Dec1 and Dec2 as controllers of the mammalian internal biological clock

Dec1 and Dec2 are identified as a fifth clock-gene family regulating circadian rhythms in mammals.

• Circadian rhythms in mammals are controlled by a pacemaker in the suprachiasmatic nucleus of the hypothalamus.
• Four known clock-gene families are involved in a feedback loop that generates these rhythms at the cellular level.
• Dec1 and Dec2 directly interact with Bmal1 and may compete for E-box elements, repressing the activation of the mouse Per1 promoter.
• Both Dec1 and Dec2 are expressed in the suprachiasmatic nucleus in a circadian pattern, peaking during the subjective day.
• A brief light pulse can induce Dec1 expression in a phase-dependent manner, while Dec2 expression remains unchanged.

Simplified