Single molecule analysis of RNA polymerase elongation reveals uniform kinetic behavior.
By using single-molecule measurements, we demonstrate that the elongation kinetics of individual Escherichia coli RNA polymerase molecules are remarkably homogeneous. We find no evidence of distinct elongation states among RNA polymerases. Instead, the observed heterogeneity in transcription rates results from statistical variation in the frequency and duration of pausing. When transcribing a gene without strong pause sites, RNA polymerase molecules display transient pauses that are distributed randomly in both time and distance. Transitions between the active elongation mode and the paused state are instantaneous within the resolution of our measurements (<1 s). This elongation behavior is compared with that of a mutant RNA polymerase that pauses more frequently and elongates more slowly than wild type.
Adelman
Karen
K
Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, USA.
La Porta
Arthur
A
Santangelo
Thomas J
TJ
Lis
John T
JT
Roberts
Jeffrey W
JW
Wang
Michelle D
MD
D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D007700:Kinetics; D017354:Point Mutation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
D011994:Recombinant Proteins; D012321:DNA-Directed RNA Polymerases; C113275:RNA polymerase alpha subunit; C105078:RNA polymerase beta subunit