Somatic mutations in DNMT3A, which encodes a de novo DNA methyltransferase, are found in ∼30% of normal karyotype acute myeloid leukemia (AML) cases. Most mutations are heterozygous and alter R882 within the catalytic domain (most commonly R882H), suggesting the possibility of dominant-negative consequences. The methyltransferase activity of R882H DNMT3A is reduced by ∼80% compared with the WT enzyme. In vitro mixing of WT and R882H DNMT3A does not affect the WT activity, but coexpression of the two proteins in cells profoundly inhibits the WT enzyme by disrupting its ability to homotetramerize. AML cells with the R882H mutation have severely reduced de novo methyltransferase activity and focal hypomethylation at specific CpGs throughout AML cell genomes.
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http://dx.doi.org/10.1016/j.ccr.2014.02.010 | DOI Listing |
bioRxiv
October 2024
Department of Medicine, Division of Hematology, Cancer Institute, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University; Stanford, CA, 94305, USA.
Leukemia
November 2024
Centre for Hemato-Oncology, Barts Cancer Institute, Queen Mary University of London, London, UK.
Clonal hematopoiesis (CH) is nearly universal in the elderly. The molecular and cellular mechanisms driving CH and the clinical consequences of carrying clonally derived mutant mature blood cells are poorly understood. We recently identified a C223Y mutation in the extracellular domain (ECD) of NOTCH3 as a putative CH driver in mice.
View Article and Find Full Text PDFHematol Rep
May 2024
Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, SK S7N 5A2, Canada.
Viral infections, including those caused by COVID-19, can produce striking morphologic changes in peripheral blood. Distinguishing between reactive changes and abnormal morphology of monocytes remains particularly difficult, with low consensus rates reported amongst hematopathologists. Here, we report a patient who developed transient monocytosis of 11.
View Article and Find Full Text PDFCell
July 2024
Department of Basic and Translational Sciences, Laboratory of Innate Immunity and Inflammation, Penn Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address:
Clonal hematopoiesis of indeterminate potential (CHIP) arises from aging-associated acquired mutations in hematopoietic progenitors, which display clonal expansion and produce phenotypically altered leukocytes. We associated CHIP-DNMT3A mutations with a higher prevalence of periodontitis and gingival inflammation among 4,946 community-dwelling adults. To model DNMT3A-driven CHIP, we used mice with the heterozygous loss-of-function mutation R878H, equivalent to the human hotspot mutation R882H.
View Article and Find Full Text PDFBiomed Res Int
May 2024
Regenerative Medicine, Organ Procurement and Transplantation Multi-Disciplinary Center, Razi Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran.
Epigenetic alterations have been observed in many hematological malignancies, including acute myeloid leukemia (AML). Many of these alterations result from mutations in DNA methyl transferase (DNMT) enzymes, disabling them to methylate target genes in a proper way. In this case-control study, we investigated the association between R882H mutation in gene and gene methylation in patients with AML.
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