Functional architecture of RNA polymerase I

Titelangaben

Kuhn, Claus-D. ; Geiger, Sebastian R. ; Baumli, Sonja ; Gartmann, Marco ; Gerber, Jochen ; Jennebach, Stefan ; Mielke, Thorsten ; Tschochner, Herbert ; Beckmann, Roland ; Cramer, Patrick:
Functional architecture of RNA polymerase I.
In: Cell. Bd. 131 (2007) Heft 7 . - S. 1260-1272.
ISSN 1097-4172
DOI: https://doi.org/10.1016/j.cell.2007.10.051

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Abstract

Synthesis of ribosomal RNA (rRNA) by RNA polymerase (Pol) I is the first step in ribosome biogenesis and a regulatory switch in eukaryotic cell growth. Here we report the 12 A cryo-electron microscopic structure for the complete 14-subunit yeast Pol I, a homology model for the core enzyme, and the crystal structure of the subcomplex A14/43. In the resulting hybrid structure of Pol I, A14/43, the clamp, and the dock domain contribute to a unique surface interacting with promoter-specific initiation factors. The Pol I-specific subunits A49 and A34.5 form a heterodimer near the enzyme funnel that acts as a built-in elongation factor and is related to the Pol II-associated factor TFIIF. In contrast to Pol II, Pol I has a strong intrinsic 3'-RNA cleavage activity, which requires the C-terminal domain of subunit A12.2 and, apparently, enables ribosomal RNA proofreading and 3'-end trimming.