We screened for differentially expressed genes in the developing notochord using the Affymetrix microarray system in Xenopus laevis. At late gastrula, we dissected four regions from the embryo, anterior mesoderm, posterior mesoderm, notochord and presomitic mesoderm. Three types of comparison were carried out to generate a list of predominantly notochord expressed genes: (1) Posterior mesoderm vs. anterior mesoderm; notochord genes are expected to be increased since the notochord is located in the posterior mesoderm. (2) Posterior mesoderm vs. whole embryos; notochord genes are expected to be increased. (3) Notochord vs. somite. This comparison sub-divided the group of posterior mesodermal genes identified in (1) and (2). All tissues are dissected using tungsten needles. We first dissected dorsal tissue above the archenteron from late gastrula to early neurula. To loosen tissue, we treated the dissected dorsal explant in a 1% cysteine solution (pH 7.4) and removed the neuroectodermal layer. Anterior mesoderm was dissected corresponding to about the anterior one-third of the archenteron roof, and the rest was collected as posterior mesoderm. The posterior mesodermal explant was dissected into notochord and somites, following a clearly visible border between the two tissues. The accuracy of all dissection was confirmed by RT-PCR of marker genes.
Coordinated activation of the secretory pathway during notochord formation in the Xenopus embryo.
Specimen part
View SamplesStudies on the early embryonic development of Xenopus laevis contributed much to the understanding of vertebrate patterning. Gastrula stages are of particular interest because establishment of the axis and germ layer formation take place during these stages. While many genes belonging to several signaling pathways including FGF, Wnt and TGF-beta, have been implicated in patterning the gastrula embryo, the hierarchical interactions between these factors are incompletely known. To study this question, we took advantage of microarray technology to create a regional gene expression profile for the Xenopus gastrula.
Coordinated activation of the secretory pathway during notochord formation in the Xenopus embryo.
No sample metadata fields
View Samplesthere is presently no methodology that adequately isolates pure MaSCs. Seeking new markers of MaSCs, we characterized the stem-like properties and expression signature of label-retaining cells from the mammary gland of mice expressing a controllable H2b-GFP transgene. According to their transcriptome profile, H2b-GFPh MaSCs are enriched for pathways thought to play important roles in adult stem cells.
Molecular hierarchy of mammary differentiation yields refined markers of mammary stem cells.
No sample metadata fields
View SamplesOur studies indicate that glucose and acetate can regulate histone acetylation by altering the acetyl-CoA concentrations in the cell. The purpose of this study was to to determine whether specific gene sets correlated with acetyl-CoA availability. We conclude that 10% of glucose-regulated genes are acetyl-CoA regulated genes (genes suppressed or induced by low glucose and reversed by acetate). Acetate usually regulated gene expression in the same direction as glucose, suggesting that acetyl-CoA is a key mediator of glucose-dependent gene expression. Overall design: The experiments were performed in quadruplicates for each condition with a total of 12 samples
Akt-dependent metabolic reprogramming regulates tumor cell histone acetylation.
Specimen part, Cell line, Subject
View SamplesDrosophila eye specification an development relies on a collection of transcription factors termed the retinal determination gene network (RDGN). Two members of this network, Eyes absent (EYA) and Sine oculis (SO), form a transcriptional complex in which EYA provides the transactivation function while SO provides the DNA binding activity. EYA also function as a protein tyrosine phosphatase, raising the question of whether transcriptional output is dependent or independent of phosphatase activity. To explore this, we used microarrays together with binding site analysis, quantitative real-time PCR, chromatin immunoprecipitation, genetics, and in vivo expression analysis to identify new EYA-SO targets. In parallel, we examined the expression profiles of tissue expressing phosphatase mutant eya and found that reducing phosphatase activity did not globally impair transcriptional output. Among the targets identified by our analysis was the cell cycle regulatory gene, string (stg), suggesting that EYA and SO may influence cell proliferation through transcriptional regulation of stg. Future investigation into the regulation of stg and other EYA-SO targets identified in this study will help elucidate the transcriptional circuitries whereby output from the RDGN integrates with other signaling inputs to coordinate retinal development.
Identification of transcriptional targets of the dual-function transcription factor/phosphatase eyes absent.
No sample metadata fields
View SamplesWe have recently demonstrated that mycobacterial ligands engage Toll like receptor 2 (TLR2) on CD4+ T cells and up-regulate T-cell receptor (TCR) triggered- Th1 responses in vitro and in vivo.
Toll like Receptor 2 engagement on CD4<sup>+</sup> T cells promotes TH9 differentiation and function.
No sample metadata fields
View SamplesDeveloping osteoblasts undergo a sequence of three consecutive phases: cell proliferation, extracellular matrix maturation, and mineralization. We investigated pH effects on these phases using the osteoblast-like cell line MC3T3-E1.
MC3T3 osteoblast-like cells cultured at alkaline pH: Microarray data (Affymetrix GeneChip Mouse 2.0 ST).
Sex, Specimen part
View SamplesThe presence of unspliced transcripts in hematopoietic stem cells (HSCs) and the proposed association of CREBBP with the constitutive production of unspliced RNA and with pre-mRNA processing prompted us to examine more closely an anomaly we had noted in microarray-based gene expression studies but had previously attributed to experimental noise. We noticed that more than half of the probe sets down-regulated in Crebbp+/- fetal liver HSCs (FLHSCs) relative to wild-type (WT) mapped entirely within introns, rather than detecting exonic or spliced sequences. We therefore set out to test whether this might be evidence that reduced CREBBP levels selectively alter the generation of full-length, unspliced pre-mRNA. We also asked whether this process might be associated with differentiation since self-renewal and lineage commitment are the both responses for which HSCs are primed.
Inactivation of a single copy of Crebbp selectively alters pre-mRNA processing in mouse hematopoietic stem cells.
Specimen part
View SamplesIn obesity an increase in -cell mass occurs to cope with the rise in insulin demand. This -cell plasticity is essential to avoid the onset of hyperglycemia, although the molecular mechanisms that regulate this process remain unclear. This study analyzed the role of adipose tissue in the control of -cell replication. Using a diet-induced model of obesity, we obtained conditioned media from three different white adipose tissue depots. Only in the adipose tissue depot surrounding the pancreas did the diet induce changes that led to an increase in INS1E cells and the islet replication rate. To identify the factors responsible for this proliferative effect, adipose tissue gene expression analysis was conducted by microarrays and quantitative RT-PCR. Of all the differentially expressed proteins, only the secreted ones were studied. IGF binding protein 3 (Igfbp3) was identified as the candidate for this effect. Furthermore, in the conditioned media, although the blockage of IGFBP3 led to an increase in the proliferation rate, the blockage of IGF-I receptor decreased it. Taken together, these data show that obesity induces specific changes in the expression profile of the adipose tissue depot surrounding the pancreas, leading to a decrease in IGFBP3 secretion. This decrease acts in a paracrine manner, stimulating the -cell proliferation rate, probably through an IGF-I-dependent mechanism. This cross talk between the visceral-pancreatic adipose tissue and -cells is a novel mechanism that participates in the control of -cell plasticity. (Endocrinology 153: 177187, 2012)
Role of IGFBP-3 in the regulation of β-cell mass during obesity: adipose tissue/β-cell cross talk.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Downregulation of Sfrp5 promotes beta cell proliferation during obesity in the rat.
Specimen part
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