title: Cytokinin stimulates polyribosome loading of nuclear-encoded mRNAs for the plastid ATP synthase in etioplasts of Lupinus luteus: the complex accumulates in the inner-envelope membrane with the CF(1) moiety located towards the stromal space.
abstract: Three of the nine subunits of the plastid ATP synthase, including the subunit of the CF(1) moiety (gene AtpC), are encoded in the nucleus. Application of cytokinin to etiolated lupine seedlings induces polyribosome association of their mRNAs. This appears to be specific as no such regulation was observed for messages for three ribosomal proteins. Cytokinin-mediated polyribosome loading was also observed for the spinach AtpC message in etiolated transgenic tobacco seedlings. Analysis of various spinach AtpC mRNA derivatives uncovered that the 5' untranslated region (5' UTR) of this message is sufficient to direct polyribosome loading, and that sequences at the 3' end of the AtpC 5' UTR, including an UC-rich motif, are crucial for this regulation. The increase in polyribosome loading of the AtpC message correlated with an increased synthesis of the polypeptide. The subunit, together with the ATP synthase complex, accumulates in the inner-envelope membrane with the CF(1) moiety located towards the stromal space of the etioplast. These results suggest that cytokinin promotes accumulation of the ATP synthase in the inner-envelope membrane of lupine etioplasts by stimulating the translation efficiency of their nuclear-encoded messages.
authors.affiliation: Institut für Allgemeine Botanik und Pflanzenphysiologie, Friedrich-Schiller-Universität Jena, Dornburger Str. 159, D-07743 Jena, Germany.
authors.forename: Irena
authors.initials: I
authors.lastname: Sherameti
authors.forename: Bationa
authors.initials: B
authors.lastname: Shahollari
authors.forename: Martin
authors.initials: M
authors.lastname: Landsberger
authors.forename: Martin
authors.initials: M
authors.lastname: Westermann
authors.forename: Galina
authors.initials: G
authors.lastname: Cherepneva
authors.forename: Victor
authors.initials: V
authors.lastname: Kusnetsov
authors.forename: Ralf
authors.initials: R
authors.lastname: Oelmüller
mesh_terms: D002467:Cell Nucleus / Q000235:genetics*; D018548:Cotyledon / Q000235:genetics; D003583:Cytokinins / Q000494:pharmacology*; D003624:Darkness; D018525:Germination; D031297:Lupinus / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics / Q000302:isolation & purification; D030821:Plants, Genetically Modified / Q000235:genetics; D018087:Plastids / Q000201:enzymology* / Q000235:genetics; D016133:Polymerase Chain Reaction; D011132:Polyribosomes / Q000187:drug effects / Q000235:genetics*; D006180:Proton-Translocating ATPases / Q000235:genetics* / Q000302:isolation & purification; D012333:RNA, Messenger / Q000235:genetics*; D014026:Nicotiana / Q000235:genetics; D014170:Transformation, Genetic
chemical_list: D003583:Cytokinins; D010940:Plant Proteins; D012333:RNA, Messenger; D006180:Proton-Translocating ATPases