Divergent human remodeling complexes remove nucleosomes from strong positioning sequences

Nucleic Acids Res. 2010 Jan;38(2):400-13. doi: 10.1093/nar/gkp1030. Epub 2009 Nov 11.

Abstract

Nucleosome positioning plays a major role in controlling the accessibility of DNA to transcription factors and other nuclear processes. Nucleosome positions after assembly are at least partially determined by the relative affinity of DNA sequences for the histone octamer. Nucleosomes can be moved, however, by a class of ATP dependent chromatin remodeling complexes. We recently showed that the human SWI/SNF remodeling complex moves nucleosomes in a sequence specific manner, away from nucleosome positioning sequences (NPSes). Here, we compare the repositioning specificity of five remodelers of diverse biological functions (hSWI/SNF, the SNF2h ATPase and the hACF, CHRAC and WICH complexes than each contain SNF2h) on 5S rDNA, MMTV and 601 NPS polynucleosomal templates. We find that all five remodelers act similarly to reduce nucleosome occupancy over the strongest NPSes, an effect that could directly contribute to the function of WICH in activating 5S rDNA transcription. While some differences were observed between complexes, all five remodelers were found to result in surprisingly similar nucleosome distributions. This suggests that remodeling complexes may share a conserved repositioning specificity, and that their divergent biological functions may largely arise from other properties conferred by complex-specific subunits.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / metabolism*
  • Chromatin Assembly and Disassembly*
  • Chromosomal Proteins, Non-Histone / metabolism*
  • DNA-Binding Proteins / metabolism
  • Humans
  • Mammary Tumor Virus, Mouse
  • Nucleoproteins / metabolism
  • Nucleosomes / metabolism*
  • Promoter Regions, Genetic
  • Protein Subunits / metabolism
  • RNA, Ribosomal, 5S / genetics
  • Transcription Factors / metabolism

Substances

  • BAZ1A protein, human
  • BAZ1B protein, human
  • Chromosomal Proteins, Non-Histone
  • DNA-Binding Proteins
  • Nucleoproteins
  • Nucleosomes
  • Protein Subunits
  • RNA, Ribosomal, 5S
  • Transcription Factors
  • Adenosine Triphosphatases
  • SMARCA5 protein, human