Loss-of-function studies are fundamental for dissecting gene function. Yet, methods to rapidly and effectively perturb genes in mammalian cells are scarce. We present a novel system, deliverable with only two lentiviral vectors, which enables simultaneous control over two different proteins in the same cell. By harnessing the plant auxin and jasmonate hormone-induced degradation pathways, combined with RNA interference, this system allows constitutive depletion of two endogenous proteins and their replacement with two exogenous proteins whose degradation is rapidly and reversibly induced by external ligands, representing a dual analog molecular tuner. Focusing on NANOG, CHK1 and NOTCH1 in embryonic stem cells and p53 in cancer cells we have validated the efficiency, rapidity, reversibility, titratability and multiplicity of the engineered tuners, and demonstrated their potential to facilitate previously-unfeasible experimental approaches and to generate novel biological insights. Overall design: For mRNA-Seq preparation, coronatine/DMSO treated cells were collected.
A dual molecular analogue tuner for dissecting protein function in mammalian cells.
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Epigenetic roles of MLL oncoproteins are dependent on NF-κB.
Specimen part, Cell line
View SamplesDetermination of the molecular properties of genetically targeted cell types has led to fundamental insights into mouse brain function and dysfunction. Here, we report an efficient strategy for precise exploration of gene expression events in specific cell types in a broad range of species. We demonstrate that classically defined, homologous neuronal and glial cell types differ between rodent and human by the expression of hundreds of orthologous, cell specific genes. Confirmation that these genes are differentially active was obtained using epigenetic mapping, quantitative PCR, and immunofluorescence localization. Studies of sixteen human postmortem brains revealed cell-specific molecular responses to aging, and the induction of a shared, robust response to an unknown external event experienced by three donors. Our data establish a comprehensive approach for analysis of unique molecular events associated with specific circuits and cell types in a wide variety of human conditions. Overall design: RNA purified from nuclei or cytoplasm from mouse, rat, or human cerebellum. ATAC-seq was also performed using cerebellar nuclei from the three species.
Species and cell-type properties of classically defined human and rodent neurons and glia.
Sex, Age, Specimen part, Subject
View SamplesDetermination of the molecular properties of genetically targeted cell types has led to fundamental insights into mouse brain function and dysfunction. Here, we report an efficient strategy for precise exploration of gene expression events in specific cell types in a broad range of species. We demonstrate that classically defined, homologous neuronal and glial cell types differ between rodent and human by the expression of hundreds of orthologous, cell specific genes. Confirmation that these genes are differentially active was obtained using epigenetic mapping, quantitative PCR, and immunofluorescence localization. Studies of sixteen human postmortem brains revealed cell-specific molecular responses to aging, and the induction of a shared, robust response to an unknown external event experienced by three donors. Our data establish a comprehensive approach for analysis of unique molecular events associated with specific circuits and cell types in a wide variety of human conditions. Overall design: RNA purified from nuclei or cytoplasm from mouse, rat, or human cerebellum. ATAC-seq was also performed using cerebellar nuclei from the three species.
Species and cell-type properties of classically defined human and rodent neurons and glia.
Specimen part, Cell line, Subject
View SamplesDefinitive hematopoiesis emerges via an endothelial-to-hematopoietic transition in the aorta-gonad-mesonephros (AGM) region and placenta. We have recently demonstrated the induction of hematopoietic stem/progenitors (HSPCs) from mouse fibroblasts with a combination of transcription factors progressing through endothelial-like precursors. Here, guided by our in vitro programming experiments we analyzed mouse placentas for the presence of the precursor phenotype. We identified a small population of CD34+ Sca1+Prom1+ (34PS) cells in mid-gestation placentas that do not express the pan-hematopoietic marker CD45. After isolation and culture 34PS cells acquire CD45 and generate large hematopoietic as well as cobblestone colonies. Prom1+ cells localize to the placental vascular labyrinth where HSPCs emerge. 34PS cells express markers associated with the hemogenic endothelium (CD31, Tie2, VE-Cadherin, Sox17, Runx1, Scl) and also markers identified by direct induction (Itga6/CD49f). This population is heterogeneous for the early hematopoietic marker CD41 and expresses the programming transcription factors. Remarkably, global gene expression profiles of placental 34PS cells correlate with AGM-derived hemogenic endothelium and fibroblast-derived precursors. Finally, when co-cultured with stroma placental 34PS cells give rise to B/T lymphoid cells as well as mixed colonies containing erythroid, myeloid and megakaryocytic cell lineages. In summary, we show that direct in vitro conversion provided a cell surface phenotype for the isolation of hemogenic precursors in vivo. Our findings provide insights into the specification of definitive hemogenesis in the placenta, in depth characterization of hemogenic precursor populations and the first evidence that direct in vitro conversion approaches can be used as a valuable tool to address basic developmental questions in vivo. Overall design: mRNAseq profiling on populations isolated by selected marker fluorescence activated cell sorting The 'E10_E12_HSPC_SingleCell_FPKM.txt.gz' contains the processed data for GSM1890353-GSM1890496.
Hematopoietic Reprogramming In Vitro Informs In Vivo Identification of Hemogenic Precursors to Definitive Hematopoietic Stem Cells.
No sample metadata fields
View SamplesA number of key regulators of mouse embryonic stem (ES) cell identity, including the transcription factor Nanog, show strong expression fluctuations at the single cell level. The molecular basis for these fluctuations is unknown. Here we used a genetic complementation strategy to investigate expression changes during transient periods of Nanog downregulation. Employing an integrated approach, that includes high-throughput single cell transcriptional profiling and mathematical modelling, we found that early molecular changes subsequent to Nanog loss are stochastic and reversible. However, analysis also revealed that Nanog loss severely compromises the self-sustaining feedback structure of the ES cell regulatory network. Consequently, these nascent changes soon become consolidated to committed fate decisions in the prolonged absence of Nanog. Consistent with this, we found that exogenous regulation of Nanog-dependent feedback control mechanisms produced more a homogeneous ES cell population. Taken together our results indicate that Nanog-dependent feedback loops play a role in controlling both ES cell fate decisions and population variability.
Nanog-dependent feedback loops regulate murine embryonic stem cell heterogeneity.
Specimen part
View SamplesDefinitive hematopoiesis emerges during embryogenesis via an endothelial-to-hematopoietic transition. We attempted to induce this process in mouse fibroblasts by screening a panel of factors for hemogenic activity. We identified a combination of four transcription factors, Gata2, Gfi1b, cFos, and Etv6 that efficiently induces endothelial-like precursor cells with the subsequent appearance of hematopoietic cells. The precursor cells express a human CD34 reporter, Sca1 and Prominin1 within a global endothelial transcription program. Emergent hematopoietic cells possess nascent/specifying hematopoietic stem cell gene expression profiles and cell surface phenotypes. After transgene silencing and reaggregation culture, the specified cells generate hematopoietic colonies in vitro. Thus, we have shown that a simple combination of transcription factors is sufficient to induce a complex, dynamic and multi-step developmental program in vitro. These findings provide insights into the specification of definitive hemogenesis and a platform for future development of patient-specific stem/progenitor cells as well as more differentiated blood products. Overall design: mRNA-seq profiling on populations generated after transduction with Gata2, Gfi1b, cFos and Etv6 at day 20 and day 35.
Induction of a hemogenic program in mouse fibroblasts.
Specimen part, Subject, Time
View SamplesThe recent interest in the role of bone marrow derived endothelial progenitor cells in the benefits of estrogen on cardiovascular health brought us to evaluate if estrogen could affect cardiac repair more broadly by regulating biological processes involved in the functional organization of the bone marrow stem cell niche.
Estrogen-induced gene expression in bone marrow c-kit+ stem cells and stromal cells: identification of specific biological processes involved in the functional organization of the stem cell niche.
Sex, Age
View SamplesExpression data from LEOPARD Syndrome-iPS clones, BJ-iPS cells and parental Fibroblasts
Patient-specific induced pluripotent stem-cell-derived models of LEOPARD syndrome.
Sex, Specimen part, Subject
View SamplesFusion of the EWS gene to FLI1 produces a fusion oncoprotein that drives an aberrant gene expression program responsible for the development of Ewing sarcoma. We used a homogenous proximity assay to screen for compounds that disrupt the binding of EWS-FLI1 to its cognate DNA targets. A number of DNA-binding chemotherapeutic agents were found to non-specifically disrupt protein binding to DNA. In contrast, actinomycin D was found to preferentially disrupt EWS-FLI1 binding by comparison to p53 binding to their respective cognate DNA targets in vitro. In cell-based assays, low concentrations of actinomycin preferentially blocked EWS-FLI1 binding to chromatin, and disrupted EWS-FLI1-mediated gene expression. Higher concentrations of actinomycin globally repressed transcription. These results demonstrate that actinomycin preferentially disrupts EWS-FLI1 binding to DNA at selected concentrations. Although the window between this preferential effect and global suppression is too narrow to exploit in a therapeutic manner, these results suggest that base-preferences may be exploited to find DNA-binding compounds that preferentially disrupt subclasses of transcription factors.
Differential disruption of EWS-FLI1 binding by DNA-binding agents.
Cell line, Treatment
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