Melatonin and chromatin

Abstract

Melatonin
 affects chromatin remodeling, thereby activating or silencing specific genes
 and, presumably, also by modulating circadian-mediated changes in chromatin
 structure. Melatonin has been shown to exert effects on chromatin under
 conditions of toxin exposure, treatment with other hormones such as glucocorticoids
 or leptin, in cancer, and during developmental processes. Most of the
 documented actions concern histone modifications or their reversal that facilitate
 or prevent nucleosome eviction. Less information is available on DNA
 methylation or demethylation at regulatory CpG islands. To date, this has been
 mainly studied under conditions of early development, occasionally concerning seasonality
 or shiftwork with light at night. Another emerging field, which is still
 insufficiently studied, concerns regulation via DNA-interacting noncoding RNAs,
 in particular, super-enhancer lncRNAs. Although the direct information on
 actions by melatonin is widely missing, this field promises to become
 important, as numerous RNAs of this type have been shown to be rhythmically
 expressed. The circadian aspect of melatonin’s role in chromatin remodeling and
 control of gene expression deserves future attention. This includes the role of
 sirtuin 1, which participates in the circadian machinery and apparently
 mediates several effects of melatonin that are suppressed by sirtuin inhibitors
 or sirtuin 1 knockdown.