title: Tet2 Catalyzes Stepwise 5-Methylcytosine Oxidation by an Iterative and de novo Mechanism.
abstract: Modification of cytosine-guanine dinucleotides (CpGs) is a key part of mammalian epigenetic regulation and helps shape cellular identity. Tet enzymes catalyze stepwise oxidation of 5-methylcytosine (mC) in CpGs to 5-hydroxymethylcytosine (hmC), or onward to 5-formylcytosine (fC) or 5-carboxylcytosine (caC). The multiple mC oxidation products, while intricately linked, are postulated to play independent epigenetic roles, making it critical to understand how the products of stepwise oxidation are established and maintained. Using highly sensitive isotope-based studies, we newly show that Tet2 can yield fC and caC by iteratively acting in a single encounter with mC-containing DNA, without release of the hmC intermediate, and that the modification state of the complementary CpG has little impact on Tet2 activity. By revealing Tet2 as an iterative, de novo mC oxygenase, our study provides insight into how features intrinsic to Tet2 shape the epigenetic landscape.
authors.affiliation: Department of Medicine, ‡Department of Biochemistry and Biophysics, and §Epigenetics Program, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Crawford
authors.affiliation: Department of Medicine, ‡Department of Biochemistry and Biophysics, and §Epigenetics Program, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Monica Yun
authors.initials: MY
authors.lastname: Liu
authors.affiliation: Department of Medicine, ‡Department of Biochemistry and Biophysics, and §Epigenetics Program, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Nabel
authors.affiliation: Department of Medicine, ‡Department of Biochemistry and Biophysics, and §Epigenetics Program, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Xing-Jun
authors.initials: XJ
authors.lastname: Cao
authors.affiliation: Department of Medicine, ‡Department of Biochemistry and Biophysics, and §Epigenetics Program, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Garcia
authors.affiliation: Department of Medicine, ‡Department of Biochemistry and Biophysics, and §Epigenetics Program, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Rahul M
authors.initials: RM
authors.lastname: Kohli
mesh_terms: D044503:5-Methylcytosine / Q000737:chemistry / Q000378:metabolism*; D055162:Biocatalysis; D049308:Dioxygenases / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D010084:Oxidation-Reduction
chemical_list: D044503:5-Methylcytosine; D049308:Dioxygenases