Figure 1

The mPER2 protein is constitutively expressed in the adult dentate gyrus. (A-B) Confocal images illustrating the expression of mPER2 in the granule cell layer (GCL), hilar region (H) and subgranular layer (SGL) of the dentate gyrus (DG) from P45 WT mice. No circadian oscillation of mPER2 expression is observed in the DG. (C-D) On the contrary, mPER2 is highly rhythmic in the SCN with a minimum of mPER2 expression at ZT0 (C) and a maximum of mPER2 expression at ZT12 (D). (A-D) Images represent «Z-stack» overlays from 40 μm-thick coronal sections of 5 adjacent confocal planes (step size = 1 μm). (E) The intensity of mPER2 labelling is constant at different circadian time points, i.e. ZT0, ZT6, ZT12 and ZT18 (mean ± SD, n = 3 independent experiments). (F) Levels of PER2 expression were analyzed by Western blot. Analysis were carried out on nuclear protein extracts from micro-dissected SCN and DG (at ZT0, ZT6, ZT12 and ZT18) of P45 WT mice, incubated with mPER2 antibody and BAF57 antibody as internal control. mPER2 antibody yielded a band at the expected size (136 KDa). Results were expressed as percentage of BAF57. Scale bar in A = 50 μm for A-B and 25 μm for C-D.