Kinetics of promoter Pol II on Hsp70 reveal stable pausing and key insights into its regulation.
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.
['Buckley|Martin S|MS|', 'Kwak|Hojoong|H|', 'Zipfel|Warren R|WR|', 'Lis|John T|JT|']
D000818:Animals D029721:Drosophila Proteins D004331:Drosophila melanogaster D005786:Gene Expression Regulation D018840:HSP70 Heat-Shock Proteins D007700:Kinetics D011401:Promoter Regions, Genetic D012319:RNA Polymerase II D019076:Transgenes
promoter-proximal pausing RNA polymerase II termination nascent RNA escape to productive elongation photoactivation