title: Kinetics of promoter Pol II on Hsp70 reveal stable pausing and key insights into its regulation.
abstract: The kinetics with which promoter-proximal paused RNA polymerase II (Pol II) undergoes premature termination versus productive elongation is central to understanding underlying mechanisms of metazoan transcription regulation. To assess the fate of Pol II quantitatively, we tracked photoactivatable GFP-tagged Pol II at uninduced Hsp70 on polytene chromosomes and showed that Pol II is stably paused with a half-life of 5 min. Biochemical analysis of short nascent RNA from Hsp70 reveals that this half-life is determined by two comparable rates of productive elongation and premature termination of paused Pol II. Importantly, heat shock dramatically increases elongating Pol II without decreasing termination, indicating that regulation acts at the step of paused Pol II entry to productive elongation.
authors.affiliation: Department of Molecular Biology and Genetics.
authors.forename: Martin S
authors.initials: MS
authors.lastname: Buckley
authors.forename: Hojoong
authors.initials: H
authors.lastname: Kwak
authors.forename: Warren R
authors.initials: WR
authors.lastname: Zipfel
authors.forename: John T
authors.initials: JT
authors.lastname: Lis
mesh_terms: D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000201:enzymology* / Q000235:genetics*; D005786:Gene Expression Regulation; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D011401:Promoter Regions, Genetic / Q000502:physiology*; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D019076:Transgenes
chemical_list: D029721:Drosophila Proteins; D018840:HSP70 Heat-Shock Proteins; D012319:RNA Polymerase II
keywords: RNA polymerase II; escape to productive elongation; nascent RNA; photoactivation; promoter-proximal pausing; termination