title: Genome-wide expression profiling and bioinformatics analysis of diurnally regulated genes in the mouse prefrontal cortex.
abstract: BACKGROUND
  The prefrontal cortex is important in regulating sleep and mood. Diurnally regulated genes in the prefrontal cortex may be controlled by the circadian system, by sleep:wake states, or by cellular metabolism or environmental responses. Bioinformatics analysis of these genes will provide insights into a wide-range of pathways that are involved in the pathophysiology of sleep disorders and psychiatric disorders with sleep disturbances.
  
  
  RESULTS
  We examined gene expression in the mouse prefrontal cortex at four time points during a 24 hour (12 hour light:12 hour dark) cycle using microarrays, and identified 3,890 transcripts corresponding to 2,927 genes with diurnally regulated expression patterns. We show that 16% of the genes identified in our study are orthologs of identified clock, clock controlled or sleep/wakefulness induced genes in the mouse liver and suprachiasmatic nucleus, rat cortex and cerebellum, or Drosophila head. The diurnal expression patterns were confirmed for 16 out of 18 genes in an independent set of RNA samples. The diurnal genes fall into eight temporal categories with distinct functional attributes, as assessed by Gene Ontology classification and analysis of enriched transcription factor binding sites.
  
  
  CONCLUSIONS
  Our analysis demonstrates that approximately 10% of transcripts have diurnally regulated expression patterns in the mouse prefrontal cortex. Functional annotation of these genes will be important for the selection of candidate genes for behavioral mutants in the mouse and for genetic studies of disorders associated with anomalies in the sleep:wake cycle and circadian rhythm.
authors.affiliation: Department of Genetics and Penn Center for Bioinformatics, University of Pennsylvania, Philadelphia, PA 19104, USA. shuzhang@mail.med.upenn.edu
authors.forename: Shuzhang
authors.initials: S
authors.lastname: Yang
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.forename: Otto
authors.initials: O
authors.lastname: Valladares
authors.forename: Sridhar
authors.initials: S
authors.lastname: Hannenhalli
authors.forename: Maja
authors.initials: M
authors.lastname: Bucan
mesh_terms: D000818:Animals; D001665:Binding Sites; D002940:Circadian Rhythm; D019295:Computational Biology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D051379:Mice; D008810:Mice, Inbred C57BL; D016133:Polymerase Chain Reaction; D017397:Prefrontal Cortex / Q000378:metabolism*; D012890:Sleep / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism; D014851:Wakefulness / Q000235:genetics
chemical_list: D014157:Transcription Factors