Circadian control of metabolic physiology and behaviour is a ubiquitous characteristic across taxa. In eukaryotes, circadian control derives from a cell-autonomous molecular oscillator, assembled from a regulatory network of transcription factors, co-factors, (co-) regulators, chromatin modifiers and an array of post-translational regulators of protein function, often
described collectively as ‘clock genes’. Clock gene oscillations coordinate the transcription of multiple genes to exert effects on global cell metabolism.
Hypoxia is defined as a state of oxygen (O2) deficiency in which the O2 delivery to a certain tissue does not meet the regular metabolic needs of that tissue. The hypoxia signalling pathway and the circadian clock have been shown to interact to regulate mitochondrial metabolism and the clock plays an important role in protecting cells and tissue from hypoxia-related disease, like myocardial infarct. Therefore, the interaction between hypoxia and clocks and the role in tissue protection and metabolic regulation are key areas of interest. In order to investigate the link between clocks and hypoxia we take advantage of two extreme examples of metabolic depression and hypoxia tolerance: Diving and hibernation.