High-frequency promoter firing links THO complex function to heavy chromatin formation

Cell Rep. 2013 Nov 27;5(4):1082-94. doi: 10.1016/j.celrep.2013.10.013. Epub 2013 Nov 7.


The THO complex is involved in transcription, genome stability, and messenger ribonucleoprotein (mRNP) formation, but its precise molecular function remains enigmatic. Under heat shock conditions, THO mutants accumulate large protein-DNA complexes that alter the chromatin density of target genes (heavy chromatin), defining a specific biochemical facet of THO function and a powerful tool of analysis. Here, we show that heavy chromatin distribution is dictated by gene boundaries and that the gene promoter is necessary and sufficient to convey THO sensitivity in these conditions. Single-molecule fluorescence in situ hybridization measurements show that heavy chromatin formation correlates with an unusually high firing pace of the promoter with more than 20 transcription events per minute. Heavy chromatin formation closely follows the modulation of promoter firing and strongly correlates with polymerase occupancy genome wide. We propose that the THO complex is required for tuning the dynamic of gene-nuclear pore association and mRNP release to the same high pace of transcription initiation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatin / genetics*
  • DNA-Binding Proteins / genetics*
  • Gene Expression Regulation, Fungal*
  • Heat-Shock Proteins / biosynthesis
  • Heat-Shock Proteins / genetics
  • Heat-Shock Response / genetics
  • Nuclear Pore / genetics*
  • Nuclear Proteins / genetics*
  • Promoter Regions, Genetic*
  • Ribonucleoproteins / genetics*
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae Proteins / biosynthesis
  • Saccharomyces cerevisiae Proteins / genetics*
  • Transcription Factors / genetics*
  • Transcription, Genetic


  • Chromatin
  • DNA-Binding Proteins
  • HPR1 protein, S cerevisiae
  • Heat-Shock Proteins
  • Nuclear Proteins
  • Ribonucleoproteins
  • Saccharomyces cerevisiae Proteins
  • THO2 protein, S cerevisiae
  • Thp2 protein, S cerevisiae
  • Transcription Factors
  • messenger ribonucleoprotein
  • MFT1 protein, S cerevisiae
  • HsP104 protein, S cerevisiae

Associated data

  • GEO/GSE32980