title: Sensitivity of housekeeping genes in the suprachiasmatic nucleus of the mouse brain to diet and the daily light-dark cycle.
abstract: The endogenous timing system within the suprachiasmatic nuclei (SCN) of the hypothalamus drives the cyclic expression of the clock molecules across the 24h day-night cycle controlling downstream molecular pathways and physiological processes. The developing fetal clock system is sensitive to the environment and physiology of the pregnant mother and as such disruption of this system could lead to altered physiology in the offspring. Characterizing the gene profiles of the endogenous molecular clock system by quantitative reverse transcription polymerase chain reaction is dependent on normalization by appropriate housekeeping genes (HKGs). However, many HKGs commonly used as internal controls, although stably expressed under control conditions, can vary significantly in their expression under certain experimental conditions. Here we analyzed the expression of 10 classic HKG across the 24h light-dark cycle in the SCN of mouse offspring exposed to normal chow or a high fat diet during early development and in postnatal life. We found that the HKGs glyceraldehyde-3-phosphate dehydrogenase, beta actin and adenosine triphosphate synthase subunit to be the most stably expressed genes in the SCN regardless of diet or time within the 24h light-dark cycle, and are therefore suitable to be used as internal controls. However SCN samples collected during the light and dark periods did show differences in expression and as such the timing of collection should be considered when carrying out gene expression studies.
authors.affiliation: Institute of Developmental Sciences, University of Southampton Faculty of Medicine, Southampton General Hospital (mailpoint 887), Southampton SO16 6YD, UK. Electronic address: j.k.cleal@soton.ac.uk.
authors.forename: Jane K
authors.initials: JK
authors.lastname: Cleal
authors.affiliation: Institute of Developmental Sciences, University of Southampton Faculty of Medicine, Southampton General Hospital (mailpoint 887), Southampton SO16 6YD, UK.
authors.forename: James N
authors.initials: JN
authors.lastname: Shepherd
authors.affiliation: Institute of Developmental Sciences, University of Southampton Faculty of Medicine, Southampton General Hospital (mailpoint 887), Southampton SO16 6YD, UK.
authors.forename: Jasmine L
authors.initials: JL
authors.lastname: Shearer
authors.affiliation: Institute of Developmental Sciences, University of Southampton Faculty of Medicine, Southampton General Hospital (mailpoint 887), Southampton SO16 6YD, UK.
authors.forename: Kimberley D
authors.initials: KD
authors.lastname: Bruce
authors.affiliation: Institute of Developmental Sciences, University of Southampton Faculty of Medicine, Southampton General Hospital (mailpoint 887), Southampton SO16 6YD, UK.
authors.forename: Felino R
authors.initials: FR
authors.lastname: Cagampang
mesh_terms: D000199:Actins / Q000235:genetics*; D000818:Animals; D002940:Circadian Rhythm / Q000235:genetics*; D059305:Diet, High-Fat; D005260:Female; D015870:Gene Expression; D020043:Genes, Essential; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D025261:Mitochondrial Proton-Translocating ATPases / Q000235:genetics*; D017440:Photoperiod; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*
chemical_list: D000199:Actins; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; C530489:ATP5b protein, mouse; D025261:Mitochondrial Proton-Translocating ATPases
keywords: High fat diet; Housekeeping gene; Light–dark cycle; Mouse; Suprachiasmatic nucleus