In order to identify targets of the transcription factor AUXIN RESPONSE FACTOR5 / MONOPTEROS (ARF5/MP), we compared transcriptomes of mp-B4149 mutant seedlings (9 day-old) and seedlings carrying the dexamethasone-inducible version of the MP inhibitor protein BODENLOS (GR-bdl). Without dexamethasone (DEX) treatment, this line is identical to the wild-type, while DEX treatment leads to strong inhibition of ARF-dependent transcription. To remove all endogenous MP-inhibiting Aux/IAA proteins, we treated mp or GR-bdl seedlings during 1 hour with auxin (50 micromolar Indole-3-Acetic Acid), either with or without a pretreatment with 10 micromolar DEX for 1 hour. Genes that are activated by MP are expected to br downregulated in mp seedlings and in the GR-bdl line afer DEX treatment. We used biological duplicates for each of the three treatments.
MONOPTEROS controls embryonic root initiation by regulating a mobile transcription factor.
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View SamplesArabidopsis plants growing under diurnal conditions were transferred to cold of approximately one day duration, starting at different times of the day. All comparisons are of unreplicated pairs and are thus not designed to identify cold-responsive gens in isolation but are rather to supplement existing publicly available data. The overall aim was to use a diverse set of experiments to see which factors have the greatest influence on the identity of cold-responsive genes.
Disruption of the Arabidopsis circadian clock is responsible for extensive variation in the cold-responsive transcriptome.
Age, Specimen part, Time
View SamplesTo address the neglected possibility for global mRNA changes in microarray experiments we developed a simple method to generate external controls for Affymetrix microarrays to allow these platforms to measure absolute mRNA expression at the global level. We used publicly available data to select probesets that never detect endogenous transcripts, and used PCR and IVT to generate synthetic mRNAs corresponding to them. After quality control and testing, these control transcripts were spiked into total RNA samples from plants before and after 24 h of cold treatment. Due to changes in the proportion of mRNA, these data reveal intensity-dependent bias in expression estimates based on standard all-gene normalizations. When not accounted for, this leads to false classification of the differential expression for thousands of genes.
Disruption of the Arabidopsis circadian clock is responsible for extensive variation in the cold-responsive transcriptome.
Age, Specimen part
View SamplesAnalysis of differences in gene expression between different cell types of the vascular niche. Looking for candidates, that could potentially be up-or downregualted in the different cell types
Pericyte-expressed Tie2 controls angiogenesis and vessel maturation.
Specimen part
View SamplesWNT-induced secreted protein 1 (WISP1/CCN4), a member of the CCN protein family, acts as a downstream factor of the canonical WNT-signaling pathway. A dysregulated expression of WISP1 often reflects its oncogenic potential by inhibition of apoptosis, a necessary form of cell death that protect cell populations for transformation into malignant phenotypes. WISP1-signaling is also known to affect proliferation and differentiation of human mesenchymal stem cells (hMSCs), which are fundamental for the constitution and maintenance of the musculoskeletal system. Our study emphasizes the importance of WISP1-signaling for cell survival of primary human cells. Therefore, we established a successful down-regulation of endogenous WISP1 transcripts through gene silencing in hMSCs. We were able to demonstrate the consequence of cell death immediately after WISP1 down-regulation took place. Bioinformatical analyses of subsequent performed microarrays from WISP1 down-regulated vs. control samples confirmed this observation. We uncovered several clusters of differential expressed genes important for cellular apoptosis induction and immuno-regulatory processes, thereby indicating TRAIL-induced and p53-mediated apoptosis as well as IFNbeta-signaling. Since all of them act as potent inhibitors for malignant cell growth, in vitro knowledge about the connection with WISP1-signaling could help to find new therapeutic approaches concerning cancerogenesis and tumor growth in musculoskeletal tissues.
WISP 1 is an important survival factor in human mesenchymal stromal cells.
Specimen part, Treatment
View SamplesIn this study we analyzed the myeloma cell contact-mediated changes on the transcriptome of skeletal precursor cells. Therefore, human mesenchymal stem cells (MSC) and osteogenic precursor cells (OPC) were co-cultured with the representative myeloma cell line INA-6 for 24 h. Afterwards, MSC and OPC were separated from INA-6 cells by fluorescence activated cell sorting. Total RNA of MSC and OPC fractions was used for whole genome array analysis.
Contact of myeloma cells induces a characteristic transcriptome signature in skeletal precursor cells -Implications for myeloma bone disease.
Sex, Age, Specimen part, Disease stage
View SamplesRecently, the p53-miR-34a network was identified to play an important role in tumorigenesis. As in acute myeloid leukemia with complex karyotype (CK-AML) TP53 alterations are the most common known molecular lesion, we further analyzed the p53-miR-34a axis in CK-AML with known TP53 status. Clinically, low miR-34a expression and TP53 alterations predicted for chemotherapy resistance and inferior outcome. Notably, in TP53unaltered CK-AML high miR-34a expression predicted for inferior overall survival (OS), whereas in TP53biallelic altered CK-AML high miR-34a expression pointed to better OS.
Altered miRNA and gene expression in acute myeloid leukemia with complex karyotype identify networks of prognostic relevance.
Disease
View SamplesTo characterize gene response in RPE65-/- mouse model of Lebers congenital amaurosis during progression of the disease, we analyzed differential gene expression in retinae early in the development of the disease, namely before and at the onset of photoreceptor cell death in knock-out mice of 2, 4 and 6 months of age.
Biological characterization of gene response in Rpe65-/- mouse model of Leber's congenital amaurosis during progression of the disease.
Age, Specimen part
View SamplesPurpose: In acute myeloid leukemia (AML) without retinoic acid receptor (RAR) rearrangement the effect of all-trans retinoic acid (ATRA) is still poorly understood despite an association of NPM1 mutation and ATRA response. Recently, PRAME (preferentially expressed antigen in melanoma) has been shown to be a dominant repressor of RAR-signaling. Experimental design: Thus, we further investigated ATRA response mechanisms, especially the impact of PRAME expression on ATRA-responsiveness by profiling gene expression in K562 cell lines. Results: Our data revealed a PRAME-expression associated gene pattern to be significantly enriched for genes involved in the retinoic acid metabolic process. In leukemia cell line models we could demonstrate that retinoic acid-regulated cell proliferation and differentiation are impacted by PRAME expression. Conclusions: PRAME seems to impair differentiation and to increase proliferation likely via blocking RAR-signaling, which might be reversed by ATRA.
PRAME-induced inhibition of retinoic acid receptor signaling-mediated differentiation--a possible target for ATRA response in AML without t(15;17).
Treatment
View SamplesThe transcription factor Evi1 is essential for the formation and maintenance of hematopoietic stem cells, and induces clonal dominance with malignant progression upon constitutive activation by chromosomal rearrangements or transgene integration events. To understand the immediate and adaptive response of primary murine hematopoietic cells to the transcriptional upregulation of Evi1, we developed an inducible lentiviral vector system with a robust expression switch. We found that Evi1 delays differentiation and promotes survival in myeloid culture conditions, orchestrating a battery of genes involved in stemness (Aldh1a1, Ly6a [Sca1], Abca1, Epcam, among others). Importantly, Evi1 suppresses Cyclins and Cyclin-dependent kinases (Cdk), while it upregulates Cdk inhibitors, inducing quiescence in various proliferation-inducing cytokine conditions and operating in a strictly dose-dependent manner. Hematopoietic cells with persisting Evi1-induction tend to adopt a relatively low expression level. We thus classify Evi1 as a dormancy-inducing oncogene, likely requiring epigenetic and genetic compensation for cell expansion and malignant progression.
Activation of Evi1 inhibits cell cycle progression and differentiation of hematopoietic progenitor cells.
Specimen part
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