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GSE56133
Escherichia coli str. k-12 substr. mg1655
26 Downloadable Samples
Affymetrix E. coli Genome 2.0 Array (ecoli2)
Description
Deeper understanding of antibiotic-induced physiological responses is critical to identifying means for enhancing our current antibiotic arsenal. Bactericidal antibiotics with diverse targets have been hypothesized to kill bacteria, in part, by inducing production of damaging reactive species. This notion has been supported by many groups, but recently challenged. Here we robustly test the hypothesis using biochemical, enzymatic and biophysical assays along with genetic and phenotypic experiments. We first used a novel intracellular hydrogen peroxide (H2O2) sensor, together with a chemically diverse panel of fluorescent dyes sensitive to an array of reactive species, to demonstrate that antibiotics broadly induce redox stress. Subsequent gene expression analyses reveal that complex antibiotic-induced oxidative stress responses are distinct from canonical responses generated by supra-physiological levels of H2O2. We next developed a method to dynamically quantify cellular respiration and found that bactericidal antibiotics elevate oxygen consumption, indicating significant alterations to bacterial redox physiology. We further show that catalase or DNA mismatch repair enzyme overexpression, as well as antioxidant pre-treatment limit antibiotic lethality, indicating that reactive oxygen species causatively contribute to antibiotic killing. Critically, the killing efficacy of antibiotics was diminished under strict anaerobic conditions, but could be enhanced by exposure to molecular oxygen or addition of alternative electron acceptors, suggesting that environmental factors play a role in killing cells physiologically primed for death. This work provides direct evidence that bactericidal antibiotics, downstream of their target-specific interactions, induce complex redox alterations that contribute to cellular damage and death, thus supporting an evolving, expanded model of antibiotic lethality.
Publication Title
Antibiotics induce redox-related physiological alterations as part of their lethality.
Sample Metadata Fields
Treatment
View Samples- Mus musculus
- 4 Downloadable Samples
- Affymetrix Mouse Gene 1.0 ST Array (mogene10st)
Description
Bivalent histone domains have been proposed to contribute to pluripotency in embryonic stem cells, suggesting an epigenetic mechanism may regulate stem cell behavior in general. Here we compare histone modifications in two other stem cells derived from the blastocyst. We show that extraembryonic stem cells have little repressive lysine 27 trimethylation and few bivalent domains. Thus, bivalent domains are not a common mechanism for maintaining the undifferentiated state in blastocyst-derived stem cells and alternative mechanisms must mediate transcriptional repression in extraembryonic cells. We show that lysine 9 trimethylation, but not DNA methylation, is likely to fulfill this role. Intriguingly, although we do detect bivalent domains in pluripotent cells in the early mouse embryo, the epigenetic status of extraembryonic cells does not entirely reflect their in vitro stem cell counterparts. Therefore, differences in epigenetic regulation between lineage progenitors in vivo and in vitro may arise during selection for self-renewal in vitro.
Publication Title
Distinct histone modifications in stem cell lines and tissue lineages from the early mouse embryo.
Sample Metadata Fields
Cell line
View Samples- Mus musculus
- 34 Downloadable Samples
Illumina HiSeq 2500
Description
While the reprogramming factors OCT4, SOX2, KLF4, and MYC (OSKM) can reactivate the pluripotency network in terminally differentiated cells, they also regulate expression of non-pluripotency genes in other contexts, such as the mouse primitive endoderm. The primitive endoderm is an extraembryonic lineage established alongside the pluripotent epiblast in the blastocyst, and is the progenitor pool for extraembryonic endoderm stem (XEN) cells. Several studies have shown that endodermal genes are upregulated in fibroblasts undergoing reprogramming, although whether endodermal genes promote or inhibit acquisition of pluripotency is unclear. We show that, in fibroblasts undergoing conventional reprogramming, OSKM-induced expression of endodermal genes leads to formation of induced XEN (iXEN) cells, which possess key properties of blastocyst-derived XEN cells, including morphology, transcription profile, self-renewal, and multipotency. Our data show that iXEN cells arise in parallel to iPS cells, indicating that OSKM are sufficient to drive cells to two distinct fates during reprogramming. Overall design: Sequence-based mRNA transcriptional profiling of three different cell lines (MEF, XEN, iXEN) with multiple biological replicates, under two different growth medium conditions (ESC medium, XEN medium) for XEN and iXEN cells.
Publication Title
OSKM Induce Extraembryonic Endoderm Stem Cells in Parallel to Induced Pluripotent Stem Cells.
Sample Metadata Fields
Specimen part, Treatment, Subject
View Samples- Mus musculus
- 7 Downloadable Samples
- Affymetrix Mouse Gene 1.1 ST Array (mogene11st)
Description
Stearoyl-CoA desaturase (SCD) is the rate-limiting enzyme catalyzing the conversion of saturated fatty acids palmitate and stearate to monounsaturated fatty acids palmitoleate and oleate. During adipocyte differentiation, SCD expression increases concomitantly with several transcription factors and lipogenic genes.
Publication Title
Inhibition of stearoyl-CoA desaturase-1 in differentiating 3T3-L1 preadipocytes upregulates elongase 6 and downregulates genes affecting triacylglycerol synthesis.
Sample Metadata Fields
Specimen part, Treatment
View Samples- Mus musculus
- 19 Downloadable Samples
- Affymetrix Mouse Gene 1.1 ST Array (mogene11st)
Description
Saturated fatty acids (SFA) are widely thought to induce inflammation in adipose tissue (AT), while monounsaturated fatty acids (MUFA) are purported to have the opposite effect; however, it is unclear if individual SFA and MUFA behave similarly. Our goal was to examine adipocyte transcriptional networks regulated by individual SFA (palmitic acid, PA; stearic acid, SA) and MUFA (palmitoleic acid, PMA; oleic acid, OA).
Publication Title
Individual saturated and monounsaturated fatty acids trigger distinct transcriptional networks in differentiated 3T3-L1 preadipocytes.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 4 Downloadable Samples
- Illumina HiSeq 2000
Description
ES cell lines were established from mouse embryos, which were homozygous for the Trim33-flox allele and carried the UbcCreERT2 transgene. Cells were cultured without feeder cells in the presence of LIF and 2i. Embryoid bodies (EBs) were generated using the ATCC protocol on low attachment dishes under differentiating conditions. EBs were induced with Tamoxifen at day 4 and harvested at day 7. Overall design: Investigate differentially expressed genes in control and Trim33-deficient embryoid bodies derived from mouse embryonic stem cells
Publication Title
Trim33 is required for appropriate development of pre-cardiogenic mesoderm.
Sample Metadata Fields
Specimen part, Cell line, Subject, Time
View Samples- Caenorhabditis elegans
- 26 Downloadable Samples
- Affymetrix C. elegans Genome Array (celegans)
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
A condensin-like dosage compensation complex acts at a distance to control expression throughout the genome.
Sample Metadata Fields
No sample metadata fields
View Samples- Caenorhabditis elegans
- 26 Downloadable Samples
- Affymetrix C. elegans Genome Array (celegans)
Description
In many species, a dosage compensation complex (DCC) is targeted to X chromosomes of one sex to equalize levels of X gene products between males (1X) and females (2X). Here we identify cis-acting regulatory elements that target the C. elegans X chromosome for repression by the DCC. The DCC binds to discrete, dispersed sites on X of two types. rex sites recruit the DCC in an autonomous, DNA sequence-dependent manner using a 12 bp consensus motif that is enriched on X. This motif is critical for DCC binding, is clustered in rex sites, and confers much of X-chromosome specificity. Motif variants enriched on X by 3.8-fold or more are highly predictive (95%) for rex sites. In contrast, dox sites lack the X-enriched variants and cannot bind the DCC when detached from X. dox sites are more prevalent than rex sites and, unlike rex sites, reside preferentially in promoters of some expressed genes. These findings fulfill predictions for a targeting model in which the DCC binds to recruitment sites on X and disperses to discrete sites lacking autonomous recruitment ability. To relate DCC binding to function, we identified dosage-compensated and non-compensated genes on X. Unexpectedly, many genes of both types have bound DCC, but many do not, suggesting the DCC acts over long distances to repress X gene expression. Remarkably, the DCC binds to autosomes, but at far fewer sites and rarely at consensus motifs. DCC disruption causes opposite effects on expression of X and autosomal genes. The DCC thus acts at a distance to impact expression throughout the genome.
Publication Title
A condensin-like dosage compensation complex acts at a distance to control expression throughout the genome.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 10 Downloadable Samples
- Illumina HiSeq 2500
Description
The function of Structural maintenance of chromosome flexible domain containing 1 (Smchd1) was examined during mouse preimplantation development using an siRNA knockdown approach. Transient SMCHD1 deficiency during the period between fertilization and morula/early blastocyst stage compromised embryo viability and resulted in reduced cell number, reduced embryo diameter, and reduced nuclear volumes at the morula stage. RNAseq analysis of Smchd1 knockdown morulae revealed aberrant increases in expression of mRNAs related to the trophoblast lineage, indicating SMCHD1 inhibits trophoblast lineage gene expression and promotes inner cell mass formation. siRNA knockdown also reduced expression of cell proliferation genes, including S-phase kinase-associated protein 2 (Skp2). Smchd1 expression was elevated in Caudal type homeobox transcription factor 2 (Cdx2)-/- blastocysts, indicating enriched expression, and further indicating a role in inner cell mass development. These results indicate that Smchd1 plays dual roles in the preimplantation embryo, promoting a lineage-appropriate pattern of gene expression supporting inner cell mass formation, whilst controlling lineage formation and gene expression in the trophectoderm. Overall design: Effects of SMCHD1 siRNA knockdown were tested in mouse embryos
Publication Title
Novel key roles for structural maintenance of chromosome flexible domain containing 1 (Smchd1) during preimplantation mouse development.
Sample Metadata Fields
Treatment, Subject
View Samples- Homo sapiens
- 2 Downloadable Samples
- Illumina HumanRef-8 v3.0 expression beadchip
Description
Gene expression analyis of two hESCs, two human neonatal fibroblasts, and four human iPSCs generated with retroviral transduction using the OSKM cocktail.
Publication Title
Human induced pluripotent stem cells harbor homoplasmic and heteroplasmic mitochondrial DNA mutations while maintaining human embryonic stem cell-like metabolic reprogramming.
Sample Metadata Fields
Specimen part, Cell line
View Samples