JMJD5 is a repressor of the circadian clock.

(A, B) Dose-response repression of CLOCK and BMAL1 (“CB”) by JMJD5 (“J”). Real-time luciferase measurements of Per1 and Per2 promoter activity in non-oscillating HEK293T cells show repression of CB by JMJD5. Shown: counts normalized to maximal CB activation of the indicated reporter (mean ± SD) (C) JMJD5 repression is E-box mediated. JMJD5 represses Per1-Luc with a wt but not one with a mutant (“mut”) E-box (mean ± SD). (D) JMJD5 effect on wt and E-box mutant Per1 reporters in the absence of CB. Shown: counts normalized to maximum signal obtained with wt reporter in the absence of JMJD5. (E) Per1 and (F) Per2 promoter is independent of the catalytic activity of JMJD5, normalizations performed as in A (mean ± SD). Please note that data plotted in A and E and in B and F were collected simultaneously; V, CB, and CB+JMJD5 in E and F are the same data as in A and B, respectively. BMAL1, brain and muscle ARNT-like protein 1; CLOCK, circadian locomotor output cycles protein kaput; HEK293T, human embryonic kidney 293T; JMDJ5, JmjC domain–containing protein 5; V, vector; wt, wild type.