Transcription factor exchange enables prolonged transcriptional bursts

Mol Cell. 2024 Mar 21;84(6):1036-1048.e9. doi: 10.1016/j.molcel.2024.01.020. Epub 2024 Feb 19.


Single-molecule imaging inside living cells has revealed that transcription factors (TFs) bind to DNA transiently, but a long-standing question is how this transient binding is related to transcription activation. Here, we devised a microscopy method to simultaneously measure transient TF binding at a single locus and the effect of these binding events on transcription. We show that DNA binding of the yeast TF Gal4 activates transcription of a target gene within a few seconds, with at least ∼20% efficiency and with a high initiation rate of ∼1 RNA/s. Gal4 DNA dissociation decreases transcription rapidly. Moreover, at a gene with multiple binding sites, individual Gal4 molecules only rarely stay bound throughout the entire burst but instead frequently exchange during a burst to increase the transcriptional burst duration. Our results suggest a mechanism for enhancer regulation in more complex eukaryotes, where TF cooperativity and exchange enable robust and responsive transcription regulation.

Keywords: DNA binding kinetics; cooperativity; single-molecule imaging; transcription factor; transcriptional bursting.

MeSH terms

  • Binding Sites
  • DNA / metabolism
  • Gene Expression Regulation*
  • Protein Binding
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Transcription Factors* / metabolism
  • Transcriptional Activation


  • Transcription Factors
  • DNA