ZEITLUPE is a circadian photoreceptor stabilized by GIGANTEA in blue light

In Aradopsis, rhythmic expression of the F–box protein, ZEITLUPE (ZTL), is necessary to sustain a normal circadian period, but the mechanism of this oscillation is unknown. GIGANTEA (GI), a protein previously implicated in the circadian clock, but with unknown molecular function, is essential to establish and sustain oscillations of ZTL by direct protein–protein interactions. Furthermore, this stabilization is modulated by light through the N–terminal flavin–binding LIGHT, OXYGEN OR VOLTAGE (LOV) domain of ZTL.