A DNMT3A mutation common in AML exhibits dominant-negative effects in murine ES cells

Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, United States
Blood (Impact Factor: 10.45). 10/2013; 122(25). DOI: 10.1182/blood-2013-02-483487
Source: PubMed


Somatic heterozygous mutations of the DNA methyltransferase gene DNMT3A occur frequently in acute myeloid leukemia and other hematological malignancies, with the majority (~60%) of mutations affecting a single amino acid, Arg882 (R882), in the catalytic domain. While the mutations impair DNMT3A catalytic activity in vitro, their effects on DNA methylation in cells have not been explored. Here, we show that exogenously expressed mouse Dnmt3a proteins harboring the corresponding R878 mutations largely fail to mediate DNA methylation in murine embryonic stem (ES) cells, but are capable of interacting with wild-type Dnmt3a and Dnmt3b. Co-expression of the Dnmt3a R878H (histidine) mutant protein results in inhibition of the ability of wild-type Dnmt3a and Dnmt3b to methylate DNA in murine ES cells. Furthermore, expression of Dnmt3a R878H in ES cells containing endogenous Dnmt3a or Dnmt3b induces hypomethylation. These results suggest that the DNMT3A R882 mutations, in addition to being hypomorphic, have dominant-negative effects.

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Available from: Anup Kumar Singh, Aug 26, 2015
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    • "This leads to a several fold drop down in its activity as a processive CpG methylase [30]. However, DNMT3A R882 mutations are not just hypomorphic and they seem to exert also dominant negative effect as the expression of the analogous mouse DNMT3A R878H mutations in embryonic stem (ES) cells containing endogenous DNMT3A or DNMT3B caused hypomethylation [31]. Xu et al. [32] just showed that the transplantation of hematopoietic stem cells (HSCs) transduced retrovirally with R882H mutant and transplanted to immunodeficient mice caused CMML disease with characteristic hypomethylation patterns. "
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