The human genome contains approximately 27,700 CpG islands (CGIs). Most are associated with promoters and their DNA is nearly always unmethylated. By contrast, CGIs lying within the bodies of genes usually become methylated during differentiation and development. CGIs also normally become methylated at X-inactivated and imprinted genes and abnormally methylated in genome rearrangements and in malignancy. In such circumstances, methylation of CGIs is often associated with RNA transcripts reading through these elements but the relationship of this RNA to methylation of CGIs is not clear. Here we investigated a previously described form of a-thalassemia caused by a genome rearrangement leading to abnormal transcription and DNA methylation of the CGI at the promoter of the a-globin gene. We show that transcription per se is responsible for DNMT3B-mediated methylation of the globin CGI, and that this is a general mechanism responsible for methylation of most intragenic CpG islands. Overall design: CapSeq was performed on day 7 in vitro differentiated EBs containing the human gene sequence of RHBDF1 with (RHBDF1+P; chr16:47,861-63,210, hg18) or without (RHBDF1-P; chr16:47,911-60,819, hg18) its promoter in the a recombination mediated cassette exchange (RMCE) system established within the mouse a-globin locus (Lynch et al., 2012, DOI: 10.1038/emboj.2011.399 ) to map transcription initiation sites within the transgene. Please note that the Cap-seq methods captures the 5' end of any short RNA that was Capped, capturing both coding and non-coding RNA.
DNA methylation of intragenic CpG islands depends on their transcriptional activity during differentiation and disease.
Specimen part, Cell line, Subject
View SamplesMany genes determining cell identity are regulated by clusters of Mediator-bound enhancer elements collectively referred to as super-enhancers. These super-enhancers have been proposed to manifest higher-order properties important in development and disease. Here we report a comprehensive functional dissection of one of the strongest putative super-enhancers in erythroid cells. By generating a series of mouse models, deleting each of the five regulatory elements of the a-globin super-enhancer individually and in informative combinations, we demonstrate that each constituent enhancer seems to act independently and in an additive fashion with respect to hematological phenotype, gene expression, chromatin structure and chromosome conformation, without clear evidence of synergistic or higher-order effects. Our study highlights the importance of functional genetic analyses for the identification of new concepts in transcriptional regulation. Overall design: Mouse fetal liver erythroid RNA-seq. The RNA of the erythroid cells was metabolically labelled using 4-thiourdine nucleotide analogue supplementation of viable cells in culture. RNA transcripts that incorporated the analogue and hence were synthesised during this period of exposure, were then isolated from the pre-exiting bulk RNA by the addition of a biotin moiety and pull down.
Genetic dissection of the α-globin super-enhancer in vivo.
Specimen part, Subject
View SamplesThe weekly turnover of the intestinal epithelium is driven by multipotent, Lgr5+, crypt base columnar cells (CBCs). In response to injury, however, Lgr5+ cells are lost but then re-emerge and are required for successful recovery. How these resurgent Lgr5+ stem cells arise is unclear. We transcriptionally profiled single cells from regenerating intestinal epithelia and identified a unique cell type we term the revival stem cell (rSC). rSCs are mutually exclusive to CBCs and are distinguished by elevated expression of cell survival and DNA repair genes. In homeostasis, rSCs are extremely rare, but nevertheless give rise to all the major cell types of the intestine including crypt-villus axes. After damage rSCs display a 20-fold, Yap-dependent, transient expansion, reconstitute the Lgr5+ CBC compartment and are required to regenerate a functional intestine. These studies define a unique stem cell phenotype that is mobilized by damage to reconstitute the intestinal epithelium. Overall design: Examination of regenerating mouse intestinal epithelium.
Single-cell transcriptomes of the regenerating intestine reveal a revival stem cell.
Specimen part, Cell line, Treatment, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A Preclinical Model for ERα-Positive Breast Cancer Points to the Epithelial Microenvironment as Determinant of Luminal Phenotype and Hormone Response.
Specimen part
View SamplesA high percentage of potential oncology drugs fail in clinical trials, partly because preclinical models used to test them are inadequate. Breast cancer is the leading cause of cancer-related death among women worldwide but we lack appropriate in vivo models for the ER+ subtypes, which represent more than 75% of all cases. We address these issues by xenografting tumor cells to their site of origin, the milk ducts. All ER+ cell lines and patient-derived xenografts grow mimicking their clinical counterparts. Disease progresses with invasion and metastasis, which become amenable to study. The action of hormones, important in breast carcinogenesis, can now be studied in a relevant context. Importantly, these open opportunities for development and evaluation of therapies.
A Preclinical Model for ERα-Positive Breast Cancer Points to the Epithelial Microenvironment as Determinant of Luminal Phenotype and Hormone Response.
Specimen part
View SamplesA high percentage of potential oncology drugs fail in clinical trials, partly because preclinical models used to test them are inadequate. Breast cancer is the leading cause of cancer-related death among women worldwide but we lack appropriate in vivo models for the ER+ subtypes, which represent more than 75% of all cases. We address these issues by xenografting tumor cells to their site of origin, the milk ducts. All ER+ cell lines and patient-derived xenografts grow mimicking their clinical counterparts. Disease progresses with invasion and metastasis, which become amenable to study. The action of hormones, important in breast carcinogenesis, can now be studied in a relevant context. Importantly, these open opportunities for development and evaluation of therapies.
A Preclinical Model for ERα-Positive Breast Cancer Points to the Epithelial Microenvironment as Determinant of Luminal Phenotype and Hormone Response.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The H3K27 demethylase Utx regulates somatic and germ cell epigenetic reprogramming.
Specimen part
View SamplesPluripotency can be induced in somatic cells by ectopic expression of defined transcription factors, however the identity of epigenetic regulators driving the progression of cellular reprogramming requires further investigation. Here we uncover a non-redundant role for the JmjC-domain-containing protein histone H3 methylated Lys 27 (H3K27) demethylase Utx, as a critical regulator for the induction, but not for the maintenance, of primed and nave pluripotency in mice and in humans. Utx depletion results in aberrant H3K27me3 repressive chromatin demethylation dynamics, which subsequently hampers the reactivation of pluripotency promoting genes during reprogramming. Remarkably, Utx deficient primordial germ cells (PGCs) display a cell autonomous aberrant epigenetic reprogramming in vivo during their embryonic maturation, resulting in the lack of functional contribution to the germ-line lineage.
The H3K27 demethylase Utx regulates somatic and germ cell epigenetic reprogramming.
Specimen part
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