Fig. 5

Clock-dependent oscillatory expression of PK2 in the ipRGC. The immunoflurescence intensity of PK2 was quantified and shown as mean ± SEM. The fluorescence intensity of PK2 levels in the ipRGC were oscillatory in wild type mice (a), but not in Bmal-deficient mice (b) (two way ANOVA, P < 0.001 genotype effect, P < 0.05 time effect). Peak and trough levels in the ipRGC of wild type mice were around ZT4 and ZT20, respectively. The PK2 levels in the ipRGC of Bmal1-deficient mice (BMAL KO) were consistently low, and displayed no apparent oscillation (b). Inserts above the columns show representative images of PK2 immunostaining of the ipRGC (green). The nuclear counterstaining is shown as blue. Bar size 10 μm