Coronal brain sections from mice sacrificed every 4 hr from 54 hr to 82 hr in constant darkness were hybridized with mPer1 and mPer2 riboprobes. (A–E) mPer1 in situ hybridization. (A) Wild-type mPer1 hybridization at 66 hr, which corresponds to CT6; (B) wild-type mPer1 hybridization at 78 hr, or CT18; (C) Mop3−/−
mPer1 hybridization at 66 hr; (D) Mop3−/−
mPer1 hybridization at 78 hr; (E) time course of mPer1 expression in the SCN of wild-type (filled circles) and Mop3−/− (open circles) mice. (F–J) mPer2 in situ hybridization. (F) Wild-type mPer2 hybridization at 70 hr, which corresponds to CT10; (G) wild-type mPer2 hybridization at 82 hr, or CT22; (H) Mop3−/−
mPer2 hybridization at 70 hr; (I) Mop3−/−
mPer2 hybridization at 82 hr; (J) time course of mPer2 expression in the SCN of wild-type (filled circles) and Mop3−/− (open circles) mice. The bar at the top indicates subjective night in black and subjective day in gray. Asterisks indicate significant differences between wild-type and Mop3−/− mice at the times shown (mPer1 GLM ANOVA, F(7,35) 16.41, p < 1.0 × 10−6; mPer2 GLM ANOVA, F(7,35) 18.61, p < 1.0 × 10−6, Tukey-Kramer posthoc comparison p < 0.05).