title: The Nuclear PolyA-Binding Protein Nab2p Is Essential for mRNA Production.
abstract: Polyadenylation of mRNA is a key step in eukaryotic gene expression. However, despite the major impact of poly(A) tails on mRNA metabolism, the precise roles of poly(A)-binding proteins (PABPs) in nuclear mRNA biogenesis remain elusive. Here, we demonstrate that rapid nuclear depletion of the S. cerevisiae PABP Nab2p leads to a global loss of cellular mRNA, but not of RNA lacking poly(A) tails. Disappearance of mRNA is a nuclear event, but not due to decreased transcription. Instead, the absence of Nab2p results in robust nuclear mRNA decay by the ribonucleolytic RNA exosome in a polyadenylation-dependent process. We conclude that Nab2p is required to protect early mRNA and therefore constitutes a crucial nuclear mRNA biogenesis factor.
authors.affiliation: Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Alle 3, Building 1130, 8000 Aarhus C., Denmark. Electronic address: ms@mbg.au.dk.
authors.forename: Manfred
authors.initials: M
authors.lastname: Schmid
authors.affiliation: Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Alle 3, Building 1130, 8000 Aarhus C., Denmark.
authors.forename: Pawel
authors.initials: P
authors.lastname: Olszewski
authors.affiliation: European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany.
authors.forename: Vicent
authors.initials: V
authors.lastname: Pelechano
authors.affiliation: European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany.
authors.forename: Ishaan
authors.initials: I
authors.lastname: Gupta
authors.affiliation: European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany; Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304, USA; Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
authors.forename: Lars M
authors.initials: LM
authors.lastname: Steinmetz
authors.affiliation: Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Alle 3, Building 1130, 8000 Aarhus C., Denmark. Electronic address: thj@mbg.au.dk.
authors.forename: Torben Heick
authors.initials: TH
authors.lastname: Jensen
mesh_terms: D063326:Exosome Multienzyme Ribonuclease Complex / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D029543:Nucleocytoplasmic Transport Proteins / Q000235:genetics / Q000378:metabolism*; D026723:Polyadenylation; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C080773:NAB2 protein, S cerevisiae; D029543:Nucleocytoplasmic Transport Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D063326:Exosome Multienzyme Ribonuclease Complex