Correction to: Nature Structural & Molecular Biology https://doi.org/10.1038/s41594-019-0303-1, published online 26 August 2019.

In the version of this article initially published, several of the links were incorrect. The correct links are as follows: Roeder, https://doi.org/10.1038/s41594-019-0287-x; Kadonaga, https://doi.org/10.1038/s41594-019-0278-y; Conaway and Conaway, https://doi.org/10.1038/s41594-019-0283-1; and Lis, https://doi.org/10.1038/s41594-019-0288-9. The errors have been corrected in the HTML and PDF versions of the article.