title: The RNA polymerase I transcription machinery.
abstract: The rRNAs constitute the catalytic and structural components of the ribosome, the protein synthesis machinery of cells. The level of rRNA synthesis, mediated by Pol I (RNA polymerase I), therefore has a major impact on the life and destiny of a cell. In order to elucidate how cells achieve the stringent control of Pol I transcription, matching the supply of rRNA to demand under different cellular growth conditions, it is essential to understand the components and mechanics of the Pol I transcription machinery. In this review, we discuss: (i) the molecular composition and functions of the Pol I enzyme complex and the two main Pol I transcription factors, SL1 (selectivity factor 1) and UBF (upstream binding factor); (ii) the interplay between these factors during pre-initiation complex formation at the rDNA promoter in mammalian cells; and (iii) the cellular control of the Pol I transcription machinery.
authors.affiliation: Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, Wellcome Trust Biocentre, Dundee DD1 5EH, UK.
authors.forename: Jackie
authors.initials: J
authors.lastname: Russell
authors.forename: Joost C B M
authors.initials: JC
authors.lastname: Zomerdijk
mesh_terms: D000818:Animals; D006801:Humans; D008954:Models, Biological; D046912:Multiprotein Complexes; D035463:Pol1 Transcription Initiation Complex Proteins / Q000378:metabolism; D021122:Protein Subunits; D012318:RNA Polymerase I / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D046912:Multiprotein Complexes; D035463:Pol1 Transcription Initiation Complex Proteins; D021122:Protein Subunits; C063844:transcription factor UBF; C063660:transcription initiation factor TIF-IB; D012318:RNA Polymerase I