title: Yeast polypeptide exit tunnel ribosomal proteins L17, L35 and L37 are necessary to recruit late-assembling factors required for 27SB pre-rRNA processing.
abstract: Ribosome synthesis involves the coordinated folding and processing of pre-rRNAs with assembly of ribosomal proteins. In eukaryotes, these events are facilitated by trans-acting factors that propel ribosome maturation from the nucleolus to the cytoplasm. However, there is a gap in understanding how ribosomal proteins configure pre-ribosomes in vivo to enable processing to occur. Here, we have examined the role of adjacent yeast r-proteins L17, L35 and L37 in folding and processing of pre-rRNAs, and binding of other proteins within assembling ribosomes. These three essential ribosomal proteins, which surround the polypeptide exit tunnel, are required for 60S subunit formation as a consequence of their role in removal of the ITS2 spacer from 27SB pre-rRNA. L17-, L35- and L37-depleted cells exhibit turnover of aberrant pre-60S assembly intermediates. Although the structure of ITS2 does not appear to be grossly affected in their absence, these three ribosomal proteins are necessary for efficient recruitment of factors required for 27SB pre-rRNA processing, namely, Nsa2 and Nog2, which associate with pre-60S ribosomal particles containing 27SB pre-rRNAs. Altogether, these data support that L17, L35 and L37 are specifically required for a recruiting step immediately preceding removal of ITS2.
authors.affiliation: Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Gamalinda
authors.forename: Jelena
authors.initials: J
authors.lastname: Jakovljevic
authors.forename: Reyes
authors.initials: R
authors.lastname: Babiano
authors.forename: Jason
authors.initials: J
authors.lastname: Talkish
authors.forename: Jesús
authors.initials: J
authors.lastname: de la Cruz
authors.forename: John L
authors.initials: JL
authors.lastname: Woolford
mesh_terms: D001483:Base Sequence; D002466:Cell Nucleolus / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D012322:RNA Precursors / Q000737:chemistry / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012335:RNA, Ribosomal / Q000737:chemistry / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054683:Ribosome Subunits, Large, Eukaryotic / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D012322:RNA Precursors; D012335:RNA, Ribosomal; C489280:RPL35A protein, S cerevisiae; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; C032493:ribosomal protein L17