Smaug, a novel RNA-binding protein that operates a translational switch in Drosophila.
During Drosophila embryogenesis, a gradient of Nanos protein emanating from the posterior pole organizes abdominal segmentation. This gradient arises from translational regulation of nanos mRNA, which is activated in the specialized cytoplasm at the posterior pole of the embryo and repressed elsewhere. Previously, we have defined cis-acting elements in the mRNA that mediate this translational switch. In this report, we identify a factor named Smaug that binds to these elements and represses translation in the bulk cytoplasm. Smaug interacts gentically and biochemically with Oskar, a key component of the pole plasm for activation of nanos mRNA and specification of the germline precursors. These observations suggest that Smaug operates a translational switch that governs the distribution of Nanos protein.
Dahanukar
A
A
Howard Hughes Medical Institute, Department of Genetics, Duke University Medical Center, Durham, North Carolina 27710, USA.
Walker
J A
JA
Wharton
R P
RP
D000005:Abdomen; D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D001665:Binding Sites; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics*; D004625:Embryo, Nonmammalian / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D015698:Genomic Library; D019476:Insect Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009024:Morphogenesis; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis
D029721:Drosophila Proteins; D019476:Insect Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C070574:nos protein, Drosophila