A fundamental question in biology is how gene expression is regulated to give rise to a phenotype. However, transcriptional variability is rarely considered and could influence the relationship between genotype and phenotype. It is known in unicellular organisms that gene expression is often noisy rather than uniform and has been proposed to be beneficial when environmental conditions are unpredictable. However, little is known about transcriptional variability in multicellular organisms. Using transcriptomic approaches, we analysed gene expression variability over a 24 hours time-course between individual Arabidopsis thaliana plants growing in stable conditions. We identified hundreds of genes that exhibit high inter-individual variability and found that many are involved in environmental responses. We also identified factors that might facilitate gene expression variability, such as gene size, the number of transcription factors regulating a gene and the chromatin environment. These results will bring a new light into the impact of transcriptional variability in gene expression regulation in plants. Overall design: RNA-seq were generated for 14 individual seedlings for each of the 12 following time points: ZT2, ZT4, ZT6, ZT8, ZT10, ZT12 (just before dusk), ZT14, ZT16, ZT18, ZT20, ZT22 and ZT24 (just before dawn).
Widespread inter-individual gene expression variability in <i>Arabidopsis thaliana</i>.
Specimen part, Subject, Time
View SamplesContrasting with fish or amphibian, retinal regeneration from Müller glial cells is largely limited in mammals. In our quest towards the identification of molecular cues that may boost their stemness potential, we investigated the involvement of the Hippo pathway effector YAP, which we previously found to be upregulated in Müller cells following retinal injury. We report that conditional Yap deletion in Müller cells prevents the upregulation of cell cycle genes that normally accompanies reactive gliosis upon photoreceptor cell death. This occurs as a consequence of defective EGFR signaling. Consistent with a function of YAP in triggering Müller glia cell cycle re-entry, we further show that in Xenopus, a species endowed with efficient regenerative capacity, YAP is required for their injury-dependent proliferative response. Finally, and noteworthy, we reveal that YAP overactivation in mouse Müller cells is sufficient to induce their reprogramming into highly proliferative cells. Overall, we unravel a pivotal role for YAP in tuning Müller cell response to injury and highlight a novel YAP-EGFR axis by which Müller cells exit their quiescence state, a critical step towards regeneration. Overall design: Retinal samples were harvested from Yapflox/flox; Rax-CreERT2 mouse line allowing for Cre-mediated conditional gene ablation specifically in Müller cells. It is named Yap CKO while “control” refers to Yapflox/flox mice. Yap deletion was induced in fully differentiated Müller cells, through 4-hydroxytamoxifen (4-OHT) intraperitoneal injection at P10. All animals were injected with 4-OHT. Each sample included 1 frozen retina and experiments were performed in triplicate. RNA-seq transcriptome libraries were constructed from 1 ug of total RNA.
Linking YAP to Müller Glia Quiescence Exit in the Degenerative Retina.
Specimen part, Subject
View SamplesPTEN is thought to play a critical role in T cell activation by negatively regulating the PI3K signaling pathway important for cellular activation, growth, and proliferation. T cells from mice in which PTEN was conditionally deleted in the thymus were reported to display CD28-independent IL-2 production and relative resistance to anergy induction. However, such observations could have stemmed from alterations in T cell development due to early deletion in thymocytes. To directly eliminate PTEN in post-thymic T cells, we utilized CAR Tg x PTENflox/flox mice which enabled gene deletion using a Cre adenovirus in vitro. Gene expression profiling revealed a small subset of induced genes that were augmented upon PTEN deletion and T cell stimulation. Our results indicate that deletion of PTEN can augment the activation of post-thymic T cells. Nonetheless, PTEN inhibition may be a viable target for immune potentiation due to increased cytokine production by activated CD4+ cells.
Conditional deletion of PTEN in peripheral T cells augments TCR-mediated activation but does not abrogate CD28 dependency or prevent anergy induction.
Specimen part
View SamplesLung cancers are a heterogeneous group of diseases with respect to biology and clinical behavior. Currently, diagnosis and classification are based on histological morphology and immunohistological methods for discrimination between two main histologic groups: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) which account for 20% and 80% of lung carcinomas, respectively. NSCLCs, which are divided into the three major subtypes adenocarcinoma, squamous cell carcinoma and dedifferentiated large cell carcinoma, show different characteristics such as the expression of certain keratins or production of mucin and lack of neuroedocrine differentiation. The molecular pathogenesis of lung cancer involves the accumulation of genetic und epigenetic alterations including the activation of proto-oncogenes and inactivation of tumor suppressor genes which are different for lung cancer subgroups. The development of microarray technologies opened up the possibility to quantify the expression of a large number of genes simultaneously in a given sample. There are several recent reports on expression profiling on lung cancers but the analysis interpretation of the results might be difficult because of the heterogeneity of cellular components. The methods used for sample selection and processing can have a strong influence on the expression values obtained through microarray profiling. Laser capture microdissection (LCM) provides higher specificity in the selection of target cells compared to traditional bulk tissue selection methods, but at an increased processing cost.
Lung cancer transcriptomes refined with laser capture microdissection.
Specimen part, Disease, Disease stage
View SamplesBipolar affective disorder is a severe psychiatric disorder with a strong genetic component but unknown pathophysiology. We used microarray technology (Affymetrix HG-U133A GeneChips) to determine the expression of approximately 22 000 mRNA transcripts in post-mortem brain tissue (dorsolateral prefrontal cortex and orbitofrontal cortex) from patients with bipolar disorder and matched healthy controls.
Gene expression analysis of bipolar disorder reveals downregulation of the ubiquitin cycle and alterations in synaptic genes.
Sex, Age, Disease
View SamplesBipolar affective disorder is a severe psychiatric disorder with a strong genetic component but unknown pathophysiology. We used microarray technology (Affymetrix HG-U133A GeneChips) to determine the expression of approximately 22 000 mRNA transcripts in post-mortem brain tissue (dorsolateral prefrontal cortex) from patients with bipolar disorder and matched healthy controls. A cohort of 70 subjects was investigated and the final analysis included 30 bipolar and 31 control subjects. Differences between disease and control groups were identified using a rigorous statistical analysis with correction for confounding variables and multiple testing.
Gene expression analysis of bipolar disorder reveals downregulation of the ubiquitin cycle and alterations in synaptic genes.
Sex, Age, Disease
View SamplesFresh frozen post mortem prefrontal cortex tissue (Brodman area 46) was obtained from 44 individuals varying in age from 0 to 49 years. RNA was extracted from these samples and hybridized to HG133plus2.0 GeneChips. The data was used to examine patterns of gene expression over the course of human postnatal developmental and ageing.
Gene expression in the prefrontal cortex during adolescence: implications for the onset of schizophrenia.
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View SamplesThe tumor suppressor protein 53BP1, a pivotal regulator of DNA double-strand break (DSB) repair, was first identified as a p53-interacting protein over two decades ago, however its direct contributions to p53-dependent cellular activities remain undefined. Here, we reveal 53BP1 stimulates genome-wide p53-dependent gene transactivation and repression events in response to ionizing radiation (IR) and synthetic p53 activation. 53BP1-dependent p53 modulation requires both auto-oligomerization and tandem-BRCT domain mediated bivalent interactions with p53 and the ubiquitin-specific protease USP28. Loss of these activities results in inefficient p53-dependent cell-cycle checkpoint and exit responses. Furthermore, we demonstrate 53BP1-USP28 cooperation to be essential for normal p53-promoter element interactions and gene transactivation-associated events, yet dispensable for 53BP1-dependent DSB repair regulation. Collectively, our data provides a mechanistic explanation for 53BP1-p53 cooperation in controlling anti-tumorigenic cell fate decisions, and reveal these activities to be distinct and separable from 53BP1’s regulation of DNA double-strand break repair pathway choice. Overall design: We evaluated the transcriptional profiles of two 53BP1? cell lines and included a positive (WT) and a negative (p53?) controls. These cell lines were treated with Nutlin-3, ionising radiation or mock treated. Three independent replicates were included for each independent condition generating a total of 36 samples.
53BP1 Integrates DNA Repair and p53-Dependent Cell Fate Decisions via Distinct Mechanisms.
Cell line, Treatment, Subject
View SamplesBipolar affective disorder is a severe psychiatric disorder with a strong genetic component but unknown pathophysiology. We used microarray technology (Affymetrix HG-U133A GeneChips) to determine the expression of approximately 22 000 mRNA transcripts in post-mortem brain tissue (orbitofrontal cortex) from patients with bipolar disorder and matched healthy controls. Orbitofrontal cortex tissue from a cohort of 30 subjects was investigated and the final analysis included 10 bipolar and 11 control subjects. Differences between disease and control groups were identified using a rigorous statistical analysis with correction for confounding variables and multiple testing.
Gene expression analysis of bipolar disorder reveals downregulation of the ubiquitin cycle and alterations in synaptic genes.
Sex, Age, Disease
View SamplesDown syndrome (DS) is the result of trisomy chromosome 21 but the mechanisms by which the genotype leads to the characteristic disease phenotype are unclear. We performed a microarray study using human adult brain tissue (dorsolateral prefrontal cortex) from DS subjects and healthy controls to characterise for the first time the human adult Down syndrome brain
Gene expression profiling in the adult Down syndrome brain.
Sex, Age, Disease
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