title: Integrity of SRP RNA is ensured by La and the nuclear RNA quality control machinery.
abstract: The RNA component of signal recognition particle (SRP) is transcribed by RNA polymerase III, and most steps in SRP biogenesis occur in the nucleolus. Here, we examine processing and quality control of the yeast SRP RNA (scR1). In common with other pol III transcripts, scR1 terminates in a U-tract, and mature scR1 retains a U4-5 sequence at its 3' end. In cells lacking the exonuclease Rex1, scR1 terminates in a longer U5-6 tail that presumably represents the primary transcript. The 3' U-tract of scR1 is protected from aberrant processing by the La homologue, Lhp1 and overexpressed Lhp1 apparently competes with both the RNA surveillance system and SRP assembly factors. Unexpectedly, the TRAMP and exosome nuclear RNA surveillance complexes are also implicated in protecting the 3' end of scR1, which accumulates in the nucleolus of cells lacking the activities of these complexes. Misassembled scR1 has a primary degradation pathway in which Rrp6 acts early, followed by TRAMP-stimulated exonuclease degradation by the exosome. We conclude that the RNA surveillance machinery has key roles in both SRP biogenesis and quality control of the RNA, potentially facilitating the decision between these alternative fates.
authors.affiliation: RNA Biology Group and Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
authors.forename: Eileen
authors.initials: E
authors.lastname: Leung
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, UK.
authors.forename: Claudia
authors.initials: C
authors.lastname: Schneider
authors.affiliation: RNA Biology Group and Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
authors.forename: Fu
authors.initials: F
authors.lastname: Yan
authors.affiliation: RNA Biology Group and Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
authors.forename: Hatem
authors.initials: H
authors.lastname: Mohi-El-Din
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, UK.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Kudla
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, UK.
authors.forename: Alex
authors.initials: A
authors.lastname: Tuck
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, UK.
authors.forename: Wiebke
authors.initials: W
authors.lastname: Wlotzka
authors.affiliation: RNA Biology Group and Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
authors.forename: Victoria A
authors.initials: VA
authors.lastname: Doronina
authors.affiliation: RNA Biology Group and Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
authors.forename: Ralph
authors.initials: R
authors.lastname: Bartley
authors.affiliation: RNA Biology Group and Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Watkins
authors.affiliation: Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, UK.
authors.forename: David
authors.initials: D
authors.lastname: Tollervey
authors.affiliation: RNA Biology Group and Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK jeremy.brown@ncl.ac.uk.
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Brown
mesh_terms: D002466:Cell Nucleolus / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D063326:Exosome Multienzyme Ribonuclease Complex / Q000378:metabolism; D026721:RNA 3' End Processing; D020871:RNA Stability; D012331:RNA, Fungal / Q000737:chemistry / Q000378:metabolism*; D020733:RNA, Small Cytoplasmic / Q000737:chemistry / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D018271:Signal Recognition Particle / Q000378:metabolism*
chemical_list: C088396:LHP1 protein, S cerevisiae; D012331:RNA, Fungal; D020733:RNA, Small Cytoplasmic; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D018271:Signal Recognition Particle; D063326:Exosome Multienzyme Ribonuclease Complex