HP1 is essential for DNA methylation in neurospora

Mol Cell. 2004 Feb 13;13(3):427-34. doi: 10.1016/s1097-2765(04)00024-3.

Abstract

Methylation of cytosines silences transposable elements and selected cellular genes in mammals, plants, and some fungi. Recent findings have revealed mechanistic connections between DNA methylation and features of specialized condensed chromatin, "heterochromatin." In Neurospora crassa, DNA methylation depends on trimethylation of Lys9 in histone H3 by DIM-5. Heterochromatin protein HP1 binds methylated Lys9 in vitro. We therefore investigated the possibility that a Neurospora HP1 homolog reads the methyl-Lys9 mark to signal DNA methylation. We identified an HP1 homolog and showed that it is essential for DNA methylation, is localized to heterochromatic foci, and that this localization is dependent on the catalytic activity of DIM-5. We conclude that HP1 serves as an adaptor between methylated H3 Lys9 and the DNA methylation machinery. Unlike mutants that lack DNA methyltransferase, mutants with defects in the HP1 gene hpo exhibit severe growth defects, suggesting that HP1 is required for processes besides DNA methylation.

Publication types

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

MeSH terms

  • Catalytic Domain / genetics
  • Chromosomal Proteins, Non-Histone / genetics
  • Chromosomal Proteins, Non-Histone / isolation & purification
  • Chromosomal Proteins, Non-Histone / metabolism*
  • DNA / metabolism
  • DNA Methylation*
  • DNA, Complementary / analysis
  • DNA, Complementary / genetics
  • Fungal Proteins / genetics
  • Fungal Proteins / isolation & purification
  • Fungal Proteins / metabolism*
  • Heterochromatin / genetics
  • Histone Methyltransferases
  • Histone-Lysine N-Methyltransferase*
  • Lysine / metabolism
  • Methyltransferases / genetics
  • Molecular Sequence Data
  • Neurospora crassa / enzymology*
  • Neurospora crassa / genetics
  • Protein Methyltransferases
  • Sequence Homology, Amino Acid
  • Sequence Homology, Nucleic Acid

Substances

  • Chromosomal Proteins, Non-Histone
  • DNA, Complementary
  • Fungal Proteins
  • Heterochromatin
  • heterochromatin-specific nonhistone chromosomal protein HP-1
  • DNA
  • Histone Methyltransferases
  • Methyltransferases
  • Protein Methyltransferases
  • Histone-Lysine N-Methyltransferase
  • Lysine

Associated data

  • GENBANK/AY363166
  • GENBANK/AY363167
  • GENBANK/AY363168
  • GENBANK/AY363169
  • GENBANK/AY363170