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Updated: Sep 26, 2025

High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
Mechanism of RNA polymerase I selection by transcription factor UAF
Florence Baudin1, Brice Murciano1, Herman K H Fung1
1Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
Abstract:
Preribosomal RNA is selectively transcribed by RNA polymerase (Pol) I in eukaryotes. The yeast transcription factor upstream activating factor (UAF) represses Pol II transcription and mediates Pol I preinitiation complex (PIC) formation at the 35S ribosomal RNA gene. To visualize the molecular intermediates toward PIC formation, we determined the structure of UAF in complex with native promoter DNA and transcription factor TATA-box-binding protein (TBP). We found that UAF recognizes DNA using a hexameric histone-like scaffold with markedly different interactions compared with the nucleosome and the histone-fold-rich transcription factor IID (TFIID). In parallel, UAF positions TBP for Core Factor binding, which leads to Pol I recruitment, while sequestering it from DNA and Pol II/III-specific transcription factors. Our work thus reveals the structural basis of RNA Pol selection by a transcription factor.
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