title: Co-transcriptional degradation by the 5'-3' exonuclease Rat1p mediates quality control of HXK1 mRNP biogenesis in S. cerevisiae.
abstract: The co-transcriptional biogenesis of export-competent messenger ribonucleoprotein particles (mRNPs) in yeast is under the surveillance of quality control (QC) steps. Aberrant mRNPs resulting from inappropriate or inefficient processing and packaging reactions are detected by the QC system and retained in the nucleus with ensuing elimination of their mRNA component by a mechanism that requires the catalytic activity of Rrp6p, a 3'-5' exonuclease associated with the RNA exosome. In previous studies, we implemented a new experimental approach in which the production of aberrant mRNPs is massively increased upon perturbation of mRNP biogenesis by the RNA-dependent helicase/translocase activity of the bacterial Rho factor expressed in S. cerevisiae. The analyses of a subset of transcripts such as PMA1 led us to substantiate the essential role of Rrp6p in the nuclear mRNP QC and to reveal a functional coordination of the process by Nrd1p. Here, we extended those results by showing that, in contrast to PMA1, Rho-induced aberrant HXK1 mRNPs are targeted for destruction by an Nrd1p- and Rrp6p-independent alternative QC pathway that relies on the 5'-3' exonuclease activity of Rat1p. We show that the degradation of aberrant HXK1 mRNPs by Rat1p occurs co-transcriptionally following decapping by Dcp2p and leads to premature transcription termination. We discuss the possibility that this alternative QC pathway might be linked to the well-known specific features of the HXK1 gene transcription such as its localization at the nuclear periphery and gene loop formation.
authors.affiliation: a Centre de Biophysique Moléculaire , Rue Charles Sadron , Orléans , France.
authors.forename: Christine
authors.initials: C
authors.lastname: Mosrin-Huaman
authors.affiliation: a Centre de Biophysique Moléculaire , Rue Charles Sadron , Orléans , France.
authors.forename: Nadège
authors.initials: N
authors.lastname: Hervouet-Coste
authors.affiliation: a Centre de Biophysique Moléculaire , Rue Charles Sadron , Orléans , France.
authors.forename: A Rachid
authors.initials: AR
authors.lastname: Rahmouni
mesh_terms: D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D004722:Endoribonucleases / Q000235:genetics; D005095:Exoribonucleases / Q000378:metabolism*; D006593:Hexokinase / Q000235:genetics*; D006180:Proton-Translocating ATPases / Q000235:genetics; D011786:Quality Control; D012331:RNA, Fungal / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D012234:Rho Factor / Q000378:metabolism*; D017414:Ribonucleoprotein, U4-U6 Small Nuclear / Q000378:metabolism*; D017415:Ribonucleoprotein, U5 Small Nuclear / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: C065573:PRP6 protein, S cerevisiae; D012331:RNA, Fungal; D012333:RNA, Messenger; D012234:Rho Factor; D017414:Ribonucleoprotein, U4-U6 Small Nuclear; D017415:Ribonucleoprotein, U5 Small Nuclear; D029701:Saccharomyces cerevisiae Proteins; C075577:RAT1 protein, S cerevisiae; D006593:Hexokinase; C400572:DCP2 protein, S cerevisiae; D004722:Endoribonucleases; D005095:Exoribonucleases; C092477:PMA1 protein, S cerevisiae; D006180:Proton-Translocating ATPases
keywords: HXK1; Rat1p; mRNP biogenesis; mRNP quality control