title: Dbp9p, a putative ATP-dependent RNA helicase involved in 60S-ribosomal-subunit biogenesis, functionally interacts with Dbp6p.
abstract: Ribosome synthesis is a highly complex process and constitutes a major cellular activity. The biogenesis of this ribonucleoprotein assembly requires a multitude of protein trans-acting factors including several putative ATP-dependent RNA helicases of the DEAD-box and related protein families. Here we show that the previously uncharacterized Saccharomyces cerevisiae open reading frame YLR276C, hereafter named DBP9 (DEAD-box protein 9), encodes an essential nucleolar protein involved in 60S-ribosomal-subunit biogenesis. Genetic depletion of Dbp9p results in a deficit in 60S ribosomal subunits and the appearance of half-mer polysomes. This terminal phenotype is likely due to the instability of early pre-ribosomal particles, as evidenced by the low steady-state levels and the decreased synthesis of the 27S precursors to mature 25S and 5.8S rRNAs. In agreement with a role of Dbp9p in 60S subunit synthesis, we find that increased Dbp9p dosage efficiently suppresses certain dbp6 alleles and that dbp6/dbp9 double mutants show synthetic lethality. Furthermore, Dbp6p and Dbp9p weakly interact in a yeast two-hybrid assay. Altogether, our findings indicate an intimate functional interaction between Dbp6p and Dbp9p during the process of 60S-ribosomal-subunit assembly.
authors.affiliation: Département de Biochimie médicale, Centre Medical Universitaire, Université de Genève, Switzerland.
authors.forename: M C
authors.initials: MC
authors.lastname: Daugeron
authors.forename: D
authors.initials: D
authors.lastname: Kressler
authors.forename: P
authors.initials: P
authors.lastname: Linder
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D002466:Cell Nucleolus / Q000378:metabolism; D053487:DEAD-box RNA Helicases; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011132:Polyribosomes; D011518:Proto-Oncogene Proteins; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012316:RNA Nucleotidyltransferases; D012335:RNA, Ribosomal / Q000096:biosynthesis; D012340:RNA, Ribosomal, 5.8S / Q000096:biosynthesis; D012270:Ribosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D020798:Two-Hybrid System Techniques
chemical_list: C436685:DBP9 protein, S cerevisiae; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D012335:RNA, Ribosomal; D012340:RNA, Ribosomal, 5.8S; D029701:Saccharomyces cerevisiae Proteins; C065039:RNA, ribosomal, 25S; D000255:Adenosine Triphosphate; D012316:RNA Nucleotidyltransferases; C490617:DBP6 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases