Supplementary Figure 2: Light-induced ERK phosphorylation and c-Fos expression in the SCN

(a) and (c) Representative micrographs of SCN tissue labeled for the phosphorylated (at Thr 202 and/or Tyr 204) form of ERK (p-ERK, a) and c-Fos (c). Relative to the control condition (No Light), photic stimulation (55 lux, 15 min) triggered a robust increase in ERK phosphorylation and c-Fos expression in the SCN of WT mice. Compared to the WT mice, light induced similar level of p-ERK and c-Fos expression in KI mice. For these experiments, mice were entrained to a 12 h/12 h LD cycle for 14 d and put in DD for 2 d. A light pulse (55 lux, 15 min) was applied at CT15. Animals were sacrificed 30 min after light. Scale bars: 100 μm. (b) and (d): Quantitation of light-induced ERK phosphorylation (b) and c-Fos expression (d). Light evoked significant p-ERK and c-Fos expression in the SCN of both WT and KI mice (*P<0.05, WT L vs. WT NL, KI L vs. KI NL by ANOVA). The p-ERK and c-Fos induction in the KI mice was not significantly different with that in the WT mice (P>0.05, KI L vs. WT L, by ANOVA). L: light; NL: no light