title: Antioxidant function of a novel selenoprotein in Drosophila melanogaster.
abstract: BACKGROUND
  Insects appear to have diverged from both higher and lower organisms in their defense mechanisms against oxidative damage. They do not encode glutathione peroxidases or glutathione reductases, and their thioredoxin reductases exhibit distinct properties from those of higher and lower species. Nonetheless, appropriate balance of anti-oxidants and pro-oxidants, and protection from damaging reactive oxygen species are clearly crucial in insects for viability, normal functioning of signalling pathways and morphogenesis, and have been implicated in studies on longevity in flies and other organisms.
  
  
  RESULTS
  Two novel selenoproteins, dselH and dselK, were recently identified in Drosophila melanogaster. We have used RNAi in D. melanogaster embryos and in Schneider S2 cells to inhibit expression of these proteins. We report that inhibition of either dselH or dselK expression significantly reduces viability in embryos. We further show that dselH silencing decreases total anti-oxidant capacity in embryos and Schneider cells, and increases lipid peroxidation in cells. Conversely, transient expression of dselH in the cell line decreases lipid peroxidation, and reverses the toxic effects of a glutathione-depleting drug. The latter correlates with sparing of glutathione levels.
  
  
  CONCLUSIONS
  These studies suggest that the well-known role of selenoproteins in vertebrate anti-oxidant defenses also extends to include invertebrates.
authors.affiliation: Thyroid Division, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Nadya
authors.initials: N
authors.lastname: Morozova
authors.forename: Erin P
authors.initials: EP
authors.lastname: Forry
authors.forename: Elena
authors.initials: E
authors.lastname: Shahid
authors.forename: Ann Marie
authors.initials: AM
authors.lastname: Zavacki
authors.forename: John W
authors.initials: JW
authors.lastname: Harney
authors.forename: Yevgenya
authors.initials: Y
authors.lastname: Kraytsberg
authors.forename: Marla J
authors.initials: MJ
authors.lastname: Berry
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000502:physiology*; D002460:Cell Line; D002470:Cell Survival; D019610:Cytoprotection; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D005314:Embryonic and Fetal Development; D005978:Glutathione / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D018384:Oxidative Stress; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D034622:RNA Interference; D051140:Selenoproteins
chemical_list: D000975:Antioxidants; C490438:BthD protein, Drosophila; D029721:Drosophila Proteins; D008565:Membrane Proteins; D011506:Proteins; C490437:SelG protein, Drosophila; D051140:Selenoproteins; D005978:Glutathione