Nat. Protoc. 9, 1825–1847 (2014); doi:10.1038/nprot.2014.103; published online 3 July 2014; corrected after print 16 January 2015

In the version of this article initially published, a sentence in Step 49 read “Order the top and bottom oligonucleotides corresponding to hit shRNA sequences formatted as in the example below for the target site TTTCTTACTCACCCTAAGAACT”. The sentence has been corrected to replace 'target site' with 'guide sequence'. The error has been corrected in the HTML and PDF versions of the article.