A dual-feedback loop model of the mammalian circadian clock for multi-input control of circadian phase
Fig 1
Molecular architecture of the mammalian circadian clock.
Two transcription-translation feedback loops drive the oscillations of the mammalian circadian clock at the cellular level. We show the architecture for the core clock species of a single cell, where the grey oval represents the nucleus of the cell. The negative loop (warm colors, solid arrows) contains the mRNAs Period and Cryptochrome and their associated proteins. The positive loop (cool colors, dashed arrows) contains Rev-erb, Ror, and Bmal mRNAs and the associated proteins. Hollow circles represent mRNAs and filled circles represent proteins of the different clock species. Arrowheads represent increased production, while flat arrows represent inhibited production. The dashed lines in the positive feedback loop represent interactions that were not included in the Hirota model [1] but that were added to our extended dual loop model to provide additional control targets acting on the core circadian clock architecture.