6ruo
RNA Polymerase I Open Complex conformation 1
Structural highlights
FunctionRRN7_YEAST Component of RNA polymerase I core factor complex (CF) that acts as a SUA7/TFIIB-like factor and plays a key role in multiple steps during transcription initiation such as pre-initiation complex (PIC) assembly and postpolymerase recruitment events in polymerase I (Pol I) transcription. Binds rDNA promoters and plays a role in Pol I recruitment. After binding of UAF (upstream activation factor) to an upstream element of the promoter, CF is recruited in a SPT15/TBP-dependent manner to form a pre-initiation complex.[1] [2] [3] Publication Abstract from PubMedRNA polymerase I (Pol I) assembles with core factor (CF) and Rrn3 on the rDNA core promoter for transcription initiation. Here, we report cryo-EM structures of closed, intermediate and open Pol I initiation complexes from 2.7 to 3.7 A resolution to visualize Pol I promoter melting and to structurally and biochemically characterize the recognition mechanism of Pol I promoter DNA. In the closed complex, double-stranded DNA runs outside the DNA-binding cleft. Rotation of CF and upstream DNA with respect to Pol I and Rrn3 results in the spontaneous loading and opening of the promoter followed by cleft closure and positioning of the Pol I A49 tandem winged helix domain (tWH) onto DNA. Conformational rearrangement of A49 tWH leads to a clash with Rrn3 to initiate complex disassembly and promoter escape. Comprehensive insight into the Pol I transcription initiation cycle allows comparisons with promoter opening by Pol II and Pol III. Molecular insight into RNA polymerase I promoter recognition and promoter melting.,Sadian Y, Baudin F, Tafur L, Murciano B, Wetzel R, Weis F, Muller CW Nat Commun. 2019 Dec 5;10(1):5543. doi: 10.1038/s41467-019-13510-w. PMID:31804486[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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