Extremely low specific growth rates (below 0.01 h-1) represent a largely unexplored area of microbial physiology. Retentostats enable controlled, energy-limited cultivation at near-zero specific growth rates while avoiding starvation. In this study, anaerobic, glucose-limited retentostats were used to analyze physiological and genome-wide transcriptional responses of Saccharomyces cerevisiae to cultivation at near-zero specific growth rates. Cultures at near-zero specific growth rates exhibited several characteristics previously associated with quiescence, including accumulation of storage polymers and an increased expression of genes involved in storage metabolism, autophagy and exit from the replicative cell cycle into G0. Analysis of transcriptome data from glucose-limited retentostat and chemostat cultures showed, as specific growth rate was decreased, quiescence-related transcriptional responses already set in at specific growth rates above 0.025 h-1. Many genes involved in mitochondrial processes were specifically upregulated at near-zero specific growth rates, possibly reflecting an increased turn-over of organelles under these conditions. Prolonged (> 2 weeks) cultivation in retentostat cultures led to induction of several genes that were previously implicated in chronological ageing. These observations stress the need for systematic dissection of physiological responses to slow growth, quiescence, ageing and starvation and indicate that controlled cultivation systems such as retentostats can contribute to this goal.
Cellular responses of Saccharomyces cerevisiae at near-zero growth rates: transcriptome analysis of anaerobic retentostat cultures.
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View SamplesThis study aimed to explore the role of NIPP1 in adult germline cell proliferation and differentiation, using a ubiquitous inducible NIPP1 knockout (TKO) mouse model. To gain unbiased insight into the molecular mechanism that underly the sertoli-only phenotype in TKO, we performed a comparative RNA sequencing profiling of control and TKO, in which NIPP1 was tamoxifin-induced depleted. Overall design: Two genotypes are compared after treatment with tamoxifen. The control genotype (UBC CRE-ERT2+/- Ppp1r8 fl/+) looses the floxed allele of PPP1R8 (aka NIPP1) as a consequence of the treatment with tamoxifen and becomes heterozygous for PPP1R8. The KO genotype (UBC CRE-ERT2+/- Ppp1r8 fl/-) also looses the floxed allele of PPP1R8 as a consequence of the tamoxifen treatment and becomes homozygous KO. For each genotype, 4 replicates are profiled.
The protein phosphatase 1 regulator NIPP1 is essential for mammalian spermatogenesis.
Age, Specimen part, Subject
View SamplesMaternal Embryonic Leucine Zipper Kinase (MELK), a Ser/Thr protein kinase, is highly over expressed in stem and cancer cells. The oncogenic role of MELK is attributed to its capacity to disable critical cell cycle checkpoints and to enhance replication. Most functional studies have relied on the use of siRNA/shRNA-mediated gene silencing, but this is often compromised by off target effects. Here we present the cellular validation of a novel, potent and selective small molecule MELK inhibitor, MELK-T1, which has enabled us to explore the biological function of MELK. Strikingly, the binding of MELK-T1 to endogenous MELK triggers a rapid and proteasome dependent degradation of the MELK protein. Treatment of MCF-7 breast adenocarcinoma cells with MELK-T1 leads to an accumulation of stalled replication forks and double strand breaks, followed by a replicative senescence phenotype. This phenotype correlates with a rapid and long-lasting ATM activation and phosphorylation of CHK2. Furthermore, MELK-T1 induces strong phosphorylation of p53 and prolonged up-regulation of p21.
MELK-T1, a small-molecule inhibitor of protein kinase MELK, decreases DNA-damage tolerance in proliferating cancer cells.
Cell line, Treatment
View SamplesExpression profiles of 917 pathway repoter genes were determined by AmpliSeq-RNA in primary human hepatocytes treated with Diclofenac and a test compound 3 hours after treatment. Overall design: Vehicle control, diclofenac, and three doses of the test compound (small-molecule neurotransmitter receptor antagonist) were applied to three primary cell lines, with three biological replicates in each group. In some treatment groups read-outs were only available for two samples. All together 41 samples were profiled.
Pathway reporter genes define molecular phenotypes of human cells.
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View SamplesGene expression studies from hematopoietic stem cell (HSC) populations purified to variable degrees have defined a set of stemness genes. The present study describes the construction and comparative molecular analysis of l-phage cDNA libraries from highly purified primitive HSCs (PHSCs) which retained their long term repopulating activities (LTRAs), and from maturing HSCs (MHSCs) which were largely depleted of LTRAs. Library inserts were amplified and tagged by a T7 RNA polymerase promoter and used to generate biotinylated cRNA for Microarray hybridization. Microarray analysis of the libraries confirmed previous results but also revealed an unforseen preferential expression of translation and metabolism associated genes in the PHSCs. Therefore these data indicate that HSCs are quiescent only in regard of proliferative activities, but are in a state of readiness to provide the metabolic and translational activities required following induction of proliferation by factors which induce differentiation and exit from the HSC pool.
Gene expression profiles in murine hematopoietic stem cells revisited: analysis of cDNA libraries reveals high levels of translational and metabolic activities.
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View SamplesA GFP-expressing recombinant A/Puerto Rico/8/1934 influenza virus was used to infect C57BL/6 wild type mice and on day 3 post infection, lung alveolar epithelial cells (AEC) were isolated and sorted based on GFP expression. GFP+ AEC represent the infected AEC and GFP- AEC represent the bystander AEC. AEC were also sorted from uninfected mice to serve as controls. Overall design: AEC from infected mice were pooled to make three (3) infected GFP+ AEC replicates for sequencing. Five (5) bystander GFP- replicates and five (5) uninfected AEC replicates were also isolated for sequencing
Transcriptome Analysis of Infected and Bystander Type 2 Alveolar Epithelial Cells during Influenza A Virus Infection Reveals <i>In Vivo</i> Wnt Pathway Downregulation.
Specimen part, Subject, Time
View SamplesWe used microarrays to analyze gene expression changes in liver after treatment of rats with two compounds from drug development (R1, R2) to identify potential effects related to hepatotoxicity.
Gene expression-based in vivo and in vitro prediction of liver toxicity allows compound selection at an early stage of drug development.
Sex, Specimen part, Treatment
View SamplesThere is increasing appreciation for sexually dimorphic effects, but the molecular mechanisms underlying these effects are only partially understood. In the present study, we explored transcriptomics and epigenetic differences in the small intestine and colon of prepubescent male and female mice. In addition, the microbiota composition of the colonic luminal content has been examined. At postnatal day 14, male and female C57BL/6 mice were sacrificed and the small intestine, colon and content of luminal colon were isolated. Gene expression of both segments of the intestine was analysed by microarray analysis. DNA methylation of the promoter regions of selected sexually dimorphic genes was examined by pyrosequencing. Composition of the microbiota was explored by deep sequencing. Sexually dimorphic genes were observed in both segments of the intestine of 2-week-old mouse pups, with a stronger effect in the small intestine. Amongst the total of 349 genes displaying a sexually dimorphic effect in the small intestine and/or colon, several candidates exhibited a previously established function in the intestine (i.e. Nts, Nucb2, Alox5ap and Retnl). In addition, differential expression of genes linked to intestinal bowel disease (i.e. Ccr3, Ccl11 and Tnfr) and colorectal cancer development (i.e. Wt1 and Mmp25) was observed between males and females. Amongst the genes displaying significant sexually dimorphic expression, nine genes were histone-modifying enzymes, suggesting that epigenetic mechanisms might be a potential underlying regulatory mechanism. However, our results reveal no significant changes in DNA methylation of analysed CpGs within the selected differentially expressed genes. With respect to the bacterial community composition in the colon, a dominant effect of litter origin was found but no significant sex effect was detected. However, a sex effect on the dominance of specific taxa was observed. This study reveals molecular dissimilarities between males and females in the small intestine and colon of prepubescent mice, which might underlie differences in physiological functioning and in disease predisposition in the two sexes.
Sexually dimorphic characteristics of the small intestine and colon of prepubescent C57BL/6 mice.
Sex, Age, Specimen part
View SamplesMicroRNA-155 (miR-155) is upregulated in primary effector CD8 T cells but is expressed at low amounts in nave cells. Anti-viral CD8 T cell responses and viral clearance were impaired in miR-155 deficient (bic-/-) mice, and this defect was intrinsic to CD8 T cells, as adoptively transferred bic-/- CD8 T cells generated greatly reduced primary and memory responses during infection. To understand the mechanism by which miR-155 regulates CD8 T cell activation, we analyzed the gene expression profiles of naive and in vitro activated wild-type and bic-/- CD8 T cells.
The microRNA miR-155 controls CD8(+) T cell responses by regulating interferon signaling.
Specimen part
View SamplesAlthough the prognosis for childhood Acute Lymphoblastic Leukemia (ALL) in general has improved tremendously over the last decades, the survival chances for infants (<1 year of age) with ALL remains poor.
Association of high-level MCL-1 expression with in vitro and in vivo prednisone resistance in MLL-rearranged infant acute lymphoblastic leukemia.
Sex, Specimen part, Disease
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