title: The retinal clock drives the expression of Kcnv2, a channel essential for visual function and cone survival.
abstract: OBJECTIVE
  The gene Kcnv2 codes for the voltage-gated potassium channel subunit Kv8.2, which can coassemble with Kv2.1 subfamily members to constitute functional voltage-gated potassium channels. Mutations in the Kcnv2 gene result in a retinal disorder designated "cone dystrophy with supernormal rod response (CDSRR)," revealing that Kcnv2 is essential for visual processing and cone survival. The aim of this study was to determine whether expression of Kcnv2 and Kv2.1 is under circadian regulation and may thus contribute to the clock-driven adjustment of photoreceptor function.
  
  
  METHODS
  Expression of the genes was recorded in preparations of the whole retina and microdissected retinal neurons by using quantitative polymerase chain reaction and Western blot.
  
  
  RESULTS
  The transcript levels of Kcnv2 and Kv2.1 in preparations of whole retina and photoreceptor cells were found to display daily rhythms, with elevated values during the night. For Kcnv2 this rhythm was shown to evoke a corresponding rhythm in Kv8.2, the protein product of this gene. The daily changes in retinal Kcnv2 and Kv2.1 mRNA levels persisted under constant darkness and are therefore driven by the endogenous retinal clock system, which itself is entrained by light.
  
  
  CONCLUSIONS
  The present data provide evidence that the transcriptional regulation of Kcnv2 and Kv2.1 is a way through which the retinal clock system drives the functional adaptation of visual function to the marked daily changes in environmental lighting conditions.
authors.affiliation: Department of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.
authors.forename: Philip
authors.initials: P
authors.lastname: Hölter
authors.forename: Stefanie
authors.initials: S
authors.lastname: Kunst
authors.forename: Tanja
authors.initials: T
authors.lastname: Wolloscheck
authors.forename: Debra K
authors.initials: DK
authors.lastname: Kelleher
authors.forename: Carsten
authors.initials: C
authors.lastname: Sticht
authors.forename: Uwe
authors.initials: U
authors.lastname: Wolfrum
authors.forename: Rainer
authors.initials: R
authors.lastname: Spessert
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D015153:Blotting, Western; D002470:Cell Survival; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D047468:Immunoprecipitation; D008297:Male; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D012160:Retina / Q000502:physiology*; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D051669:Shab Potassium Channels / Q000235:genetics*; D014785:Vision, Ocular / Q000502:physiology*
chemical_list: C496991:Kcnb1 protein, rat; D024642:Potassium Channels, Voltage-Gated; D012333:RNA, Messenger; D051669:Shab Potassium Channels