title: Smaug, a novel and conserved protein, contributes to repression of nanos mRNA translation in vitro.
abstract: Proper deployment of Nanos protein at the posterior of the Drosophila embryo, where it directs posterior development, requires a combination of RNA localization and translational controls. These controls ensure that only the posteriorly-localized nanos mRNA is translated, whereas unlocalized nanos mRNA is translationally repressed. Here we describe cloning of the gene encoding Smaug, an RNA-binding protein that interacts with the sequences, SREs, in the nanos mRNA that mediate translational repression. Using an in vitro translation assay, we demonstrate that SRE-dependent repression occurs in extracts from early stage embryos. Immunodepletion of Smaug from the extracts eliminates repression, consistent with the notion that Smaug is involved. Smaug is a novel gene and the existence of potential mammalian Smaug homologs raises the possibility that Smaug represents a new class of conserved translational repressor.
authors.affiliation: Department of Biological Sciences, Stanford University, California 94305-5020, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Smibert
authors.forename: Y S
authors.initials: YS
authors.lastname: Lie
authors.forename: W
authors.initials: W
authors.lastname: Shillinglaw
authors.forename: W J
authors.initials: WJ
authors.lastname: Henzel
authors.forename: P M
authors.initials: PM
authors.lastname: Macdonald
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D019521:Body Patterning; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian / Q000502:physiology; D020224:Expressed Sequence Tags; D018507:Gene Expression Regulation, Developmental; D019476:Insect Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009024:Morphogenesis; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
chemical_list: D029721:Drosophila Proteins; D019476:Insect Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; C402587:smg protein, Drosophila; C070574:nos protein, Drosophila