The Histone Chaperone Asf1p Mediates Global Chromatin Disassembly in Vivo

J Biol Chem. 2004 Dec 10;279(50):52069-74. doi: 10.1074/jbc.M406113200. Epub 2004 Sep 26.

Abstract

The packaging of the eukaryotic genome into chromatin is likely to be mediated by chromatin assembly factors, including histone chaperones. We investigated the function of the histone H3/H4 chaperones anti-silencing function 1 (Asf1p) and chromatin assembly factor 1 (CAF-1) in vivo. Analysis of chromatin structure by accessibility to micrococcal nuclease and DNase I digestion demonstrated that the chromatin from CAF-1 mutant yeast has increased accessibility to these enzymes. In agreement, the supercoiling of the endogenous 2mu plasmid is reduced in yeast lacking CAF-1. These results indicate that CAF-1 mutant yeast globally under-assemble their genome into chromatin, consistent with a role for CAF-1 in chromatin assembly in vivo. By contrast, asf1 mutants globally over-assemble their genome into chromatin, as suggested by decreased accessibility of their chromatin to micrococcal nuclease and DNase I digestion and increased supercoiling of the endogenous 2mu plasmid. Deletion of ASF1 causes a striking loss of acetylation on histone H3 lysine 9, but this is not responsible for the altered chromatin structure in asf1 mutants. These data indicate that Asf1p may have a global role in chromatin disassembly and an unexpected role in histone acetylation in vivo.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetylation
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Chromatin / metabolism*
  • Chromatin Assembly Factor-1
  • Chromosomal Proteins, Non-Histone / genetics
  • Chromosomal Proteins, Non-Histone / metabolism
  • DNA, Fungal / genetics
  • DNA, Fungal / metabolism
  • DNA, Superhelical / genetics
  • DNA, Superhelical / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Deoxyribonuclease I / metabolism
  • Genes, Fungal
  • Histones / chemistry
  • Histones / genetics
  • Histones / metabolism*
  • Micrococcal Nuclease / metabolism
  • Molecular Chaperones / genetics
  • Molecular Chaperones / metabolism*
  • Mutation
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*

Substances

  • ASF1 protein, S cerevisiae
  • Cell Cycle Proteins
  • Chromatin
  • Chromatin Assembly Factor-1
  • Chromosomal Proteins, Non-Histone
  • DNA, Fungal
  • DNA, Superhelical
  • DNA-Binding Proteins
  • Histones
  • Molecular Chaperones
  • Recombinant Proteins
  • Saccharomyces cerevisiae Proteins
  • Deoxyribonuclease I
  • Micrococcal Nuclease