title: The THO complex cooperates with the nuclear RNA surveillance machinery to control small nucleolar RNA expression.
abstract: THO is a multi-protein complex that promotes coupling between transcription and mRNA processing. In contrast to its role in mRNA biogenesis, we show here that the fission yeast THO complex negatively controls the expression of non-coding small nucleolar (sno) RNAs. Accordingly, the deletion of genes encoding subunits of the evolutionarily conserved THO complex results in increased levels of mature snoRNAs. We also show physical and functional connections between THO and components of the TRAMP polyadenylation complex, whose loss of function also results in snoRNA accumulation. Consistent with a role in snoRNA expression, we demonstrate that THO and TRAMP complexes are recruited to snoRNA genes, and that a functional THO complex is required to maintain TRAMP occupancy at sites of snoRNA transcription. Our findings suggest that THO promotes exosome-mediated degradation of snoRNA precursors by ensuring the presence of the TRAMP complex at snoRNA genes. This study unveils an unexpected role for THO in the control of snoRNA expression and provides a new link between transcription and nuclear RNA decay.
authors.affiliation: Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec, Canada J1H 5N4.
authors.forename: Marc
authors.initials: M
authors.lastname: Larochelle
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Lemay
authors.forename: François
authors.initials: F
authors.lastname: Bachand
mesh_terms: D002467:Cell Nucleus / Q000201:enzymology / Q000235:genetics; D063326:Exosome Multienzyme Ribonuclease Complex / Q000378:metabolism; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D039103:Poly(A)-Binding Protein II / Q000378:metabolism; D026723:Polyadenylation; D011062:Polynucleotide Adenylyltransferase / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D020871:RNA Stability; D020537:RNA, Small Nucleolar / Q000235:genetics* / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D009687:Nuclear Proteins; D039103:Poly(A)-Binding Protein II; D020537:RNA, Small Nucleolar; D029702:Schizosaccharomyces pombe Proteins; C509157:Cid14 protein, S pombe; D011062:Polynucleotide Adenylyltransferase; D063326:Exosome Multienzyme Ribonuclease Complex