Structural mechanism of ATP-independent transcription initiation by RNA polymerase I
Abstract
Transcription initiation by RNA Polymerase I (Pol I) depends on the Core Factor (CF) complex to recognize the upstream promoter and assemble into a Pre-Initiation Complex (PIC). Here, we solve a structure of Saccharomyces cerevisiae Pol I-CF-DNA to 3.8Å resolution using single-particle cryo-electron microscopy. The structure reveals a bipartite architecture of Core Factor and its recognition of the promoter from -27 to -16. Core Factor's intrinsic mobility correlates well with different conformational states of the Pol I cleft, in addition to the stabilization of either Rrn7 N-terminal domain near Pol I wall or the tandem winged helix domain of A49 at a partially overlapping location. Comparison of the three states in this study with the Pol II system suggests that a ratchet motion of the Core Factor-DNA sub-complex at upstream facilitates promoter melting in an ATP-independent manner, distinct from a DNA translocase actively threading the downstream DNA in the Pol II PIC.
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Author details
Funding
Northwestern University (Cornew Innovation Award)
- Yuan He
Alexandrine and Alexander L. Sinsheimer Fund (Sinsheimer Scholar award)
- Bruce A Knutson
Chicago Community Trust (Catalyst Award)
- Yuan He
American Cancer Society (Institutional Research Grant IRG-15-173-21)
- Yuan He
SUNY Research Foundation
- Bruce A Knutson
Central New York Community Foundation
- Bruce A Knutson
National Cancer Institute (5K22CA184235)
- Bruce A Knutson
National Institute of General Medical Sciences (GM110387)
- Ivaylo Ivanov
National Science Foundation (MCB-1149521)
- Ivaylo Ivanov
Chicago Community Trust (Chicago Biomedical Consortium Postdoctoral Research Grant)
- Yan Han
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2017, Han et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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