Figure 3. M cells use the PDF peptide and neuronal activity to adjust period in DD.
(A) Accelerated M cells send PDF as a resetting signal to cause a daily advanced activity phase. Double plotted averaged actograms of representative individual flies from each genotype are shown. Experimental group were transferred to RU486 food for 2 days in LD and the maintained for 3 days in DD before being returned back to food containing vehicle. Control group were maintained in vehicle food. Flies expressing Kir and PDF RNAi in M cells gradually lose rhythmicity during the 3 drug feeding DD days. In the actograms, white background represents day, gray background represents darkness. Red lines indicate the DD phase of the experimental group, and the blue lines indicate the DD phase of control group. The genotype of each group was labeled above the panels. (B)The quantification of phase change for the genotypes described in (A). n = 60-64 for each group. ‘***’ means p<0.001 as determined by one way analysis of variance (ANOVA), Tukey post hoc test, and the error bars indicate SEM. (C) Co-expression of PDF RNAi in accelerates M cells prevented period shortening. The histogram shows the period of five genotypes: UAS-SGG; Pdf-GAL4/+, UAS-SGG; Pdf-GAL4/UAS-TNT, UAS-SGG; Pdf-GAL4/UAS-Tet, UAS-SGG; Pdf-GAL4/UAS-Trh RNAi, UAS-SGG; Pdf-GAL4/UAS-PDF RNAi. Tetanus toxin light chain (TNT) was used to block neurotransmitter releasing, and Tet is an inactive form of TNT, Trh RNAi was used as control of PDF RNAi since PDF cells do not express tryptophan hydroxylase (Trh), PDF RNAi is as in Figure 2B n = 13–15 for each group. ‘***’ represents p<0.001 as determined by one way analysis of variance (ANOVA), Tukey post hoc test, and the error bar indicates SEM.