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Network Dynamics Mediate Circadian Clock Plasticity, Abdelhalim Azzi, Jennifer A. Evans, Tanya Leise, Jihwan Myung, Toru Takumi, Alec J. Davidson, Steven A. Brown

Biological Sciences Faculty Research and Publications

A circadian clock governs most aspects of mammalian behavior. Although its properties are in part genetically determined, altered light-dark environment can change circadian period length through a mechanism requiring de novo DNA methylation. We show here that this mechanism is mediated not via cell-autonomous clock properties, but rather through altered networking within the suprachiasmatic nuclei (SCN), the circadian “master clock,” which is DNA methylated in region-specific manner. DNA methylation is necessary to temporally reorganize circadian phasing among SCN neurons, which in turn changes the period length of the network as a whole. Interruption of neural communication by inhibiting neuronal firing …