Fig. 4.

Schematic representing clock contribution to Fgf21 regulation in the liver. REV-ERBα (R orange circle) represses the Fgf21 promoter involving HNF6 (olive trapezoid). Furthermore, PPARα (green oval) with its heterodimerizing partner RXR (light blue oval) activates the Fgf21 promoter. PER2 (P2, red circle) most likely modulates one or both of these regulations due to its capacity to bind to PPARα and REV-ERBα. Our data indicate that BMAL1 (B blue circle) and CLOCK (C/N purple oval) are not significantly involved in the regulation of Fgf21.