title: Aberrant translation of cytochrome c oxidase subunit 1 mRNA species in the absence of Mss51p in the yeast Saccharomyces cerevisiae.
abstract: Expression of yeast mitochondrial genes depends on specific translational activators acting on the 5'-untranslated region of their target mRNAs. Mss51p is a translational factor for cytochrome c oxidase subunit 1 (COX1) mRNA and a key player in down-regulating Cox1p expression when subunits with which it normally interacts are not available. Mss51p probably acts on the 5'-untranslated region of COX1 mRNA to initiate translation and on the coding sequence itself to facilitate elongation. Mss51p binds newly synthesized Cox1p, an interaction that could be necessary for translation. To gain insight into the different roles of Mss51p on Cox1p biogenesis, we have analyzed the properties of a new mitochondrial protein, mp15, which is synthesized in mss51 mutants and in cytochrome oxidase mutants in which Cox1p translation is suppressed. The mp15 polypeptide is not detected in cox14 mutants that express Cox1p normally. We show that mp15 is a truncated translation product of COX1 mRNA whose synthesis requires the COX1 mRNA-specific translational activator Pet309p. These results support a key role for Mss51p in translationally regulating Cox1p synthesis by the status of cytochrome oxidase assembly.
authors.affiliation: Department of Neurology and Biochemistry and Molecular Biology, The John T. Macdonald Foundation Center for Medical Genetics, University of Miami School of Medicine, Miami, FL 33136, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Zambrano
authors.forename: Flavia
authors.initials: F
authors.lastname: Fontanesi
authors.forename: Asun
authors.initials: A
authors.lastname: Solans
authors.forename: Rodrigo Leite
authors.initials: RL
authors.lastname: de Oliveira
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Fox
authors.forename: Alexander
authors.initials: A
authors.lastname: Tzagoloff
authors.forename: Antoni
authors.initials: A
authors.lastname: Barrientos
mesh_terms: D020121:5' Untranslated Regions / Q000378:metabolism; D002701:Chloramphenicol / Q000494:pharmacology; D003575:Cytochromes c1 / Q000096:biosynthesis* / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D024101:Mitochondrial Proteins; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics; D010448:Peptide Initiation Factors; D010455:Peptides / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D020121:5' Untranslated Regions; C094357:COX14 protein, S cerevisiae; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; C519191:Mss51 protein, S cerevisiae; D009687:Nuclear Proteins; C095480:PET309 protein, S cerevisiae; D010448:Peptide Initiation Factors; D010455:Peptides; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D002701:Chloramphenicol; D003575:Cytochromes c1