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- Title
RNA polymerase I structure and transcription regulation.
- Authors
Engel, Christoph; Sainsbury, Sarah; Cheung, Alan C.; Kostrewa, Dirk; Cramer, Patrick
- Abstract
Transcription of ribosomal RNA by RNA polymerase (Pol) I initiates ribosome biogenesis and regulates eukaryotic cell growth. The crystal structure of Pol I from the yeast Saccharomyces cerevisiae at 2.8 Å resolution reveals all 14 subunits of the 590-kilodalton enzyme, and shows differences to Pol II. An 'expander' element occupies the DNA template site and stabilizes an expanded active centre cleft with an unwound bridge helix. A 'connector' element invades the cleft of an adjacent polymerase and stabilizes an inactive polymerase dimer. The connector and expander must detach during Pol I activation to enable transcription initiation and cleft contraction by convergent movement of the polymerase 'core' and 'shelf' modules. Conversion between an inactive expanded and an active contracted polymerase state may generally underlie transcription. Regulatory factors can modulate the core-shelf interface that includes a 'composite' active site for RNA chain initiation, elongation, proofreading and termination.
- Subjects
RNA polymerases; GENETIC transcription regulation; RIBOSOMES; EUKARYOTIC cells; CRYSTAL structure; CELLULAR control mechanisms
- Publication
Nature, 2013, Vol 502, Issue 7473, p650
- ISSN
0028-0836
- Publication type
Article
- DOI
10.1038/nature12712