Compared gene expression in lymphoblasoid cell lines from alcholics and controls and 24 hr treatment with ethanol.
Ethanol treatment of lymphoblastoid cell lines from alcoholics and non-alcoholics causes many subtle changes in gene expression.
Sex, Disease stage, Cell lineView Samples
Two nutrient sensing and regulatory pathways, the general amino acid control (GAAC) and the target of rapamycin (TOR), control yeast growth and metabolism in response to changes in nutrient availability. Starvation for amino acids activates the GAAC pathway, involving Gcn2p phosphorylation of eIF2 and preferential translation of GCN4, a transcription activator of genes involved in amino acid metabolism. TOR senses nitrogen availability and regulates gene expression through transcription factors, such as Gln3p. We used microarray analyses to address the integration of the GAAC and TOR pathways in directing the yeast transcriptome in response to amino acid starvation and rapamycin treatment. Of the ~2500 genes whose expression was changed by 2-fold or greater, Gcn4p and Gln3p were required for 542 and 657 genes, respectively. While Gcn4p activates a common core of 57 genes in response to amino acid starvation or rapamycin treatment, the different stress arrangements allow for variations in Gcn4p-directed transcription. With few exceptions, genes requiring Gcn2p eIF2 kinase for induced expression also required Gcn4p, emphasizing the role of Gcn2p as an upstream activator of Gcn4p-directed transcription. There is also significant coordination between the GAAC and TOR pathways, with Gcn4p being required for activation of more genes during rapamycin treatment than Gln3p. Importantly, TOR regulates the GAAC-directed transcription of genes required for assimilation of nitrogen sources, such as -amino-butyric acid. Therefore, yeast has integrated gene expression responses to amino acid abundance and nitrogen source quality through the control of Gcn2p phosphorylation of eIF2 and GCN4 translation.
Integration of general amino acid control and target of rapamycin (TOR) regulatory pathways in nitrogen assimilation in yeast.
This SuperSeries is composed of the SubSeries listed below.
CHOP induces activating transcription factor 5 (ATF5) to trigger apoptosis in response to perturbations in protein homeostasis.
Specimen part, TreatmentView Samples
Comparison of gene expression from subjects who resolved or formed pustules to H.ducreyi.
Dysregulated immune profiles for skin and dendritic cells are associated with increased host susceptibility to Haemophilus ducreyi infection in human volunteers.
No sample metadata fieldsView Samples
Specific changes in gene expression during cancer initiation should enable discovery of biomarkers for risk assessment, early detection and targets for chemoprevention. It has been previously demonstrated that altered mRNA and proteome signatures of morphologically normal cells bearing a single inherited hit in a tumor suppressor gene parallel many changes observed in the corresponding sporadic cancer. Here, we report on the global gene expression profile of morphologically normal, cultured primary breast epithelial and stromal cells from Li-Fraumeni syndrome (LFS) TP53 mutation carriers. Our analyses identified multiple changes in gene expression in both morphologically normal breast epithelial and stromal cells associated with TP53 haploinsufficiency, as well as interlocking pathways. Notably, a dysregulated p53 signaling pathway was readily detectable. Pharmacological intervention with the p53 rescue compounds CP-31398 and PRIMA-1 provided further evidence in support of the central role of p53 in affecting these changes in LFS cells and treatment for this cancer. Because loss of signaling mediated by TP53 is associated with the development and survival of many human tumors, identification of gene expression profiles in morphologically normal cells that carry one-hit p53 mutations may reveal novel biomarkers, enabling the discovery of potential targets for chemoprevention of sporadic tumors as well.
A molecular signature of normal breast epithelial and stromal cells from Li-Fraumeni syndrome mutation carriers.
Specimen partView Samples
Disruption of protein folding in the endoplasmic reticulum triggers the Unfolded Protein Response (UPR), a transcriptional and translational control network designed to restore protein homeostasis. Central to the UPR is PERK phosphorylation of the alpha subunit of eIF2 (eIF2~P), which represses global translation coincident with preferential translation of mRNAs, such as ATF4 and CHOP, that serve to implement the UPR transcriptional regulation. In this study, we used sucrose gradient ultracentrifugation and a genome-wide microarray approach to measure changes in mRNA translation during ER stress. Our analysis suggests that translational efficiencies vary across a broad range during ER stress, with the majority of transcripts being either repressed or resistant to eIF2~P, while a notable cohort of key regulators are subject to preferential translation. From this latter group, we identify IBTKa as being subject to both translation and transcriptional induction during eIF2~P in both cell lines and a mouse model of ER stress. Translational regulation of IBTKalpha mRNA involves the stress-induced relief of two inhibitory uORFs in the 5'-leader of the transcript. Depletion of IBTKalpha by shRNA reduced viability of cultured cells coincident with increased caspase 3/7 cleavage, suggesting that IBTKalpha is a key regulator in determining cell fate during the UPR.
Selective mRNA translation during eIF2 phosphorylation induces expression of IBTKα.
Specimen partView Samples
Mouse model for Fetal Alcohol Syndrome. Embryos exposed to alcohol in controlled environment to assess teratogenic effects.
Identification of transcription factor and microRNA binding sites in responsible to fetal alcohol syndrome.
No sample metadata fieldsView Samples
The role of reproductive hormones in lung cancer is controversial; obervations from epidemiological studies support the possibilities that estrogen either promotes or protects against the disease. In an earlier study we reported that estradiol (E2) stimulated tumorigenesis in a genetically defined mouse model based on the conditional expression of oncogenic Kras and concomitant deletion of p53. The present study was meant to further examine the effects of estrogens in this model. Instead we found that tumorigenesis was inhibited by the presence of the ovaries and that E2 proved protective against tumorigenesis in ovariectomized animals. Specifically, E2 and the Esr1-specific agonist PPT reduced the number and size of tumors that developed; furthermore, the protective effects of these two steroids were dose-dependent. However, the Esr2 agonist DPN produced no effect. Since Esr2 predominates in the lung, these results suggest that the E2 effect is indirect, perhaps being mediated by an endocrine factor from another organ. Furthermore, the fact that the E2 effect in this second iteration of the mouse model was diametrically opposed to our earlier results suggests that genetic background plays a critical role in determining the effect of estrogen.
No associated publication