Project description:Reprogramming of the gamete into a developmentally competent embryo identity is a fundamental aspect of preimplantation development. One of the most important processes of this reprogramming is the transcriptional awakening during embryonic genome activation (EGA), which robustly occurs in fertilized embryos but is defective in most somatic cell nuclear transfer (SCNT) embryos. However, little is known about the genome-wide underlying chromatin landscape during EGA in SCNT embryos and how it differs from a fertilized embryo. By profiling open chromatin genome-wide in both types of bovine embryos, we find that SCNT embryos fail to reprogram a subset of the EGA gene targets that are normally activated in fertilized embryos. Importantly, a small number of transcription factor (TF) motifs explain most chromatin regions that fail to open in SCNT embryos suggesting that over-expression of a limited number of TFs may provide more robust reprogramming. One such TF, the zygotically-expressed bovine gene DUXC which is a homologue of EGA factors DUX/DUX4 in mouse/human, is alone capable of activating ~84% of all EGA transcripts that fail to activate normally in SCNT embryos. Additionally, single-cell chromatin profiling revealed low intra-embryo heterogeneity but high inter-embryo heterogeneity in SCNT embryos and an uncoupling of cell division and open chromatin reprogramming during EGA. Surprisingly, our data also indicate that transcriptional defects may arise downstream of promoter chromatin opening in SCNT embryos, suggesting additional mechanistic insights into how and why transcription at EGA is dysregulated. We anticipate that our work will lead to altered SCNT protocols to increase the developmental competency of bovine SCNT embryos.
Project description:Reprogramming of the gamete into a developmentally competent embryo identity is a fundamental aspect of preimplantation development. One of the most important processes of this reprogramming is the transcriptional awakening during embryonic genome activation (EGA), which robustly occurs in fertilized embryos but is defective in most somatic cell nuclear transfer (SCNT) embryos. However, little is known about the genome-wide underlying chromatin landscape during EGA in SCNT embryos and how it differs from a fertilized embryo. By profiling open chromatin genome-wide in both types of bovine embryos, we find that SCNT embryos fail to reprogram a subset of the EGA gene targets that are normally activated in fertilized embryos. Importantly, a small number of transcription factor (TF) motifs explain most chromatin regions that fail to open in SCNT embryos suggesting that over-expression of a limited number of TFs may provide more robust reprogramming. One such TF, the zygotically-expressed bovine gene DUXC which is a homologue of EGA factors DUX/DUX4 in mouse/human, is alone capable of activating ~84% of all EGA transcripts that fail to activate normally in SCNT embryos. Additionally, single-cell chromatin profiling revealed low intra-embryo heterogeneity but high inter-embryo heterogeneity in SCNT embryos and an uncoupling of cell division and open chromatin reprogramming during EGA. Surprisingly, our data also indicate that transcriptional defects may arise downstream of promoter chromatin opening in SCNT embryos, suggesting additional mechanistic insights into how and why transcription at EGA is dysregulated. We anticipate that our work will lead to altered SCNT protocols to increase the developmental competency of bovine SCNT embryos.
Project description:Reprogramming of histone modification regulates gene expression and mammal preimplantation development. Trimethylation of lysine 4 on histone 3 (H3K4me3) has unique landscape in mouse oocytes and early embryos. However, the dynamics and function of H3K4me3 in livestock embryos remain unclear. To address how it is reprogrammed in domestic animals, we profiled changes of H3K4me3 during bovine early embryo development. Notably, the overall signal of H3K4me3 decreased during embryonic genome activation (EGA). By utilizing ultra-low-input native ChIP-seq (ULI-NChIP-seq) technology, we observed widespread broad H3K4me3 domains in oocytes and embryos. The signal of broad H3K4me3 began to decrease after fertilization and was lowest after EGA. Along with the removal of broad H3K4me3, deposition of H3K4me3 at promoter regions enhanced gradually. Besides, the transcriptional activity and signal of promoter H3K4me3 showed positive correlation after the erasure of broad H3K4me3 at 16-cell stage. Moreover, knocking down of demethylases KDM5A, KDM5B and KDM5C caused EGA delay and blastocyst formation failure. RNA-seq analysis revealed 47.8% down-regulated genes in knockdown embryos at 8/16-cell stage were EGA genes, and 63.1% of up-regulated genes were maternal transcripts. Particularly, the positive correlation between transcriptional activity and promoter H3K4me3 during EGA was restrained when knocking down of KDM5A, KDM5B and KDM5C. Overall, our work initiatively mapped the genomic reprogramming of H3K4me3 during bovine preimplantation development, and KDM5A/B/C played roles in modulating oocyte-to-embryonic transition (OET) through timely erasure of broad H3K4me3 domains far away from promoters.
Project description:CTCF ChIP-seq of 39 primary samples derived from human acute leukemias, namely AML, T-ALL and mixed myeloid/lymphoid leukemias with CpG Island Methylator Phenotype (CIMP). Due to patient confidentiality considerations, the raw data files for this dataset have been deposited to the EGA controlled-access archive under the accession numbers EGAS00001007094 (study); EGAD00001011059 (dataset).
Project description:Bariatric surgical techniques are known to cause weight loss and diabetes remission to varying degrees in severly obese patients. However, the mechanisms involved in the restoration of beta-cell function remain to be uncovered. In this study, the leptin-deficient ob/ob mouse was used as a model to investigate the effect of EGA bariactric surgery on pancreatic islet miRNA expression.
Project description:Reprogramming of the gamete into a developmentally competent embryo identity is a fundamental aspect of preimplantation development. One of the most important processes of this reprogramming is the transcriptional awakening during embryonic genome activation (EGA), which robustly occurs in fertilized embryos but is defective in most somatic cell nuclear transfer (SCNT) embryos. However, little is known about the genome-wide underlying chromatin landscape during EGA in SCNT embryos and how it differs from a fertilized embryo. By profiling open chromatin genome-wide in both types of bovine embryos, we find that SCNT embryos fail to reprogram a subset of the EGA gene targets that are normally activated in fertilized embryos. Importantly, a small number of transcription factor (TF) motifs explain most chromatin regions that fail to open in SCNT embryos suggesting that over-expression of a limited number of TFs may provide more robust reprogramming. One such TF, the zygotically-expressed bovine gene DUXC which is a homologue of EGA factors DUX/DUX4 in mouse/human, is alone capable of activating ~84% of all EGA transcripts that fail to activate normally in SCNT embryos. Additionally, single-cell chromatin profiling revealed low intra-embryo heterogeneity but high inter-embryo heterogeneity in SCNT embryos and an uncoupling of cell division and open chromatin reprogramming during EGA. Surprisingly, our data also indicate that transcriptional defects may arise downstream of promoter chromatin opening in SCNT embryos, suggesting additional mechanistic insights into how and why transcription at EGA is dysregulated. We anticipate that our work will lead to altered SCNT protocols to increase the developmental competency of bovine SCNT embryos.
Project description:Reprogramming of the gamete into a developmentally competent embryo identity is a fundamental aspect of preimplantation development. One of the most important processes of this reprogramming is the transcriptional awakening during embryonic genome activation (EGA), which robustly occurs in fertilized embryos but is defective in most somatic cell nuclear transfer (SCNT) embryos. However, little is known about the genome-wide underlying chromatin landscape during EGA in SCNT embryos and how it differs from a fertilized embryo. By profiling open chromatin genome-wide in both types of bovine embryos, we find that SCNT embryos fail to reprogram a subset of the EGA gene targets that are normally activated in fertilized embryos. Importantly, a small number of transcription factor (TF) motifs explain most chromatin regions that fail to open in SCNT embryos suggesting that over-expression of a limited number of TFs may provide more robust reprogramming. One such TF, the zygotically-expressed bovine gene DUXC which is a homologue of EGA factors DUX/DUX4 in mouse/human, is alone capable of activating ~84% of all EGA transcripts that fail to activate normally in SCNT embryos. Additionally, single-cell chromatin profiling revealed low intra-embryo heterogeneity but high inter-embryo heterogeneity in SCNT embryos and an uncoupling of cell division and open chromatin reprogramming during EGA. Surprisingly, our data also indicate that transcriptional defects may arise downstream of promoter chromatin opening in SCNT embryos, suggesting additional mechanistic insights into how and why transcription at EGA is dysregulated. We anticipate that our work will lead to altered SCNT protocols to increase the developmental competency of bovine SCNT embryos.
Project description:H3K27ac ChIP-seq of 79 primary samples derived from human acute leukemias, namely AML, T-ALL and mixed myeloid/lymphoid leukemias with CpG Island Methylator Phenotype (CIMP). In addition, 4 samples derived from CD34+ cord blood cells of healthy donors were included. Due to patient confidentiality considerations, the raw data files for this dataset have been deposited to the EGA controlled-access archive under the accession numbers EGAS00001007094 (study); EGAD00001011060 (dataset).
Project description:At the moment of union in fertilization, sperm and oocyte are transcriptionally silent. The ensuing onset of embryonic transcription (embryonic genome activation, EGA) is critical for development, yet its timing and profile are unknown in any vertebrate species. We here dissect hitherto inaccessible transcription during EGA by high resolution single-cell RNA-sequencing of precisely synchronized mouse one-cell embryos. This reveals a program of embryonic gene expression (immediate EGA, iEGA) initiating within four hours of fertilization. Expression during iEGA produces canonically-spliced transcripts, occurs substantially from the maternal genome, and is mostly down-regulated at the two-cell stage. Transcribed genes predict regulation by transcription factors (TFs) associated with cancer, including c-Myc. Blocking c- Myc or other predicted regulatory TF activities disrupts iEGA and induces acute developmental arrest. These findings illuminate intracellular mechanisms that regulate the onset of mammalian development and promise a new paradigm for the study of cancer
Project description:Cancer cell lines can provide robust and facile biological models for the generation and testing of hypothesis in the early stages of drug development and caner biology. Although clinical trials remain the ultimate scientific testing ground for anticancer therapies, the use of appropriate model systems to explore the molecular basis of drug activity and to identify predictive biomarkers during their development can have a profound effect on the design, cost and ultimate success of new cancer drug development. In order to capture the high degree of genomic diversity in cancer and to identify rare molecular subtypes, we have assembled a collection of >1000 cancer cell lines. These lines have been characterised using whole exome sequencing, genome wide analysis of copy number, mRNA gene expression profiling and DNA methylation analysis (http://cancer.sanger.ac.uk/cell_lines). To further characterise this panel of cell lines we have now compiled data for RNA sequencing. The current study represent data for ~450 of the cell lines in the panel, data for the remaining lines can be accessed via the CGHUB data browser hosted at UCSC. <br>This ArrayExpress record contains only meta-data. Raw data files have been archived at the European Genome-Phenome Archive (EGA, www.ebi.ac.uk/ega) by the consortium, with restricted access to protect sample donors' identity. The relevant accessions of the EGA data set is EGAD00001001357 under EGA study accession EGAS00001000828.