Figure 1.
Model of the molecular clock feedback loops in Drosophila. The clock is composed of two interconnected transcriptional-translational feedback loops. (A) In s-LNVs, cry is not required for rhythms and is omitted from the model, although it acts as a cell-autonomous photoreceptor in these cells. (B) In peripheral clocks, CRY has an important clock role and acts as a transcriptional repressor of CLK/CYC activity in conjunction with PER. Because cry expression is regulated by VRI and because VRI- and PDP1-binding sites are very similar, cry is probably also regulated by PDP1 (dashed line).