Control of mRNA half-life is a powerful strategy to adjust individual mRNA levels to various stress conditions, because the mRNA degradation rate controls not only the steady-state mRNA level but also the transition speed of mRNA levels. Here, we analyzed mRNA half-life changes in response to cold stress in Arabidopsis cells using genome-wide analysis, in which mRNA half-life measurements and transcriptome analysis were combined. Half-lives of average transcripts were determined to be elongated under cold conditions. Taking this general shift into account, we identified more than a thousand transcripts that were classified as relatively stabilized or relatively destabilized. The relatively stabilized class was predominantly observed in functional categories that included various regulators involved in transcriptional, post-transcriptional and post-translational processes. On the other hand, the relatively destabilized class was enriched in categories related to stress and hormonal response proteins, supporting the idea that rapid decay of mRNA is advanta- geous for swift responses to stress. In addition, pentatricopeptide repeat, cyclin-like F-box and Myb transcription factor protein families were significantly over-represented in the relatively destabilized class. The global analysis presented here demonstrates not only the importance of mRNA turn-over control in the cold stress response but also several structural characteristics that might be important in the control of mRNA stability.
Changes in mRNA stability associated with cold stress in Arabidopsis cells.
Cell line
View SamplesPlants possess a cold acclimation system to acquire freezing tolerance through pre-exposure to non-freezing low temperatures. The transcriptional cascade of C-repeat binding factors (CBFs)/dehydration response element-binding factors (DREBs) is considered a major transcriptional regulatory pathway during cold acclimation. However, little is known regarding the functional significance of mRNA stability regulation in the response of gene expression to cold stress. The actual level of individual mRNAs is determined by a balance between mRNA synthesis and degradation. Therefore, it is important to assess the regulatory steps to increase our understanding of gene regulation. Here, we analyzed temporal changes in mRNA amounts and half-lives in response to cold stress in Arabidopsis cell cultures based on genome-wide analysis. In this mRNA decay array method, mRNA half-life measurements and microarray analyses were combined. In addition, temporal changes in the integrated value of transcription rates were estimated from the above two parameters using a mathematical approach. Our results showed that several cold-responsive genes, including Cold-regulated 15a, were relatively destabilized, whereas the mRNA amounts were increased during cold treatment by accelerating the transcription rate to overcome the destabilization. Considering the kinetics of mRNA synthesis and degradation, this apparently contradictory result supports that mRNA destabilization is advantageous for the swift increase in CBF-responsive genes in response to cold stress.
Co-ordinated Regulations of mRNA Synthesis and Decay during Cold Acclimation in Arabidopsis Cells.
Cell line
View SamplesWe examined global gene expression patterns in response to PGC-1 expression in cells derived from liver or muscle.
Direct link between metabolic regulation and the heat-shock response through the transcriptional regulator PGC-1α.
Specimen part
View SamplesCell adhesion plays an important role in determining cell shape and function in a variety of physiological and pathophysiological conditions. While links between metabolism and cell adhesion were previously suggested, the exact context and molecular details of such a cross-talk remain incompletely understood.
Inhibition of Adhesion Molecule Gene Expression and Cell Adhesion by the Metabolic Regulator PGC-1α.
Specimen part, Cell line
View SamplesSecreted proteins serve pivotal roles in the development of multicellular organisms, acting as structural matrix, extracellular enzymes and signal molecules. In this study we demonstrate, unexpectedly, that PGC-1, a critical transcriptional co-activator of metabolic gene expression, functions to down-regulate expression of diverse genes encoding secreted molecules and extracellular matrix (ECM) components to modulate the secretome. We show that both endogenous and exogenous PGC-1 down-regulate expression of numerous genes encoding secreted molecules. Mechanistically, results obtained using mRNA stability measurements as well as intronic RNA expression analysis are consistent with a transcriptional effect of PGC-1 on expression of genes encoding secreted proteins. Interestingly, PGC-1 requires the central heat shock response regulator HSF1 to affect some of its targets, and both factors co-reside on several target genes encoding secreted molecules in cells. Finally, using a mass spectrometric analysis of secreted proteins, we demonstrate that PGC-1 modulates the secretome of mouse embryonic fibroblasts (MEFs).
Control of Secreted Protein Gene Expression and the Mammalian Secretome by the Metabolic Regulator PGC-1α.
Specimen part
View SamplesPurpose: The objective of this study was to determine cardiac transcriptional pathways regulated in response to 1.) hypothyroidism and re-establishment of a euthyroid state and 2.) Med13-dependent cardiac transcriptional pathways regulated in response to hypothyroidism and re-establishment of a euthyroid state Overall design: Methods: WT and Med13 cardiac-specific knockout mice (Med13cKO) were put on a normal chow or PTU diet at 8 weeks of age for a duration of 4 weeks. A third group was put on a PTU diet for 4 weeks followed by 3 daily injections of T3.
Regulation of cardiac transcription by thyroid hormone and Med13.
No sample metadata fields
View SamplesPrevious results suggest that Bmh might inhibit the activity of the transcription factor Adr1 after binding to Adr1-dependent promoters. In a strain lacking the two major histone deacetylases, Hda1 and Rpd3 (hdac), Adr1 is bound to its target promoters recruiting what appears to be an inactive RNA ploymerase II preinitiation complex (PIC). To determine whether Bmh activity inhibits this inactive PIC and the generality of this effect on glucose-repressed gene expression, the mRNA profiles of wild type, bmh mutant, hdac mutant, and bmh hdac mutant cells grown in high glucose medium were compared.
14-3-3 (Bmh) proteins regulate combinatorial transcription following RNA polymerase II recruitment by binding at Adr1-dependent promoters in Saccharomyces cerevisiae.
No sample metadata fields
View SamplesLoss of function mutations in the SCN9a gene encoding voltage-gated sodium channel Nav1.7 cause congenital insensitivity to pain (CIP) and anosmia in otherwise normal humans and mice, suggesting that this channel may be a good analgesic drug target. Surprisingly, potent selective antagonists of Nav1.7 are weak analgesics. We therefore investigated whether Nav1.7 , as well as contributing to electrical signalling may have an additional function. Here we report that Nav1.7 deletion has profound effects on the sensory neuron transcriptome, leading to dysregulation of a number of transcription factors as well as upregulation of enkephalin precursor PENK mRNA and down regulation of CEACAM10 mRNA, a protein involved in noxious thermosensation. PENK mRNA is transcriptionally upregulated in Nav1.7 null mutant female sensory neurons, resulting in increased enkephalin expression in the dorsal horn of the spinal cord. PENK expression is down-regulated by addition of the sodium ionophore monensin, suggesting that sodium may play a role as a second messenger. Application of the opioid antagonist naloxone strongly enhances noxious peripheral input into the spinal cord, and dramatically reduces analgesia in both male and female Nav1.7 null mutant mice, as well as in human Nav1.7 null mutants. These data show that loss of Nav1.7 expression increases opioid drive over the lifetime of mice and humans. They further suggest that Nav1.7 channel blockers alone may not replicate the phenotype of null mutant humans and mice, but should be potentiated with exogenous opioids.
Endogenous opioids contribute to insensitivity to pain in humans and mice lacking sodium channel Nav1.7.
Specimen part
View SamplesThe white adipose tissue (WAT) rapidly loses mass when mice are fed a diet containing trans-10, cis-12 conjugated linoleic acid (t10c12 CLA). A microarray analysis of WAT due to CLA feeding was performed to better define the processes and genes involved. WAT weight decreased by ca. 80% over 17 days of feeding a 0.5% t10c12 CLA diet. The lipid volume decreased by 90% and the number of adipocytes and total cells were reduced by15% and 47%, respectively. Microarray profiling of replicated pools of control and treated mice (n=140) at seven time points over the 17day feeding indicated between 2798 to 4318 genes showed mRNA changes of 2-fold or more. Transcript levels for genes of glucose and fatty acid import or biosynthesis were significantly reduced. A prolific inflammation response was indicated by the 2 to100-fold induction of many cytokine transcripts, including those for IL-6, IL1?, TNF ligands, and CXC family members
Trans-10, cis-12 conjugated linoleic acid causes inflammation and delipidation of white adipose tissue in mice: a microarray and histological analysis.
Age
View SamplesWe are studying signaling pathways and growth properties of cultured human ovarian cancer cells that are expressing the G protein-coupled receptor, luteinizing hormone receptor (LHR),particularly interested in the changes that occur when the receptor is activated by its cognate ligand, gonadotropin (LH). To investigate these questions, we have employed the SKOV3 ovarian cancer cell line that has been stably transfected with LHR, and can then test the response of these cells in culture following exposure to LH.
Regulation of gene expression in ovarian cancer cells by luteinizing hormone receptor expression and activation.
Cell line, Treatment, Time
View Samples