The Structural Maintenance of Chromosomes (SMC) complexes regulate the chromosome structures essential for proper genome regulation and cell viability. In mammals, the coordinated actions of the SMC complexes condensin I, condensin II and cohesin regulate dynamic chromosome structures throughout the cell cycle, but it is not clear how these complexes are positioned across the genome. We report here that condensin I, condensin II and cohesin occupy active euchromatic regions of the embryonic stem cell genome, but not heterochromatic regions. Like cohesin, we find that condensin II is deposited at active genes by the SMC loading factor Nipbl. The recruitment of Condensin II to active genes is dependent on their transcriptional activation. Subsequent transcriptional elongation by RNA polymerase II distributes condensin II across gene bodies. During mitosis, condensin I occupies the same set of active genes occupied by condensin II during interphase. Thus, SMC complexes are positioned in the genome by transcription-dependent processes, indicating that condensin-dependent condensation mechanisms are preferentially utilized in euchromatic regions. Overall design: RNA-seq in mES cells after known-down of Smc1, CapH2 or Smc2.
Multiple structural maintenance of chromosome complexes at transcriptional regulatory elements.
Specimen part, Subject
View SamplesYeast cell cycle transcription dynamics in two S. cerevisae strains grown at 37C: BF264-15DU (MATa ade1 his2 leu2-3, 112 trp1-1 ura3Dns, bar1) (wild type) and a mutant of the wild type strain lacking all Cdk1 activity, cdc28-4.
Cyclin-dependent kinases are regulators and effectors of oscillations driven by a transcription factor network.
Time
View SamplesTranscriptional programs that regulate development are exquisitely controlled in space and time. Elucidating these programs that underlie development is essential to understanding the acquisition of cell and tissue identity. We present microarray expression profiles of a high resolution set of developmental time points within a single Arabidopsis root, and a comprehensive map of nearly all root cell-types. These cell-type specific transcriptional signatures often predict novel cellular functions. A computational pipeline identified dominant expression patterns that demonstrate transcriptional connections between disparate cell types. Dominant expression patterns along the roots longitudinal axis do not strictly correlate with previously defined developmental zones, and in many cases, expression fluctuation along this axis was observed. Both robust co-regulation of gene expression and potential phasing of gene expression were identified between individual roots. Methods that combine these two sets of profiles demonstrate transcriptionally rich and complex programs that define Arabidopsis root development in both space and time.
A high-resolution root spatiotemporal map reveals dominant expression patterns.
No sample metadata fields
View SamplesGene expression analysis is a widely used and powerful method for investigating the transcriptional behavior of biological systems, for classifying cell states in disease and for many other purposes. Recent studies indicate that common assumptions currently embedded in experimental and analytical practices can lead to misinterpretation of global gene expression data. We discuss these assumptions and describe solutions that should minimize erroneous interpretation of gene expression data from multiple analysis platforms. Overall design: Polyadenylated RNA depleted of ribosomal content was used for preparation of two independent sequencing libraries (low-Myc & high-Myc). A panel of synthetic RNA''s was added to these populations, based on cell number.
Revisiting global gene expression analysis.
Specimen part, Cell line, Subject
View SamplesA remarkable number of long non-coding RNA (lncRNA) species have been identified in mammalian cells, but the genomic origins of these molecules in individual cell types is poorly understood. As a prerequisite to studying the transcriptional regulation of lncRNAs, we conducted a comprehensive analysis of the genomic origins of lncRNAs expressed in embryonic stem cells (ESCs). Overall design: Polyadenylated RNA and total RNA depleted of ribosomal content was used for preparation of two independent sequencing libraries
Divergent transcription of long noncoding RNA/mRNA gene pairs in embryonic stem cells.
Specimen part, Cell line, Subject
View Samplesmmunosuppressive drugs can be completely withdrawn in up to 20% of liver transplant recipients, commonly referred to as operationally tolerant. Immune characterization of these patients, however, has not been performed in detail, and we lack tests capable of identifying tolerant patients among recipients receiving maintenance immunosuppression. In the current study we have analyzed a variety of biological traits in peripheral blood of operationally tolerant liver recipients in an attempt to define a multiparameter fingerprint of tolerance. Thus, we have performed peripheral blood gene expression profiling and extensive blood cell immunophenotyping on 16 operationally tolerant liver recipients, 16 recipients requiring on-going immunosuppressive therapy, and 10 healthy individuals. Microarray profiling identified a gene expression signature that could discriminate tolerant recipients from immunosuppression-dependent patients with high accuracy. This signature included genes encoding for ?d T-cell and NK receptors, and for proteins involved in cell proliferation arrest. In addition, tolerant recipients exhibited significantly greater numbers of circulating potentially regulatory T-cell subsets (CD4+CD25+ T-cells and Vd1+ T cells) than either non-tolerant patients or healthy individuals. Our data provide novel mechanistic insight on liver allograft operational tolerance, and constitute a first step in the search for a non-invasive diagnostic signature capable of predicting tolerance before undergoing drug weaning.
Multiparameter immune profiling of operational tolerance in liver transplantation.
No sample metadata fields
View SamplesLow levels of the cell cycle regulator p27Kip1 are associated with a worse outcome in many tumor types. We report here a new regulatory role of p27Kip1 as a transcriptional regulator. In association with transcriptional factors such as ETS and E2F4 and co-repressors like p130, HDACs and mSin3A, p27 binds to promoters of multiple genes leading to their repression. The p27-target genes participate in RNA processing, translation, respiration and cell cycle. Remarkably, p27-target genes are over-expressed in different human tumors in tight association with a poor clinical prognosis. We also observed a clear correlation between low levels of p27 and over-expression of p27-target genes in tumors. Overall, our findings indicate new tumor suppressor roles of p271 as a transcriptional regulator of genes relevant for oncogenesis.
p27Kip1 represses transcription by direct interaction with p130/E2F4 at the promoters of target genes.
Specimen part
View SamplesReliable identification of cancer markers can have substantial implications to early detection of cancer. We report here an integrated computational and experimental study on identification of gastric cancer markers in patients tissue and sera based on (i) genome-scale transcriptomic analyses on 80 paired gastric cancer/reference tissues, with the aim of identifying abnormally expressed genes at various subtypes/stages of gastric carcinoma (ii) a computational identification of differentially expressed genes that may have their proteins secreted into blood circulation, followed by experimental validations.
An integrated transcriptomic and computational analysis for biomarker identification in gastric cancer.
Sex, Age, Specimen part, Disease stage
View SamplesAlthough a considerable number of reports indicate an involvement of the Hox-A10 gene in the molecular control of hematopoiesis, the conclusions of such studies are quite controversial since they support, in some cases, a role in the stimulation of stem cell self-renewal and myeloid progenitor expansion while, in others, implicate this transcription factor in the induction of monocyte - macrophage differentiation. To clarify this issue we analyzed the biological effects and the transcriptome changes determined in human primary CD34+ hematopoietic progenitors by retroviral transduction of a full length Hox-A10 cDNA. The results obtained clearly indicated that this homeogene is an inducer of monocyte differentiation, at least partly acting through the up-regulation of MafB gene, recently identified as master regulator of such maturation pathway. By using a combined approach based on computational analysis, EMSA experiments and luciferase assays, we were able to demonstrate the presence of a Hox-A10 binding site in the promoter region of the MafB gene, which suggested the likely molecular mechanism underlying the observed effect. Interestingly, stimulation of the same cells with the Vitamin D3 monocyte differentiation inducer resulted in a clear increase of Hox-A10 and MafB transcripts, indicating the existence of a precise transactivation cascade involving VDR, Hox-A10 and MafB transcription factors. Altogether these data allow to conclude that the Vitamin D3 / Hox-A10 pathway supports MafB function during the induction of monocyte differentiation.
The vitamin D3/Hox-A10 pathway supports MafB function during the monocyte differentiation of human CD34+ hemopoietic progenitors.
No sample metadata fields
View SamplesIncreasing evidence suggests that cancer arises from cells that are capable of initiating and sustaining neoplastic tissue growth, termed cancer stem cells (CSCs). Of central scientific and clinical relevance, cells with CSC properties are enriched for chemo- and radiation resistance and therefore may represent a population of cells that must be therapeutically targeted to prevent cancer recurrence/relapse 1. Human CSCs were first isolated in neoplastic hematopoietic tissue that manifests leukemias such as adult acute myeloid leukemia (AML) 2. AML stem cells represent a benchmark model of human CSC biology, ultimately motivating foundational studies leading to the identification of CSCs from solid tumours such as breast and colon 3. Independent of tissue type, a consistent feature of CSCs is their uncontrolled self-renewal capacity and differentiation blockade that have been commonly related to aberrant activation of pro-oncogenic events such as dysregulation of CBP/p300 transcriptional regulation involving -catenin 4. However, the transcriptional networks involving CBP/p300/-catenin complex have been shown to be equally critical to maintain normal stem cell (SCs) self-renewal for tissue homeostasis and regeneration 5. Here, we identify Sam68 as a distinct target that affords the ability to uniquely regulate CBP mediated transcription in human CSCs. Using a small molecule that targets Sam68, we reveal that shifting its affinity for CBP disrupts CBP/-catenin complexes, leading to immediate changes in histone H3 (K14 and K18) acetylation. Chemical targeting of Sam68 induced global changes in transcriptional programs of patient AML cells involving apoptosis and differentiation and was able to uniquely reduce neoplastic self-renewal of human CSCs in an in vivo model of patient specific acute myeloid leukemia (AML). Our study establishes an approach whereby the CBP/-catenin transcriptome can be uniquely targeted via Sam68 based vulnerability of CSCs that impacts neoplastic differentiation and self-renewal.
Sam68 Allows Selective Targeting of Human Cancer Stem Cells.
Specimen part, Treatment
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