Light Directs Zebrafish period2 Expression via Conserved D and E Boxes
Figure 4
The per2 minimal promoter is clock driven under LL conditions in vitro.
Bioluminescence assay of cells stably transfected with −1.7per2:luc and −0.43per2:luc. Cells were maintained under LD and then transferred to DD (A) or LL (B). Relative bioluminescence is plotted on the y-axis and time (days) on the x-axis. For each point, error bars (grey) represent the SD. White/black bars show the light and dark periods, respectively. Both −1.7 and −0.43 kb promoters drive rhythmic luciferase expression under LD and LL but not under DD. These results indicate that, in addition to being light responsive, the per2 promoter is clock driven under LL conditions.