Signaling to the circadian clock: plasticity by chromatin remodeling

Circadian rhythms govern several fundamental physiological functions in almost all organisms, from prokaryotes to humans. The circadian clocks are intrinsic time-tracking systems with which organisms can anticipate environmental changes and adapt to the appropriate time of day. In mammals, circadian rhythms are generated in pacemaker neurons within the suprachiasmatic nuclei (SCN), a small area of the hypotha