6asd | pdb_00006asd
Zinc finger region of human TET1 in complex with CpG DNA
Structural highlights
DiseaseTET1_HUMAN A chromosomal aberration involving TET1 may be a cause of acute leukemias (PubMed:12646957). Translocation t(10;11)(q22;q23) with KMT2A/MLL1. This is a rare chromosomal translocation 5' KMT2A/MLL1-TET1 3' (PubMed:12124344, PubMed:12646957).[1] [2] FunctionTET1_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, plays a more general role in chromatin regulation. Preferentially binds to CpG-rich sequences at promoters of both transcriptionally active and Polycomb-repressed genes. 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. Also involved in transcription repression of a subset of genes through recruitment of transcriptional repressors to promoters. Involved in the balance between pluripotency and lineage commitment of cells it plays a role in embryonic stem cells maintenance and inner cell mass cell specification. Plays an important role in the tumorigenicity of glioblastoma cells. TET1-mediated production of 5hmC acts as a recruitment signal for the CHTOP-methylosome complex to selective sites on the chromosome, where it methylates H4R3 and activates the transcription of genes involved in glioblastomagenesis (PubMed:25284789).[3] [4] [5] [6] [7] [8] Publication Abstract from PubMedThe CXXC domain, first identified as the reader of unmodified CpG dinucleotide, plays important roles in epigenetic regulation by targeting various activities to CpG islands. Here we systematically measured and compared the DNA-binding selectivities of all known human CXXC domains by different binding assays, and complemented the existing function-based classification of human CXXC domains with a classification based on their DNA selectivities. Through a series of crystal structures of CXXC domains with DNA ligands, we unravel the molecular mechanisms of how these CXXC domains, including single CXXC domains and tandem CXXC-PHD domains, recognize distinct DNA ligands, which further supports our classification of human CXXC domains and also provides insights into selective recruitment of chromatin modifiers to their respective targets via CXXC domains recognizing different genomic DNA sequences. Our study facilitates the understanding of the relationship between the DNA-binding specificities of the CXXC proteins and their biological functions. DNA Sequence Recognition of Human CXXC Domains and Their Structural Determinants.,Xu C, Liu K, Lei M, Yang A, Li Y, Hughes TR, Min J Structure. 2017 Dec 16. pii: S0969-2126(17)30396-9. doi:, 10.1016/j.str.2017.11.022. PMID:29276034[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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