title: A kinetic framework for a mammalian RNA polymerase in vivo.
abstract: We have analyzed the kinetics of assembly and elongation of the mammalian RNA polymerase I complex on endogenous ribosomal genes in the nuclei of living cells with the use of in vivo microscopy. We show that components of the RNA polymerase I machinery are brought to ribosomal genes as distinct subunits and that assembly occurs via metastable intermediates. With the use of computational modeling of imaging data, we have determined the in vivo elongation time of the polymerase, and measurements of recruitment and incorporation frequencies show that incorporation of components into the assembling polymerase is inefficient. Our data provide a kinetic and mechanistic framework for the function of a mammalian RNA polymerase in living cells.
authors.affiliation: National Cancer Institute (NCI), National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Dundr
authors.forename: Urs
authors.initials: U
authors.lastname: Hoffmann-Rohrer
authors.forename: Qiyue
authors.initials: Q
authors.lastname: Hu
authors.forename: Ingrid
authors.initials: I
authors.lastname: Grummt
authors.forename: Lawrence I
authors.initials: LI
authors.lastname: Rothblum
authors.forename: Robert D
authors.initials: RD
authors.lastname: Phair
authors.forename: Tom
authors.initials: T
authors.lastname: Misteli
mesh_terms: D000818:Animals; D020134:Catalytic Domain; D002460:Cell Line; D002466:Cell Nucleolus / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D003198:Computer Simulation; D004275:DNA, Ribosomal / Q000235:genetics; D005453:Fluorescence; D036681:Fluorescence Recovery After Photobleaching; D005456:Fluorescent Dyes; D049452:Green Fluorescent Proteins; D000882:Haplorhini; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007700:Kinetics; D016018:Least-Squares Analysis; D008164:Luminescent Proteins; D008853:Microscopy; D035463:Pol1 Transcription Initiation Complex Proteins / Q000378:metabolism; D011336:Probability; D011401:Promoter Regions, Genetic; D021122:Protein Subunits; D012318:RNA Polymerase I / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D004275:DNA, Ribosomal; D005456:Fluorescent Dyes; D008164:Luminescent Proteins; D035463:Pol1 Transcription Initiation Complex Proteins; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D012318:RNA Polymerase I