Fig. 7
From: The role of clockwork orange in the circadian clock of the cricket Gryllus bimaculatus
A model of the clock oscillatory mechanism in the cricket Gryllus bimaculatus. The clock most likely oscillates based on transcriptional/translational feedback loops. Transcription of per, tim, cry2, vri, Pdp1, E75, and HR3 is activated by CLK and CYC through the E-box. The protein products PER and TIM form heterodimers and suppress the transcriptional activity of CLK/CYC, while CRY2 also suppresses CLK/CYC through a pathway that is different from that of PER/TIM. Previous results have suggested that both Clk and cyc could be rhythmically expressed. According to the circadian oscillatory mechanism of Drosophila and firebrats [4, 33], VRI and E75 suppress, while PDP1 and HR3 activate, the transcription of Clk and cyc, respectively. CWO probably enhances the transcription of CLK/CYC target genes through upregulation of Clk and cyc. When cwo is downregulated, light promotes the expression of HR3 and E75. See text for details