title: mtRF1a is a human mitochondrial translation release factor decoding the major termination codons UAA and UAG.
abstract: Human mitochondria contain their own genome, encoding 13 polypeptides that are synthesized within the organelle. The molecular processes that govern and facilitate this mitochondrial translation remain unclear. Many key factors have yet to be characterized-for example, those required for translation termination. All other systems have two classes of release factors that either promote codon-specific hydrolysis of peptidyl-tRNA (class I) or lack specificity but stimulate the dissociation of class I factors from the ribosome (class II). One human mitochondrial protein has been previously identified in silico as a putative member of the class I release factors. Although we could not confirm the function of this factor, we report the identification of a different mitochondrial protein, mtRF1a, that is capable in vitro and in vivo of terminating translation at UAA/UAG codons. Further, mtRF1a depletion in HeLa cells led to compromised growth in galactose and increased production of reactive oxygen species.
authors.affiliation: Mitochondrial Research Group, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
authors.forename: Hamid Reza
authors.initials: HR
authors.lastname: Soleimanpour-Lichaei
authors.forename: Inge
authors.initials: I
authors.lastname: Kühl
authors.forename: Mauricette
authors.initials: M
authors.lastname: Gaisne
authors.forename: Joao F
authors.initials: JF
authors.lastname: Passos
authors.forename: Mateusz
authors.initials: M
authors.lastname: Wydro
authors.forename: Joanna
authors.initials: J
authors.lastname: Rorbach
authors.forename: Richard
authors.initials: R
authors.lastname: Temperley
authors.forename: Nathalie
authors.initials: N
authors.lastname: Bonnefoy
authors.forename: Warren
authors.initials: W
authors.lastname: Tate
authors.forename: Robert
authors.initials: R
authors.lastname: Lightowlers
authors.forename: Zofia
authors.initials: Z
authors.lastname: Chrzanowska-Lightowlers
mesh_terms: D049109:Cell Proliferation; D018388:Codon, Terminator; D018628:Gene Dosage; D005816:Genetic Complementation Test; D006367:HeLa Cells; D006801:Humans; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008957:Models, Genetic; D010443:Peptide Chain Termination, Translational; D010454:Peptide Termination Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014176:Protein Biosynthesis / Q000502:physiology; D012313:RNA / Q000378:metabolism; D034622:RNA Interference; D000077278:RNA, Mitochondrial; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*