Molecular insight into RNA polymerase I promoter recognition and promoter melting.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31804486.
- Also identified by DOI 10.1038/s41467-019-13510-w and PMC identifier 6895186.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
RNA 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 Å 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.
Medical subject headings
- DNA, Fungal
- Promoter Regions, Genetic
- RNA Polymerase I
- Saccharomyces cerevisiae
- Saccharomyces cerevisiae Proteins
- Transcription, Genetic