Molecular architecture of the mammalian circadian clock

Highlights • The circadian clock generates molecular rhythms with 24 h periodicity. • Circadian control of physiology is distributed to peripheral tissues. • 24 h timing arises from the ordered recruitment of clock proteins to promoters. • Many mechanisms are used to generate rhythmic output from the core molecular clock. • Clocks integrate with systemic cues to give flexibility to circadian physiology.