Fig. 3.

Time-dependent response of liver core clock components to hypoxia is circadian-clock–controlled. (A) qPCR analysis of clock-associated transcript levels in the livers of WT or Per1,2^−/− mice housed in constant dark and exposed to hypoxia (6% O₂) or normoxia (21% O₂) in the respective light (CT 4–8) or dark (CT 16–20) phase (mean ± SE, n = 4 per condition; *P < 0.05, **P < 0.01, two-sample Student’s t test). (B) Immunoblot analysis of total liver protein extracts from WT or Per1,2^−/− mice as in A (pools of n = 4; n.s., nonspecific band). (C) Immunoblot analysis of liver nuclear extracts from WT or Per1,2^−/− mice as in A (pools of n = 4).