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Arabidopsis DEMETER-LIKE proteins DML2 and DML3 are required for appropriate distribution of DNA methylation marks.

Plant Mol Biol. 2008 Aug;67(6):671-81. doi:10.1007/s11103-008-9346-0. Epub 2008 May 21
Ana Pilar Ortega-Galisteo 1 , Teresa Morales-Ruiz , Rafael R Ariza , Teresa Roldán-Arjona
Ana Pilar Ortega-Galisteo 1 , Teresa Morales-Ruiz , Rafael R Ariza , Teresa Roldán-Arjona

[No authors listed]

Author information
  • 1 Departamento de Genética, Universidad de Córdoba, Edificio Gregor Mendel, Campus de Rabanales s/n, 14071, Córdoba, Spain.

摘要


Cytosine DNA methylation is a stable epigenetic mark for maintenance of gene silencing across cellular divisions, but it is a reversible modification. Genetic and biochemical studies have revealed that the Arabidopsis DNA glycosylase domain-containing proteins (REPRESSOR OF SILENCING 1) and DME (DEMETER) initiate erasure of 5-methylcytosine through a base excision repair process. The Arabidopsis genome encodes two paralogs of duanyu16701 and DME, referred to as DEMETER-LIKE proteins DML2 and DML3. We have found that DML2 and DML3 are 5-methylcytosine DNA glycosylases that are expressed in a wide range of plant organs. We analyzed the distribution of methylation marks at two methylated loci in wild-type and dml mutant plants. Mutations in DML2 and/or DML3 lead to hypermethylation of cytosine residues that are unmethylated or weakly methylated in wild-type plants. In contrast, sites that are heavily methylated in wild-type plants are hypomethylated in mutants. These results suggest that DML2 and DML3 are required not only for removing DNA methylation marks from improperly-methylated cytosines, but also for maintenance of high methylation levels in properly targeted sites.