The FUSE/FBP/FIR/TFIIH system is a molecular machine programming a pulse of c-myc expression

EMBO J. 2006 May 17;25(10):2119-30. doi: 10.1038/sj.emboj.7601101. Epub 2006 Apr 20.

Abstract

FarUpStream Element (FUSE) Binding Protein (FBP) binds the human c-myc FUSE in vitro only in single-stranded or supercoiled DNA. Because transcriptionally generated torsion melts FUSE in vitro even in linear DNA, and FBP/FBP Interacting Repressor (FIR) regulates transcription through TFIIH, these components have been speculated to be the mechanosensor (FUSE) and effectors (FBP/FIR) of a real-time mechanism controlling c-myc transcription. To ascertain whether the FUSE/FBP/FIR system operates according to this hypothesis in vivo, the flux of activators, repressors and chromatin remodeling complexes on the c-myc promoter was monitored throughout the serum-induced pulse of transcription. After transcription was switched on by conventional factors and chromatin regulators, FBP and FIR were recruited and established a dynamically remodeled loop with TFIIH at the P2 promoter. In XPB cells carrying mutant TFIIH, loop formation failed and the serum response was abnormal; RNAi depletion of FIR similarly disabled c-myc regulation. Engineering FUSE into episomal vectors predictably re-programmed metallothionein-promoter-driven reporter expression. The in vitro recruitment of FBP and FIR to dynamically stressed c-myc DNA paralleled the in vivo process.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Chromatin / chemistry
  • Chromatin / metabolism
  • DNA, Superhelical / chemistry
  • DNA, Superhelical / metabolism
  • Gene Expression Regulation*
  • Genes, Reporter
  • Humans
  • Metallothionein / genetics
  • Metallothionein / metabolism
  • Nucleic Acid Conformation
  • Promoter Regions, Genetic
  • Protein Binding
  • Proto-Oncogene Proteins c-myc / genetics
  • Proto-Oncogene Proteins c-myc / metabolism*
  • RNA Interference
  • RNA Splicing Factors
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Transcription Factor TFIIH / genetics
  • Transcription Factor TFIIH / metabolism*
  • Transcription, Genetic

Substances

  • Chromatin
  • DNA, Superhelical
  • MT2A protein, human
  • MYC protein, human
  • Proto-Oncogene Proteins c-myc
  • RNA Splicing Factors
  • RNA-Binding Proteins
  • Repressor Proteins
  • Trans-Activators
  • poly-U binding splicing factor 60KDa
  • Transcription Factor TFIIH
  • Metallothionein