The extent to which carbon flux is directed towards fermentation vs. respiration differs between cell types and environmental conditions. Understanding the basic cellular processes governing carbon flux is challenged by the complexity of the metabolic and regulatory networks. To reveal the genetic basis for natural diversity in channeling carbon flux, we applied Quantitative Trait Loci analysis by phenotyping and genotyping hundreds of individual F2 segregants of budding yeast that differ in their capacity to ferment the pentose sugar xylulose. Causal alleles were mapped to the RXT3 and PHO23 genes, two components of the large Rpd3 histone deacetylation complex. We show that these allelic variants modulate the expression of SNF1/AMPK-dependent respiratory genes. Our results suggest that over close evolutionary distances, diversification of carbon flow is driven by changes in global regulators, rather than adaptation of specific metabolic nodes. Such regulators may improve the ability to direct metabolic fluxes for biotechnological applications. Overall design: mRNA profiles of S. cerevisiae strain BY4741 with either the RXT3 or PHO23 genes either deleted, replaced by S. cerevisiae T73 allele or replaced by S. cerevisiae PHO23 allele
Natural Diversity in Pentose Fermentation Is Explained by Variations in Histone Deacetylases.
Cell line, Subject
View SamplesThis study was designed to investigate gene expression in kidneys of adult female Sabra rats (SBH/y and SBN/y rat strains) with two indwelling kidneys or after uni-ninephrectomy, seeking those genes that are differentially expressed between the two strains, and between animals with one or two kidneys. SBH/y after uninephrectomy develop proteinuria to a much greater extent than SBN/y. The study was performed as part of an overall effort to detect the genes that are associated with the pathophysiology of proteinuria.
Geno-transcriptomic dissection of proteinuria in the uninephrectomized rat uncovers a molecular complexity with sexual dimorphism.
No sample metadata fields
View SamplesPrevalence and severity of allergic diseases have increased worldwide. To date, respiratory allergy phenotypes are not fully characterized and, in addition, the mechanisms underlying sublingual immunotherapy (SLIT) are still unknown.
Exploring novel systemic biomarker approaches in grass-pollen sublingual immunotherapy using omics.
Specimen part, Treatment, Time
View SamplesCells constantly adapt to changes in their environment. In the majority of cases, the environment shifts between conditions that were previously encountered during the course of evolution, thus enabling evolutionary-programmed responses. In rare cases, however, cells may encounter a new environment to which a novel response is required. To characterize the first steps in adaptation to a novel condition, we studied budding yeast growth on xylulose, a sugar that is very rarely found in the wild. We previously reported that growth on xylulose induces the expression of amino-acid biosynthesis genes, in multiple natural yeast isolates. This induction occurs despite the presence of amino acids in the growth medium and is a unique response to xylulose, not triggered by any of the naturally available carbon sources tested. Propagating these strains for ~300 generations on xylulose significantly improved their growth rate. Notably, the most significant change in gene expression was the loss of amino acid biosynthesis gene induction. Furthermore, the reduction in amino-acid biosynthesis gene expression on xylulose was strongly correlated with the improvement in growth rate, suggesting that internal depletion of amino-acids presented the major bottleneck limiting growth in xylulose. We discuss the possible implications of our results for explaining how cells maintain the balance between supply and demand of amino acids during growth in evolutionary 'familiar' vs. 'novel' conditions. Overall design: mRNA profiles of 12 wt S. cerevisiae strains grown on either YPD or YP-xylulose, before and after 300 generations evolution on YP-xylulose
Rapid evolutionary adaptation to growth on an 'unfamiliar' carbon source.
Cell line, Subject
View SamplesEpimorphic regeneration is the process by which complete regeneration of a complex structure such as a limb occurs through production of a proliferating blastema. This type of regeneration is rare among vertebrates but does occur in the African clawed frog Xenopus laevis, traditionally a model organism for the study of early development. Xenopus tadpoles can regenerate tails, limb buds and the lens of the eye, although the ability of the latter two organs to regenerate diminishes with advancing developmental stage. Using a heat shock inducible transgene that remains silent unless activated, we have established a stable line of transgenic Xenopus in which the BMP inhibitor Noggin can be over-expressed at any time during development. We have previously shown that activation of this transgene blocks regeneration of the tail and limb of Xenopus tadpoles. In the current study, we have taken advantage of this transgenic line to directly compare gene expression in same stage regenerating vs. non-regenerating hind limb buds. Using Affymetrix gene chip analysis, we have identified genes whose expression levels are linked to regenerative success. These include the BMP inhibitor Gremlin and the stress protein Hsp60 (no blastema in zebrafish). Analysis of overrepresented Gene Ontology functional groupings suggests that successful regeneration in the Xenopus hind limb depends on induction of stress response pathways. Furthermore, as expected, genes involved in embryonic development and growth are also significantly over-represented in regenerating early hind limb buds.
Identification of genes associated with regenerative success of Xenopus laevis hindlimbs.
No sample metadata fields
View SamplesSubpopulations of human fetal thymocyte and circulating nave T cells were obtained through FACS sorting, including CD3-CD4+CD8- intrathymic T progenitor cells (ITTP), CD3intCD4+CD8+ "double positive" thymocytes (DP), CD3highCD4+CD8- "single positive" thymocytes (SP4), CD3+CD4+CD8-CD45RA+CD62L+ nave T cells from cord blood (CB4+), and CD3+CD4+CD8-CD45RA+CD62L+ nave T cells from adult blood (AB4+).
Gene expression profiles during human CD4+ T cell differentiation.
No sample metadata fields
View SamplesOligodendrocytes undergo extensive changes as they differentiate from progenitors into myelinating cells. To better understand the
Identification of a novel oligodendrocyte cell adhesion protein using gene expression profiling.
No sample metadata fields
View SamplesCortical development is a complex process involving the generation of neuronal progenitors, which proliferate and migrate to form the stratified layers of the maturing cortex. To identify microRNAs (miRNAs) and genes that may be important during early cortical development, we analyzed the expression profiles of rat neuronal progenitors obtained at embryonic day 11 (E11), E12 and E13 using microarrays. Neuronal progenitors were purified from telencephalic dissociates with a positive-selection strategy using surface labeling tetanus-toxin and cholera-toxin and fluorescence-activated cell sorting. We identified classes of miRNAs and mRNAs that were up-regulated or down-regulated in these neuronal progenitors as cortical development progressed from E11 to E13. We present data that supports a regulatory role for miRNAs during the transition from neuronal progenitors into differentiating cortical neurons.
Integrating microRNA and mRNA expression profiles of neuronal progenitors to identify regulatory networks underlying the onset of cortical neurogenesis.
No sample metadata fields
View SamplesThis research identifies a novel protein required for paramutation at the maize purple plant1 locus. This 'required to maintain repression2' (RMR2) protein represents the founding member of a plant-specific clade of hypothetical proteins. We show that RMR2 is required for transcriptional repression at the Pl1-Rhoades haplotype, for accumulation of 24 nt RNA species, and for maintenance of a 5-methylcytosine pattern distinct from that maintained by RNA polymerase IV. Genetic tests indicate that RMR2 is not required for paramutation occurring at the red1 locus. These results distinguish the paramutation-type mechanisms operating at specific haplotypes. The RMR2 clade of proteins provides a new entry point for understanding the diversity of epigenomic control operating in higher plants. Overall design: Examination of small RNAs using Illumina's sequencing-by-synthesis (SBS) platform to deep sequence small RNA libraries made from the 4-cm cobs of rmr2 mutant and non-mutant siblings.
required to maintain repression2 is a novel protein that facilitates locus-specific paramutation in maize.
Specimen part, Subject
View SamplesWe perform microarray analysis of HUVECs upon stimulation with virulent wildtype C. albicans strain SC5314 or its efg1/efg1 cph1/cph1 hyphal-deficient derivative strain CAN34 to compare the gene expression profiles elicited from HUVECs in response to these strains. In addition, these responses are compared to that of TNF-alpha induced responses to determine which responses are Candida-specific.
Transcriptome profile of the vascular endothelial cell response to Candida albicans.
No sample metadata fields
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