title: Expression of rhodopsin and arrestin during the light-dark cycle in Drosophila.
abstract: OBJECTIVE
  To determine the protein and transcript levels for rhodopsin (Rh1), arrestin 1 (Arr1), and arrestin 2 (Arr2) over a 12 h light/12 h dark cycle in the retina of the fruit fly, Drosophila melanogaster. This information is important for understanding the process of photoreceptor membrane turnover.
  
  
  METHODS
  Drosophila were entrained for several generations to a daily 12 h light/12 h dark cycle. They were sacrificed at 4 h intervals, beginning at the time of onset of the light phase. Proteins were resolved by polyacrylamide gel electrophoresis (PAGE) and subjected to immunoblot analysis using antibodies directed to rhodopsin, NinaA, Arr1, and Arr2. Northern blots were incubated with riboprobes corresponding to the rhodopsin gene (ninaE), arrestin1 (arr1), and arrestin2 (arr2).
  
  
  RESULTS
  In entrained Drosophila, protein and mRNA levels for rhodopsin, arrestin1, and arrestin2 were constant during a 12 h light/12 h dark cycle.
  
  
  CONCLUSIONS
  These results indicate that rhodopsin and arrestin protein synthesis in Drosophila photoreceptors do not fluctuate on a daily cycle. These findings are similar to those obtained in Xenopus laevis, but in contrast to a variety of other vertebrate and invertebrate species.
authors.affiliation: Department of Ophthalmology & Visual Science, University of Wisconsin, Madison, WI 53706, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Hartman
authors.forename: I
authors.initials: I
authors.lastname: Menon
authors.forename: K
authors.initials: K
authors.lastname: Haug-Collet
authors.forename: N J
authors.initials: NJ
authors.lastname: Colley
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D019390:Arrestins / Q000235:genetics* / Q000378:metabolism; D015152:Blotting, Northern; D002940:Circadian Rhythm / Q000502:physiology*; D015342:DNA Probes; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D015151:Immunoblotting; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D017956:Photoreceptor Cells, Invertebrate / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D012243:Rhodopsin / Q000235:genetics* / Q000378:metabolism
chemical_list: C504665:Arr1 protein, Drosophila; C504666:Arr2 protein, Drosophila; D019390:Arrestins; D015342:DNA Probes; D029721:Drosophila Proteins; D005136:Eye Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; C083315:ninaE protein, Drosophila; D012243:Rhodopsin