Deficiencies in the ATM gene are the underlying cause for ataxia telangiectasia, a congenital syndrome characterized by neurological, motor and immunological defects, as well as a predisposition to cancer risks. MicroRNAs (miRNAs) are small regulators of post-transcriptional gene expression and a useful tool for cancer diagnosis, staging, and prediction of therapeutic responses to clinical regimens. In particular, miRNAs have been used to develop signatures for breast cancer profiling. We are interested in the consequences of ATM deficiency on miRNA expression in breast epithelial cells and the potential contribution to cancer predisposition. In this study we investigate the effects of ATM loss on the miRNA expression and related gene expression changes in normal human mammary epithelial cells (HME-CC). We have identified 81 significantly differently expressed miRNAs in the ATM-deficient HME-CCs using small RNA sequencing. Many of these differentially expressed miRNAs have been described and implicated in tumorigenesis and proliferation. These changes include down-regulation of tumor suppressor miRNAs, such as hsa-miR-29c and hsa-miR-16, as well as the over-expression of pro-oncogenic miRNAs hsa-miR-93 and hsa-mir-221. All 81 miRNAs were combined with genome wide gene expression profiles to investigate possible targets of miRNA regulation. We identified messenger RNA (mRNA) targets of these miRNAs that were also significantly regulated after the depletion of ATM. Predicted targets included many genes implicated in cancer formation and progression, including SOCS1 and the proto-oncogene MAF. Integrated analysis of miRNA and mRNA expression allows us to build a more complete understanding of the pathways and networks involved in the breast cancer predisposition observed in individuals deficient in ATM. This study highlights miRNA and predicted mRNA target expression changes in ATM-deficient HME-CCs and suggests a mechanism for the breast cancer-prone phenotype seen in ATM deficient cells and patients. Additionally, this study provides preliminary data for defining miRNA profiles that may be used prognostic biomarkers for breast cancer predisposition. Overall design: Examination of small RNA population in human mammary epithelial cell lines. Each condition was preformed in triplicate.
Genome-wide small RNA sequencing and gene expression analysis reveals a microRNA profile of cancer susceptibility in ATM-deficient human mammary epithelial cells.
Specimen part, Cell line, Subject
View SamplesThe simultaneous genotyping of tens of thousands of SNP using SNP microarrays is a very important tool that is revolutionizing genetics and molecular biology. In this work, we present a new application of this technique by using it to assess chromatin immunoprecipitation (CHIP) as a means to assess the multiple genomic locations bound by a protein complex recognized by an antibody. We illustrate the use of this technique with an analysis of the change in histone H4 acetylation, a marker of open chromatin and transcriptionally active genomic regions, which occur during the differentiation of human myoblasts into myotubes. Our results are validated by the observation of a significant correlation between the histone modifications detected and the expression of the nearby genes, as measured by DNA microarrays.
ChIP on SNP-chip for genome-wide analysis of human histone H4 hyperacetylation.
No sample metadata fields
View SamplesGene expression was determined for both myotubes and myoblasts using Affymetrix HG-U133 A/B arrays.
ChIP on SNP-chip for genome-wide analysis of human histone H4 hyperacetylation.
No sample metadata fields
View SamplesThe objective of this set of samples is to identify genes that are differentially expressed following the introduction of DNA double strand breaks (DSBs) by ionizing radiation in wild-type murine pre-B cells. The data generated in this project will be compared to the data generated in GSE9024, in which genes that are differentially expressed following the introduction of DNA double strand breaks (DSBs) by the Rag proteins in murine pre-B cells were examined. In order to understand the differences between the physiologic and genotoxic responses to DSB DNA damage, we need to compare cells that are all in the same compartment of the cell cycle. We are therefore examining the response to IR-induced damage in cells that are arrested in G1, which would correspond to our previous study of G1 arrested cells with Rag-induced breaks. This will illuminate the difference directly, allowing us to better understand the signaling responses to the different types of DNA damage.
DNA damage activates a complex transcriptional response in murine lymphocytes that includes both physiological and cancer-predisposition programs.
Specimen part
View SamplesThe objective is to identify genes that are differentially expressed following the introduction of DNA double-strand breaks (DSBs) by the Rag proteins in murine pre-B cells. Cells lacking Artemis are used since the Rag-induced DSBs will not be repaired, and thus, will provide a continuous stimulus to the cell.
DNA damage activates a complex transcriptional response in murine lymphocytes that includes both physiological and cancer-predisposition programs.
Specimen part, Disease, Treatment
View SamplesRenal hypoxia is widespread in acute kidney injury (AKI) of various aetiologies. Hypoxia adaptation, conferred through the hypoxia-inducible factor (HIF), appears to be insufficient. Here we show that HIF activation in renal tubules through Pax8-rtTA-based inducible knockout of von Hippel-Lindau protein (VHL-KO) protects from rhabdomyolysis-induced AKI. In this model, histological observations indicate that injury mainly affects proximal convoluted tubules, with 5% necrosis at d1 and 40% necrosis at d2. HIF-1alpha up-regulation in distal tubules reflects renal hypoxia. However, lack of HIF in proximal tubules suggests insufficient adaptation by HIF.
Tubular von Hippel-Lindau knockout protects against rhabdomyolysis-induced AKI.
Specimen part, Disease, Disease stage, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Differential genomic targeting of the transcription factor TAL1 in alternate haematopoietic lineages.
No sample metadata fields
View SamplesThe KDM6 histone demethylases (UTX/KDM6A and JMJD3/KDM6B) mediate removal of repressive histone H3K27me3 marks to establish transcriptionally permissive chromatin. Loss of UTX in female mice is embryonic lethal. Unexpectedly, male UTX-null mice escape embryonic lethality due to expression of UTY, a paralog lacking H3K27-demethylase activity. This suggests that UTX plays an enzyme-independent role in development, and challenges the need for active H3K27-demethylation in vivo. However, the requirement for active H3K27-demethylation in stem cell-mediated tissue regeneration remains untested. Using an inducible mouse knockout that ablates UTX in satellite cells, we show that active H3K27-demethylation is necessary for muscle regeneration. Indeed, loss of UTX in satellite cells blocks myofiber regeneration in both male and female mice. Furthermore, we demonstrate that UTX mediates muscle regeneration through its H3K27-demethylase activity using a chemical inhibitor, and a demethylase-dead UTX knock-in mouse. Mechanistically, dissection of the muscle regenerative process revealed that UTX is required for expression of the transcription factor Myogenin that drives differentiation of muscle progenitors. Thus, we have identified a critical role for the enzymatic activity of UTX in activating muscle-specific gene expression during myofiber regeneration, revealing for the first time that active H3K27-demethylation has a physiological role in vivo. Overall design: Satellite cells were sorted based on Cre-dependent expression of TdT reporter gene. Sorted UTXmKO or UTX WT satellite cells were then induced to differentiate for 24 hrs. RNA was then isolated and subjected to RNA-Seq analysis.
UTX demethylase activity is required for satellite cell-mediated muscle regeneration.
No sample metadata fields
View SamplesWe probed the mechanism of cross-regulation of osmotic and heat stress responses by characterizing the effects of high osmolarity (0.3M vs. 0.0M NaCl) and temperature (43oC vs. 30oC) on the transcriptome of Escherichia coli K12 using E. coli Genome 2 Array (Affymetrix, Inc.). Independent array hybridizations were carried out for 3 biological replicates (independent cultures). Total RNA was extracted using a hot phenol-chloroform method. cDNA synthesis, fragmentation and labeling, and washing and scanning of E. coli GeneChip Arrays were performed according to the instructions of the manufacturer (Affymetrix Technical Manual, Affymetrix, Inc., USA). Labeled cDNA was hybridized to E. coli Genome 2 Array (Affymetrix, Inc.). Independent array hybridizations were carried out for 3 biological replicates (independent cultures) of each condition. A number of genes in the SoxRS and OxyR oxidative stress regulons were up-regulated by high osmolarity, high temperature, and/or by the combination of both stresses. This result could account for cross-protection of osmotic stress against oxidative stress. The trehalose biosynthetic genes were induced by both stresses, in accord with the proposed protective role of this disaccharide against thermal and oxidative damage.
Genome-wide transcriptional responses of Escherichia coli K-12 to continuous osmotic and heat stresses.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Adenosine-to-inosine RNA editing by ADAR1 is essential for normal murine erythropoiesis.
Sex, Specimen part
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