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GSE7439
Escherichia coli
5 Downloadable Samples
Affymetrix E. coli Genome 2.0 Array (ecoli2)
Description
These E. coli strains were grown with various signaling molecules and the expression profiles were determined.
Publication Title
Global effects of the cell-to-cell signaling molecules autoinducer-2, autoinducer-3, and epinephrine in a luxS mutant of enterohemorrhagic Escherichia coli.
Sample Metadata Fields
No sample metadata fields
View Samples- Escherichia coli
- 2 Downloadable Samples
- Affymetrix E. coli Genome 2.0 Array (ecoli2)
Description
Enterohemorrhagic E. coli (EHEC) colonizes the large intestine and causes attaching and effacing lesions (AE). Most of the genes involved in the formation of AE lesions are encoded within a chromosomal pathogenicity island termed the Locus of Enterocyte Effacement (LEE). The LysR-like transcriptional factor QseA regulates the LEE by binding directly to the regulatory region of ler. Here, we performed transcriptome analyses comparing WT EHEC and the isogenic qseA mutant in order to elucidate the extent of QseAs role in gene regulation in EHEC. The following results compare genes that were up-regulated and down-regulated ! 2-fold in the qseA mutant strain compared to the WT strain. At mid-exponential growth, 222 genes were up-regulated and 1874 were downregulated. At late-exponential growth, a total of 55 genes were up-regulated and 605 genes were down-regulated. During mid-exponential growth, QseA represses its own transcription, whereas during late-logarithmic growth, QseA activates expression of the LEE genes as well as non-LEE encoded effector proteins. During both growth phases, several genes carried in O-islands, were activated by QseA, whereas genes involved in cell metabolism were repressed. We also performed electrophoretic mobility shift assays, competition experiments, and DNAseI footprints, and the results suggested that QseA directly binds both the ler proximal and distal promoters, its own promoter, as well as promoters of genes encoded in EHEC-specific O-islands. Additionally, we mapped the transcriptional start site of qseA, leading to the identification of two promoter sequences. Taken together, these results indicate that QseA acts as a global regulator in EHEC, coordinating expression of virulence genes.
Publication Title
The LysR-type regulator QseA regulates both characterized and putative virulence genes in enterohaemorrhagic Escherichia coli O157:H7.
Sample Metadata Fields
No sample metadata fields
View Samples- Escherichia coli
- 2 Downloadable Samples
- Affymetrix E. coli Genome 2.0 Array (ecoli2)
Description
Bacterial pathogens must be able to both recognize suitable niches within the host for colonization and successfully compete with commensal flora for nutrients in order to establish infection. Ethanolamine (EA) is a major component of mammalian and bacterial membranes and may be used by pathogens as a carbon and/or nitrogen source in the gastrointestinal tract. We examined how EA influences gene expression in the human pathogen enterohemorrhagic Escherichia coli O157:H7 (EHEC). Our results indicate EA is not only important for nitrogen metabolism, but that EA is used in cell-to-cell signaling to activate virulence gene expression. Genes encoding for the global regulatory proteins QseC, QseE, and QseA, as well as for attaching and effacement (AE) lesion formation and Shiga toxin are differentially regulated when EHEC is grown with micromolar concentrations of EA. We also constructed a deletion of eutR that encodes the regulator of the eut (EA utilization) operon and examined virulence gene expression. These results suggest that EutR is important in regulating gene expression in response to EA, but that EA signaling does not occur solely through EutR. This is the first report linking EA to cell-to-cell signaling and pathogenesis.
Publication Title
Ethanolamine controls expression of genes encoding components involved in interkingdom signaling and virulence in enterohemorrhagic Escherichia coli O157:H7.
Sample Metadata Fields
No sample metadata fields
View Samples- Arabidopsis thaliana
- 12 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
Maternal environment is an important regultor of seed dormancy, but the mechanisms underlying the process are poorly understood. We have found that genes in the circadian clock control dormancy, in part through their regulation of the canonical photoperiod pathway known from research into flowering time control. In this experiment we compare the affects of altering seed maturation temperature or maternal photoperiod on dry seed transcriptomes, and the photoperiod-insenstive ft-1 mutant to wt type Ler. In this way we are identifying gene expression programmes which result from the seed's response to maternal environmental experience.
Publication Title
Induction of dormancy in Arabidopsis summer annuals requires parallel regulation of DOG1 and hormone metabolism by low temperature and CBF transcription factors.
Sample Metadata Fields
Specimen part
View Samples- Escherichia coli
- 2 Downloadable Samples
- Affymetrix E. coli Genome 2.0 Array (ecoli2)
Description
Adherence of pathogenic Escherichia coli strains to intestinal epithelia is essential for infection. For enterohemorrhagic E. coli (EHEC) serotype O157:H7, we have previously demonstrated that multiple factors govern this pathogens adherence to HeLa cells (39). One of these factors is CadA, a lysine decarboxylase, and this protein has been proposed to negatively regulate virulence in several enteric pathogens. In the case of EHEC strains, CadA modulates expression of the intimin, an outer membrane adhesin involved in pathogenesis. Here, we experimentally inactivated cadA in O157:H7 strain 86-24 to investigate the role of this gene in EHEC adhesion to tissue culture monolayers, global gene expression patterns, and colonization of the infant rabbit intestine. As expected, the cadA mutant did not possess lysine decarboxylation activity and was hyper-adherent to tissue-culture cells. Adherence of the cadA mutant was nearly 2-fold greater than that of the wt and complementation of the cadA defect reduced adherence back to wt levels. Furthermore, the cadA mutant affected the expression of intimin protein. Disruption of the eae gene (encoding the intimin protein) in the cadA mutant significantly reduced its adherence to tissue-culture cells. However, adherence of the cadA eae double mutant was greater than that of an 86-24 eae mutant, suggesting that the enhanced adherence of the cadA mutant is not entirely attributable to enhanced expression of intimin in this background. Gene array analysis revealed that the cadA mutation significantly altered EHEC gene expression patterns; expression of 1332 genes was down-regulated and 132 genes up-regulated in the mutant compared to the wild type strain. Interestingly, the gene expression variation shows an EHEC-biased gene alteration including intergenic regions. Two putative adhesins: flagella and F9 fimbriae were up-regulated in the cadA mutant, suggestive of their association with adherence in absence of the Cad regulatory mechanism. Remarkably, in the infant rabbit model, the cadA mutant out-competed the wild type strain in the ileum but not in the cecum or mid-colon, raising the possibility that CadA negatively regulates EHEC pathogenicity in a tissue-specific fashion.
Publication Title
CadA negatively regulates Escherichia coli O157:H7 adherence and intestinal colonization.
Sample Metadata Fields
No sample metadata fields
View Samples- Rattus norvegicus
- 54 Downloadable Samples
- Affymetrix Rat Genome 230 2.0 Array (rat2302)
Description
Molecular mechanisms underlying sarcopenia, the age-related loss of skeletal muscle mass and function, remain unclear. To identify molecular changes that correlated best with sarcopenia and might contribute to its pathogenesis, we determined global gene expression profiles in muscles of rats aged 6, 12, 18, 21, 24, and 27 months. These rats exhibit sarcopenia beginning at 21 months. Correlation of the gene expression versus muscle mass or age changes, and functional annotation analysis identified gene signatures of sarcopenia distinct from gene signatures of aging. Specifically, mitochondrial energy metabolism (e.g., tricarboxylic acid cycle and oxidative phosphorylation) pathway genes were the most downregulated and most significantly correlated with sarcopenia. Also, perturbed were genes/pathways associated with neuromuscular junction patency (providing molecular evidence of sarcopenia-related functional denervation and neuromuscular junction remodeling), protein degradation, and inflammation. Proteomic analysis of samples at 6, 18, and 27 months confirmed the depletion of mitochondrial energy metabolism proteins and neuromuscular junction proteins. Together, these findings suggest that therapeutic approaches that simultaneously stimulate mitochondrogenesis and reduce muscle proteolysis and inflammation have potential for treating sarcopenia.
Publication Title
Genomic and proteomic profiling reveals reduced mitochondrial function and disruption of the neuromuscular junction driving rat sarcopenia.
Sample Metadata Fields
Sex, Age, Specimen part
View Samples- Danio rerio
- 7 Downloadable Samples
IlluminaGenomeAnalyzerII
Description
To identify genes regulated by Rx3 during optic vesicle morphogenesis, adult zebrafish carriers of a null rx3 mutation were mated. Before 13 hours post fertilization (hpf), the earliest time point at which optic vesicle evagination phenotypes could be reliably detected, offspring were phenotypically separated into pools comprising of mutants with an absence of optic vesicles or siblings exhibiting a wild-type phenotype. Three replicates of pooled RNA samples from 13 hpf eyeless mutants (rx3-/-) or phenotypically wild-type siblings (rx3+/+ or rx3+/-), and one replicate of 13 hpf wild-type zebrafish larva were collected for whole transcriptome sequencing. Overall design: Whole transcriptome sequencing (RNA-seq) was performed on zebrafish rx3-/- mutants, wild-type siblings and wild-type AB strains at 13 hpf
Publication Title
Genes and signaling networks regulated during zebrafish optic vesicle morphogenesis.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 9 Downloadable Samples
- Affymetrix Mouse Gene 1.0 ST Array (mogene10st)
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
Role of SWI/SNF in acute leukemia maintenance and enhancer-mediated Myc regulation.
Sample Metadata Fields
Specimen part, Cell line, Treatment
View Samples- Mus musculus
- 21 Downloadable Samples
- IlluminaHiSeq2000
Description
Cancer cells frequently depend on chromatin regulatory activities to maintain a malignant phenotype. Here, we show that leukemia cells require the mammalian SWI/SNF chromatin remodeling complex for their survival and aberrant self-renewal potential. While Brg1, an ATPase subunit of SWI/SNF, is known to suppress tumor formation in several cancer types, we found that leukemia cells instead rely on Brg1 to support their oncogenic transcriptional program, which includes Myc as one of its key targets. To account for this context-specific function, we identify a cluster of lineage-specific enhancers located 1.7 megabases downstream of Myc that are occupied by SWI/SNF, as well as the BET protein Brd4. Brg1 is required at these distal elements to maintain transcription factor occupancy and for long-range chromatin looping interactions with the Myc promoter. Notably, these distal Myc enhancers coincide with a region that is focally amplified in 3% of acute myeloid leukemia. Together, these findings define a leukemia maintenance function for SWI/SNF that is linked to enhancer-mediated gene regulation, providing general insights into how cancer cells exploit transcriptional coactivators to maintain oncogenic gene expression programs Overall design: To profile the basal transcription level, we performed NSR and PolyA+ (illumine TruSeq) in a murine AML RN2 cell lines. To define the rapid downregulated genes in response to JQ1, BET bromodomian inhibitor, in RN2 cell, we performed RNA-seq in RN2 exposing to 250nM JQ1 for 48h time course.
Publication Title
Role of SWI/SNF in acute leukemia maintenance and enhancer-mediated Myc regulation.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 9 Downloadable Samples
- Affymetrix Mouse Gene 1.0 ST Array (mogene10st)
Description
Cancer cells frequently depend on chromatin regulatory activities to maintain a malignant phenotype. Here, we show that leukemia cells require the mammalian SWI/SNF chromatin remodeling complex for their survival and aberrant self-renewal potential. While Brg1, an ATPase subunit of SWI/SNF, is known to suppress tumor formation in several cancer types, we found that leukemia cells instead rely on Brg1 to support their oncogenic transcriptional program, which includes Myc as one of its key targets. To account for this context-specific function, we identify a cluster of lineage-specific enhancers located 1.7 megabases downstream of Myc that are occupied by SWI/SNF, as well as the BET protein Brd4. Brg1 is required at these distal elements to maintain transcription factor occupancy and for long-range chromatin looping interactions with the Myc promoter. Notably, these distal Myc enhancers coincide with a region that is focally amplified in 3% of acute myeloid leukemia. Together, these findings define a leukemia maintenance function for SWI/SNF that is linked to enhancer-mediated gene regulation, providing general insights into how cancer cells exploit transcriptional coactivators to maintain oncogenic gene expression programs
Publication Title
Role of SWI/SNF in acute leukemia maintenance and enhancer-mediated Myc regulation.
Sample Metadata Fields
Specimen part, Cell line
View Samples