7ne6
From Proteopedia
Human TET2 in complex with unfavourable DNA substrate.
Structural highlights
DiseaseTET2_HUMAN Refractory anemia;Polycythemia vera;Acute myeloid leukemia with multilineage dysplasia;Essential thrombocythemia;Myelofibrosis with myeloid metaplasia;Refractory anemia with excess blasts;Acquired idiopathic sideroblastic anemia. TET2 is frequently mutated in myeloproliferative disorders (MPD). These constitute a heterogeneous group of disorders, also known as myeloproliferative diseases or myeloproliferative neoplasms (MPN), characterized by cellular proliferation of one or more hematologic cell lines in the peripheral blood, distinct from acute leukemia. Included diseases are: essential thrombocythemia, polycythemia vera, primary myelofibrosis (chronic idiopathic myelofibrosis). Bone marrow samples from patients display uniformly low levels of hmC in genomic DNA compared to bone marrow samples from healthy controls as well as hypomethylation relative to controls at the majority of differentially methylated CpG sites. The disease is caused by mutations affecting the gene represented in this entry. TET2 is frequently mutated in systemic mastocytosis; also known as systemic mast cell disease. A condition with features in common with myeloproliferative diseases. It is a clonal disorder of the mast cell and its precursor cells. The clinical symptoms and signs of systemic mastocytosis are due to accumulation of clonally derived mast cells in different tissues, including bone marrow, skin, the gastrointestinal tract, the liver, and the spleen. The disease is caused by mutations affecting the gene represented in this entry. Bone marrow samples from patients display uniformly low levels of hmC in genomic DNA compared to bone marrow samples from healthy controls as well as hypomethylation relative to controls at the majority of differentially methylated CpG sites. FunctionTET2_HUMAN Dioxygenase that catalyzes the conversion of the modified genomic base 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC) and plays a key role in active DNA demethylation. Also mediates subsequent conversion of 5hmC into 5-formylcytosine (5fC), and conversion of 5fC to 5-carboxylcytosine (5caC). Conversion of 5mC into 5hmC, 5fC and 5caC probably constitutes the first step in cytosine demethylation. Methylation at the C5 position of cytosine bases is an epigenetic modification of the mammalian genome which plays an important role in transcriptional regulation. In addition to its role in DNA demethylation, also involved in the recruitment of the O-GlcNAc transferase OGT to CpG-rich transcription start sites of active genes, thereby promoting histone H2B GlcNAcylation by OGT.[1] [2] [3] [4] [5] Publication Abstract from PubMedTET (ten-eleven translocation) enzymes catalyze the oxidation of 5-methylcytosine bases in DNA, thus driving active and passive DNA demethylation. Here, we report that the catalytic domain of mammalian TET enzymes favor CGs embedded within basic helix-loop-helix and basic leucine zipper domain transcription factor-binding sites, with up to 250-fold preference in vitro. Crystal structures and molecular dynamics calculations show that sequence preference is caused by intrasubstrate interactions and CG flanking sequence indirectly affecting enzyme conformation. TET sequence preferences are physiologically relevant as they explain the rates of DNA demethylation in TET-rescue experiments in culture and in vivo within the zygote and germ line. Most and least favorable TET motifs represent DNA sites that are bound by methylation-sensitive immediate-early transcription factors and octamer-binding transcription factor 4 (OCT4), respectively, illuminating TET function in transcriptional responses and pluripotency support. Pronounced sequence specificity of the TET enzyme catalytic domain guides its cellular function.,Ravichandran M, Rafalski D, Davies CI, Ortega-Recalde O, Nan X, Glanfield CR, Kotter A, Misztal K, Wang AH, Wojciechowski M, Razew M, Mayyas IM, Kardailsky O, Schwartz U, Zembrzycki K, Morison IM, Helm M, Weichenhan D, Jurkowska RZ, Krueger F, Plass C, Zacharias M, Bochtler M, Hore TA, Jurkowski TP Sci Adv. 2022 Sep 9;8(36):eabm2427. doi: 10.1126/sciadv.abm2427. Epub 2022 Sep 7. PMID:36070377[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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