title: The DEAD box protein Mrh4 functions in the assembly of the mitochondrial large ribosomal subunit.
abstract: Proteins in a cell are universally synthesized by ribosomes. Mitochondria contain their own ribosomes, which specialize in the synthesis of a handful of proteins required for oxidative phosphorylation. The pathway of mitoribosomal biogenesis and factors involved are poorly characterized. An example is the DEAD box proteins, widely known to participate in the biogenesis of bacterial and cytoplasmic eukaryotic ribosomes as either RNA helicases or RNA chaperones, whose mitochondrial counterparts remain completely unknown. Here, we have identified the Saccharomyces cerevisiae mitochondrial DEAD box protein Mrh4 as essential for large mitoribosome subunit biogenesis. Mrh4 interacts with the 21S rRNA, mitoribosome subassemblies, and fully assembled mitoribosomes. In the absence of Mrh4, the 21S rRNA is matured and forms part of a large on-pathway assembly intermediate missing proteins Mrpl16 and Mrpl39. We conclude that Mrh4 plays an essential role during the late stages of mitoribosome assembly by promoting remodeling of the 21S rRNA-protein interactions.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
authors.forename: Dasmanthie
authors.initials: D
authors.lastname: De Silva
authors.forename: Flavia
authors.initials: F
authors.lastname: Fontanesi
authors.forename: Antoni
authors.initials: A
authors.lastname: Barrientos
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D017124:Conserved Sequence; D053487:DEAD-box RNA Helicases / Q000737:chemistry / Q000378:metabolism*; D004272:DNA, Mitochondrial / Q000235:genetics; D006801:Humans; D007438:Introns / Q000235:genetics; D008928:Mitochondria / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000096:biosynthesis; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010085:Oxidative Phosphorylation; D011485:Protein Binding / Q000235:genetics; D014176:Protein Biosynthesis; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics; D020871:RNA Stability / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism; D054683:Ribosome Subunits, Large, Eukaryotic / Q000378:metabolism*; D054682:Ribosome Subunits, Small, Eukaryotic / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature
chemical_list: C454219:21S rRNA; D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; D000255:Adenosine Triphosphate; C478542:MRH4 protein, S cerevisiae; D053487:DEAD-box RNA Helicases