title: Rat1p maintains RNA polymerase II CTD phosphorylation balance.
abstract: In S. cerevisiae, the 5'-3' exonuclease Rat1p partakes in transcription termination. Although Rat1p-mediated RNA degradation has been suggested to play a role for this activity, the exact mechanisms by which Rat1p helps release RNA polymerase II (RNAPII) from the DNA template are poorly understood. Here we describe a function of Rat1p in regulating phosphorylation levels of the C-terminal domain (CTD) of the largest RNAPII subunit, Rpb1p, during transcription elongation. The rat1-1 mutant exhibits highly elevated levels of CTD phosphorylation as well as RNAPII distribution and transcription termination defects. These phenotypes are all rescued by overexpression of the CTD phosphatase Fcp1p, suggesting a functional relationship between the absence of Rat1p activity, elevated CTD phosphorylation, and transcription defects. We also demonstrate that rat1-1 cells display increased RNAPII transcription kinetics, a feature that may contribute to the cellular phenotypes of the mutant. Consistently, the rat1-1 allele is synthetic lethal with the rpb1-E1103G mutation, causing increased RNAPII speed, and is suppressed by the rpb2-10 mutation, causing slowed transcription. Thus, Rat1p plays more complex roles in controlling transcription than previously thought.
authors: Silvia
authors: S
authors: Jimeno-González
authors: Manfred
authors: M
authors: Schmid
authors: Francisco
authors: F
authors: Malagon
authors: Line Lindegaard
authors: LL
authors: Haaning
authors: Torben Heick
authors: TH
authors: Jensen
mesh_terms: D015153:Blotting, Western; D002843:Chromatin / Q000235:genetics; D047369:Chromatin Immunoprecipitation; D005095:Exoribonucleases / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D012694:Serine / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: C118305:CTDK-I protein complex, S cerevisiae; D002843:Chromatin; D029701:Saccharomyces cerevisiae Proteins; C075577:RAT1 protein, S cerevisiae; D012694:Serine; D011494:Protein Kinases; D012319:RNA Polymerase II; D005095:Exoribonucleases; D010749:Phosphoprotein Phosphatases; C116022:carboxy-terminal domain phosphatase
keywords: CTD phosphorylation; RNA polymerase II; transcription elongation; transcription termination