Selective recognition of acetylated histones by bromodomains in transcriptional co-activators

Ahmed H. Hassan, Salma Awad, Zeina Al-Natour, Samah Othman, Farah Mustafa, Tahir A. Rizvi

Research output: Contribution to journalArticlepeer-review

55 Citations (Scopus)


Bromodomains are present in many chromatin-associated proteins such as the SWI/SNF and RSC chromatin remodelling and the SAGA HAT (histone acetyltransferase) complexes, and can bind to acetylated lysine residues in the N-terminal tails of the histones. Lysine acetylation is a histone modification that forms a stable epigenetic mark on chromatin for bromodomain-containing proteins to dock and in turn regulate gene expression. In order to better understand how bromodomains read the 'histone code' and interact with acetylated histones, we have tested the interactions of several bromodomains within transcriptional coactivators with differentially acetylated histone tail peptides and HAT-acetylated histones. Using GST (glutathione S-transferase) pull-down assays, we show specificity of binding of some bromodomains to differentially acetylated H3 and H4 peptides as well as HAT-acetylated histones. Our results reveal that the Swi2/Snf2 bromodomain interacts with various acetylated H3 and H4 peptides, whereas the Gcn5 bromodomain interacts only with acetylated H3 peptides and tetra-acetylated H4 peptides. Additionally we show that the Spt7 bromodomain interacts with acetylated H3 peptides weakly, but not with acetylated H4 peptides. Some bromodomains such as the Bdf1-2 do not interact with most of the acetylated peptides tested. Results of the peptide experiments are confirmed with tests of interactions between these bromodomains and HAT-acetylated histones. Furthermore, we demonstrate that the Swi2/Snf2 bromodomain is important for the binding and the remodelling activity of the SWI/SNF complex on hyperacetylated nucleosomes. The selective recognition of the bromodomains observed in the present study accounts for the broad effects of bromodomain-containing proteins observed on binding to histones.

Original languageEnglish
Pages (from-to)125-133
Number of pages9
JournalBiochemical Journal
Issue number1
Publication statusPublished - Feb 15 2007


  • Acetylation
  • Bromodomain
  • Histone

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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