The class 2 selenophosphate synthetase gene of Drosophila contains a functional mammalian-type SECIS.
Synthesis of monoselenophosphate, the selenium donor required for the synthesis of selenocysteine (Sec) is catalyzed by the enzyme selenophosphate synthetase (SPS), first described in Escherichia coli. SPS homologs were identified in archaea, mammals and Drosophila. In the latter, however, an amino acid replacement is present within the catalytic domain and lacks selenide-dependent SPS activity. We describe the identification of a novel Drosophila homolog, Dsps2. The open reading frame of Dsps2 mRNA is interrupted by an UGA stop codon. The 3'UTR contains a mammalian-like Sec insertion sequence which causes translational readthrough in both transfected Drosophila cells and transgenic embryos. Thus, like vertebrates, Drosophila contains two SPS enzymes one with and one without Sec in its catalytic domain. Our data indicate further that the selenoprotein biosynthesis machinery is conserved between mammals and fly, promoting the use of Drosophila as a genetic tool to identify components and mechanistic features of the synthesis pathway.
Max-Planck-Institut für biophysikalische Chemie, Abt Molekulare Entwicklungsbiologie, Göttingen, Germany.
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Hirosawa-Takamori
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Jäckle
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Vorbrüggen
D020413:3' Untranslated Regions; D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D015153:Blotting, Western; D020134:Catalytic Domain; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018388:Codon, Terminator; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004330:Drosophila / Q000201:enzymology* / Q000235:genetics*; D029721:Drosophila Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D004625:Embryo, Nonmammalian / Q000378:metabolism; D020224:Expressed Sequence Tags; D006801:Humans; D017403:In Situ Hybridization; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010770:Phosphotransferases / Q000737:chemistry* / Q000235:genetics*; D014176:Protein Biosynthesis; D011506:Proteins; D012333:RNA, Messenger / Q000378:metabolism; D051140:Selenoproteins; D017422:Sequence Analysis, DNA; D014162:Transfection
D020413:3' Untranslated Regions; D018388:Codon, Terminator; D018076:DNA, Complementary; D029721:Drosophila Proteins; D011506:Proteins; D012333:RNA, Messenger; D051140:Selenoproteins; D010770:Phosphotransferases; C499550:Sps2 protein, Drosophila; C062762:selenophosphate synthetase; C109636:sps1 protein, Drosophila