Loss of genomic methylation causes p53-dependent apoptosis and epigenetic deregulation

Nat Genet. 2001 Jan;27(1):31-9. doi: 10.1038/83730.

Abstract

Cytosine methylation of mammalian DNA is essential for the proper epigenetic regulation of gene expression and maintenance of genomic integrity. To define the mechanism through which demethylated cells die, and to establish a paradigm for identifying genes regulated by DNA methylation, we have generated mice with a conditional allele for the maintenance DNA methyltransferase gene Dnmt1. Cre-mediated deletion of Dnmt1 causes demethylation of cultured fibroblasts and a uniform p53-dependent cell death. Mutational inactivation of Trp53 partially rescues the demethylated fibroblasts for up to five population doublings in culture. Oligonucleotide microarray analysis showed that up to 10% of genes are aberrantly expressed in demethylated fibroblasts. Our results demonstrate that loss of Dnmt1 causes cell-type-specific changes in gene expression that impinge on several pathways, including expression of imprinted genes, cell-cycle control, growth factor/receptor signal transduction and mobilization of retroelements.

Publication types

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

MeSH terms

  • Alleles
  • Animals
  • Apoptosis*
  • Attachment Sites, Microbiological / genetics
  • Cell Division
  • Cell Line, Transformed
  • Cells, Cultured
  • DNA (Cytosine-5-)-Methyltransferase 1
  • DNA (Cytosine-5-)-Methyltransferases / genetics
  • DNA (Cytosine-5-)-Methyltransferases / metabolism
  • DNA Methylation*
  • Evolution, Molecular
  • Fibroblasts
  • Gene Deletion
  • Gene Expression Profiling
  • Gene Expression Regulation*
  • Genes, Intracisternal A-Particle / genetics
  • Genome*
  • Genomic Imprinting*
  • Integrases / genetics
  • Integrases / metabolism
  • Mice
  • Oligonucleotide Array Sequence Analysis
  • RNA, Messenger / analysis
  • RNA, Messenger / genetics
  • Recombination, Genetic / genetics
  • Stem Cells / enzymology
  • Stem Cells / metabolism
  • Tumor Suppressor Protein p53 / metabolism*
  • Viral Proteins*

Substances

  • RNA, Messenger
  • Tumor Suppressor Protein p53
  • Viral Proteins
  • DNA (Cytosine-5-)-Methyltransferase 1
  • DNA (Cytosine-5-)-Methyltransferases
  • Dnmt1 protein, mouse
  • Cre recombinase
  • Integrases