title: Transcription regulation by the noncoding RNA SRG1 requires Spt2-dependent chromatin deposition in the wake of RNA polymerase II.
abstract: Spt2 is a chromatin component with roles in transcription and posttranscriptional regulation. Recently, we found that Spt2 travels with RNA polymerase II (RNAP II), is involved in elongation, and plays important roles in chromatin modulations associated with this process. In this work, we dissect the function of Spt2 in the repression of SER3. This gene is repressed by a transcription interference mechanism involving the transcription of an adjacent intergenic region, SRG1, that leads to the production of a noncoding RNA (ncRNA). We find that Spt2 and Spt6 are required for the repression of SER3 by SRG1 transcription. Intriguingly, we demonstrate that these effects are not mediated through modulations of the SRG1 transcription rate. Instead, we show that the SRG1 region overlapping the SER3 promoter is occluded by randomly positioned nucleosomes that are deposited behind RNAP II transcribing SRG1 and that their deposition is dependent on the presence of Spt2. Our data indicate that Spt2 is required for the major chromatin deposition pathway that uses old histones to refold nucleosomes in the wake of RNAP II at the SRG1-SER3 locus. Altogether, these observations suggest a new mechanism of repression by ncRNA transcription involving a repressive nucleosomal structure produced by an Spt2-dependent pathway following RNAP II passage.
authors.affiliation: Centre de Recherche en Cancérologie de l'Université Laval, L'Hôtel-Dieu de Québec (CHUQ), Québec, Québec G1R2J6, Canada.
authors.forename: Philippe
authors.initials: P
authors.lastname: Thebault
authors.forename: Geneviève
authors.initials: G
authors.lastname: Boutin
authors.forename: Wajid
authors.initials: W
authors.lastname: Bhat
authors.forename: Anne
authors.initials: A
authors.lastname: Rufiange
authors.forename: Joseph
authors.initials: J
authors.lastname: Martens
authors.forename: Amine
authors.initials: A
authors.lastname: Nourani
mesh_terms: D002843:Chromatin / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D056488:Histone Chaperones; D006657:Histones / Q000378:metabolism; D008745:Methylation; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D009707:Nucleosomes / Q000378:metabolism; D050543:Phosphoglycerate Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism*; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D022661:RNA, Untranslated / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D056488:Histone Chaperones; D006657:Histones; D009687:Nuclear Proteins; D009707:Nucleosomes; D012331:RNA, Fungal; D022661:RNA, Untranslated; C065456:SPT6 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035602:Transcriptional Elongation Factors; C069938:SPT2 protein, S cerevisiae; D050543:Phosphoglycerate Dehydrogenase; C493278:SER3 protein, S cerevisiae; D012319:RNA Polymerase II