3 (HF-BE3) essentially improved editing specificity. Collectively, this work provides a powerful new tool for genome editing in Streptomyces.

Read in full at bioRxiv.

This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.

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Nature Communications

Nature Research, Springer Nature