Correction to: Nature Protocols https://doi.org/10.1038/s41596-020-0379-4, published online 14 September 2020.

In the version of this article initially published, the ‘Reagent setup’ section contained two errors. First, the final concentration for CHIR-99021 was incorrectly given as 3 µM; the correct concentration is 0.3 μM. Second, the instructions for preparing the PGE2 solution said to dissolve 1 mg of PGE2; the sentence should have read ‘Dissolve 10 mg of PGE2 in 2.84 ml of DMSO to make a 10 mM stock solution.’

The errors have been corrected in the HTML and PDF versions of the article.