We measured transcriptional changes in an effort to understand mechanisms of action resulting from the introduction of global transcriptional machinery engineering in E. coli in the presence and absence of ethanol.
Global transcription machinery engineering: a new approach for improving cellular phenotype.
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View SamplesS288C was transformed with plasmids expressing the GCN5 F221A mutant at varying levels. We sought to examine the global impact on gene expression
Linking yeast Gcn5p catalytic function and gene regulation using a quantitative, graded dominant mutant approach.
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View SamplesGlobal transcription machinery engineering (gTME) is an approach for reprogramming gene transcription to elicit cellular phenotypes important for technological applications. Here we show the application of gTME to Saccharomyces cerevisiae for improved glucose/ethanol tolerance, a key trait for many biofuels programs. Mutagenesis of the transcription factor Spt15p and selection led to dominant mutations that conferred increased tolerance and more efficient glucose conversion to ethanol. The desired phenotype results from the combined effect of three separate mutations in the SPT15 gene [serine substituted for phenylalanine (Phe177Ser) and, similarly, Tyr195His, and Lys218Arg]. Thus, gTME can provide a route to complex phenotypes that are not readily accessible by traditional methods.
Engineering yeast transcription machinery for improved ethanol tolerance and production.
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View SamplesDuring low temperature exposure, temperate plant species increase their freezing tolerance in a process termed cold acclimation. During deacclimation in response to warm temperatures cold acclimated plants lose freezing tolerance and resume growth and development. While considerable effort has been directed toward understanding the molecular and metabolic basis of cold acclimation, much less information is available about the regulation of deacclimation. Here, we report metabolic (GC-MS) and transcriptional (microarrays, qRT-PCR) responses underlying deacclimation during the first 24 h after a shift of cold acclimated Arabidopsis thaliana (Columbia-0) plants to warm temperature. The data revealed a faster response of the transcriptome than of the metabolome and provided evidence for tightly regulated temporal responses at both levels. Metabolically deacclimation is associated with decreasing contents of sugars, amino acids and glycolytic and TCA cycle intermediates, indicating an increased need for carbon sources and respiratory energy production associated with growth resumption under warm temperature conditions. Deacclimation also involves extensive down-regulation of protein synthesis and changes in the metabolism of lipids and cell wall components. Altered hormonal regulation appears particularly important during deacclimation, with changes in the expression of genes related to auxin, gibberellin, brassinosteroid, jasmonate and ethylene metabolisms. Several transcription factor families controlling fundamental aspects of plant development are significantly regulated during deacclimation, emphasizing that loss of freezing tolerance and growth resumption are interrelated processes that are transcriptionally highly interrelated. Expression patterns of some clock oscillator components during deacclimation resembled those under warm conditions, indicating at least partial re-activation of the circadian clock. This study provide the first comprehensive analysis of the regulation of deacclimation in cold acclimated plants. The data indicate cascades of rapidly regulated genes and metabolites that underly the developmental switch resulting in reduced freezing tolerance and the resumption of growth. They constitute a reference dataset of genes, metabolites and pathways that are crucial during the first rapid phase of deacclimation and will be useful for the further analysis of this important but under-researched plant process.
Rapid transcriptional and metabolic regulation of the deacclimation process in cold acclimated Arabidopsis thaliana.
Specimen part, Treatment
View SamplesThe nuclear receptor HNF4A regulates embryonic and post-natal hepatocyte gene expression. Using hepatocyte-specific inactivation in mice, we show that the TAF4 subunit of TFIID acts as a cofactor for HNF4A in vivo and that HNF4A interacts directly with the TAF4-TAF12 heterodimer in vitro. In vivo, TAF4 is required to maintain HNF4A-directed embryonic gene expression at post-natal stages and for HNF4A-directed activation of post-natal gene expression. TAF4 promotes HNF4A occupancy of functional cis-regulatory elements located adjacent to the transcription start sites of post-natal expressed genes and for pre-initiation complex formation required for their expression. Promoter-proximal HNF4A-TFIID interactions are therefore required for pre-initiation complex formation and stable HNF4A occupancy of regulatory elements as two concomitant mutually dependent processes. Overall design: RNA profiles in wild-type and Taf4-/- livers by deep sequencing
TAF4, a subunit of transcription factor II D, directs promoter occupancy of nuclear receptor HNF4A during post-natal hepatocyte differentiation.
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View SamplesWe previously found that the SF3A mRNA splicing complex was required for a robust innate immune response; SF3A acts in part by inhibiting the production of a negatively acting splice form of the TLR signaling adaptor MyD88. Here we inhibit SF3A1 using RNAi and subsequently perform an RNAseq study to identify the full complement of genes and splicing events regulated by SF3A in murine macrophages. Surprisingly, SF3A has substantial specificity for mRNA splicing events in innate immune signaling pathways compared to other pathways, affecting the splicing of many genes in the TLR signaling pathway to modulate the innate immune response. Overall design: RNAseq was used to monitor the effects of SF3A1 siRNA-mediated knockdown in murine macrophages. Three biological replicates were used for each of the four treatment combinations (with/without siRNA, with/without LPS). The first replicates for each combination were each sequenced in two runs, which were combined in the analysis.
Regulation of toll-like receptor signaling by the SF3a mRNA splicing complex.
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View SamplesWe determined the Taf4 dependent differential expression of RNAs in WT as well as KO cells in their pluripotent state, before and after treatment with retinoic acid and immediately before plating to form neuronal precursors. Overall design: Examination of RNA expression in 4 different cell lines (2 independent Taf4 WT and 2 independent Taf4 KO) in ES cells and at 3 timepoints during differentiation into neurons.
Essential role of the TFIID subunit TAF4 in murine embryogenesis and embryonic stem cell differentiation.
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View SamplesWe determined the Taf4 dependent differential expression of RNAs in WT as well as KO cells at day 9 of the differentiation into the cardiac lineage. Overall design: Examination of RNA expression in 4 different cell lines (2 independent Taf4 WT and 2 independent Taf4 KO) in 1 timepoint during cardiac differentiation.
Essential role of the TFIID subunit TAF4 in murine embryogenesis and embryonic stem cell differentiation.
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View SamplesThe molecular mechanism regulating phasic corticotropin-releasing hormone (CRH) release from parvocellular neurons (PVN) remains poorly understood. Here, we find a cohort of parvocellular cells interspersed with magnocellular PVN neurons expressing secretagogin. Single-cell transcriptome analysis combined with protein interactome profiling identifies secretagogin neurons as a distinct CRH-releasing neuron population reliant on secretagogin’s Ca2+ sensor properties and protein interactions with the vesicular traffic and exocytosis release machineries to liberate this key hypothalamic releasing hormone. Overall design: single cells from the PVN region juvenile (21-28 days) mice were dissected and subject to whole transcriptome analysis
A secretagogin locus of the mammalian hypothalamus controls stress hormone release.
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View SamplesThe clinical impact of aberrant CEBPA promoter methylation (PM) in AML is controversial discussed. The aim of this study was to clarify the significance of aberrant CEBPA PM with regard to clinical features in a cohort of 572 de novo AML with wildtype CEBPA and normal karyotype. The distal promoter was methylated in 54/572 cases (9.41%) whereas proximal PM was never detected. Methylation of the core promoter was detected in only 8 of 326 cases (2.45%) and thus seems to be a rare event in AML. There was no correlation between CEBPA distal PM, age, sex, white blood cell (WBC) count or Hb levels at diagnosis. We also were not able to detect a significant correlation between the presence of CEBPA distal PM and molecular mutations such as FLT3-ITD, NPM1, AML1, MLL-PTD and IDH1. Solely the frequency of IDH2R140 mutations was significantly reduced in CEBPA distal PM positive compared to CEBPA distal PM negative cases (p=0.01). Furthermore, analysis of CEBPA mRNA expression level revealed no difference between CEBPA distal PM positive and CEBPA distal PM negative cases, suggesting that CEBPA distal PM has no influence on CEBPA expression. CEBPA distal PM did not show impact on overall survival (OS), event free survival (EFS) or incidence of relapse. Also when other mutations were taken into regard no prognostic impact of CEBPA distal PM could be shown. In contrast, a distinct expression profile of CEBPA distal PM positive cases compared to CEBPA mutated and CEBPA distal PM negative cases was observed. In addition, a significantly higher frequency of CEBPA distal PM was detected in RUNX1-RUNX1T1 positive AML compared to the CEBPA witdtype cases. We conclude that the presence of aberrant CEBPA PM has no clinical relevance and is therefore a negligible prognostic marker in de novo AML with normal karyotype.
Frequency and prognostic impact of CEBPA proximal, distal and core promoter methylation in normal karyotype AML: a study on 623 cases.
Disease
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