Project description:Whole genome bisulfite sequencing of wild type embryonic stem cells and cells bearing a mutation that perturbs the OGT-TET1 interaction Overall design: Whole genome bisulfite sequencing in wild type and Tet1 D2018A mutant mESCs
Project description:Background: Recent genome-wide association studies (GWAS) have identified more than 100 loci associated with increased risk of prostate cancer, most of which are in non-coding regions of the genome. Understanding the function of these non-coding risk loci is critical to elucidate the genetic susceptibility to prostate cancer. Results: We generated genome-wide regulatory element maps and performed genome-wide chromosome confirmation capture assays (in situ Hi-C) in normal and tumorigenic prostate cells. Using this information, we annotated the regulatory potential of 2,181 fine-mapped PCa risk-associated SNPs and predicted a set of target genes that are regulated by PCa risk-related H3K27Ac-mediated loops. We next identified PCa risk-associated CTCF sites involved in long-range chromatin loops. We used CRISPR-mediated deletion to remove PCa risk-associated CTCF anchor regions and the CTCF anchor regions looped to the PCa risk-associated CTCF sites; we observed up to 100 fold increases in expression of genes within the loops when the PCa risk-associated CTCF anchor regions were deleted. Conclusions: We have identified GWAS risk loci involved in long-range loops that function to repress gene expression within chromatin loops. Our studies provide new insights into the genetic susceptibility to prostate cancer. Overall design: ChIP-seq, RNA-seq, Hi-C in prostate cells.
Project description:Genome organization involves cis and trans chromosomal interactions, both implicated in gene regulation, development, and disease. Here, we focused on trans interactions in Drosophila, where homologous chromosomes are paired in somatic cells from embryogenesis through adulthood. We first addressed the long-standing question of whether pairing extends genome-wide and, to this end, developed a haplotype-resolved Hi-C approach that uses a new strategy to minimize homolog misassignment and thus robustly distinguish trans-homolog from cis contacts. This approach revealed striking genome-wide pairing in Drosophila embryos. Moreover, we discovered pairing to be surprisingly structured, with trans-homolog domains and interaction peaks, many coinciding with the positions of analogous cis features. We also found a significant correlation between pairing and the chromatin accessibility mediated by the pioneer factor Zelda. Our findings reveal a complex, highly structured organization underlying homolog pairing, first discovered more than a century ago. Overall design: This submission contains data from a Hi-C experiment on Early Drosophila embryos (2 biological replicates).
Project description:Trans-homolog interactions encompass potent regulatory functions, which have been studied extensively in Drosophila, where homologs are paired in somatic cells and pairing-dependent gene regulation, or transvection, is well-documented. Nevertheless, the structure of pairing and whether its functional impact is genome-wide have eluded analysis. Accordingly, we generated a diploid cell line from divergent parents and applied haplotype-resolved Hi-C, discovering that homologs pair relatively precisely genome-wide in addition to establishing trans-homolog domains and compartments. We also elucidated the structure of pairing with unprecedented detail, documenting significant variation across the genome. In particular, we characterized two forms: tight pairing, consisting of contiguous small domains, and loose pairing, consisting of single larger domains. Strikingly, active genomic regions (A-type compartments, active chromatin, expressed genes) correlated with tight pairing, suggesting that pairing has a functional role genome-wide. Finally, using RNAi and haplotype-resolved Hi-C, we show that disruption of pairing-promoting factors results in global changes in pairing. Overall design: This submission contains four Hi-C experiments on a Drosophila cell line: 2 biological replicates of Hi-C on a wild type sample, 2 biological replicates of Hi-C on a mock RNAi sample, 2 biological replicates of Hi-C on a Slmb RNAi sample, 2 biological replicates of Hi-C on a Top2 RNAi sample. The submission also contain 4 biological replica of a RNA-Seq experiment on a Wild Type sample.
Project description:MeCP2 plays a multifaceted role in gene expression regulation and chromatin organization. Interaction between MeCP2 and methylated DNA to regulate gene expression is well established. However, the widespread MeCP2 distribution suggests its additional interactions with chromatin. Here we show, by both biochemical and ChIP-seq analyses, that MeCP2 directly binds to nucleosome subunit proteins and is recruited to distinct chromatin regions where H3K27me3 is enriched. We further observed that the impact of MeCP2 on transcriptional changes is correlated with histone post-translational modification patterns. Our findings indicate that MeCP2 can be recruited to genomic loci via indirect binding and that interaction between MeCP2 and histone proteins plays a significant role in gene expression regulation. Overall design: In order to perform genome-wide quantitative comparisons of histone modification difference between DMSO and GSK343 treatment, the drosophila S2 genome was added to each experiment. An exogenous genome-derived normalizing factor was used for normalization. Please note that each processed data file was generated from both rep1 and rep2 samples, and is linked to the corresponding rep1 sample records.
Project description:Genomic sequences, as well as its covalent epigenetic modifications, are spatially organized into three-dimensional structures. Here, we developed Methyl-HiC by combining in situ Hi-C and whole genome bisulfite sequencing (WGBS) to simultaneously capture genome-wide chromosome conformation changes and DNA methylation within the same DNA molecule. Methyl-HiC generated consistent information compared with in situ Hi-C and WGBS from the same cell line. We detected long-range DNA methylation concordance in general but varied in different chromatin states. We extended Methyl-HiC to single cell level and applied it on 103 primed and 47 naïve mouse embryonic stem cells (mESCs). We revealed the heterogeneity of chromosomal conformation changes by grouping cells in their DNA methylation level alone. We also observed increases of DNA methylation stochasticity and decreases of contact frequency together in late replication timing regions. Our method here paves the road to evaluate the direct long-range effect of epigenetic alterations in different pathological and healthy conditions at genome-wide and single cell level. Overall design: Methyl-HiC and single cell Methyl-HiC experiments applied to mouse embryonic stem cell (F123).
Project description:What genomic changes led to the origin of vertebrates remains a mystery. On the one hand, animal evolution is thought to be driven mostly by changes in the cis-regulatory regions of a shared conserved and toolkit of developmental genes. On the other hand, vertebrates experienced two rounds of whole genome duplication (WGD) that increased their gene repertoire, particularly of regulatory genes controlling embryo development. To shed light into the origin and evolution of the vertebrate regulatory genome, we have generated an unprecedented transcriptomic and epigenomic resource for the non-duplicated genome of the European amphioxus, a closely related invertebrate chordate. These data include RNA-seq for more than 35 developmental stages and adult tissues, CAGE-seq, ChIP-seq, bisulphite-seq and ATAC-seq for several developmental stages and adult tissues. By comparing these data sets with equivalent novel and previously available data for various vertebrate species, especially zebrafish, we uncovered multiple conserved and vertebrate-specific regulatory landmarks. We first identify a conserved chordate phylotypic stage, a developmental period in which different chordate species show the highest gene expression similarity. We also shed light on the origin of enhancer demethylation in vertebrates, by identifying, for the first time in an invertebrate species, differentially methylated enhancers. Furthermore, we show that conserved clusters of co-expressed and tissue-specific genes display similar enrichments for cis-regulatory motifs between amphioxus and vertebrates. Finally, we study the impact of vertebrate WGDs on the evolution of gene regulation, providing the first genome-wide quantitative assessment of sub-functionalization and neo-functionalization processes after the vertebrate WGDs; changing the way in which these evolutionary mechanisms have been traditionally understood. Overall design: ChIPseq assays in different developmental stages of european amphioxus
Project description:Somatic cell nuclear transfer (SCNT) enables the genome of a differentiated somatic cell to be reprogrammed to totipotency. However, this process is extremely inefficient, and the underlying mechanism of the epigenetic rearrangements following SCNT remains largely unknown. Here, we generated a genome-wide DNA methylome of mouse SCNT preimplantation embryos. Surprisingly, we identified widespread re-methylated regions (rDMRs) in 2- to 4-cell stage cloned embryos, which caused mis-expression of genes and retrotransposons important for zygotic genome activation and embryo development. Knocking-down DNA methyltransferases can specifically rescue the re-methylation defects of SCNT embryos and evidently improve the poor developmental capacity of cloned embryos. In addition, inactivation of DNA methyltransferases combined with overexpression of histone demethylases led to a more significant reduction in DNA methylation as well as exhibited a synergistic enhancement effect on the full-term development of nuclear transfer embryos. Our study therefore reveals that aberrant re-methylation functions as an unavoidable barrier for SCNT embryo development, and that the removal of multiple epigenetic barriers would be a promising approach to achieve the highest cloning efficiency. Overall design: For SCNT embryos 4-8 replicates were performed for each stage . As the control, 3 replicates were performed for each stage of wild type samples