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Abortive Initiation and Productive Initiation by RNA Polymerase Involve DNA Scrunching
Andrey Revyakin,1,2*Chenyu Liu,1,2,3Richard H. Ebright,1Terence R. Strick2,3
Using single-molecule DNA nanomanipulation, we show that abortiveinitiation involves DNA "scrunching"—in which RNA polymerase(RNAP) remains stationary and unwinds and pulls downstream DNAinto itself—and that scrunching requires RNA synthesisand depends on RNA length. We show further that promoter escapeinvolves scrunching, and that scrunching occurs in most or allinstances of promoter escape. Our results support the existenceof an obligatory stressed intermediate, with approximately oneturn of additional DNA unwinding, in escape and are consistentwith the proposal that stress in this intermediate providesthe driving force to break RNAP-promoter and RNAP-initiation-factorinteractions in escape.
1 Howard Hughes Medical Institute, Waksman Institute, and Department of Chemistry, Rutgers University, Piscataway, NJ 08854, USA. 2 Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA. 3 Institut Jacques Monod, Centre National de la Recherche Scientifique UMR 7592 and Universités de Paris VI et Paris VII, 2 Place Jussieu, 75251 Paris Cedex 05, France.
* Present address: Howard Hughes Medical Institute and Departmentof Molecular and Cell Biology, 16 Barker Hall, University ofCalifornia, Berkeley, CA 94720–3204, USA.
To whom correspondence should be addressed. E-mail: strick{at}ijm.jussieu.fr (T.R.S.); ebright{at}waksman.rutgers.edu (R.H.E.)
To whom correspondence should be addressed. E-mail: 
