Inducible overexpression of Arabidopsis meristem regulators by AlcR / AlcA system. Plants harboring 35S::AlcR/AlcA::GOI (GUS control, LEAFY, SHOOTMERSTEMLESS, WUSCHEL)constructs were grown in continous light for 12 days and induced with 1% Ethanol. After 12h of EtOH treatment, seedlings were dissected and RNA was processed from the shoot apex and young leaves. Affymetrix Ath1 arrays were hybridized in duplicates from each experiment.
WUSCHEL controls meristem function by direct regulation of cytokinin-inducible response regulators.
Age, Specimen part, Subject, Compound
View SamplesThe biology of chronic myeloid leukemia (CML)-stem cells is still incompletely understood. Therefore, we previously developed an inducible transgenic mouse model in which stem cell targeted induction of BCR-ABL expression leads to chronic phase CML-like disease. Here, we now demonstrate that the disease is transplantable using BCR-ABL positive LSK cells (lin-Sca-1+c-kit+). Interestingly, the phenotype is enhanced when unfractionated bone marrow (BM) cells are transplanted. However, neither progenitor cells (lin-Sca-1-c-kit+) nor mature granulocytes (CD11b+Gr-1+), or potential stem cell niche cells were able to transmit the disease or alter the phenotype. The phenotype was largely independent of BCR ABL priming prior to transplant. However, BCR-ABL abrogated the potential of LSK cells to induce full blown disease in secondary recipients. Subsequently, we found that BCR-ABL increased the fraction of multipotent progenitor cells (MPP) at the expense of long term HSC (LT-HSC) in the BM. Microarray analyses of LSK cells revealed that BCR-ABL alters the expression of genes involved in proliferation, survival, and hematopoietic development. Our results suggest that BCR-ABL induces differentiation of LT-HSC and decreases their self renewal capacity. Furthermore, reversion of BCR-ABL eradicates mature cells while leukemic stem cells persist, giving rise to relapsed CML upon re-induction of BCR-ABL.
BCR-ABL enhances differentiation of long-term repopulating hematopoietic stem cells.
Specimen part
View SamplesMaintaining cell fate relies on robust mechanisms that prevent the differentiation of specified cells into other cell types. This is especially critical during embryogenesis, when extensive cell proliferation, patterning and migration events take place. Here we show that vertebrate primordial germ cells (PGCs) are protected from reprogramming into other cell types by the RNA-binding protein Dead end (Dnd). PGCs knocked down for Dnd lose their characteristic morphology and adopt that of various somatic cell types. Concomitantly, they gain a gene expression profile reflecting differentiation into cells of different germ layers, in a process that we could direct by expression of specific cell-fate determinants. Importantly, we visualized these events within live zebrafish embryos, which provide temporal information regarding cell reprogramming. Our results shed light on the mechanisms controlling germ cell fate maintenance and are relevant for the formation of teratoma, a tumor class composed of cells from more than one germ layer. Overall design: Transcriptome profiling of 13hpf sorted germ cells of zebrafish embryos injected with either control or dead end Morpholino
The Vertebrate Protein Dead End Maintains Primordial Germ Cell Fate by Inhibiting Somatic Differentiation.
Specimen part, Cell line, Subject
View SamplesMouse and human stem cells with features similar to those of embryonic stem cells have been derived from testicular cells. Although pluripotent stem cells have been obtained from defined germline stem cells (GSCs) of mouse neonatal testis, only multipotent stem cells have been obtained so far from defined cells of mouse adult testis. In this study we describe a robust and reproducible protocol for obtaining germline-derived pluripotent stem (gPS) cells from adult unipotent GSCs. Pluripotency of gPS cells was confirmed by in vitro and in vivo differentiation, including germ cell contribution and transmission. As determined by clonal analyses, gPS cells indeed originate from unipotent GSCs. We propose that the conversion process requires a GSC culture microenvironment that depends on the initial number of plated GSCs and the length of culture time.
Induction of pluripotency in adult unipotent germline stem cells.
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View SamplesMouse and human stem cells with features similar to those of embryonic stem cells have been derived from testicular cells. Although pluripotent stem cells have been obtained from defined germline stem cells (GSCs) of mouse neonatal testis, only multipotent stem cells have been obtained so far from defined cells of mouse adult testis. In this study we describe a robust and reproducible protocol for obtaining germline-derived pluripotent stem (gPS) cells from adult unipotent GSCs. Pluripotency of gPS cells was confirmed by in vitro and in vivo differentiation, including germ cell contribution and transmission. As determined by clonal analyses gPS cells indeed originate from unipotent GSCs. We propose that the conversion process requires a GSC culture microenvironment that depends on the initial number of plated GSCs and the length of culture time.
Induction of pluripotency in adult unipotent germline stem cells.
Specimen part
View SamplesThe original objectives of the study were to identify surface markers specifically expressed in motor neurons. We now use the data to profile the expression of Cdk family members in motor neurons.
Dual Inhibition of GSK3β and CDK5 Protects the Cytoskeleton of Neurons from Neuroinflammatory-Mediated Degeneration In Vitro and In Vivo.
Specimen part
View SamplesAnalysis of the effect on global gene regulation in epididymal adipose tissue of overexpressing the cytoskeletal tropomyosin, Tm5NM1 to help understand the transcriptional events that lead to increased fat mass in transgenic mice.
Regulation of cell proliferation by ERK and signal-dependent nuclear translocation of ERK is dependent on Tm5NM1-containing actin filaments.
Specimen part
View SamplesIschemic tolerance can be induced by numerous preconditioning stimuli, including various Toll-like receptor (TLR) ligands. We have shown previously that systemic administration of the TLR4 ligand, lipopolysaccharide (LPS) or the TLR9 ligand, unmethylated CpG ODNs prior to transient brain ischemia in mice confers substantial protection against ischemic damage. To elucidate the molecular mechanisms of preconditioning, we compared brain and blood genomic profiles in response to preconditioning with these TLR ligands and to preconditioning via exposure to brief ischemia.
Multiple preconditioning paradigms converge on interferon regulatory factor-dependent signaling to promote tolerance to ischemic brain injury.
Specimen part, Treatment
View SamplesPrimary tumor growth induces host tissue responses that are believed to support and promote tumor progression. Identification of the molecular characteristics of the tumor microenvironment and elucidation of its crosstalk with tumor cells may therefore be crucial for improving our understanding of the processes implicated in cancer progression, identifying potential therapeutic targets, and uncovering stromal gene expression signatures that may predict clinical outcome. A key issue to resolve, therefore, is whether the stromal response to tumor growth is largely a generic phenomenon, irrespective of the tumor type, or whether the response reflects tumor-specific properties. To address similarity or distinction of stromal gene expression changes during cancer progression, oligonucleotide-based Affymetrix microarray technology was used to compare the transcriptomes of laser-microdissected stromal cells derived from invasive human breast and prostate carcinoma. Invasive breast and prostate cancer-associated stroma was observed to display distinct transcriptomes, with a limited number of shared genes. Interestingly, both breast and prostate tumor-specific dysregulated stromal genes were observed to cluster breast and prostate cancer patients, respectively, into two distinct groups with statistically different clinical outcomes. By contrast, a gene signature that was common to the reactive stroma of both tumor types did not have survival predictive value. Univariate Cox analysis identified genes whose expression level was most strongly associated with patient survival. Taken together, these observations suggest that the tumor microenvironment displays distinct features according to the tumor type that provides survival-predictive value.
Identification of prognostic molecular features in the reactive stroma of human breast and prostate cancer.
Specimen part
View SamplesWe used microarrays to detail the global program of gene expression during early hESC differentiation to mesendoderm using FBS, with and without RUNX1 depletion.
Transient RUNX1 Expression during Early Mesendodermal Differentiation of hESCs Promotes Epithelial to Mesenchymal Transition through TGFB2 Signaling.
Specimen part, Cell line
View Samples