Genetic ablation of the maintenance methyltransferase Dnmt1 induces widespread demethylation and transcriptional activation of CpG-rich IAP (intracisternal A particle) proviruses. Here, we report that this phenomenon is not simply a consequence of loss of DNA methylation. By exploiting conditional deletions of Dnmt1 and Np95, each of which is essential for maintenance methylation, we find that while IAPs are indeed de-repressed in Dnmt1-ablated embryos and embryonic stem cells (ESCs), these proviruses remain silenced in Np95-ablated cells, despite similar kinetics of passive demethylation. Paradoxically, transient IAP activation in Dnmt1-ablated ESCs requires the presence of NP95. We subsequently show that in the absence of NP95, the H3K9 methyltransferase SETDB1 maintains IAP silencing; while in the absence of DNMT1, prolonged binding of NP95 to hemimethylated DNA perturbs SETDB1-dependent H3K9me3 deposition. Taken together, these observations reveal that following acute loss of Dnmt1, H3K9 methylation-dependent IAP silencing is disrupted by aberrant NP95 binding to hemimethylated DNA. Overall design: RNA-seq for Np95, Dnmt1 and Setdb1 wt, single conditional KO (cKO) and double cKO ES cells; RRBS-seq for Dnmt1 and Np95 single and double cKO ESCs; Myc-tagged NP95, DNMT1 ChIP-seq; and wt and Np95wt and cKO H3K9me3 ChIP-seq.
Activation of Endogenous Retroviruses in Dnmt1(-/-) ESCs Involves Disruption of SETDB1-Mediated Repression by NP95 Binding to Hemimethylated DNA.
Subject, Time
View SamplesMED23, a subunit of the Mediator coactivator complex, is important for the expression of a subset of MAPK/ERK pathway-dependent target genes; however, the genes in this subset varies between cell types. MAPK/ERK pathway-dependent processes are essential for T-cell development and function, but whether MED23 has a role in this context is unknown. We generated Med23 conditional knockout mice and induced Med23 deletion in early T cell development using the lineage specific Lck-Cre transgene. While the total cell number and distribution of cell populations in the thymuses of Med23flox/flox;Lck-Cre mice were essentially normal, MED23 null T-cells failed to efficiently populate the peripheral lymphoid organs. MED23 null thymocytes displayed decreased expression of the MAPK/ERK-responsive genes Egr1, Egr2, as well as of the membrane glycoprotein Cd52 (CAMPATH-1). MED23 null CD4 single-positive thymocytes also showed decreased expression of KLF2 (LKLF), a T cell master regulatory transcription factor. Indeed, similarities between the phenotypes of mice lacking MED23 or KLF2 in T-cells suggest that KLF2 deficiency in MED23 null T-cells is one of their key defects. Mechanistic experiments using MED23 null MEFs further suggest that MED23 is required for full activity of the MAPK-responsive transcription factor MEF2, which has previously been shown to mediate Klf2 expression. In summary, our data indicate that MED23 has critical roles in enabling T-cells to populate the peripheral lymphoid organs, possibly by potentiating MEF2-dependent expression of the T-cell transcription factor KLF2.
T-cells null for the MED23 subunit of mediator express decreased levels of KLF2 and inefficiently populate the peripheral lymphoid organs.
Sex, Specimen part
View SamplesPurpose: The goals of this study are to understand ZIKV induced immune responses in the developing brain at genome-wide level. Methods: Total RNA was isolated from E17.5 mouse brains after viral infection at E14.5. After genomic DNA and ribosomal RNA removal, fractionated RNA were subjected to strand-specific library preparation using NEBNext Ultra RNA Library Prep Kit. Sequencing was performed on Nextseq500 (Illumina). The sequencing reads that passed quality filters were analyzed with TopHat followed by Cufflinks. Results: After performed Gene Ontology analyses with RNA-seq data, our results revealed a set of genes that are associated with the immune response and apoptosis pathways. Gene Set Enrichment Analysis (GSEA) further show significant enrichments on both the immune system response and apoptosis pathways. Some of these results were also verified with qRT-PCR. Conclusions: Our results suggest that ZIKV infection triggers an aggressive immune response, which has the potential to cause exacerbation of brain damage by enhancing neuronal death and generating vascular abnormalities. Our discovery of massive neuronal death, leaky blood-brain-barrier (BBB), and astrogliosis in ZIKV infected brains is the first study to suggest that ZIKA causes extensive brain damage. Overall design: RNA-seq of C56BL/6 mouse E17.5 brain with or without Zika virus infection.
Zika virus infection disrupts neurovascular development and results in postnatal microcephaly with brain damage.
Specimen part, Subject
View SamplesTF1a AML cell line was selected for in vitro modelling of dormancy in AML. TF1-a were subjected to AML-niche-mimicking in vitro conditioning by culture with TGFB1 and the mTOR inhibitor rapamycin. Also TF1a cells were in vitro cultured with prolonged sublethal doses of Etoposide.
A molecular signature of dormancy in CD34<sup>+</sup>CD38<sup>-</sup> acute myeloid leukaemia cells.
Specimen part
View SamplesThe mammalian liver, the largest solid organ in the body, accomplishes multiple critical roles necessary to preserve homeostasis. Human liver diseases are debilitating, costly and very often result in death. Uncovering developmental mechanisms that establish the complex architecture of the liver or generate the cellular diversity of this organ is necessary to develop more adequate methods to prevent, diagnose and cure liver diseases. This study investigated the role of the homeobox gene Prox1 during mouse hepatogenesis.
Prox1 ablation in hepatic progenitors causes defective hepatocyte specification and increases biliary cell commitment.
Specimen part
View SamplesT-regulatory (Treg) cells are important to immune homeostasis, and Treg cell deficiency or dysfunction leads to autoimmune disease. An histone/protein acetyltransferase (HAT), p300, was recently found important for Treg function and stability, but further insights into the mechanisms by which p300 or other HATs affect Treg biology are needed. Here we show that CBP, a p300 paralog, is also important in controlling Treg function and stability. Thus, while mice with Treg-specific deletion of CBP or p300 developed minimal autoimmune disease, the combined deletion of CBP and p300 led to fatal autoimmunity by 3-4 weeks of age. The effects of CBP and p300 deletion on Treg development are dose-dependent, and involve multiple mechanisms. CBP and p300 cooperate with several key Treg transcription factors that act on the Foxp3 promoter to promote Foxp3 production. CBP and p300 also act on the Foxp3 CNS2 region to maintain Treg stability in inflammatory environments by regulating pCREB function and GATA3 expression, respectively. Lastly, CBP and p300 regulate the epigenetic status and function of Foxp3. Our findings provide insights into how HATs orchestrate multiple aspects of Treg development and function, and identify overlapping but also discrete activities for p300 and CBP in control of Treg cells.
Two histone/protein acetyltransferases, CBP and p300, are indispensable for Foxp3+ T-regulatory cell development and function.
No sample metadata fields
View SamplesInsight into mechanisms controlling gene expression in the spermatogonial stem cell (SSC) will improve our understanding of the processes regulating spermatogenesis and aid in treating problems associated with male infertility.
Spermatogonial stem cell self-renewal requires ETV5-mediated downstream activation of Brachyury in mice.
Specimen part, Treatment
View SamplesExpression of GDNF-regulated genes was studied in cultures of self-renewing rat spermatogonial stem cells established from 8-10 day old rat pups maintained in a defined serum free medium. GDNF is the primary regulator of spermatogonial stem cell self renewal in the rat.
Identification of glial cell line-derived neurotrophic factor-regulated genes important for spermatogonial stem cell self-renewal in the rat.
Specimen part
View SamplesSelf-renewal and differentiation of spermatogonial stem cells (SSCs) provides the foundation for testis homeostasis, yet mechanisms that control their functions in mammals are poorly defined. We used microarray transcript profiling to identify specific genes whose expression are augmented in the SSC-enriched Thy1+ germ cell fraction of mouse pup testes. Comparisons of gene expression in the Thy1+ germ cell fraction to the Thy1-depeleted testis cell population identified 202 genes that are expressed 10-fold or higher in Thy1+ cells. This database provided a mining tool to investigate specific characteristics of SSCs and identify novel mechanisms that potentially influence their functions.
Colony stimulating factor 1 is an extrinsic stimulator of mouse spermatogonial stem cell self-renewal.
No sample metadata fields
View SamplesInactivating mutations of the gene encoding for the CREBBP acetyltransferase are highly frequent in diffuse large B cell lymphoma (DLBCL, 30% of cases) and follicular lymphoma (FL, 60% of cases), the two most common cancers derived from thegerminal-center (GC). However, the role of CREBBP inactivation in lymphomagenesisremains unclear. Using functional epigenomics and mouse genetics, here we definethe program modulated by CREBBP in primary human GC B cells and show thatCREBBP regulates enhancer/super-enhancer networks, with specific roles in GC/post-GC cell fate decisions. Conditional GC-specific deletion of Crebbp in the mouseperturbs the expression of a limited set of genes involved in the regulation of signaltransduction (BCR, TLR and CD40), lineage specification (NF-B and BCL6) andterminal B cell differentiation (PRDM1, IRF4). Consistently, Crebbp-deficient B cellsexhibit proliferative advantage and show impaired plasma cell differentiation. WhileGC-specific loss of Crebbp was not sufficient to initiate malignant transformation,compound Crebbp-haploinsufficient/BCL2-transgenic mice, mimicking the genetics ofFL and DLBCL, display an increased incidence of clonal lymphoid malignanciesrecapitulating the features of the human diseases. These findings establish CREBBPas a haploinsufficient tumor suppressor gene in GC B cells and provide insights intothe mechanisms and targes by which loss of CREBBP contributes to lymphomagenesis.
The CREBBP Acetyltransferase Is a Haploinsufficient Tumor Suppressor in B-cell Lymphoma.
Sex, Specimen part
View Samples