Rhythmic and Temporal Processes in Biology

Long-Term Constant Light Induces Constitutive Elevated Expression of mPER2 Protein in the Murine SCN: A Molecular Basis for Aschoff’s Rule?

“…Circadian rhythms are generated by the coordinated activity of cell-autonomous circadian oscillators with period lengths of approximately 24 h (Welsh et al, 1995;Herzog et al, 1998). In all species examined, these endogenous 24-h rhythms appear to be based on transcriptional and translational feedback loops, involving a core set of clock genes (Dunlap, 1999;Shearman et al, 2000;Reppert and Weaver, 2002;Foster et al, 2004). In mammals, the PAS helix-loop-helix transcription factors CLOCK and BMAL1 drive the rhythmic transcription of 3 Period genes (Per1, Per2, and Per3) and 2 Cryptochrome genes (Cry1 and Cry2) (Gekakis et al, 1998;Hogenesch et al, 1998).…”

“…Circadian rhythms in behavior, metabolism, and physiology are a conserved feature across eukaryotic and some prokaryote taxa (Pittendrigh, 1993;Dunlap, 1999;Shearman et al, 2000;Foster et al, 2004). The "master circadian pacemaker" of mammals is located within the paired SCN of the anterior hypothalamus (Ralph et al, 1990).…”