A stable complex of a novel transcription factor IIB- related factor, human TFIIIB50, and associated proteins mediate selective transcription by RNA polymerase III of genes with upstream promoter elements

Proc Natl Acad Sci U S A. 2000 Dec 19;97(26):14200-5. doi: 10.1073/pnas.97.26.14200.

Abstract

Transcription factor IIIB (TFIIIB) is directly involved in transcription initiation by RNA polymerase III in eukaryotes. Yeast contain a single TFIIIB activity that is comprised of the TATA-binding protein (TBP), TFIIB-related factor 1 (BRF1), and TFIIIB", whereas two distinct TFIIIB activities, TFIIIB-alpha and TFIIIB-beta, have been described in human cells. Human TFIIIB-beta is required for transcription of genes with internal promoter elements, and contains TBP, a TFIIIB" homologue (TFIIIB150), and a BRF1 homologue (TFIIIB90), whereas TFIIIB-alpha is required for transcription of genes with promoter elements upstream of the initiation site. Here we describe the identification, cloning, and characterization of TFIIIB50, a novel homologue of TFIIB and TFIIIB90. TFIIIB50 and tightly associated factors, along with TBP and TFIIIB150, reconstitute human TFIIIB-alpha activity. Thus, higher eukaryotes, in contrast to the yeast Saccharomyces cerevisiae, have evolved two distinct TFIIB-related factors that mediate promoter selectivity by RNA polymerase III.

Publication types

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

MeSH terms

  • Base Sequence
  • Cell Fractionation
  • DNA, Complementary
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Promoter Regions, Genetic*
  • RNA Polymerase III / metabolism*
  • Saccharomyces cerevisiae Proteins
  • TATA-Binding Protein Associated Factors*
  • Transcription Factor TFIIB
  • Transcription Factor TFIIIB
  • Transcription Factors / immunology
  • Transcription Factors / metabolism*
  • Transcription, Genetic

Substances

  • BRF1 protein, S cerevisiae
  • BRF1 protein, human
  • DNA, Complementary
  • Saccharomyces cerevisiae Proteins
  • TATA-Binding Protein Associated Factors
  • Transcription Factor TFIIB
  • Transcription Factor TFIIIB
  • Transcription Factors
  • RNA Polymerase III

Associated data

  • GENBANK/AF206673