Imatinib has become the current standard therapy for patients with chronic myelogenous leukaemia (CML). For a better understanding of the Imatinib-related molecular effects in vivo, we assessed gene expression profiles of Philadelphia Chromosome positive (Ph+) CD34+ cells from peripheral blood of 6 patients with de novo CML in chronic phase. After 7 days of treatment with Imatinib the Ph+ CD34+ cells were reassessed to look for changes in the transcriptome. The expression level of 303 genes was significantly different comparing the transcriptome of the Ph+ CD34+ cells before and after 7 days of Imatinib therapy (183 down-regulated, 120 up-regulated, lower bound 1.2-fold). For a substantial number of genes governing cell cycle and DNA replication, the level of expression significantly decreased (CDC2, RRM2, PCNA, MCM4). On the other hand, therapy with Imatinib was associated with an increase of genes related to adhesive interactions, such as L-selectin or CD44. A group of 8 genes with differential expression levels were confirmed using a gene specific quantitative real-time PCR. Thus, during the first week of treatment, Imatinib is preferentially counteracting the bcr-abl induced effects related to a disturbed cell cycle and defective adhesion of leukemic Ph+ CD34+ cells.
Early in vivo changes of the transcriptome in Philadelphia chromosome-positive CD34+ cells from patients with chronic myelogenous leukaemia following imatinib therapy.
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View SamplesAcetyltransferases and histone deacetylases regulate gene expression at the level of chromatin, mainly by affecting transcription. In this study, we report that hyperacetylation induced by inhibition of histone deacetylases (HDACs) causes massive degradation of mRNA. The effect is promoter-independent and affects poly-A mRNA globally. HDAC inhibition leads to the removal of poly-A tails from mRNAs through activation of the deadenylase CAF1a, which we find to be acetylated together with its activator BTG2 by the histone acetyl transferases (HATs) p300 and CBP. By mutation of critical lysine residues, we provide evidence that acetylation of CAF1a and BTG2 induces enhanced poly-A mRNA degradation. Our study reveals a fundamental mechanism by which cells coordinate epigenetic and transcriptional control of gene expression with posttranscriptional control of poly-A mRNA stability. In this experiment, HeLa cells were exposed to the HDAC inhibitor trichostatin A (TSA) for 16 hours, followed by treatment with actinomycin D. Total RNA was isolated after 0, 2, 4 and 6 hours, and analysed by RNA sequencing. The half-lives of 7431 RNAs were calculated after normalization to rRNA (18S + 28S) levels. The experiment shows that TSA treatment causes a general reduction of poly-A RNA stability, while replication-dependent histone mRNA stability is not affected. Overall design: RNA half-lives were measured in TSA-treated or untreated HeLa cells by RNA-Seq using Illumina HiSeq 2000.
Acetylation-Dependent Control of Global Poly(A) RNA Degradation by CBP/p300 and HDAC1/2.
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View SamplesFlowering time is a complex trait regulated by many genes that are integrated in different genetic pathways. Different genetic screenings carried out during the past decades have revealed an intrincated genetic regulatory network governing this trait. Efforts aimed at improving our understanding of how such genetic pathways respond to genetic and enviromental cues are needed.
The arabidopsis DNA polymerase δ has a role in the deposition of transcriptionally active epigenetic marks, development and flowering.
Age, Specimen part
View SamplesWe found that composition of cell subsets within the CD34+ cell population is markedly altered in chronic phase (CP) chronic myeloid leukemia (CML). Specifically, proportions and absolute cell counts of common myeloid progenitors (CMP) and megakaryocyte-erythrocyte progenitors (MEP) are significantly greater in comparison to normal bone marrow whereas absolute numbers of hematopoietic stem cells (HSC) are equal. To understand the basis for this, we performed gene expression profiling (Affymetrix HU-133A 2.0) of the distinct CD34+ cell subsets from six patients with CP CML and five healthy donors. Euclidean distance analysis revealed a remarkable transcriptional similarity between the CML patients' HSC and normal progenitors, especially CMP. CP CML HSC were transcriptionally more similar to their progeny than normal HSC to theirs, suggesting a more mature phenotype. Hence, the greatest differences between CP CML patients and normal donors were apparent in HSC including downregulation of genes encoding adhesion molecules, transcription factors, regulators of stem-cell fate and inhibitors of cell proliferation in CP CML. Impaired adhesive and migratory capacities were functionally corroborated by fibronectin detachment analysis and transwell assays, respectively. Based on our findings we propose a loss of quiescence of the CML HSC on detachment from the niche leading to expansion of myeloid progenitors.
The hematopoietic stem cell in chronic phase CML is characterized by a transcriptional profile resembling normal myeloid progenitor cells and reflecting loss of quiescence.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Telomerase inhibition effectively targets mouse and human AML stem cells and delays relapse following chemotherapy.
Specimen part
View SamplesGenome-wide transcriptional profiling of purified telomerase deficient (Terc-/-) and WT LSCs was performed in order to gain insights into the mechanisms underlying the susceptibilities of Terc-/- LSCs in vivo.
Telomerase inhibition effectively targets mouse and human AML stem cells and delays relapse following chemotherapy.
Specimen part
View SamplesThe root epidermis of Arabidopsis provides a simple and experimentally useful model for studying the molecular basis of cell fate and differentiation. The goal of this study was to define the transcript changes in the root epidermis of mutants associated with root epidermis cell specification, including mutants that lack a visible phenotypic alteration (try, egl3, myb23, and ttg2). Transcript levels were assessed by purifying populations of root epidermal cells using fluorescence-based cell-sorting with the WER::GFP transgene. These microarray results were used to compare the effects of single and double mutants on the gene regulatory network that controls root epidermal cell fate and differentiation in Arabidopsis.
Tissue-specific profiling reveals transcriptome alterations in Arabidopsis mutants lacking morphological phenotypes.
Specimen part
View SamplesMultiple myeloma (MM) is a clonal plasma cell disorder frequently accompanied by hematopoietic impairment. Genomic profiling of distinct HSPC subsets revealed a consistent deregulation of signaling cascades, including TGF beta signaling, p38MAPK signaling and pathways involved in cytoskeletal organization, migration, adhesion and cell cycle regulation in MM patients.
Multiple myeloma-related deregulation of bone marrow-derived CD34(+) hematopoietic stem and progenitor cells.
Specimen part, Disease, Disease stage
View SamplesThe root epidermis of Arabidopsis provides a simple and experimentally useful model for studying the molecular basis of cell fate and differentiation. The goal of this study was to define the larger gene regulatory network that governs the differentiation of the root hair and non-hair cell types of the Arabidopsis root epidermis. Transcript levels in the root epidermis of wild-type and mutant lines were assessed by purifying populations of root epidermal cells using fluorescence-based cell-sorting. Further, the role of the plant hormones auxin and ethylene on root epidermis development was assessed by defining transcript levels in the root epidermis of plants grown on media containing IAA or ACC. These microarray results were used to construct a comprehensive gene regulatory network that depicts the transcriptional control of root epidermal cell fate and differentiation in Arabidopsis.
A gene regulatory network for root epidermis cell differentiation in Arabidopsis.
Specimen part
View SamplesAssessing the impact of HIV-1 infection on trancriptional program of quiescent CD4 T lymphocytes. Such cells were made susceptible to HIV-1 by dowmodulating SAMHD1 restriction factor using VLP-Vpx without any activation signal.
CD32a is a marker of a CD4 T-cell HIV reservoir harbouring replication-competent proviruses.
Sex, Specimen part
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