Rrp17p is a eukaryotic exonuclease required for 5' end processing of Pre-60S ribosomal RNA.
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.
Oeffinger
Marlene
M
Rockefeller University, New York, NY 10065, USA.
Zenklusen
Daniel
D
Ferguson
Angelica
A
Wei
Karen E
KE
El Hage
Aziz
A
Tollervey
David
D
Chait
Brian T
BT
Singer
Robert H
RH
Rout
Michael P
MP
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
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