Yeast Rrn7 and Human TAF1B Are TFIIB-related RNA Polymerase I General Transcription Factors

Science. 2011 Sep 16;333(6049):1637-40. doi: 10.1126/science.1207699.


Eukaryotic and archaeal multisubunit RNA polymerases (Pols) are structurally related and require several similar components for transcription initiation. However, none of the Pol I factors were known to share homology with transcription factor IIB (TFIIB) or TFIIB-related proteins, key factors in the initiation mechanisms of the other Pols. Here we show that Rrn7, a subunit of the yeast Pol I core factor, and its human ortholog TAF1B are TFIIB-like factors. Although distantly related, Rrn7 shares many activities associated with TFIIB-like factors. Domain swaps between TFIIB-related factors show that Rrn7 is most closely related to the Pol III general factor Brf1. Our results point to the conservation of initiation mechanisms among multisubunit Pols and reveal a key function of yeast core factor/human SL1 in Pol I transcription.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Sequence
  • Amino Acid Substitution
  • Humans
  • Molecular Sequence Data
  • Pol1 Transcription Initiation Complex Proteins / chemistry*
  • Pol1 Transcription Initiation Complex Proteins / genetics
  • Pol1 Transcription Initiation Complex Proteins / metabolism*
  • Protein Folding
  • Protein Interaction Domains and Motifs
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • RNA Polymerase I / metabolism*
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Sequence Alignment
  • TATA-Box Binding Protein / metabolism
  • Transcription Factor TFIIB / chemistry
  • Transcription Factor TFIIB / metabolism
  • Transcription Factor TFIIIB / chemistry
  • Transcription Factor TFIIIB / genetics
  • Transcription Factor TFIIIB / metabolism
  • Transcription, Genetic


  • BRF1 protein, S cerevisiae
  • Pol1 Transcription Initiation Complex Proteins
  • RRN7 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • TAF1B protein, human
  • TATA-Box Binding Protein
  • Transcription Factor TFIIB
  • Transcription Factor TFIIIB
  • RNA Polymerase I