Visualizing the histone code on LSD1.

In this issue, Garcia-Bassets et al. (2007) show that spurious transcriptional activation by unliganded nuclear receptors is inhibited by histone lysine methylation. This inhibitory histone modification code is efficiently countered by the ligand-dependent recruitment of histone lysine demethylases, including lysine-specific demethylase 1 (LSD1), which appear to be used for this purpose by a number of signal-regulated transcriptional activators.