title: Proteins participating to the post-transcriptional regulation of the mitochondrial cytochrome c oxidase subunit IV via elements located in the 3'UTR.
abstract: In developing rat brain cytochrome c oxidase subunit IV (COXIV) expression is also regulated at post-transcriptional level and two 3'UTR-COXIV RNA-binding factors have been identified. Here, we report the enrichment and identification of the factors from just born rat brains by affinity chromatography of biotinylated 3'UTR-COXIV RNA-protein complexes on streptavidin-conjugated paramagnetic particles. We successfully isolated two main proteins of about 86 and 42kDa, whose sequences were highly attributable to Hsp90 and Actin. The purified proteins maintain RNA-binding ability and specificity for COXIV messenger and, interacting with the 3'UTR, then could negatively modulate mRNA translation. We also studied the content of Hsp90 and Actin during postnatal brain development and demonstrated that in just born rat brain, when the COXIV protein appears at low level, Hsp90 was not phosphorylated. Vice versa in the adult tissue, when COXIV accumulates, Hsp90 appeared phosphorylated in serine therefore it could be unable to bind COXIV messenger, suggesting that the phosphorylation event could provoke the loss of Hsp90 binding to mRNA. We hypothesize a new post-transcriptional mechanism regulating a messenger encoded by nuclear genome for a mitochondrial protein and that Hsp90 and Actin, could represent key players in COXIV translation.
authors.affiliation: Dipartimento di Biologia Cellulare e dello Sviluppo "A. Monroy", Università di Palermo, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cannino
authors.forename: Elisa
authors.initials: E
authors.lastname: Ferruggia
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Rinaldi
mesh_terms: D020413:3' Untranslated Regions; D000199:Actins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000201:enzymology; D002846:Chromatography, Affinity / Q000379:methods; D003576:Electron Transport Complex IV / Q000096:biosynthesis*; D005786:Gene Expression Regulation; D018841:HSP90 Heat-Shock Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000096:biosynthesis*; D008970:Molecular Weight; D010766:Phosphorylation; D011485:Protein Binding; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020539:Sequence Analysis, Protein; D012694:Serine / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D000199:Actins; D018841:HSP90 Heat-Shock Proteins; D024101:Mitochondrial Proteins; D016601:RNA-Binding Proteins; D012694:Serine; D003576:Electron Transport Complex IV