Conservation between the RNA polymerase I, II, and III transcription initiation machineries

Mol Cell. 2012 Feb 24;45(4):439-46. doi: 10.1016/j.molcel.2012.01.023.


Recent studies of the three eukaryotic transcription machineries revealed that all initiation complexes share a conserved core. This core consists of the RNA polymerase (I, II, or III), the TATA box-binding protein (TBP), and transcription factors TFIIB, TFIIE, and TFIIF (for Pol II) or proteins structurally and functionally related to parts of these factors (for Pol I and Pol III). The conserved core initiation complex stabilizes the open DNA promoter complex and directs initial RNA synthesis. The periphery of the core initiation complex is decorated by additional polymerase-specific factors that account for functional differences in promoter recognition and opening, and gene class-specific regulation. This review outlines the similarities and differences between these important molecular machines.

Publication types

  • Review

MeSH terms

  • Conserved Sequence
  • Models, Molecular
  • Protein Structure, Quaternary
  • Protein Structure, Tertiary
  • RNA Polymerase I / chemistry
  • RNA Polymerase I / metabolism*
  • RNA Polymerase I / physiology
  • RNA Polymerase II / chemistry
  • RNA Polymerase II / metabolism*
  • RNA Polymerase II / physiology
  • RNA Polymerase III / chemistry
  • RNA Polymerase III / metabolism*
  • RNA Polymerase III / physiology
  • TATA-Box Binding Protein / chemistry
  • TATA-Box Binding Protein / physiology
  • Transcription Factor TFIIB / chemistry
  • Transcription Factor TFIIB / physiology
  • Transcription Factors, TFII / chemistry
  • Transcription Factors, TFII / physiology
  • Transcription, Genetic*


  • TATA-Box Binding Protein
  • Transcription Factor TFIIB
  • Transcription Factors, TFII
  • transcription factor TFIIE
  • RNA Polymerase II
  • RNA Polymerase I
  • RNA Polymerase III
  • transcription factor TFIIF