Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Dec 22;540(7634):607-610.
doi: 10.1038/nature20561. Epub 2016 Nov 14.

Structure of RNA polymerase I transcribing ribosomal DNA genes

Simon Neyer  1 , Michael Kunz  2 , Christian Geiss  2 , Merle Hantsche  1 , Victor-Valentin Hodirnau  2 , Anja Seybert  2 , Christoph Engel  1 , Margot P Scheffer  2 , Patrick Cramer  1 , Achilleas S Frangakis  2
Affiliations

Structure of RNA polymerase I transcribing ribosomal DNA genes

Simon Neyer et al. Nature. .

Abstract

RNA polymerase I (Pol I) is a highly processive enzyme that transcribes ribosomal DNA (rDNA) and regulates growth of eukaryotic cells. Crystal structures of free Pol I from the yeast Saccharomyces cerevisiae have revealed dimers of the enzyme stabilized by a 'connector' element and an expanded cleft containing the active centre in an inactive conformation. The central bridge helix was unfolded and a Pol-I-specific 'expander' element occupied the DNA-template-binding site. The structure of Pol I in its active transcribing conformation has yet to be determined, whereas structures of Pol II and Pol III have been solved with bound DNA template and RNA transcript. Here we report structures of active transcribing Pol I from yeast solved by two different cryo-electron microscopy approaches. A single-particle structure at 3.8 Å resolution reveals a contracted active centre cleft with bound DNA and RNA, and a narrowed pore beneath the active site that no longer holds the RNA-cleavage-stimulating domain of subunit A12.2. A structure at 29 Å resolution that was determined from cryo-electron tomograms of Pol I enzymes transcribing cellular rDNA confirms contraction of the cleft and reveals that incoming and exiting rDNA enclose an angle of around 150°. The structures suggest a model for the regulation of transcription elongation in which contracted and expanded polymerase conformations are associated with active and inactive states, respectively.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. EMBO J. 2003 May 1;22(9):2234-44 - PubMed
    1. J Struct Biol. 2015 Nov;192(2):216-21 - PubMed
    1. Nature. 1969 Oct 18;224(5216):234-7 - PubMed
    1. Acta Crystallogr D Biol Crystallogr. 2010 Apr;66(Pt 4):486-501 - PubMed
    1. Mol Cell. 2015 Feb 5;57(3):408-21 - PubMed