title: Rapid damping of food-entrained circadian rhythm of clock gene expression in clock-defective peripheral tissues under fasting conditions.
abstract: Restricted feeding-induced free-running oscillation of clock genes in the liver was studied in homozygous Clock-mutant (Clock/Clock) mice. Similar to wild-type mice, Clock/Clock mice showed robust food-anticipatory behavioral activity in accordance with a restricted feeding schedule. Also, the peak of all clock gene mRNAs tested was phase-advanced in the liver of Clock/Clock mice as well as wild-type mice, although the amplitude of clock gene expression was low in Clock/Clock mice. The food-anticipatory behavioral rhythm in Clock/Clock mice maintained a period similar to wild-type mice during 2-day fasting after the cessation of restricted feeding. However, during the fasting days after temporal feeding cues were removed, the oscillation of clock genes in the liver and heart, excluding the suprachiasmatic nuclei, appeared to result in arrhythmicity in Clock/Clock mice. Thus, although the CLOCK-based molecular mechanism is not required for the expression of food-anticipatory activity, intact CLOCK protein might be involved in sustaining several cycles of peripheral circadian oscillations after restricted feeding-induced resetting.
authors.affiliation: Department of Pharmacology, School of Science and Engineering, Waseda University, Higashifushimi 2-7-5, Nishitokyo-Shi, Tokyo 202-0021, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Horikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Minami
authors.forename: M
authors.initials: M
authors.lastname: Iijima
authors.forename: M
authors.initials: M
authors.lastname: Akiyama
authors.forename: S
authors.initials: S
authors.lastname: Shibata
mesh_terms: D056930:ARNTL Transcription Factors; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D001522:Behavior, Animal; D015152:Blotting, Northern / Q000379:methods; D056926:CLOCK Proteins; D018797:Cell Cycle Proteins; D002940:Circadian Rhythm / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D005508:Food Deprivation / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology*; D017403:In Situ Hybridization / Q000379:methods; D051379:Mice; D008817:Mice, Mutant Strains; D009043:Motor Activity / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D056950:Period Circadian Proteins; D017440:Photoperiod; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*; D013997:Time Factors; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D056930:ARNTL Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D056926:CLOCK Proteins; D018797:Cell Cycle Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D056950:Period Circadian Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; C538961:Bmal1 protein, mouse; C491259:Npas2 protein, mouse; C539023:Per1 protein, mouse; C513312:Per2 protein, mouse; C538944:Clock protein, mouse