Nat. Immunol. 18, 173–183 (2017); published online 19 December 2016; corrected after print 23 January 2017

In the version of this article initially published, the labels above the plots in Figure 4b were incorrect (with 'Open chromatin' above the first two columns and 'Closed chromatin' above the second two columns). The correct labeling is 'Open chromatin' above the first column, 'Closed chromatin' above the second column, 'Open chromatin' above the third column and 'Closed chromatin' above the fourth column. The error has been corrected in the HTML and PDF versions of the article.