Figure 4.

Irradiation-dependent effects of DK325 and DK359 on circadian rhythms in human U2OS cells. (A) Effect of UV light. Bmal1-dLuc reporter cells were treated with various concentrations of compound (six points of 3-fold dilution series in DMSO) and irradiated with 365 nm light for 0–30 min. Luminescence rhythms were then monitored (the left panel, mean of n = 4). Rhythms of DMSO and longdaysin controls are also shown. Period changes compared to a DMSO control are plotted in the right panels (n = 4); p values are summarized in Table S1. (B, C) Effect of visible light (λ = 400 nm). Bmal1-dLuc reporter cells were treated with compounds and irradiated with 400 nm light for 0–30 min at the beginning (B) or in the middle (C, indicated by arrows) of luminescence monitoring. In (C), period changes pre- and postirradiation are plotted in the top right and bottom right panels, respectively.