title: Nocturnin regulates circadian trafficking of dietary lipid in intestinal enterocytes.
abstract: BACKGROUND
  Efficient metabolic function in mammals depends on the circadian clock, which drives temporal regulation of metabolic processes. Nocturnin is a clock-regulated deadenylase that controls its target mRNA expression posttranscriptionally through poly(A) tail removal. Mice lacking nocturnin (Noc(-/-) mice) are resistant to diet-induced obesity and hepatic steatosis yet are not hyperactive or hypophagic.
  
  
  RESULTS
  Here we show that nocturnin is expressed rhythmically in the small intestine and is induced by olive oil gavage and that the Noc(-/-) mice have reduced chylomicron transit into the plasma following the ingestion of dietary lipids. Genes involved in triglyceride synthesis and storage and chylomicron formation have altered expression, and large cytoplasmic lipid droplets accumulate in the apical domains of the Noc(-/-) enterocytes. The physiological significance of this deficit in absorption is clear because maintenance of Noc(-/-) mice on diets that challenge the chylomicron synthesis pathway result in significant reductions in body weight, whereas diets that bypass this pathway do not.
  
  
  CONCLUSIONS
  Therefore, we propose that nocturnin plays an important role in the trafficking of dietary lipid in the intestinal enterocytes by optimizing efficient absorption of lipids.
authors.affiliation: Department of Biology, University of Virginia, Charlottesville, VA 22904, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Douris
authors.forename: Shihoko
authors.initials: S
authors.lastname: Kojima
authors.forename: Xiaoyue
authors.initials: X
authors.lastname: Pan
authors.forename: Alexandra F
authors.initials: AF
authors.lastname: Lerch-Gaggl
authors.forename: Son Q
authors.initials: SQ
authors.lastname: Duong
authors.forename: M Mahmood
authors.initials: MM
authors.lastname: Hussain
authors.forename: Carla B
authors.initials: CB
authors.lastname: Green
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology; D001835:Body Weight; D002784:Cholesterol / Q000378:metabolism; D002940:Circadian Rhythm / Q000502:physiology*; D004041:Dietary Fats / Q000378:metabolism*; D020895:Enterocytes / Q000378:metabolism* / Q000648:ultrastructure; D007421:Intestine, Small / Q000166:cytology* / Q000378:metabolism; D050356:Lipid Metabolism; D008074:Lipoproteins / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008861:Microsomes / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014280:Triglycerides / Q000378:metabolism
chemical_list: D004041:Dietary Fats; D008074:Lipoproteins; D009687:Nuclear Proteins; D014157:Transcription Factors; D014280:Triglycerides; C102804:nocturnin; D002784:Cholesterol