Project description:Ten-eleven translocation (Tet) enzymes (Tet1/2/3) mediate 5-methylcytosine (5mC) hydroxylation, which can facilitate DNA demethylation and thereby impact gene expression. Studied mostly for how mutant isoforms impact cancer, the normal roles for Tet enzymes during organogenesis are largely unknown. By analyzing compound mutant zebrafish, we discovered a requirement for Tet2/3 activity in embryonic heart for recruitment of epicardial progenitors, associated with defects in development of the atrial-ventricular canal (AVC). Through a combination of methylation, hydroxymethylation, and transcript profiling, the genes encoding the ActivinA subunit Inhbaa (in endocardium) and Sox9b (in myocardium) were implicated as demethylation targets of Tet2/3 and critical for organization of AVC-localized extracellular matrix (ECM), facilitating migration of epicardial progenitors onto the developing heart tube. This study elucidates essential DNA epigenetic modifications that govern gene expression changes during cardiac development with striking temporal and lineage specificities, highlighting complex interactions in multiple cell populations during development of the vertebrate heart.
Project description:Extensive DNA methylation in promoter regions is observed in gastric cancer with Epstein-barr virus (EBV) infection and EBV infection is the cause to induce this extensive hypermethylaiton phenotype in gastric epithelial cells. From transcriptome analysis, we found that TET2, one of the demethylase enzymes, was downregulated by EBV infection in gastric epithelial cell line MKN7. TET2 was overexpressed in a gastric epithelial cell line, GES1, to see its function and the hydroxymethylation, a byproduct of DNA demethylation, acquired genes by TET2 overexpression and methylation acquired genes by EBV infection were significantly overlapped. These suggested that hydroxymethylation by TET2 could function to keep unmethylated status of genes before EBV infection, and TET2 depression could contribute to methylation acquisition of these target genes after EBV infection.
Project description:Nephron endowment is a key determinant of later life hypertension and kidney disease. Here we studied whether epigenetic changes, specifically the ten–eleven translocation (Tet) DNA demethylase family, Tet1, Tet2, and Tet3-mediated active DNA hydroxymethylation is necessary for gene expression regulation and kidney differentiation. We generated mice with deletion of Tet1, Tet2 or Tet3 in Six2 positive nephron progenitors (NP). We did not observe changes in development or kidney function in mice with nephron progenitor-specific deletion of Tet1, Tet2, Tet3 or Tet1/Tet2 or Tet1/Tet3. On the other hand, mice with combined Tet2 and Tet3 loss in Six2-positive NPCs failed to form nephrons leading to kidney failure and perinatal death. Tet2 and Tet3 loss in Six2-positive NPs resulted in defect in mesenchymal to epithelial transition and renal vesicle differentiation. Whole genome bisulfite sequencing, single cell RNA sequencing, and gene and protein expression assay identified a defect in expression in genes in the WNT-β-catenin signaling pathway in absence of Tet2 and Tet3 due to a failure in demethylation of these loci. Our results indicate the key role of Tet2 and Tet3-mediated active cytosine hydroxymethylation in NPs in kidney development and nephron endowment.
Project description:We performed methylation, hydroxymethylation, and gene expression profiling using MeDIP-seq, hMeDIP-seq, and RNA-seq, respectively, to investigate the role of TET1 and TET2 in MYC-driven tumor maintenance. We compared T-ALL tumor cells before and upon MYC inactivation and revealed genome-wide changes in the DNA methylation and hydroxymethylation patterns. Furthermore, TET1 knock-down or ectopic TET2 expression in T-ALL revealed genome-wide changes in DNA methylation and hydroxymethylation patterns corresponding to changes in gene expression.
Project description:Using zebrafish tet2-/-;tet3-/- mutants, we identify functions for Tet enzymes and 5-hydroxymethylcytosine (5hmC) in regulating gene expression and cell type-specific differentiation during retinal development.