To gain insight into FTO function, we knocked down and overexpressed FTO in HEK293 cells.Genetrail analyses of expression profiles pointed to the RNA splicing and processing machinery. Intriguingly, using immunocytochemistry and confocal laser scanning microscopy, we observed strong enrichment of FTO in nuclear speckles and - to a lesser extent - in nucleoli, but not in other known nuclear bodies. We also studied RNA samples of Fto knockout and wild type mice with regard to content of methylated and unmethylated nucleosidesand observed that ratios of modified and unmodified uracil and adenine were different depending on the presence of FTO. Taken together, our data suggest that FTO is involved in RNA processing and modification.
FTO levels affect RNA modification and the transcriptome.
Treatment
View SamplesGene expression microarray profile for human embryonic kidney cells (HEK293T, CRL-11268) under untreated conditions.
The identification of protein kinase C iota as a regulator of the Mammalian heat shock response using functional genomic screens.
Specimen part, Cell line
View SamplesGene expression profiling is a promising diagnostic and prognostic tool. Expression profiles are snap-shots of mRNA levels at time of extraction and they have been shown to be affected by tissue handling during sample collection. The effect of cold (room temperature) ischemia in the time interval between surgical removal of the specimen and freezing has been described in a number of studies. However, not much is known about the effect of warm (body temperature) ischemia during surgery.
Differential effect of surgical manipulation on gene expression in normal breast tissue and breast tumor tissue.
Sex, Specimen part, Disease, Subject
View SamplesConjugated linoleic acid (CLA), a class of fatty acids found in beef and dairy products, has been shown to inhibit tumorigenesis in a variety of cancer model systems. Based on previously well-documented anti-tumor activity of CLA in rodent models of breast cancer, a pilot study was initiated to examine the effect of dietary CLA in a well-established transgenic model of breast cancer. Western blots were performed for the detection of AKT, c-Src, ERK1/2, and Cdc24. CLA significantly increased tumor burden (p<0.1) independent of an increase in oncogenic signaling. Mammary gland whole mounts indicated a loss of mammary adipose and extensive epithelial expansion in CLA-treated animals. Microarray analysis indicated a significant reduction in cytoskeletal related genes with at least a two-fold decrease in five out of six CLA-fed animals compared to untreated controls. Reduction of Cdc42, a key regulator of cell adhesion and cytoskeletal arrangements, was confirmed at the protein level by western blot (p<0.01). These findings suggest that dietary CLA may advance the malignant phenotype by promoting a loss of cell polarity and adhesion in the mammary gland epithelium. This action may have serious clinical implications for a subset high-risk population and warrants further investigation.
Pilot study on the effects of dietary conjugated linoleic acid on tumorigenesis and gene expression in PyMT transgenic mice.
Sex, Age, Specimen part
View SamplesSox3 has been shown to be expressed within neural progenitors of the developing mouse central nervous system. However, identification of Sox3 targets within neural progenitors has remained elusive.
Dbx1 is a direct target of SOX3 in the spinal cord.
Specimen part, Cell line
View SamplesWe profile gene expression changes in two mutant strains lacking the D. melanogaster HP1 homolog HP1B at the third instar larval stage. Compared to the yw control strain, several hundred genes are deregulated, with metabolic genes being over-represented among the deregulated gene set. Overall design: Examination of gene expression in two genotypes
HP1B is a euchromatic Drosophila HP1 homolog with links to metabolism.
Specimen part, Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Profiling of the transcriptional response to all-trans retinoic acid in breast cancer cells reveals RARE-independent mechanisms of gene expression.
Cell line
View SamplesThe primary goal of toxicology and safety testing is to identify agents that have the potential to cause adverse effects in humans. Unfortunately, many of these tests have not changed significantly in the past 30 years and most are inefficient, costly, and rely heavily on the use of animals. The rodent cancer bioassay is one of these safety tests and was originally established as a screen to identify potential carcinogens that would be further analyzed in human epidemiological studies. Today, the rodent cancer bioassay has evolved into the primary means to determine the carcinogenic potential of a chemical and generate quantitative information on dose-response behavior in chemical risk assessments. Due to the resource-intensive nature of these studies, each bioassay costs $2 to $4 million and takes over three years to complete. Over the past 30 years, only 1,468 chemicals have been tested in a rodent cancer bioassay. By comparison, approximately 9,000 chemicals are used by industry in quantities greater than 10,000 lbs and nearly 90,000 chemicals have been inventoried by the U.S. Environmental Protection Agency as part of the Toxic Substances Control Act. Given the disparity between the number of chemicals tested in a rodent cancer bioassay and the number of chemicals used by industry, a more efficient and economical system of identifying chemical carcinogens needs to be developed.
Application of genomic biomarkers to predict increased lung tumor incidence in 2-year rodent cancer bioassays.
Sex, Age, Subject
View SamplesRetinoids, derivatives of vitamin A, are key physiological molecules with regulatory effects on cell differentiation, proliferation and apoptosis. As a result, they are of interest for cancer therapy. Specifically, models of breast cancer have varied responses to manipulations of the retinoid signaling cascade. This study characterizes the transcriptional response of MDA-MB-231 and MDA-MB-468 breast cancer cells to retinaldehyde dehydrogenase 1A3 (ALDH1A3) and to all-trans retinoic acid (atRA). We demonstrate limited overlap between ALDH1A3-induced gene expression and atRA-induced gene expression in both cell lines, suggesting that the function of ALDH1A3 in breast cancer progression extends beyond its role as a retinaldehyde dehydrogenase. Our data reveals divergent transcriptional responses to atRA, which are largely independent of genomic retinoic acid response elements (RAREs) and consistent with the opposing responses of MDA-MB-231 and MDA-MB-468 to in vivo atRA treatment. We identify transcription factors associated with each gene set. Manipulation of one of the transcription factors (i.e. interferon regulatory factor 1; IRF1) demonstrates that it is the level of atRA-inducible and epigenetically regulated transcription factors that determine expression of target genes (e.g. CTSS, cathepsin S). This study provides a paradigm for complex, combinatorial responses of breast cancer models to atRA treatment, and illustrates the need to characterize RARE-independent responses to atRA in a variety of models.
Profiling of the transcriptional response to all-trans retinoic acid in breast cancer cells reveals RARE-independent mechanisms of gene expression.
Cell line
View SamplesTo determine whether immortalized cells derived from the rat SCN (SCN 2.2) retain intrinsic rhythm-generating properties characteristic of the SCN, oscillatory properties of the SCN2.2 transcriptome were analyzed and compared to those found in the rat SCN in vivo using rat U34A Affymetrix GeneChips. SCN2.2 cells were expanded in 6-well plates. At 6-hour interval across 2 circadian cycles, cells from single 6-well plates were harvested and pooled for total RNA extraction.
Circadian profiling of the transcriptome in immortalized rat SCN cells.
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