The NAD+-dependent deacetylase SIRT1 modulates CLOCK-mediated chromatin remodeling and circadian control

Cell. 2008 Jul 25;134(2):329-40. doi: 10.1016/j.cell.2008.07.002.


Circadian rhythms govern a large array of metabolic and physiological functions. The central clock protein CLOCK has HAT properties. It directs acetylation of histone H3 and of its dimerization partner BMAL1 at Lys537, an event essential for circadian function. We show that the HDAC activity of the NAD(+)-dependent SIRT1 enzyme is regulated in a circadian manner, correlating with rhythmic acetylation of BMAL1 and H3 Lys9/Lys14 at circadian promoters. SIRT1 associates with CLOCK and is recruited to the CLOCK:BMAL1 chromatin complex at circadian promoters. Genetic ablation of the Sirt1 gene or pharmacological inhibition of SIRT1 activity lead to disturbances in the circadian cycle and in the acetylation of H3 and BMAL1. Finally, using liver-specific SIRT1 mutant mice we show that SIRT1 contributes to circadian control in vivo. We propose that SIRT1 functions as an enzymatic rheostat of circadian function, transducing signals originated by cellular metabolites to the circadian clock.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • ARNTL Transcription Factors
  • Acetylation
  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / metabolism
  • CLOCK Proteins
  • Chromatin Assembly and Disassembly*
  • Circadian Rhythm*
  • DNA-Binding Proteins / metabolism
  • Embryo, Mammalian / cytology
  • Gene Expression
  • Histones / metabolism
  • Liver / metabolism
  • Lysine / metabolism
  • Mice
  • Mice, Inbred BALB C
  • NAD / metabolism
  • Promoter Regions, Genetic
  • Sirtuin 1
  • Sirtuins / genetics
  • Sirtuins / metabolism*
  • Trans-Activators / metabolism*
  • Transcription Factors / metabolism


  • ARNTL Transcription Factors
  • Arntl protein, mouse
  • Basic Helix-Loop-Helix Transcription Factors
  • DNA-Binding Proteins
  • Dbp protein, mouse
  • Histones
  • Trans-Activators
  • Transcription Factors
  • NAD
  • CLOCK Proteins
  • Clock protein, mouse
  • Sirt1 protein, mouse
  • Sirtuin 1
  • Sirtuins
  • Lysine