TAF1B Is a TFIIB-like Component of the Basal Transcription Machinery for RNA Polymerase I

Science. 2011 Sep 16;333(6049):1640-2. doi: 10.1126/science.1207656.


Transcription by eukaryotic RNA polymerases (Pols) II and III and archaeal Pol requires structurally related general transcription factors TFIIB, Brf1, and TFB, respectively, which are essential for polymerase recruitment and initiation events. A TFIIB-like protein was not evident in the Pol I basal transcription machinery. We report that TAF1B, a subunit of human Pol I basal transcription factor SL1, is structurally related to TFIIB/TFIIB-like proteins, through predicted amino-terminal zinc ribbon and cyclin-like fold domains. SL1, essential for Pol I recruitment to the ribosomal RNA gene promoter, also has an essential postpolymerase recruitment role, operating through TAF1B. Therefore, a TFIIB-related protein is implicated in preinitiation complex assembly and postpolymerase recruitment events in Pol I transcription, underscoring the parallels between eukaryotic Pol I, II, and III and archaeal transcription machineries.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • DNA, Ribosomal
  • Humans
  • Molecular Sequence Data
  • Mutant Proteins / chemistry
  • Mutant Proteins / metabolism
  • Mutation
  • Pol1 Transcription Initiation Complex Proteins / chemistry*
  • Pol1 Transcription Initiation Complex Proteins / genetics
  • Pol1 Transcription Initiation Complex Proteins / metabolism*
  • Promoter Regions, Genetic
  • Protein Binding
  • Protein Folding
  • Protein Structure, Tertiary
  • Protein Subunits / chemistry
  • Protein Subunits / metabolism
  • RNA Polymerase I / metabolism*
  • Transcription Factor TFIIB / chemistry*
  • Transcription Factor TFIIB / metabolism
  • Transcription, Genetic*


  • DNA, Ribosomal
  • Mutant Proteins
  • Pol1 Transcription Initiation Complex Proteins
  • Protein Subunits
  • TAF1B protein, human
  • Transcription Factor TFIIB
  • RNA Polymerase I