FIGURE 5.

Exogenous expression of PER1 or PER2 via the Per2 promoter can rescue arrhythmicity in Per1 and Per2 mutant fibroblasts. A, rescued rhythmicity in Per1 mutant fibroblasts by exogenous expression of PER. Results are representative of at least five experiments. B, rescued rhythmicity in Per2 mutant fibroblasts by exogenous expression of PER. Note that bioluminescence rhythms are presented after the base-line luminescence is subtracted because of increased base line of wild-type luciferase. Two traces of each sample are shown, representative of three experiments. Rhythms were not detectible after the second peak in GFP-overexpressing Per2 mutant fibroblasts.