Current expression profiling methods use RNA from hundreds of thousands or thousands cells. Many fields of biology can not use microarrays due to the nature of the biological systems used that are formed by hundreds or dozens of cells. Here we present a method that can handle RNA amount limitation and gives gene expression profiles from as little as 10 cells. We first validate the method hybridizing amplified RNA from MAQC samples A and B. To do that, 25 ng or 100 pg were used and expression profiles obtained as good as when compared to Affymetrix's chemistry for amplification and labeling. The same experiment was done but using sorted cells from two comercial cell lines (SW620 and SW480) obtaining the same differential expression profiling from 2000 cells or 10 cells. The central step of the method is Whole Transcriptome Amplification (WTA) from Sigma that allows the amplification of very small amounts of RNA as starting material.
Accurate expression profiling of very small cell populations.
Cell line
View SamplesWe present a novel method of using commercial oligonucleotide expression microarrays for aCGH, enabling DNA copy number measurements and expression profiles to be combined using the same platform. This method yields aCGH data from genomic DNA without complexity reduction at a median resolution of approximately 17,500 base pairs. Due to the well-defined nature of oligonucleotide probes, DNA amplification and deletion can be defined at the level of individual genes and can easily be combined with gene expression data.
Gene-resolution analysis of DNA copy number variation using oligonucleotide expression microarrays.
No sample metadata fields
View SamplesHOXB4 mediates expansion of adult and embryo-derived hematopoietic stem cells (HSCs) when expressed ectopically. To define the underlying molecular mechanisms, we performed gene expression profiling in combination with subsequent functional analysis using enriched adult HSCs expressing inducible HOXB4. A substantial number of the identified HOXB4 target genes are involved in signaling pathways important for controlling self-renewal, maintenance and differentiation of stem cells. Functional assays performed on selected pathways confirmed the biological coherence of the array results. HOXB4 activity protected adult HSCs from the detrimental effects mediated by the proinflammatory cytokine TNF-alpha. Furthermore, we demonstrate that HOXB4 activity and FGF-signaling are intertwined. HOXB4-mediated expansion of adult HSCs was enhanced by specific and complete inhibition of FGF-receptors. Based on our results we propose that HOXB4 governs pivotal cell-intrinsic pathways involved in the regulation of cell cycle, differentiation and apoptosis. Our results strongly suggest that HOXB4 modulates the response of HSCs to multiple extrinsic signals in a concerted manner, thereby shifting the balance towards stem cell self-renewal.
HOXB4's road map to stem cell expansion.
No sample metadata fields
View SamplesTo unravel the molecular mechanism by which HOXB4 promotes the expansion of early hematopoietic progenitors within differentiating ES cells, we analzed the gene expression profiles of embryoid bodies (EBs) in which transcription of HOXB4 had been induced or not induced. A substantial number of the identified HOXB4 target genes are involved in signaling pathways important for controlling self-renewal, maintenance and differentiation of stem cells. Furthermore, we demonstrate that HOXB4 activity and FGF-signaling are intertwined. HOXB4-mediated expansion of ES cell-derived early progenitors was enhanced by specific and complete inhibition of FGF-receptors. In contrast, the expanding activity of HOXB4 on hematopoietic progenitors in day4-6 embryoid bodies was blunted in the presence of basic FGF (FGF2) indicating a dominant negative effect of FGF-signaling on the earliest hematopoietic cells. Taken together, we show that modulation of FGF signaling is an essential feature of HOXB4 activity in the context of embryonic hematopoiesis.
HOXB4's road map to stem cell expansion.
No sample metadata fields
View SamplesThis sample is part of a study that compares small sample amplification technologies. The analysis looks at differential gene expression when compared to one round of T7 amplification. A tumor cell line was used in comparison to a human reference RNA in this study.
Big results from small samples: evaluation of amplification protocols for gene expression profiling.
No sample metadata fields
View SamplesAnalysis of the transcriptome of dry hda9-1 mutant seeds with those of Col wild-type seeds, using Affymetrix GeneChip Arabidopsis ATH1 Genome Array.
HISTONE DEACETYLASE 9 represses seedling traits in Arabidopsis thaliana dry seeds.
Specimen part
View SamplesMutations in the genes encoding isocitrate dehydrogenase 1 and 2 (IDH1/2) occur in a variety of tumor types, resulting in production of the proposed oncometabolite, 2-hydroxyglutarate (2-HG). How mutant IDH and 2-HG alter signaling pathways to promote cancer, though, remains unclear. Additionally, there exist relatively few cell lines with IDH mutations. To examine the effect of endogenous IDH mutations and 2-HG, we created a panel of isogenic epithelial cell lines with either wild-type IDH1/2 or clinically relevant IDH1/2 mutations. Differences were noted in the ability of IDH mutations to cause robust 2-HG accumulation. IDH1/2 mutants that produce high levels of 2-HG cause an epithelial-mesenchymal transition (EMT)-like phenotype, characterized by changes in EMT-related gene expression and cellular morphology. 2-HG is sufficient to recapitulate aspects of this phenotype in the absence of an IDH mutation. In the cells types examined, mutant IDH-induced EMT is dependent on upregulation of the transcription factor ZEB1 and downregulation of the mir-200 family of microRNAs. Furthermore, sustained knockdown of IDH1 in IDH1 R132H mutant cells is sufficient to reverse many characteristics of EMT, demonstrating that continued expression of mutant IDH is required to maintain this phenotype. These results suggest mutant IDH proteins can reversibly deregulate discrete signaling pathways that contribute to tumorigenesis
Isocitrate dehydrogenase (IDH) mutations promote a reversible ZEB1/microRNA (miR)-200-dependent epithelial-mesenchymal transition (EMT).
Cell line
View Samples3 pairs of wt and ClC-6 knockout mice, RNA from p14 hippocampus
Lysosomal storage disease upon disruption of the neuronal chloride transport protein ClC-6.
Sex, Age, Specimen part, Subject, Time
View SamplesBackground. Multiple myeloma (MM) cells depend on the bone marrow (BM) niche for growth and survival. However, the tumor genes regulated by the niche are largely unknown.
Niche-modulated and niche-modulating genes in bone marrow cells.
Disease, Disease stage, Time
View SamplesGene expression profile (GEP) was analyzed in bone marrow (BM) samples from patients with leukemia or leukemic phase of lymphoma at different time points following aspiration. Among numerous changes in GEP evolved over time a discrete subset of > 60 genes exhibited prompt and sustained switch in expression consistently. Similar results were discovered recently in BM samples from patients with multiple myeloma (GSE36036). GEP was also examined in peripheral blood as well as in BM samples depleted of red blood cells (=WBC) and in cultured cells from some of the patients.
Niche-modulated and niche-modulating genes in bone marrow cells.
Specimen part, Disease
View Samples