title: Differential rescue of light- and food-entrainable circadian rhythms.
abstract: When food is plentiful, circadian rhythms of animals are powerfully entrained by the light-dark cycle. However, if animals have access to food only during their normal sleep cycle, they will shift most of their circadian rhythms to match the food availability. We studied the basis for entrainment of circadian rhythms by food and light in mice with targeted disruption of the clock gene Bmal1, which lack circadian rhythmicity. Injection of a viral vector containing the Bmal1 gene into the suprachiasmatic nuclei of the hypothalamus restored light-entrainable, but not food-entrainable, circadian rhythms. In contrast, restoration of the Bmal1 gene only in the dorsomedial hypothalamic nucleus restored the ability of animals to entrain to food but not to light. These results demonstrate that the dorsomedial hypothalamus contains a Bmal1-based oscillator that can drive food entrainment of circadian rhythms.
authors.affiliation: Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Fuller
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.forename: Clifford B
authors.initials: CB
authors.lastname: Saper
mesh_terms: D056930:ARNTL Transcription Factors; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000502:physiology*; D001683:Biological Clocks / Q000502:physiology*; D001831:Body Temperature; D018797:Cell Cycle Proteins / Q000235:genetics; D002940:Circadian Rhythm / Q000502:physiology*; D004302:Dorsomedial Hypothalamic Nucleus / Q000378:metabolism*; D005502:Food; D015870:Gene Expression; D018014:Gene Transfer Techniques; D008027:Light; D051379:Mice; D009043:Motor Activity; D009687:Nuclear Proteins / Q000235:genetics; D056950:Period Circadian Proteins; D013217:Starvation; D013493:Suprachiasmatic Nucleus / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics
chemical_list: D056930:ARNTL Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D056950:Period Circadian Proteins; D014157:Transcription Factors; C538961:Bmal1 protein, mouse; C539023:Per1 protein, mouse; C513312:Per2 protein, mouse