title: UtpA and UtpB chaperone nascent pre-ribosomal RNA and U3 snoRNA to initiate eukaryotic ribosome assembly.
abstract: Early eukaryotic ribosome biogenesis involves large multi-protein complexes, which co-transcriptionally associate with pre-ribosomal RNA to form the small subunit processome. The precise mechanisms by which two of the largest multi-protein complexes-UtpA and UtpB-interact with nascent pre-ribosomal RNA are poorly understood. Here, we combined biochemical and structural biology approaches with ensembles of RNA-protein cross-linking data to elucidate the essential functions of both complexes. We show that UtpA contains a large composite RNA-binding site and captures the 5' end of pre-ribosomal RNA. UtpB forms an extended structure that binds early pre-ribosomal intermediates in close proximity to architectural sites such as an RNA duplex formed by the 5' ETS and U3 snoRNA as well as the 3' boundary of the 18S rRNA. Both complexes therefore act as vital RNA chaperones to initiate eukaryotic ribosome assembly.
authors.affiliation: Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA.
authors.forename: Mirjam
authors.initials: M
authors.lastname: Hunziker
authors.affiliation: Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA.
authors.forename: Jonas
authors.initials: J
authors.lastname: Barandun
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Petfalski
authors.affiliation: Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Dongyan
authors.initials: D
authors.lastname: Tan
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK.
authors.forename: Clémentine
authors.initials: C
authors.lastname: Delan-Forino
authors.affiliation: Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York 10065, USA.
authors.forename: Kelly R
authors.initials: KR
authors.lastname: Molloy
authors.affiliation: Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, New York 10065, USA.
authors.forename: Kelly H
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK.
authors.forename: Hywel
authors.initials: H
authors.lastname: Dunn-Davies
authors.affiliation: Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York 10065, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA.|Tri-Institutional Training Program in Chemical Biology, The Rockefeller University, New York, New York 10065, USA.
authors.forename: Malik
authors.initials: M
authors.lastname: Chaker-Margot
authors.affiliation: Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York 10065, USA.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Chait
authors.affiliation: Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, New York 10065, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Walz
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK.
authors.forename: David
authors.initials: D
authors.lastname: Tollervey
authors.affiliation: Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, New York 10065, USA.
authors.forename: Sebastian
authors.identifier: 0000-0002-9373-4737
authors.initials: S
authors.lastname: Klinge
mesh_terms: D015966:Gene Expression Regulation, Fungal; D018832:Molecular Chaperones / Q000502:physiology*; D012322:RNA Precursors / Q000235:genetics; D012323:RNA Processing, Post-Transcriptional; D012331:RNA, Fungal / Q000378:metabolism*; D012337:RNA, Ribosomal, 18S; D020537:RNA, Small Nucleolar / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D012269:Ribosomal Proteins / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D018832:Molecular Chaperones; D012322:RNA Precursors; D012331:RNA, Fungal; D012337:RNA, Ribosomal, 18S; D020537:RNA, Small Nucleolar; C117378:RNA, U3 small nucleolar; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins