title: Cytoskeletal proteins associate with components of the ribosomal maturation and translation apparatus in Xenopus stage I oocytes.
abstract: Actin-based cytoskeleton (CSK) and microtubules may bind to RNAs and related molecules implicated in translation. However, many questions remain to be answered regarding the role of cytoskeletal components in supporting the proteins involved in steps in the maturation and translation processes. Here, we performed co-immunoprecipitation and immunofluorescence to examine the association between spectrins, keratins and tubulin and proteins involved in 60S ribosomal maturation and translation in Xenopus stage I oocytes, including ribosomal rpl10, eukaryotic initiation factor 6 (Eif6), thesaurins A/B, homologs of the eEF1α elongation factor, and P0, the ribosomal stalk protein. We found that rpl10 and eif6 cross-reacted with the actin-based CSK and with tubulin. rpl10 co-localizes with spectrin, particularly in the perinuclear region. eif6 is similarly localized. Given that upon ribosomal maturation, the insertion of rpl10 into the 60S subunit occurs simultaneously with the release of eif6, one can hypothesise that actin-based CSK and microtubules provide the necessary scaffold for the insertion/release of these two molecules and, subsequently, for eif6 transport and binding to the mature 60S subunit. P0 and thesaurins cross-reacted with only spectrin and cytokeratins. Thesaurins aggregated at the oocyte periphery, rendering this a territory favourable site for protein synthesis; the CSK may support the interaction between thesaurins and sites of the translating ribosome. Moreover, given that the assembly of the ribosome stalk, where P0 is located, to the 60S subunit is essential for the release of eif6, it can be hypothesised that the CSK can facilitate the binding of the stalk to the 60S.
authors.affiliation: Department of Biology,University of Naples Federico II,Naples,Italy.
authors.forename: Loredana
authors.initials: L
authors.lastname: Chierchia
authors.affiliation: Department of Biology,University of Naples Federico II,Naples,Italy.
authors.forename: Margherita
authors.initials: M
authors.lastname: Tussellino
authors.affiliation: Department of Biology,University of Naples Federico II,Naples,Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Guarino
authors.affiliation: Department of Biology,University of Naples Federico II,Naples,Italy.
authors.forename: Rosa
authors.initials: R
authors.lastname: Carotenuto
authors.affiliation: Department of Biology,University of Naples Federico II,Naples,Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: DeMarco
authors.affiliation: Department of Pharmacy University of Salerno,ItalyorDepartment of Biology,University of Naples Federico II,Naples,Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Campanella
authors.affiliation: Department of Science and Advanced Technology,University of Eastern Piedmont 'Amedeo Avogadro',Alessandria,Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Biffo
authors.affiliation: Department of Pharmacy University of Salerno,ItalyorDepartment of Biology,University of Naples Federico II,Naples,Italy.
authors.forename: Maria Carmela
authors.initials: MC
authors.lastname: Vaccaro
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D047468:Immunoprecipitation; D009865:Oocytes / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000378:metabolism*; D012270:Ribosomes / Q000502:physiology*; D029867:Xenopus Proteins / Q000378:metabolism*; D014982:Xenopus laevis / Q000254:growth & development / Q000378:metabolism*
chemical_list: D003598:Cytoskeletal Proteins; D012269:Ribosomal Proteins; D029867:Xenopus Proteins
keywords: 60S; Cytoskeleton; Eif6; Translation; rpl10