Nature Reviews Molecular Cell Biology 15, 108–122 (2014)

In table 1 (page 116) of the above article, the secondary structure of the snRNAs (small nuclear RNAs) for the U4–U6 di-snRNP (small nuclear ribonucleoprotein) was incorrect. This has now been rectified in the online version of the article. Nature Reviews Molecular Cell Biology apologizes for any confusion caused to readers.