Covalent modification of DNA regulates memory formation

Neuron. 2007 Mar 15;53(6):857-69. doi: 10.1016/j.neuron.2007.02.022.


DNA methylation is a covalent chemical modification of DNA catalyzed by DNA methyltransferases (DNMTs). DNA methylation is associated with transcriptional silencing and has been studied extensively as a lifelong molecular information storage mechanism put in place during development. Here we report that DNMT gene expression is upregulated in the adult rat hippocampus following contextual fear conditioning and that DNMT inhibition blocks memory formation. In addition, fear conditioning is associated with rapid methylation and transcriptional silencing of the memory suppressor gene PP1 and demethylation and transcriptional activation of the synaptic plasticity gene reelin, indicating both methyltransferase and demethylase activity during consolidation. DNMT inhibition prevents the PP1 methylation increase, resulting in aberrant transcription of the gene during the memory-consolidation period. These results demonstrate that DNA methylation is dynamically regulated in the adult nervous system and that this cellular mechanism is a crucial step in memory formation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Azacitidine / analogs & derivatives
  • Azacitidine / pharmacology
  • Behavior, Animal
  • Cell Adhesion Molecules, Neuronal / genetics
  • Cell Adhesion Molecules, Neuronal / metabolism
  • Conditioning, Classical / physiology
  • DNA (Cytosine-5-)-Methyltransferases / genetics
  • DNA (Cytosine-5-)-Methyltransferases / metabolism
  • DNA / physiology*
  • DNA Methylation* / drug effects
  • Decitabine
  • Enzyme Inhibitors / pharmacology
  • Extracellular Matrix Proteins / genetics
  • Extracellular Matrix Proteins / metabolism
  • Fear
  • Gene Expression Regulation, Enzymologic / drug effects
  • Gene Expression Regulation, Enzymologic / physiology*
  • Hippocampus / drug effects
  • Hippocampus / physiology
  • Male
  • Memory / drug effects
  • Memory / physiology*
  • Models, Biological
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Phosphoprotein Phosphatases / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Reverse Transcriptase Polymerase Chain Reaction / methods
  • Serine Endopeptidases / genetics
  • Serine Endopeptidases / metabolism


  • Cell Adhesion Molecules, Neuronal
  • Enzyme Inhibitors
  • Extracellular Matrix Proteins
  • Nerve Tissue Proteins
  • Decitabine
  • DNA
  • DNA (Cytosine-5-)-Methyltransferases
  • Phosphoprotein Phosphatases
  • Serine Endopeptidases
  • reelin protein
  • Azacitidine