Correction to: Nature Biotechnology https://doi.org/10.1038/s41587-019-0178-z, published online 15 July 2019.

In the version of this article initially published, a relevant work was not cited properly. To correct this error, the first sentence of the second paragraph has been changed from “All these reported nucleic acid editing methods in mammalian systems rely on ectopic expression of two components: an enzyme and a gRNA” to “All these reported nucleic acid editing methods in mammalian systems rely almost exclusively on ectopic expression of two components, an enzyme and a gRNA, although Katrekar et al.27 have obtained preliminary evidence for editing in the absence of ADAR overexpression.” In addition, ref. 42 has been changed from “Abudayyeh, O. O. et al. C2c2 is a single-component programmable RNA-guided RNA-targeting CRISPR effector. Science 353, aaf5573 (2016)” to “East-Seletsky, A. et al. Two distinct RNase activities of CRISPR-C2c2 enable guide-RNA processing and RNA detection. Nature 538, 270–273 (2016).” Finally, arRNA70 has been changed to arRNA111 in the second-to-last sentence of the sixth paragraph: “The quantitative PCR (qPCR) analysis showed that arRNA111 did not perturb the expression of targeted transcripts (Supplementary Fig. 3), ruling out the possible RNA interference (RNAi) effect of the arRNA.” The errors have been corrected in the HTML and PDF versions of the article.