Fig. 4

Daily expression profiles of Gb’E(z) and clock genes in the optic lobe of the cricket Gryllus bimaculatus under LD 20:4. Blue and green symbols with solid lines indicate the mRNA levels of Gb’E(z) (a), Gb’per (b), Gb’tim (c), and Gb’cyc (d) in DsRed2 ^RNAi and Gb’E(z)^RNAi crickets, respectively. For reference, data for LD 12:12 are shown by broken lines (blue, DsRed2 ^RNAi crickets; green, Gb’E(z)^RNAi crickets). mRNA abundance was measured by qPCR, with total RNA extracted from the optic lobes collected seven days after transfer to LD 20:4. Data collected from 3–10 independent measurements were averaged and plotted as mean ± SEM. The values shown are relative to those of Gb’rpl18a mRNA, which was used as an internal reference. In LD 20:4, Gb’E(z) mRNA showed no significant daily oscillation in DsRed2 ^RNAi crickets (ANOVA, P > 0.05) but a significantly lower level at ZT 6 and 10 in comparison with that in LD 12:12 (a). Gb’E(z)^RNAi reduced the Gb’E(z) levels which were even lower than those of Gb’E(z)^RNAi crickets in LD 12:12 at ZT 2–10 and ZT 18 (Tukey-test, P < 0.01). The values with different lower case letters at each ZT significantly differ from each other (Tukey-test, P < 0.01, except between DsRed2 ^RNAi in LD 20:4 and Gb’E(z)^RNAi in LD 12:12 at ZT 10 and ZT 18 where P < 0.05). The mRNA levels of Gb’per (b), Gb’tim (c), and Gb’cyc (d) showed clear oscillatory profiles in both DsRed2 ^RNAi and Gb’E(z)^RNAi crickets (ANOVA, P < 0.05 for Gb’cyc in DsRed2 ^RNAi, and P < 0.01 for all other combinations). Values with different lower case letters differ significantly from each other (Tukey-test, P < 0.05). *P < 0.05, **P < 0.01, t-test vs DsRed2 ^RNAi crickets in LD 20:4