Figure 3.

cwo is directly controlled by circadian clock. (A) The averaged expression levels of cwo, per, and tim mRNA in wild-type and arrhythmic mutant flies (per⁰¹ and Clk^Jrk). Temporal expression profiles in mutant flies are shown in Supplementary Figure 4. (B) Evolutionarily conserved E-box sequences in cwo promoter region. Relative positions of E-boxes to the transcription start site of cwo are indicated. Multiple alignments of seven Drosophila species and its conservation score are represented (University of California at Santa Cruz Genome Browser Database [Hinrichs et al. 2006] version dm2). (C) The cwo promoter is activated by CLK. (Top panel) The three tandem repeats of an 18-bp fragment containing wild-type and mutant E-boxes were fused to a TATA sequence driving a destabilized luciferase (dLuc) reporter gene. Well-conserved base pairs (bold) and mutated base pairs (red) are also indicated. Relative luciferase activities of cwo promoter, wild-type, and mutant E-box reporters in the presence of 0 and 100 ng of Clk are shown in the bottom panel. Signals were normalized with Rluc activity. Error bars represent the SEM (n = 3).