Acetylation of novel sites in the nucleosomal binding domain of chromosomal protein HMG-14 by p300 alters its interaction with nucleosomes

J Biol Chem. 2000 Apr 14;275(15):11514-20. doi: 10.1074/jbc.275.15.11514.

Abstract

The reversible acetylation of histones is associated with structural alterations in the chromatin fiber that affect various DNA-related activities. Here we show that the histone acetyltransferase p300 specifically acetylates HMG-14, a nonhistone structural protein that binds to nucleosomes and reduces the compactness of the chromatin fiber. We identify 7 major acetylation sites, 6 of which are novel and have not been known to be acetylated in either HMG-14 or the closely related HMG-17 protein. All the acetylation sites involve evolutionarily conserved residues: 3 within the HMG-14/-17 nucleosomal binding domain and 4 in or near the bipartite nuclear localization domains of the proteins. In tissue culture cells the acetylation pattern is indicative of a selective process in which a subfraction of HMG-14 is preferentially acetylated. We find that the nucleosomal binding domain is a major target for acetylation in vivo and that the specific acetylation of HMG-14 by p300 weakens its interaction with nucleosome cores. Our results suggest that p300 modulates the interaction of HMG-14 with nucleosomes. Thus, p300 may affect chromatin-related activities not only by modifying histones or transcription factors but also by targeting structural nonhistone proteins.

MeSH terms

  • Acetylation
  • Binding Sites
  • DNA-Binding Proteins / physiology
  • HeLa Cells
  • High Mobility Group Proteins / metabolism*
  • Humans
  • Nucleosomes / metabolism*
  • Trans-Activators / physiology*
  • Transcription Factors / physiology

Substances

  • DNA-Binding Proteins
  • High Mobility Group Proteins
  • Nucleosomes
  • Trans-Activators
  • Transcription Factors