-cell identity is determined by tightly regulated transcriptional networks that are modulated by extracellular cues, thereby ensuring -cell adaptation to the organisms insulin demands. We have observed in pancreatic islets that stimulatory glucose concentrations induced a gene profile that was similar to that of freshly isolated islets, indicating that glucose-elicited cues are involved in maintaining -cell identity. Low glucose induces the expression of ubiquitous genes involved in stress responses, nutrient sensing, and organelle biogenesis. By contrast, stimulatory glucose concentrations activate genes with a more restricted expression pattern (- and neuronal- cell identity). Consistently, glucose-induced genes are globally reduced in islets deficient with Hnf1a (MODY3), characterized by a deficient glucose metabolism. Of interest, a cell cycle gene module was the most enriched among the variable genes between intermediate and stimulatory glucose concentrations. Glucose regulation of the islet transcriptome was unexpectedly broadly maintained in islets from aged mice. However, the cell cycle gene module is selectively lost in old islets and the glucose activation of this module is not recovered even in the absence of the cell cycle inhibitor p16.
Glucose regulation of a cell cycle gene module is selectively lost in mouse pancreatic islets during ageing.
Specimen part
View SamplesHeat stress is one of the most prominent and deleterious environmental threads affecting plant growth and development. Upon high temperatures, plants launch specialized gene expression programs that promote stress protection and survival. These programs involve global and specific changes at the transcriptional and translational levels. However the coordination of these processes and their specific role in the establishment of the heat stress response is not fully elucidated.
Analysis of genome-wide changes in the translatome of Arabidopsis seedlings subjected to heat stress.
Specimen part
View SamplesWe used microarrays to compare the global programme of gene expression in primary cultures of neurons and astrocytes. These data sets were compared to the expression profiles of other tissues, including pancreatic islets, in order to identify a specific neuroendocrine program in pancreatic islets.
Glucose regulation of a cell cycle gene module is selectively lost in mouse pancreatic islets during ageing.
Specimen part
View SamplesPiwi-interacting small RNAs (piRNAs) of fetal prospermatogonia of mice have been strongly implicated in transposon control. In contrast, little is known about biogenesis and function of abundant piRNAs from adult testes expressed in late spermatocytes and round spermatids. These so-called "pachytene" piRNAs are processed from long non-coding piRNA precursors and have no defined RNA targets in the transcriptome even though their binding partner Piwi, MIWI, is essential for spermiogenesis and fertility. Here we report that 129SvJae mice lacking Maelstrom (MAEL), a conserved piRNA pathway protein, exhibit spermiogenic arrest with defects in acrosome and flagellum formation. Further analysis revealed MAEL association with RNPs containing MIWI, TDRD6, and processed intermediates of pachytene piRNA precursors of various length. Loss of MAEL causes a 10-fold drop in pachytene piRNA levels but an increase in piRNAs from abundantly expressed mRNAs. These results suggest a MAEL-dependent mechanism for the selective processing of pachytene piRNA precursor into piRNAs. Strikingly, ribosome profiling of Mael-null testes revealed that reduced piRNA production is accompanied by reduced translation of over 800 spermiogenic mRNAs including those encoding acrosome and flagellum proteins. In light of recent reports of piRNA-independent protection of translationally repressed mRNPs by MIWI and piRNA-dependent turnover of MIWI, we propose that pachytene piRNAs function by controlling the availably of MIWI for the translational repression of spermiogenic mRNAs. Overall design: piRNA sequencing, RNA immunoprecipitation, and expression measurements (RNA-Seq and ribosome profiling) in wild-type and Mael -/- testes
Reduced pachytene piRNAs and translation underlie spermiogenic arrest in Maelstrom mutant mice.
Specimen part, Cell line, Subject
View SamplesWe analyzed the role of the histone lysine methyltransferase Set7/9 in the differentiation of human embryonic stem (ES) cells. Human ES cell lines expressing a control short hairpin and a short hairpin against Set7/9 were established and the genome wide expression profile was compared between both cell lines at different days during differentiation. Analysis of both profiles indicates that in the absence of Set7/9 there is a delay in the silencing of self-renewal factors as well as in the induction of differentiation markers. These results indicate that Set7/9 plays an active role in the differentiation of human ES cells.
SETD7 Regulates the Differentiation of Human Embryonic Stem Cells.
Specimen part, Cell line
View SamplesDespite the benefits associated with healthy diets, data on the mechanisms by which these benefits are promoted are scarce. Our aim was to explore the global transcriptomic response of biological pathways related to cardiovascular disease associated with traditional Mediterranean diet (TMD) intervention. The PREDIMED study is a large on-going, parallel, multicentre, randomised, controlled trial aimed at assessing the TMD effect on primary cardiovascular prevention. High cardiovascular risk participants were recruited and assigned to one of the following interventions: 1) TMD plus virgin olive oil (VOO); 2) TMD plus mixed nuts; or 3) low-fat diet (control group). In a sub sample of 30 volunteers of the PREDIMED- Barcelona Sur Centre, gene expression changes in peripheral mononuclear cells, after 3 months of intervention, were assessed by microarray analysis.
In vivo transcriptomic profile after a Mediterranean diet in high-cardiovascular risk patients: a randomized controlled trial.
Time
View SamplesAlthough protein acetylation is widely observed, it has been associated with few specific regulatory functions making it poorly understood. To interrogate its functionality, we analyzed the acetylome in Escherichia coli knockout mutants of cobB, the only known sirtuin-like deacetylase, and patZ, the best-known protein acetyltransferase. For four growth conditions, more than 2,000 unique acetylated peptides, belonging to 809 proteins, were identified and differentially quantified. Nearly 65% of these proteins are related to metabolism. The global activity of CobB contributes to the deacetylation of a large number of substrates and has a major impact on physiology. Apart from the regulation of acetyl-CoA synthetase, we found that CobB-controlled acetylation of isocitrate lyase contributes to the fine-tuning of the glyoxylate shunt. Acetylation of the transcription factor RcsB prevents DNA binding, activating flagella biosynthesis and motility, and increases acid stress susceptibility. Surprisingly, deletion of patZ increased acetylation in acetate cultures, which suggests that it regulates the levels of acetylating agents. The results presented offer new insights into functional roles of protein acetylation in metabolic fitness and global cell regulation.
Protein acetylation affects acetate metabolism, motility and acid stress response in Escherichia coli.
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The transcription factor GATA6 enables self-renewal of colon adenoma stem cells by repressing BMP gene expression.
Specimen part, Cell line
View SamplesAberrant activation of WNT signaling and loss of BMP signals represent the two main alterations leading to the initiation of colorectal cancer (CRC). Here we screen for genes required for maintaining the tumor stem cell phenotype and identify the zinc-finger transcription factor GATA6 as key regulator of the WNT and BMP pathways in CRC. GATA6 directly drives the expression of LGR5 in adenoma stem cells while it restricts BMP signaling to differentiated tumor cells. Genetic deletion of Gata6 in mouse colon adenomas increases the levels of BMP factors, which signal to block self-renewal of tumor stem cells. In human tumors, GATA6 competes with beta-catenin/TCF4 for binding to a distal regulatory region of the BMP4 locus that has been previously linked to increased susceptibility to develop CRC. Hence, GATA6 creates a permissive environment for tumor stem cell expansion by controlling the major signaling pathways that influence CRC initiation.
The transcription factor GATA6 enables self-renewal of colon adenoma stem cells by repressing BMP gene expression.
Specimen part, Cell line
View SamplesAberrant activation of WNT signaling and loss of BMP signals represent the two main alterations leading to the initiation of colorectal cancer (CRC). Here we screen for genes required for maintaining the tumor stem cell phenotype and identify the zinc-finger transcription factor GATA6 as key regulator of the WNT and BMP pathways in CRC. GATA6 directly drives the expression of LGR5 in adenoma stem cells while it restricts BMP signaling to differentiated tumor cells. Genetic deletion of Gata6 in mouse colon adenomas increases the levels of BMP factors, which signal to block self-renewal of tumor stem cells. In human tumors, GATA6 competes with beta-catenin/TCF4 for binding to a distal regulatory region of the BMP4 locus that has been previously linked to increased susceptibility to develop CRC. Hence, GATA6 creates a permissive environment for tumor stem cell expansion by controlling the major signaling pathways that influence CRC initiation.
The transcription factor GATA6 enables self-renewal of colon adenoma stem cells by repressing BMP gene expression.
Specimen part, Cell line
View Samples