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GSE19655
Escherichia coli
6 Downloadable Samples
Affymetrix E. coli Genome 2.0 Array (ecoli2)
Description
Small RNAs (sRNA) that act by base pairing with trans-encoded mRNAs modulate metabolism in response to a variety of environmental stimuli. Here, we describe an Hfq-binding sRNA (FnrS) whose expression is induced upon a shift from aerobic to anaerobic conditions and which acts to down regulate the levels of a variety of mRNAs encoding metabolic enzymes. Anaerobic induction in minimal medium depends strongly on FNR but is also affected by ArcA and CRP. Whole genome expression analysis showed that the levels of at least 32 mRNAs are down regulated upon FnrS overexpression, 15 of which are predicted to base pair with FnrS by TargetRNA. The sRNA is highly conserved across its entire length in numerous enterobacteria, and mutation analysis revealed that two separate regions of FnrS base pair with different sets of target mRNAs. The majority of the target genes previously reported to be down regulated in an FNR-dependent manner lack recognizable FNR binding sites. We thus suggest that FnrS extends the FNR regulon and increases the efficiency of anaerobic metabolism by repressing the synthesis of enzymes that are not needed under these conditions.
Publication Title
Reprogramming of anaerobic metabolism by the FnrS small RNA.
Sample Metadata Fields
No sample metadata fields
View Samples- Escherichia coli str. k-12 substr. mg1655
- 6 Downloadable Samples
- Affymetrix E. coli Genome 2.0 Array (ecoli2)
Description
Bacteria selectively consume some carbon sources over others through a regulatory mechanism termed catabolite repression. Here, we show that the base pairing RNA Spot 42 plays a broad role in catabolite repression in Escherichia coli by directly repressing genes involved in central and secondary metabolism, redox balancing, and the consumption of diverse non-preferred carbon sources. Many of the genes repressed by Spot 42 are transcriptionally activated by the global regulator CRP. Since CRP represses Spot 42, these regulators participate in a specific regulatory circuit called a multi-output feedforward loop. We found that this loop can reduce leaky expression of target genes in the presence of glucose and can maintain repression of target genes under changing nutrient conditions. Our results suggest that base pairing RNAs in feedforward loops can help shape the steady-state levels and dynamics of gene expression.
Publication Title
The base-pairing RNA spot 42 participates in a multioutput feedforward loop to help enact catabolite repression in Escherichia coli.
Sample Metadata Fields
Specimen part
View Samples- Escherichia coli str. k-12 substr. mg1655
- 4 Downloadable Samples
- Affymetrix E. coli Genome 2.0 Array (ecoli2)
Description
Escherichia coli possesses >65 small proteins of <50 amino acids, many of which are uncharacterized. We have identified a new small protein, MntS, involved in manganese homeostasis. Manganese is a critical micronutrient, serving as an enzyme cofactor and protecting against oxidative stress. Yet manganese is toxic in excess and little is known about its function in cells. Bacteria carefully control intracellular manganese levels using the transcription regulator MntR. Before this work, mntH, which encodes a manganese importer, was the only gene known to respond to manganese via MntR repression in E. coli K12. We demonstrated that mntS is another member of the MntR manganese regulon. We also identified yebN, which encodes a putative manganese efflux pump, as the first gene positively regulated by MntR in Enterobacteria. Since MntS is expressed when manganese levels are low, causes manganese sensitivity when overexpressed, and binds manganese, we propose that MntS may be a manganese chaperone. This study reveals new factors involved in manganese regulation and metabolism and expands our knowledge of how small proteins function.
Publication Title
The Escherichia coli MntR miniregulon includes genes encoding a small protein and an efflux pump required for manganese homeostasis.
Sample Metadata Fields
Treatment
View Samples- Homo sapiens
- 17 Downloadable Samples
- Affymetrix Human Transcriptome Array 2.0 (hta20)
Description
EpsteinBarr virus (EBV) is a common human pathogen that infects over 95% of the population worldwide. In the present study, the whole transcriptome microarray data were generated from peripheral blood mononuclear cells from Chinese children with acute infectious mononucleosis (AIM) and chronic active EBV infection (CAEBV) that were also compared with a publicly available microarray dataset from a study of American college students with AIM. Our study characterized for the first time a broad spectrum of molecular signatures in AIM and CAEBV. The key findings from the transcriptome profiling were validated with qPCR and flow cytometry assays. The most important finding in our study is the discovery of predominant TCR expression and T cell expansion in AIM. This finding, in combination with the striking up-regulation of CD3, CD8 and CD94, suggests that CD8+ T cells and CD94+ NK cells may play a major role in AIM. Moreover, the unique up-regulation of CD64A/B and its significant correlation with the monocyte marker CD14 was observed in CAEBV and that implies an important role of monocytes in CAEBV. In conclusion, our study reveals major cell types (particularly T cells) in the host cellular immune response against AIM and CAEBV.
Publication Title
Whole transcriptome profiling reveals major cell types in the cellular immune response against acute and chronic active Epstein-Barr virus infection.
Sample Metadata Fields
Sex, Age, Specimen part, Disease
View Samples- Caenorhabditis elegans
- 8 Downloadable Samples
- Affymetrix C. elegans Genome Array (celegans)
Description
RRF-3 and ERI-1 are first identified proteins required for accumulation of at least some endogenous secondary siRNAs in C.elegans. Genome wide gene expression analysis was performed on L4 stage rrf-3 and eri-1 mutant C. elegans to study effects caused by loss of these proteins. Mutant rrf-3 and eri-1 strains exhibited similar expression patterns when compared to N2 wild type, while 72 transcripts were found to be co-overexpressed and 4 transcripts co-underexpressed (> 2-fold, p< 0.05). Ontology analysis indicated many of the gene products were associated with protein phosphorylation and sperm function. These results provide additional support for the hypothesis that RRF-3 and ERI-1 act together in a siRNA pathway and may indicate biological processes that are related to endo-siRNAs.
Publication Title
Whole genome microarray analysis of C. elegans rrf-3 and eri-1 mutants.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 7 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
ARC (NSC 188491, SMA-491), 4-amino-6-hydrazino-7-beta-d-ribofuranosyl-7H-pyrrolo-(2,3-d)-pyrimidine-5-carboxamide, is a nucleoside analog with profound in vitro anti-cancer activity. First identified in a high-throughput screen for inhibitors of p21 mRNA expression, subsequent experiments showed that ARC also repressed expression of hdm2 and survivin, leading to its classification as a global inhibitor of transcription 1. The following Hu U133 plus 2.0 arrays represent single time point (24 hour) gene expression analysis of transcripts altered by ARC treatment. Arrays for the other compounds (sangivamycin and doxorubicin) are included as comparators.
Publication Title
ARC (NSC 188491) has identical activity to Sangivamycin (NSC 65346) including inhibition of both P-TEFb and PKC.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 13 Downloadable Samples
- Affymetrix Human Genome U95 Version 2 Array (hgu95av2)
Description
We hypothesized that broad-scale expression profiling would provide insight into the regulatory pathways that control gene expression in response to stress, and potentially identify novel heat-responsive genes. HEp2 cells were heated at 37 to 43 C for 60 min to gauge the heat shock response, using as a proxy inducible HSP-70 quantified by western blot analysis. Based on these results, microarray experiments were conducted at 37, 40, 41, 42 and 43C (3 replicates/temperature x 5 groups = 15 U95Aver2 GeneChips). Using linear modeling, we compared the sets of microarrays at 40, 41, 42 and 43C with the 37C baseline temperature and took the union of the genes exhibiting differential gene expression signal to create two sets of heat shock response genes, each set reflecting either increased or decreased RNA abundance. Leveraging human and mouse orthologous alignments, we used the two lists of co-expressed genes to predict transcription factor binding sites in silico, including those for heat shock factor 1 (HSF1) and heat shock factor 2 (HSF2) transcription factors. We discovered HSF1 and HSF2 binding sites in 15 genes not previously associated with the heat shock response. We conclude that microarray experiments coupled with upstream promoter analysis can be used to identify novel genes that respond to heat shock. Additional experiments are required to validate these putative heat shock proteins and facilitate a deeper understanding of the mechanisms involved during the stress response.
Publication Title
Transcriptional profiles of human epithelial cells in response to heat: computational evidence for novel heat shock proteins.
Sample Metadata Fields
No sample metadata fields
View Samples- Saccharomyces cerevisiae
- 8 Downloadable Samples
- Affymetrix Yeast Genome S98 Array (ygs98)
Description
We addressed changes in gene expression profile in response to
Publication Title
Role of PUG1 in inducible porphyrin and heme transport in Saccharomyces cerevisiae.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 6 Downloadable Samples
Ion Torrent Proton
Description
Background: Whole transcriptome sequencing (RNA-seq) represents a powerful approach for whole transcriptome gene expression analysis. However, RNA-seq carries a few limitations, e.g., the requirement of a significant amount of input RNA and complications led by non-specific mapping of short reads. The Ion AmpliSeqTM Transcriptome Human Gene Expression Kit (AmpliSeq) was recently introduced by Life Technologies as a whole-transcriptome, targeted gene quantification kit to overcome these limitations of RNA-seq.To assess the performance of this new methodology, we performed a comprehensive comparison of AmpliSeq with RNA-seq using two well-established next-generation sequencing platforms (Illumina HiSeq and Ion Torrent Proton). We analyzed standard reference RNA samples and RNA samples obtained from human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs). Results: Using published data from two standard RNA reference samples, we observed a strong concordance of log2 fold change for all genes when comparing AmpliSeq to Illumina HiSeq (Pearson’s r=0.92) and Ion Torrent Proton (Pearson’s r=0.92). We used ROC, Matthew’s correlation coefficient and RMSD to determine the overall performance characteristics. All three statistical methods demonstrate AmpliSeq as a highly accurate method for differential gene expression analysis. Additionally, for genes with high abundance, AmpliSeq outperforms the two RNA-seq methods. When analyzing four closely related hiPSC-CM lines, we show that both AmpliSeq and RNA-seq capture similar global gene expression patterns consistent with known sources of variations. Conclusions: Our study indicates that AmpliSeq excels in the limiting areas of RNA-seq for gene expression quantification analysis. Thus, AmpliSeq stands as a very sensitive and cost-effective approach for very large scale gene expression analysis and mRNA marker screening with high accuracy. Overall design: Comprehensive, performance evaluation of AmpliSeq Transcriptome to standard whole-transcriptome RNA-sequencing methods for large-scale, genome-wide differential gene expression analysis. We analyzed standard reference RNA samples and RNA samples obtained from human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs).
Publication Title
Comprehensive evaluation of AmpliSeq transcriptome, a novel targeted whole transcriptome RNA sequencing methodology for global gene expression analysis.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 5 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Human pluripotent stem cells (hPSCs) tend to acquire chromosomal aberrations in culture, which may increase their tumorigenicity. However, the cellular mechanism(s) underlying these aberrations are largely unknown. Here we show that the DNA replication in aneuploid hPSCs is perturbed, resulting in high prevalence of defects in chromosome condensation and segregation. Global gene expression analyses in aneuploid hPSCs revealed decreased levels of actin cytoskeleton genes and their common transcription factor SRF. Down-regulation of SRF or chemical perturbation of actin cytoskeleton organization in diploid hPSCs resulted in increased replication stress and perturbation of chromosome condensation, recapitulating the findings in aneuploid hPSCs. Altogether, our results revealed that in hPSCs DNA replication stress results in a distinctive defect in chromosome condensation, underlying their ongoing chromosomal instability. Our results shed a new light on the mechanisms leading to ongoing chromosomal instability in hPSCs, and may be relevant to tumor development as well.
Publication Title
Genomic Instability in Human Pluripotent Stem Cells Arises from Replicative Stress and Chromosome Condensation Defects.
Sample Metadata Fields
Specimen part, Cell line
View Samples