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

作者：Bartee L; Malagnac F; Bender J^*

来源：Genes & Development, 2001, 15(14): 1753-1758.

DOI：10.1101/gad.905701

• cytosine methyltransferase
• gene silencing
• Arabidopsis thaliana

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-CC cytosines. CNG methylation was also reduced at repetitive centromeric sequences. Thus, CMT3 is a key determinant for non-CC methylation. The lack of CMT homologs in animal genomes could account for the observation that in contrast to plants, animals maintain primarily CG methylation.

• 出版日期2001-7-15