title: Rrp17p is a eukaryotic exonuclease required for 5' end processing of Pre-60S ribosomal RNA.
abstract: Ribosomal processing requires a series of endo- and exonucleolytic steps for the production of mature ribosomes, of which most have been described. To ensure ribosome synthesis, 3' end formation of rRNA uses multiple nucleases acting in parallel; however, a similar parallel mechanism had not been described for 5' end maturation. Here, we identify Rrp17p as a previously unidentified 5'-3' exonuclease essential for ribosome biogenesis, functioning with Rat1p in a parallel processing pathway analogous to that of 3' end formation. Rrp17p is required for efficient exonuclease digestion of the mature 5' ends of 5.8S(S) and 25S rRNAs, contains a catalytic domain close to its N terminus, and is highly conserved among higher eukaryotes, being a member of a family of exonucleases. We show that Rrp17p binds late pre-60S ribosomes, accompanying them from the nucleolus to the nuclear periphery, and provide evidence for physical and functional links between late 60S subunit processing and export.
authors.affiliation: Rockefeller University, New York, NY 10065, USA.
authors.forename: Marlene
authors.initials: M
authors.lastname: Oeffinger
authors.forename: Daniel
authors.initials: D
authors.lastname: Zenklusen
authors.forename: Angelica
authors.initials: A
authors.lastname: Ferguson
authors.forename: Karen E
authors.initials: KE
authors.lastname: Wei
authors.forename: Aziz
authors.initials: A
authors.lastname: El Hage
authors.forename: David
authors.initials: D
authors.lastname: Tollervey
authors.forename: Brian T
authors.initials: BT
authors.lastname: Chait
authors.forename: Robert H
authors.initials: RH
authors.lastname: Singer
authors.forename: Michael P
authors.initials: MP
authors.lastname: Rout
mesh_terms: D000595:Amino Acid Sequence; D005092:Exonucleases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005095:Exoribonucleases / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012322:RNA Precursors / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012335:RNA, Ribosomal / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D008565:Membrane Proteins; D012322:RNA Precursors; D012335:RNA, Ribosomal; D029701:Saccharomyces cerevisiae Proteins; C075577:RAT1 protein, S cerevisiae; D005092:Exonucleases; D005095:Exoribonucleases; C546988:Rrp17 exonuclease, human