title: C7orf30 specifically associates with the large subunit of the mitochondrial ribosome and is involved in translation.
abstract: In a comparative genomics study for mitochondrial ribosome-associated proteins, we identified C7orf30, the human homolog of the plant protein iojap. Gene order conservation among bacteria and the observation that iojap orthologs cannot be transferred between bacterial species predict this protein to be associated with the mitochondrial ribosome. Here, we show colocalization of C7orf30 with the large subunit of the mitochondrial ribosome using isokinetic sucrose gradient and 2D Blue Native polyacrylamide gel electrophoresis (BN-PAGE) analysis. We co-purified C7orf30 with proteins of the large subunit, and not with proteins of the small subunit, supporting interaction that is specific to the large mitoribosomal complex. Consistent with this physical association, a mitochondrial translation assay reveals negative effects of C7orf30 siRNA knock-down on mitochondrial gene expression. Based on our data we propose that C7orf30 is involved in ribosomal large subunit function. Sequencing the gene in 35 patients with impaired mitochondrial translation did not reveal disease-causing mutations in C7orf30.
authors.affiliation: Centre for Molecular and Biomolecular Informatics, Radboud University Nijmegen Medical Centre, The Netherlands.
authors.forename: Bas F J
authors.initials: BF
authors.lastname: Wanschers
authors.forename: Radek
authors.initials: R
authors.lastname: Szklarczyk
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Pajak
authors.forename: Mariël A M
authors.initials: MA
authors.lastname: van den Brand
authors.forename: Jolein
authors.initials: J
authors.lastname: Gloerich
authors.forename: Richard J T
authors.initials: RJ
authors.lastname: Rodenburg
authors.forename: Robert N
authors.initials: RN
authors.lastname: Lightowlers
authors.forename: Leo G
authors.initials: LG
authors.lastname: Nijtmans
authors.forename: Martijn A
authors.initials: MA
authors.lastname: Huynen
mesh_terms: D000595:Amino Acid Sequence; D045744:Cell Line, Tumor; D055785:Gene Knockdown Techniques; D005798:Genes, Bacterial; D057809:HEK293 Cells; D006801:Humans; D008928:Mitochondria / Q000235:genetics; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009711:Nucleotides / Q000378:metabolism; D009876:Operon; D010802:Phylogeny; D014176:Protein Biosynthesis; D017434:Protein Structure, Tertiary; D012269:Ribosomal Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D054683:Ribosome Subunits, Large, Eukaryotic / Q000737:chemistry*; D017422:Sequence Analysis, DNA
chemical_list: C573551:MALSU1 protein, human; D024101:Mitochondrial Proteins; D009711:Nucleotides; D012269:Ribosomal Proteins