title: The molecular chaperone Hsp90 is required for mRNA localization in Drosophila melanogaster embryos.
abstract: Localization of maternal nanos mRNA to the posterior pole is essential for development of both the abdominal segments and primordial germ cells in the Drosophila embryo. Unlike maternal mRNAs such as bicoid and oskar that are localized by directed transport along microtubules, nanos is thought to be trapped as it swirls past the posterior pole during cytoplasmic streaming. Anchoring of nanos depends on integrity of the actin cytoskeleton and the pole plasm; other factors involved specifically in its localization have not been described to date. Here we use genetic approaches to show that the Hsp90 chaperone (encoded by Hsp83 in Drosophila) is a localization factor for two mRNAs, nanos and pgc. Other components of the pole plasm are localized normally when Hsp90 function is partially compromised, suggesting a specific role for the chaperone in localization of nanos and pgc mRNAs. Although the mechanism by which Hsp90 acts is unclear, we find that levels of the LKB1 kinase are reduced in Hsp83 mutant egg chambers and that localization of pgc (but not nos) is rescued upon overexpression of LKB1 in such mutants. These observations suggest that LKB1 is a primary Hsp90 target for pgc localization and that other Hsp90 partners mediate localization of nos.
authors.affiliation: Department of Cell Biology, Duke University Medical School, Durham, NC 27710, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Song
authors.forename: Lanette
authors.initials: L
authors.lastname: Fee
authors.forename: Tammy H
authors.initials: TH
authors.lastname: Lee
authors.forename: Robin P
authors.initials: RP
authors.lastname: Wharton
mesh_terms: D000091162:AMP-Activated Protein Kinase Kinases; D000818:Animals; D030801:Animals, Genetically Modified; D019521:Body Patterning / Q000235:genetics / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D017344:Genes, Insect; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D009154:Mutation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics
chemical_list: D029721:Drosophila Proteins; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C089272:Hsp83 protein, Drosophila; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C070574:nos protein, Drosophila; D011494:Protein Kinases; C495775:LKB1 protein, Drosophila; D000091162:AMP-Activated Protein Kinase Kinases