Fig 2. The human core clock network (CCN) and the extended core clock network (ECCN).

The CCN (orange) contains the known core-clock elements (Per1,2,3, Cry1,2, Rev-Erbα,β, Rorα,β,γ, Bmal1,2, Clock and Npas). The ECCN (green) was obtained after an extensive collection of CCN-interacting genes followed by a detailed curation for direct interactions [21] and a further update to the recent literature. Activation (green lines), inhibition (red lines) and other sort of interactions (grey lines) are represented. The resulting clock network contains 43 elements and more than 200 regulatory relationships.