Arabidopsis cmt3 chromomethylase mutations block non-CG methylation and silencing of an endogenous gene

Genes Dev. 2001 Jul 15;15(14):1753-8. doi: 10.1101/gad.905701.

Abstract

Plants maintain cytosine methylation at CG and non-CG residues to control gene expression and genome stability. In a screen for Arabidopsis mutants that alter methylation and silencing of a densely methylated endogenous reporter gene, we recovered 11 loss-of-function alleles in the CMT3 chromomethylase gene. The cmt3 mutants displayed enhanced expression and reduced methylation of the reporter, particularly at non-CG cytosines. CNG methylation was also reduced at repetitive centromeric sequences. Thus, CMT3 is a key determinant for non-CG methylation. The lack of CMT homologs in animal genomes could account for the observation that in contrast to plants, animals maintain primarily CG methylation.

Publication types

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

MeSH terms

  • Aldose-Ketose Isomerases / genetics*
  • Amino Acid Sequence
  • Arabidopsis / genetics*
  • Arabidopsis Proteins*
  • DNA Methylation*
  • DNA-Cytosine Methylases / genetics*
  • Gene Silencing*
  • Genes, Reporter
  • Molecular Sequence Data
  • Mutation*
  • Phenotype
  • Selection, Genetic
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid

Substances

  • Arabidopsis Proteins
  • DNA-Cytosine Methylases
  • CMT3 protein, Arabidopsis
  • Aldose-Ketose Isomerases
  • phosphoribosylanthranilate isomerase