Abstract
The transcriptional activator CLOCK is a histone acetyltransferase that is required for the circadian expression of many genes.
Asher et al. (2008) and
Nakahata et al. (2008) now demonstrate that the NAD
+-dependent enzyme SIRT1 functions as a histone deacetylase that counteracts the activity of CLOCK. These results broaden our understanding of the impact of cellular metabolism on the circadian system.