ABSTRACT: Gene expressioin signatures in human lymphoblastoid cell lines with different ataxia telangiectasia-mutated (ATM) genotypes post sham- or IR-treatment
Project description:Transcriptional profiling of human lymphoblastoid cell lines with different ATM genotypes 6h post sham- or 1.5 Gy IR-treatmentl was compared to extract IR-related gene expression signatures that can identify ataxia telangiectasia (AT) carries from non AT carries and AT patients.
Project description:Transcriptional profiling of human lymphoblastoid cell lines with different ATM genotypes 6h post sham- or 1.5 Gy IR-treatmentl was compared to extract IR-related gene expression signatures that can identify ataxia telangiectasia (AT) carries from non AT carries and AT patients. Biological replicates: 6 or 4; Technical replicates: 2 with C3 and C5 dye swap.
Project description:Transcription profiling of ATM (Ataxia Telangiectasia Mutated) +/+ (Control), ATM +/- (AT Carrier) and ATM -/- (AT patient) human lymphoblastoid cell lines exposed to 5 Gy IR at 0, 4 and 24 hours to identify expression phenotypes in Ataxia Telangiectasia carriers and patients
Project description:Transcriptional profiling of human lymphoblastoid cell lines with different ATM genotypes at basal level was compared to extract gene expression signatures that can identify ataxia telangiectasia (AT) carries from non AT carries and AT patients.
Project description:Transcriptional profiling of human lymphoblastoid cell lines with different ATM genotypes at basal level was compared to extract gene expression signatures that can identify ataxia telangiectasia (AT) carries from non AT carries and AT patients. Biological replicates: 4; Technical replicates: 2 with C3 and C5 dye swap.
Project description:Ataxia telangiectasia (AT) is an autosomal recessive disorder characterized by neuronal degeneration, telangiectasias, acute cancer predisposition, and hypersensitivity to ionizing radiation (IR). The gene defective in AT, ATM (for AT-mutated), encodes a protein, pATM that has been found to have IR-inducible kinase activity. Cells from individuals with AT exhibit severely attenuated cell cycle checkpoints in response to gamma radiation exposure. pATM has been hypothesized to act as part of a complex that senses DNA damage, in particular, DNA double strand breaks. We are studying the pATM-dependent gene expression responses to a dose of 1.5 Gy radiation in lymphoblastoid cell lines from multiple individuals with either wild type or mutated ATM. The gene expression analyses were performed on Agilent Human 1A Oligo chips containing approximately 16,000 60mer probes. We identified a set of genes whose gene expression changes are ATM-dependent following exposure to 1.5 Gy IR. This set of genes was tested by real time quantitative PCR analysis.
Project description:Gene expressioin signatures at basal level in human lymphoblastoid cell lines with different ataxia telangiectasia-mutated (ATM) genotypes
Project description:Recent observations show that the single-cell response of p53 to ionizing radiation (IR) is “digital” in that it is the number of oscillations rather than the amplitude of p53 that shows dependence on the radiation dose. We present a model of this phenomenon. In our model, double-strand break (DSB) sites induced by IR interact with a limiting pool of DNA repair proteins, forming DSB–protein complexes at DNA damage foci. The persisting complexes are sensed by ataxia telangiectasia mutated (ATM), a protein kinase that activates p53 once it is phosphorylated by DNA damage. The ATM-sensing module switches on or off the downstream p53 oscillator, consisting of a feedback loop formed by p53 and its negative regulator, Mdm2. In agreement with experiments, our simulations show that by assuming stochasticity in the initial number of DSBs and the DNA repair process, p53 and Mdm2 exhibit a coordinated oscillatory dynamics upon IR stimulation in single cells, with a stochastic number of oscillations whose mean increases with IR dose. The damped oscillations previously observed in cell populations can be explained as the aggregate behavior of single cell
Project description:Maintenance of genomic stability depends on the DNA damage response (DDR), a biological barrier in early stages of cancer development. Failure of this response results in genomic instability and high predisposition toward lymphoma, as seen in patients with ataxia-telangiectasia mutated (ATM) dysfunction. ATM activates multiple cell cycle checkpoints and DNA repair following DNA damage, but its influence on posttranscriptional gene expression has not been examined on a global level. We show that ionizing radiation (IR) modulates the dynamic association of the RNA-binding protein HuR with target mRNAs in an ATM-dependent manner, potentially coordinating the genotoxic response as an RNA operon. Pharmacologic ATM inhibition and use of ATM-null cells revealed a critical role for ATM in this process. Numerous mRNAs encoding cancer-related proteins were differentially associated with HuR depending on the functional state of ATM, in turn affecting expression of encoded proteins. The findings presented here reveal a previously unidentified role of ATM in controlling gene expression post-transcriptionally. Dysregulation of this DDR RNA operon is likely relevant to lymphoma development in ataxia-telangiectasia individuals. These novel RNA regulatory modules and genetic networks provide critical insight into the function of ATM in oncogenesis. B-lymphocyte cell lines GM02184 (wild type, ATM +/+) and GM03332 (AT, ATM -/-) were either untreated or exposed to 1 Gy of IR. 6 h later cells were harvested and used for immunoprecipitation (IP) in the presence of HuR antibody (Santa Cruz Biotech.). RNA from IP material was extracted and used for microarray analysis.
Project description:Maintenance of genomic stability depends on the DNA damage response (DDR), a biological barrier in early stages of cancer development. Failure of this response results in genomic instability and high predisposition toward lymphoma, as seen in patients with ataxia-telangiectasia mutated (ATM) dysfunction. ATM activates multiple cell cycle checkpoints and DNA repair following DNA damage, but its influence on posttranscriptional gene expression has not been examined on a global level. We show that ionizing radiation (IR) modulates the dynamic association of the RNA-binding protein HuR with target mRNAs in an ATM-dependent manner, potentially coordinating the genotoxic response as an RNA operon. Pharmacologic ATM inhibition and use of ATM-null cells revealed a critical role for ATM in this process. Numerous mRNAs encoding cancer-related proteins were differentially associated with HuR depending on the functional state of ATM, in turn affecting expression of encoded proteins. The findings presented here reveal a previously unidentified role of ATM in controlling gene expression post-transcriptionally. Dysregulation of this DDR RNA operon is likely relevant to lymphoma development in ataxia-telangiectasia individuals. These novel RNA regulatory modules and genetic networks provide critical insight into the function of ATM in oncogenesis.
