title: The molecular chaperone Hsp90 is a component of the cap-binding complex and interacts with the translational repressor Cup during Drosophila oogenesis.
abstract: In metazoa, the spatio-temporal translation of diverse mRNAs is essential to guarantee proper oocyte maturation and early embryogenesis. The eukaryotic translation initiation factor 4E (eIF4E), which binds the 5' cap structure of eukaryotic mRNAs, associates with either stimulatory or inhibitory factors to modulate protein synthesis. In order to identify novel factors that might act at the translational level during Drosophila oogenesis, we have undertaken a functional proteomic approach and isolated the product of the Hsp83 gene, the evolutionarily conserved chaperone Hsp90, as a specific component of the cap-binding complex. Here we report that Hsp90 interacts in vitro with the translational repressor Cup. In addition, we show that Hsp83 and cup interact genetically, since lowering Hsp90 activity enhances the oogenesis alterations linked to diverse cup mutant alleles. Hsp90 and Cup co-localize in the cytoplasm of the developing germ-line cells within the germarium, thus suggesting a common function from the earliest stages of oogenesis. Taken together, our data start elucidating the role of Hsp90 during Drosophila female germ-line development and strengthen the idea that Cup has multiple essential functions during egg chamber development.
authors.affiliation: CEINGE-Biotecnologie Avanzate, Naples, Italy.
authors.forename: Viviana
authors.initials: V
authors.lastname: Pisa
authors.forename: Marianna
authors.initials: M
authors.lastname: Cozzolino
authors.forename: Serena
authors.initials: S
authors.lastname: Gargiulo
authors.forename: Cristina
authors.initials: C
authors.lastname: Ottone
authors.forename: Federica
authors.initials: F
authors.lastname: Piccioni
authors.forename: Maria
authors.initials: M
authors.lastname: Monti
authors.forename: Silvia
authors.initials: S
authors.lastname: Gigliotti
authors.forename: Fabio
authors.initials: F
authors.lastname: Talamo
authors.forename: Franco
authors.initials: F
authors.lastname: Graziani
authors.forename: Piero
authors.initials: P
authors.lastname: Pucci
authors.forename: Arturo C
authors.initials: AC
authors.lastname: Verrotti
mesh_terms: D000483:Alleles; D000818:Animals; D002460:Cell Line; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000378:metabolism; D005260:Female; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D013058:Mass Spectrometry; D009154:Mutation / Q000235:genetics; D009866:Oogenesis; D010053:Ovary / Q000166:cytology / Q000378:metabolism; D011485:Protein Binding; D014176:Protein Biosynthesis; D021381:Protein Transport; D040901:Proteomics; D012315:RNA Caps / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D018841:HSP90 Heat-Shock Proteins; D012315:RNA Caps; D012097:Repressor Proteins; C105238:cup protein, Drosophila