FIG. 9.

PER levels are similar in per^A, per^B′, and per^G transgenic flies. (A) Flies from the three transgenic strains were entrained in LD cycles for 3 days before collection at the time points indicated. Head protein extracts were made and subjected to Western blotting. The gel strip shows the level of PER immunoreactivity for each sample. Head extracts from wild-type (WT; CS) and per⁰¹ flies collected at ZT24 were used as positive and negative controls, respectively, for PER immunoreactivity. Similar results were obtained in three independent time courses. (B) Quantitation of PER cycling in panel A. Data from three independent time courses of per^A, per^B′, and per^G are plotted. For each Western blot, the highest time point was set to 100 and all other time points from the three (per^A, per^B′, and per^G) time courses were set relative to that value. The error bars represent standard errors for the three time courses.