title: Oligomerization of DNMT3A controls the mechanism of de novo DNA methylation.
abstract: DNMT3A is one of two human de novo DNA methyltransferases essential for regulating gene expression through cellular development and differentiation. Here we describe the consequences of single amino acid mutations, including those implicated in the development of acute myeloid leukemia (AML) and myelodysplastic syndromes, at the DNMT3A·DNMT3A homotetramer and DNMT3A·DNMT3L heterotetramer interfaces. A model for the DNMT3A homotetramer was developed via computational interface scanning and tested using light scattering and electrophoretic mobility shift assays. Distinct oligomeric states were functionally characterized using fluorescence anisotropy and steady-state kinetics. Replacement of residues that result in DNMT3A dimers, including those identified in AML patients, show minor changes in methylation activity but lose the capacity for processive catalysis on multisite DNA substrates, unlike the highly processive wild-type enzyme. Our results are consistent with the bimodal distribution of DNA methylation in vivo and the loss of clustered methylation in AML patients. Tetramerization with the known interacting partner DNMT3L rescues processive catalysis, demonstrating that protein binding at the DNMT3A tetramer interface can modulate methylation patterning. Our results provide a structural mechanism for the regulation of DNMT3A activity and epigenetic imprinting.
authors: Interdepartmental Program in Biomolecular Science & Engineering, University of California, Santa Barbara, California 93106-9510.
authors: Celeste
authors: C
authors: Holz-Schietinger
authors: Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106-9510.
authors: Douglas M
authors: DM
authors: Matje
authors: Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106-9510.
authors: Madeleine Flexer
authors: MF
authors: Harrison
authors: Interdepartmental Program in Biomolecular Science & Engineering, University of California, Santa Barbara, California 93106-9510; Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106-9510. Electronic address: reich@chem.ucsb.edu.
authors: Norbert O
authors: NO
authors: Reich
mesh_terms: D004248:DNA (Cytosine-5-)-Methyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D000090205:DNA Methyltransferase 3A; D004273:DNA, Neoplasm / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000235:genetics / Q000378:metabolism*; D054802:Molecular Imprinting; D009190:Myelodysplastic Syndromes / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D013329:Structure-Activity Relationship
chemical_list: D004273:DNA, Neoplasm; C000717967:DNMT3A protein, human; D009363:Neoplasm Proteins; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A