Role of the RNA Polymerase Alpha Subunit in Transcription Activation

Mol Microbiol. 1992 Nov;6(22):3283-8. doi: 10.1111/j.1365-2958.1992.tb02196.x.


The N-terminal two-thirds of the alpha subunit of Escherichia coli RNA polymerase plays an essential role in the initiation of subunit assembly, by gathering two large subunits, beta and beta', together into a core-enzyme complex. One group of RNA polymerase mutants deficient in response to transcription activation carries mutations in the C-terminal region of the alpha subunit, indicating that the C-terminal region of the alpha subunit is involved in protein-protein contact in positive control of transcription. A set of activators (class I transcription factors) which make contact with this contact site I region on RNA polymerase alpha subunit bind in most cases to DNA upstream of the promoter -35 signal. Genetic fine mapping indicates that a cluster of subsites exists in the contact site I region, each interacting with a set of the class I factors and each consisting of a structure formed by only 5-10 amino acid residues.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Bacterial Proteins / metabolism*
  • Binding Sites
  • DNA, Bacterial / metabolism
  • Escherichia coli / genetics*
  • Promoter Regions, Genetic
  • Protein Conformation
  • RNA Polymerase I / chemistry
  • RNA Polymerase I / physiology*
  • Regulatory Sequences, Nucleic Acid
  • Transcription Factors / metabolism
  • Transcription, Genetic*


  • Bacterial Proteins
  • DNA, Bacterial
  • Transcription Factors
  • RNA Polymerase I