title: Independent RNA polymerase II preinitiation complex dynamics and nucleosome turnover at promoter sites in vivo.
abstract: Transcription by all three eukaryotic RNA polymerases involves the assembly of a large preinitiation complex (PIC) at gene promoters. The PIC comprises several general transcription factors (GTFs), including TBP, and the respective RNA polymerase. It has been suggested that some GTFs remain stably bound at active promoters to facilitate multiple transcription events. Here we used two complementary approaches to show that, in G1-arrested yeast cells, TBP exchanges very rapidly even at the most highly active RNA Pol II promoters. A similar situation is observed at RNA Pol III promoters. In contrast, TBP remains stably bound at RNA Pol I promoters. We also provide evidence that, unexpectedly, PIC dynamics are neither the cause nor the consequence of nucleosome exchange at most of the RNA Pol II promoters we analyzed. These results point to a stable reinitiation complex at RNA Pol I promoters and suggest independent PIC and nucleosome turnover at many RNA Pol II promoters.
authors.affiliation: Department of Microbiology and Molecular Medicine, University Medical Centre (C.M.U.), 1211 Geneva 4, Switzerland.
authors.forename: Yoselin
authors.initials: Y
authors.lastname: Grimaldi
authors.forename: Paolo
authors.initials: P
authors.lastname: Ferrari
authors.forename: Michel
authors.initials: M
authors.lastname: Strubin
mesh_terms: D004271:DNA, Fungal / Q000378:metabolism; D059585:G1 Phase Cell Cycle Checkpoints; D009707:Nucleosomes / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012318:RNA Polymerase I / Q000235:genetics / Q000378:metabolism; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D012320:RNA Polymerase III / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D035181:TATA-Box Binding Protein / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D004271:DNA, Fungal; D009707:Nucleosomes; D029701:Saccharomyces cerevisiae Proteins; D035181:TATA-Box Binding Protein; D012319:RNA Polymerase II; D012318:RNA Polymerase I; D012320:RNA Polymerase III