A leukemia cell fraction highly enriched for LSCs was generated in a mouse model of AML induced by co-expression of MLL target genes Hoxa9 and Meis1. Limit dilution transplantation analyses performed on various prospectively isolated leukemia cell subpopulations revealed that cells capable of transplanting AML to syngeneic recipient mice (the operational definition of LSCs) were highly enriched in the leukemia cell fraction displaying an immunophenotype (Lin- Sca1- c-kit+ CD16/32+ CD34+) comparable to normal GMPs, referred to as L-GMPs. For the purpose of identifying genes that are differentially expressed in LSCs, microarray expression profiling was performed on L-GMPs (from leukemic mice) and GMPs (from normal mouse BM) purified by flow cytometry.
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View SamplesMouse lung samples from mice challenged with OVA or PBS control. Wildtype (B6) mice were tested, as well as mast cell deficient mice with engraftment of normal mast cells and mast cells deficient in IgE or Ifn-gamma signaling.
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Sex, Specimen part
View SamplesAfter 8 days of OKSM induction via doxycycline, Nanog-Neo secondary MEFs (Wernig et al. Nature Biotechnology 2008) were FACS sorted by KLF4, Oct4, and EpCAM expression. Four major subsets of MEFs have been sorted and analysed for gene expression.
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Specimen part
View SamplesGene expression profiling using microarray has been limited to profiling of differentially expressed genes at comparison setting since probesets for different genes have different sensitivities. We overcome this limitation by using a very large number of varied microarray datasets as a common reference, so that statistical attributes of each probeset, such as dynamic range or a threshold between low and high expression can be reliably discovered through meta-analysis. This strategy is implemented in web-based platform named Gene Expression Commons (http://gexc.stanford.edu/ ) with datasets of 39 distinct highly purified mouse hematopoietic stem/progenitor/functional cell populations covering almost the entire hematopoietic system. Since the Gene Expression Commons is designed as an open platform, any scientist can explore gene expression of any gene, search by expression pattern of interest, submit their own microarray datasets, and design their own working models.
Gene Expression Commons: an open platform for absolute gene expression profiling.
Sex, Age
View SamplesWe tested the hypothesis that a set of differentially expressed genes could be used to predict cardiovascular phenotype in mice after prolonged catecholamine stress.
Gene expression profiling: classification of mice with left ventricle systolic dysfunction using microarray analysis.
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View SamplesThe regulatory logic underlying global transcriptional programs controlling development of visceral organs like the pancreas remains undiscovered. Here, we profiled gene expression in 12 purified populations of fetal and adult pancreatic epithelial cells representing crucial progenitor cell subsets, and their endocrine or exocrine progeny. Using probabilistic models to decode the general programs organizing gene expression, we identified co-expressed gene modules in cell subsets that revealed patterns and processes governing progenitor cell development, lineage specification, and endocrine cell maturation. Module network analysis linked established regulators like Neurog3 to unrecognized roles in endocrine secretion and protein transport, and nominated multiple candidate regulators of pancreas development. Phenotyping mutant mice revealed that candidate regulatory genes encoding transcription factors, including Bcl11a, Etv1, Prdm16 and Runx1t1, are essential for pancreas development or glucose control. Our integrated approach provides a unique framework for identifying regulatory networks underlying pancreas development and diseases like diabetes mellitus.
An integrated cell purification and genomics strategy reveals multiple regulators of pancreas development.
Specimen part
View SamplesInfection of RAW264.7 cells for 24 hours with 32 Toxoplasma Progeny from a Type II x Type III cross
GRA25 is a novel virulence factor of Toxoplasma gondii and influences the host immune response.
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View SamplesEpigenetic modifications must underlie lineage-specific differentiation since terminally differentiated cells express tissue-specific genes, but their DNA sequence is unchanged. Hematopoiesis provides a well-defined model of progressive differentiation in which to study the role of epigenetic modifications in cell fate decisions. Multi-potent progenitors (MPPs) can differentiate into all blood cell lineages, while downstream progenitors commit to either myeloerythroid or lymphoid lineages. While DNA methylation is critical for myeloid versus lymphoid differentiation, as demonstrated by the myeloerythroid bias in Dnmt1 hypomorphs {Broske, 2009 #6}, a comprehensive DNA methylation map of hematopoietic progenitors, or of any cell lineage, does not exist. Here we have generated a mouse DNA methylation map, examining 4.6 million CpG sites throughout the genome including all CpG islands and shores, examining MPPs, all lymphoid progenitors (ALPs), common myeloid progenitors (CMPs), granulocyte/macrophage progenitors (GMPs), and thymocyte progenitors (DN1, DN2, DN3). Interestingly, differentiation towards the myeloid lineage corresponds with a net decrease in DNA methylation, while lymphoid commitment involves a net increase in DNA methylation, but both show substantial dynamic changes consistent with epigenetic plasticity during development. By comparing lineage-specific DNA methylation to gene expression array data, we find many examples of genes and pathways not previously known to be involved in lymphoid/myeloid differentiation, such as Gcnt2, Arl4c, Gadd45, and Jdp2. Several transcription factors, including Meis1 and Prdm16 were methylated and silenced during differentiation, suggesting a role in maintaining an undifferentiated state. Additionally, epigenetic modification of modifiers of the epigenome appears to be important in hematopoietic differentiation. Our results directly demonstrate that modulation of DNA methylation occurs during lineage-specific differentiation, often correlating with gene expression changes, and define a comprehensive map of the methylation and transcriptional changes that accompany myeloid versus lymphoid fate decisions.
Comprehensive methylome map of lineage commitment from haematopoietic progenitors.
Sex, Age
View SamplesAs a critical cellular stress sensor, p53 mediates a variety of defensive processes including cell-cycle arrest, apoptosis, and senescence to prevent propagation of hyperproliferative cells or cells with a damaged genome, hence the formation of neoplasia. Transactivation of downstream genes plays an important while sometimes controversial role in regulating these cellular processes. To evaluate the dependence on transcriptional activation in p53s activities, we generated genetically-modified mouse lines carrying mutations in the transactivation domains (TADs) of p53. These transactivatio-deficient mutants serve as unique reagents to probe the dependence on robust transactivation in p53-mediated cellular functions, as well as the underneath mechanisms. To identify genes differentially regulated by these p53 mutants, we performed gene expression profiling analysis on mouse embryonic fibroblast cells (MEFs) from these mice in the context of oncogenic Ras-induced premature cellular senescence.
Distinct p53 transcriptional programs dictate acute DNA-damage responses and tumor suppression.
Specimen part
View SamplesK-ras is one of the most frequently mutated human oncogenes. Activation of K-ras can lead to either senescence or proliferation in primary cells. The precise mechanism governing these distinct outcomes remains unclear. Here we utilized a loss-of-function screen to assess the role of specific genes identified as potential key regulators of K-ras driven oncogenesis. Using this approach, we identify the transcription factor Wt1 as an inhibitor of senescence in primary cells expressing oncogenic K-ras. Deletion or suppression of Wt1 expression leads to senescence of primary cells expressing oncogenic K-ras under the control of the native promotor at physiological levels, but has no effect on cells expressing wild-type K-ras. Wt1 contributes to K-ras driven lung tumorigenesis in vivo and loss of Wt1 is specifically deleterious to human lung cancer cell lines that are dependent on oncogenic K-ras. Taken together, these observations reveal a novel role for Wt1 as a key regulator of the complex genetic network required for the oncogenic effect of the small GTPase K-ras.
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Specimen part
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