RNA polymerase III-specific general transcription factor IIIC contains a heterodimer resembling TFIIF Rap30/Rap74

Nucleic Acids Res. 2013 Oct;41(19):9183-96. doi: 10.1093/nar/gkt664. Epub 2013 Aug 5.

Abstract

Transcription of tRNA-encoding genes by RNA polymerase (Pol) III requires the six-subunit general transcription factor IIIC that uses subcomplexes τA and τB to recognize two gene-internal promoter elements named A- and B-box. The Schizosaccharomyces pombe τA subcomplex comprises subunits Sfc1, Sfc4 and Sfc7. The crystal structure of the Sfc1/Sfc7 heterodimer reveals similar domains and overall domain architecture to the Pol II-specific general transcription factor TFIIF Rap30/Rap74. The N-terminal Sfc1/Sfc7 dimerization module consists of a triple β-barrel similar to the N-terminal TFIIF Rap30/Rap74 dimerization module, whereas the C-terminal Sfc1 DNA-binding domain contains a winged-helix domain most similar to the TFIIF Rap30 C-terminal winged-helix domain. Sfc1 DNA-binding domain recognizes single and double-stranded DNA by an unknown mechanism. Several features observed for A-box recognition by τA resemble the recognition of promoters by bacterial RNA polymerase, where σ factor unfolds double-stranded DNA and stabilizes the non-coding DNA strand in an open conformation. Such a function has also been proposed for TFIIF, suggesting that the observed structural similarity between Sfc1/Sfc7 and TFIIF Rap30/Rap74 might also reflect similar functions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • DNA / metabolism
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Multimerization
  • Protein Structure, Tertiary
  • Schizosaccharomyces pombe Proteins / chemistry*
  • Schizosaccharomyces pombe Proteins / metabolism
  • Transcription Factors / chemistry*
  • Transcription Factors / metabolism
  • Transcription Factors, TFII / chemistry*
  • Transcription Factors, TFIII / chemistry*
  • Transcription Factors, TFIII / metabolism

Substances

  • Schizosaccharomyces pombe Proteins
  • Sfc1 protein, S pombe
  • Sfc7 protein, S pombe
  • Transcription Factors
  • Transcription Factors, TFII
  • Transcription Factors, TFIII
  • transcription factor TFIIIC
  • DNA
  • transcription factor TFIIF

Associated data

  • PDB/4BJI
  • PDB/4BJJ