title: Epigenetic regulation of intestinal stem cells by Tet1-mediated DNA hydroxymethylation.
abstract: Methylated cytosines are associated with gene silencing. The ten-eleven translocation (TET) hydroxylases, which oxidize methylated cytosines to 5-hydroxymethylcytosine (5hmC), are essential for cytosine demethylation. Gene silencing and activation are critical for intestinal stem cell (ISC) maintenance and differentiation, but the potential role of TET hydroxylases in these processes has not yet been examined. Here, we generated genome-wide maps of the 5hmC mark in ISCs and their differentiated progeny. Genes with high levels of hydroxymethylation in ISCs are strongly associated with Wnt signaling and developmental processes. We found Tet1 to be the most abundantly expressed Tet gene in ISCs; therefore, we analyzed intestinal development in Tet1-deficient mice and determined that these mice are growth-retarded, exhibit partial postnatal lethality, and have significantly reduced numbers of proliferative cells in the intestinal epithelium. In addition, the Tet1-deficient intestine displays reduced organoid-forming capacity. In the Tet1-deficient crypt, decreased expression of Wnt target genes such as Axin2 and Lgr5 correlates with lower 5hmC levels at their promoters. These data demonstrate that Tet1-mediated DNA hydroxymethylation plays a critical role in the epigenetic regulation of the Wnt pathway in intestinal stem and progenitor cells and consequently in the self-renewal of the intestinal epithelium.
authors.affiliation: Department of Genetics, Center for Molecular Studies in Digestive and Liver Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Rinho
authors.initials: R
authors.lastname: Kim
authors.affiliation: Department of Genetics, Center for Molecular Studies in Digestive and Liver Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Karyn L
authors.initials: KL
authors.lastname: Sheaffer
authors.affiliation: Department of Genetics, Center for Molecular Studies in Digestive and Liver Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Inchan
authors.initials: I
authors.lastname: Choi
authors.affiliation: Department of Genetics, Center for Molecular Studies in Digestive and Liver Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Kyoung-Jae
authors.initials: KJ
authors.lastname: Won
authors.affiliation: Department of Genetics, Center for Molecular Studies in Digestive and Liver Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Klaus H
authors.identifier: 0000-0002-1228-021X
authors.initials: KH
authors.lastname: Kaestner
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D044127:Epigenesis, Genetic; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D007422:Intestines / Q000166:cytology / Q000254:growth & development*; D051379:Mice; D008810:Mice, Inbred C57BL; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000235:genetics; D017384:Sequence Deletion; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D060449:Wnt Signaling Pathway / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; C493597:Lgr5 protein, mouse; D011518:Proto-Oncogene Proteins; D043562:Receptors, G-Protein-Coupled; C540839:TET1 protein, mouse
keywords: Tet1; epigenomics; hydroxymethylation; intestinal differentiation; intestinal stem cell