title: Aep3p-dependent translation of yeast mitochondrialATP8.
abstract: Translation of mitochondrial gene products inSaccharomyces cerevisiaedepends on mRNA-specific activators that bind to the 5' untranslated regions and promote translation on mitochondrial ribosomes. Here we find that Aep3p, previously shown to stabilize the bicistronicATP8-ATP6mRNA and facilitate initiation of translation from unformylated methionine, also activates specifically translation ofATP8This is supported by several lines of evidence. Temperature-sensitiveaep3mutants are selectively blocked in incorporating [35S]methionine into Atp8p at nonpermissive but not at the permissive temperature. This phenotype is not a consequence of defective transcription or processing of the pre-mRNA. Neither is it explained by turnover of Aep3p, as evidenced by the failure ofaep3mutants to express a recodedARG8mwhen this normally nuclear gene is substituted forATP8in mitochondrial DNA. Finally, translational ofATP8mRNA inaep3mutants is partially rescued by recoded allotopicATP8(nATP8) in a high-expression plasmid or in a CEN plasmid in the presence of recessive mutations in genes involved in stability and polyadenylation of RNA.
authors.affiliation: Departamento de Microbiologia, Universidade de Sao Paulo, Sao Paulo 05508-900, Brazil.
authors.forename: Mario H
authors.initials: MH
authors.lastname: Barros
authors.affiliation: Department of Biological Sciences, Columbia University, New York, NY 10027 spud@columbia.edu.
authors.forename: Alexander
authors.initials: A
authors.lastname: Tzagoloff
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D004272:DNA, Mitochondrial / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D005800:Genes, Fungal / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism; D025261:Mitochondrial Proton-Translocating ATPases; D009154:Mutation; D010442:Peptide Chain Initiation, Translational / Q000235:genetics; D014176:Protein Biosynthesis; D006180:Proton-Translocating ATPases / Q000235:genetics* / Q000378:metabolism*; D012322:RNA Precursors / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*
chemical_list: D020121:5' Untranslated Regions; C545722:AEP3 protein, S cerevisiae; D004272:DNA, Mitochondrial; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D012322:RNA Precursors; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D025261:Mitochondrial Proton-Translocating ATPases; D006180:Proton-Translocating ATPases; C545198:Atp8 protein, S cerevisiae