title: Nonsense-mediated mRNA decay controls the changes in yeast ribosomal protein pre-mRNAs levels upon osmotic stress.
abstract: The expression of ribosomal protein (RP) genes requires a substantial part of cellular transcription, processing and translation resources. Thus, the RP expression must be tightly regulated in response to conditions that compromise cell survival. In Saccharomyces cerevisiae cells, regulation of the RP gene expression at the transcriptional, mature mRNA stability and translational levels during the response to osmotic stress has been reported. Reprogramming global protein synthesis upon osmotic shock includes the movement of ribosomes from RP transcripts to stress-induced mRNAs. Using tiling arrays, we show that osmotic stress yields a drop in the levels of RP pre-mRNAs in S. cerevisiae cells. An analysis of the tiling array data, together with transcription rates data, shows a poor correlation, indicating that the drop in the RP pre-mRNA levels is not merely a result of the lowered RP transcription rates. A kinetic study using quantitative RT-PCR confirmed the decrease in the levels of several RP-unspliced transcripts during the first 15 minutes of osmotic stress, which seems independent of MAP kinase Hog1. Moreover, we found that the mutations in the components of the nonsense-mediated mRNA decay (NMD), Upf1, Upf2, Upf3 or in exonuclease Xrn1, eliminate the osmotic stress-induced drop in RP pre-mRNAs. Altogether, our results indicate that the degradation of yeast RP unspliced transcripts by NMD increases during osmotic stress, and suggest that this might be another mechanism to control RP synthesis during the stress response.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas Universitat de València, Valencia, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Garre
authors.forename: Lorena
authors.initials: L
authors.lastname: Romero-Santacreu
authors.forename: Manuela
authors.initials: M
authors.lastname: Barneo-Muñoz
authors.forename: Ana
authors.initials: A
authors.lastname: Miguel
authors.forename: José E
authors.initials: JE
authors.lastname: Pérez-Ortín
authors.forename: Paula
authors.initials: P
authors.lastname: Alepuz
mesh_terms: D005091:Exons / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal / Q000235:genetics; D007438:Introns / Q000235:genetics; D007700:Kinetics; D008954:Models, Biological; D059365:Nonsense Mediated mRNA Decay / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D009995:Osmosis; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics; D012269:Ribosomal Proteins / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D013312:Stress, Physiological / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D012322:RNA Precursors; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins