Project description:DNA methylation and hydroxymethylation have been implicated in normal development and differentiation, but our knowledge about the genome-wide distribution of 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) during cellular differentiation remains limited. Using in vitro model system of gradual differentiation of human embryonic stem (hES) cells into ventral midbrain-type neural precursor (NP) cells and terminally into dopamine (DA) neurons, we explored changes in 5mC or 5hmC patterns during lineage commitment. We used three techniques, 450K DNA methylation array, MBD-seq, and hMeDIP-seq, and found combination of these methods can provide comprehensive information on the genome-wide 5mC or 5hmC patterns. We observed dramatic changes of 5mC patterns during differentiation of hES cells into NP cells. Although genome-wide 5hmC distribution was more stable than 5mC, coding exons, CpG islands and shores showed dynamic 5hmC patterns during differentiation. In addition to the role of DNA methylation as a mechanism to initiating gene silencing, we also found DNA methylation as a locking system to maintain gene silencing. More than 1,000 genes including mesoderm development related genes acquired promoter methylation during neuronal differentiation even though they were already silenced in hES cells. Finally, we found that activated genes lost 5mC in transcription start site (TSS) but acquired 5hmC around TSS and gene body during differentiation. Our findings may provide clues for elucidating the molecular mechanisms underlying lineage specific differentiation of pluripotent stem cells during human embryonic development. Examination of genome-wide DNA methylation in 3 cell types (human embryonic stem, neural precursor, and dopamine neuron cells)
Project description:DNA methylation and hydroxymethylation have been implicated in normal development and differentiation, but our knowledge about the genome-wide distribution of 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) during cellular differentiation remains limited. Using in vitro model system of gradual differentiation of human embryonic stem (hES) cells into ventral midbrain-type neural precursor (NP) cells and terminally into dopamine (DA) neurons, we explored changes in 5mC or 5hmC patterns during lineage commitment. We used three techniques, 450K DNA methylation array, MBD-seq, and hMeDIP-seq, and found combination of these methods can provide comprehensive information on the genome-wide 5mC or 5hmC patterns. We observed dramatic changes of 5mC patterns during differentiation of hES cells into NP cells. Although genome-wide 5hmC distribution was more stable than 5mC, coding exons, CpG islands and shores showed dynamic 5hmC patterns during differentiation. In addition to the role of DNA methylation as a mechanism to initiating gene silencing, we also found DNA methylation as a locking system to maintain gene silencing. More than 1,000 genes including mesoderm development related genes acquired promoter methylation during neuronal differentiation even though they were already silenced in hES cells. Finally, we found that activated genes lost 5mC in transcription start site (TSS) but acquired 5hmC around TSS and gene body during differentiation. Our findings may provide clues for elucidating the molecular mechanisms underlying lineage specific differentiation of pluripotent stem cells during human embryonic development. Examination of hMeDIP-Seq and MBD-Seq in 3 cell types (human embryonic stem, neural precursor, and dopamine neuron cells)
Project description:DNA methylation and hydroxymethylation have been implicated in normal development and differentiation, but our knowledge about the genome-wide distribution of 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) during cellular differentiation remains limited. Using in vitro model system of gradual differentiation of human embryonic stem (hES) cells into ventral midbrain-type neural precursor (NP) cells and terminally into dopamine (DA) neurons, we explored changes in 5mC or 5hmC patterns during lineage commitment. We used three techniques, 450K DNA methylation array, MBD-seq, and hMeDIP-seq, and found combination of these methods can provide comprehensive information on the genome-wide 5mC or 5hmC patterns. We observed dramatic changes of 5mC patterns during differentiation of hES cells into NP cells. Although genome-wide 5hmC distribution was more stable than 5mC, coding exons, CpG islands and shores showed dynamic 5hmC patterns during differentiation. In addition to the role of DNA methylation as a mechanism to initiating gene silencing, we also found DNA methylation as a locking system to maintain gene silencing. More than 1,000 genes including mesoderm development related genes acquired promoter methylation during neuronal differentiation even though they were already silenced in hES cells. Finally, we found that activated genes lost 5mC in transcription start site (TSS) but acquired 5hmC around TSS and gene body during differentiation. Our findings may provide clues for elucidating the molecular mechanisms underlying lineage specific differentiation of pluripotent stem cells during human embryonic development.
Project description:DNA methylation and hydroxymethylation have been implicated in normal development and differentiation, but our knowledge about the genome-wide distribution of 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) during cellular differentiation remains limited. Using in vitro model system of gradual differentiation of human embryonic stem (hES) cells into ventral midbrain-type neural precursor (NP) cells and terminally into dopamine (DA) neurons, we explored changes in 5mC or 5hmC patterns during lineage commitment. We used three techniques, 450K DNA methylation array, MBD-seq, and hMeDIP-seq, and found combination of these methods can provide comprehensive information on the genome-wide 5mC or 5hmC patterns. We observed dramatic changes of 5mC patterns during differentiation of hES cells into NP cells. Although genome-wide 5hmC distribution was more stable than 5mC, coding exons, CpG islands and shores showed dynamic 5hmC patterns during differentiation. In addition to the role of DNA methylation as a mechanism to initiating gene silencing, we also found DNA methylation as a locking system to maintain gene silencing. More than 1,000 genes including mesoderm development related genes acquired promoter methylation during neuronal differentiation even though they were already silenced in hES cells. Finally, we found that activated genes lost 5mC in transcription start site (TSS) but acquired 5hmC around TSS and gene body during differentiation. Our findings may provide clues for elucidating the molecular mechanisms underlying lineage specific differentiation of pluripotent stem cells during human embryonic development.
Project description:The mammalian intestinal epithelium has a unique organization where crypts harboring stem cells produce progenitors and finally clonal populations of differentiated cells. Remarkably, the epithelium is replaced every three to five days throughout adult life. Disrupted maintenance of the intricate balance of proliferation and differentiation leads to loss of epithelial integrity, barrier function, or cancer. There is a tight correlation between epigenetic status of genes and expression changes during differentiation; however, the mechanism of how changes in DNA methylation direct gene expression and the progression from stem cells to their differentiated descendants is unclear. Using conditional gene ablation of the maintenance methyltransferase Dnmt1, we demonstrate that reducing DNA methylation causes intestinal crypt expansion in vivo. Determination of the base-resolution DNA methylome in stem cells and their differentiated descendants shows that DNA methylation is dynamic at enhancers, which are often associated with genes important for both stem cell maintenance and differentiation. We establish that the loss of DNA methylation at intestinal stem cell gene enhancers causes inappropriate gene expression and delayed differentiation.
Project description:Here we used Illumina NGS for high-throughput profiling of the DNA methylome(ERRBS) and hydroxymethylome(hMe-Seal) of primary tumor samples with Acute Myeloid Leukemia(AML). The data can be used to compare hydroxymethylation and methylation patterns from different AML subtypes and normal bone marrow samples.
Project description:Aberrant methylation at the promoter region of tumor suppressors is frequently reported in NPC; however, genome-wide methylation changes have not been comprehensively investigated. Therefore, we systematically analyzed methylome data in 25 primary NPC tumors and non-tumor counterparts using Illumina HumanMethylation450 BeadChip. Bisulphite converted DNA from 50 samples were hybridized to the Illumina HumanMethylation450 BeadChip. Bisulphite pyrosequencing was used as an independent method to validate the BeadChip results.