Circadian and photic regulation of clock and clock-controlled proteins in the suprachiasmatic nuclei of calorie-restricted mice.
In mammals, behavioural and physiological rhythms as well as clock gene expression in the central suprachiasmatic clock (SCN) are phase-shifted by a timed calorie restriction (T-CR; animals receiving at midday 66% of their daily food intake). The molecular mechanism of SCN depends on feedback loops involving clock genes and their protein products. To understand how T-CR mediates its synchronizing effects, we examined the rhythmic expression of three clock proteins, PERIOD (PER) 1, 2 and CLOCK, and one clock-controlled protein (i.e. vasopressin; AVP) in the SCN of mice either fed ad libitum (AL) or with T-CR. Moreover, we evaluated expression of these proteins in the SCN of AL and T-CR mice following a 1-h light pulse. The results indicate that, while PER1 and AVP rhythms were phase-advanced in T-CR mice, the PER2 rhythm showed an increased amplitude. CLOCK was expressed constitutively in AL mice while in T-CR it was significantly reduced, especially after feeding time. A light pulse produced a delayed increase in PER1 and a larger increase in PER2 expression in the SCN of T-CR mice than in AL animals. In addition, light exposure triggered an increase in AVP-ir cells in both AL and T-CR mice, and also of CLOCK expression but in T-CR mice only. The circadian changes in clock and clock-controlled proteins and their acute responses to light in the SCN of T-CR mice demonstrate that metabolic cues induced by a calorie restriction modulate the translational regulation of the SCN clock.
Mendoza
Jorge
J
Institut de Neurosciences Cellulaires et Intégratives, Département de Neurobiologie des Rythmes, UMR7168/LC2, CNRS et Université Louis Pasteur, 5 rue Blaise Pascal, 67084 Strasbourg cedex, France. jmendoza@neurochem.u-strasbg.fr
Pévet
Paul
P
Challet
Etienne
E
D000818:Animals; D001522:Behavior, Animal; D001683:Biological Clocks / Q000502:physiology; D056926:CLOCK Proteins; D031204:Caloric Restriction; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology / Q000528:radiation effects; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D056950:Period Circadian Proteins; D010775:Photic Stimulation / Q000379:methods; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism*; D014667:Vasopressins / Q000378:metabolism
D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C539023:Per1 protein, mouse; C539024:Per1 protein, rat; C513311:Per2 protein, rat; D056950:Period Circadian Proteins; D015534:Trans-Activators; D014667:Vasopressins; D056926:CLOCK Proteins; C538944:Clock protein, mouse; C538945:Clock protein, rat