Project description:EGFRvIII is the most common deletion mutant of EGFR in human cancer and its levels are highly correlated with poor prognosis in GBM. The deletion of exons 2-7 removes most of the extracellular ligand binding domain, so it is unable to bind EGF or other EGFR-binding ligands. Nevertheless, the mutant receptor is constitutively phosphorylated, and is capable of activating downstream signaling pathways at a low level. To comprehensively identify the downstream signaling consequences of the EGFRvIII, we incorporated phosphoproteomic, transcription profiling and DNase-Seq data from U87MG glioblastoma cells expressing titrated levels of this mutant receptor. Total RNA were extracted from U87MG cells engineered to expressed different levels of EGFRvIII: medium (U87M; 1.5 million copies of EGFRvIII receptor per cell), high (U87H; 2 million copies per cell), super-high (U87SH; 2.5 million copies per cell), and kinase-dead EGFRvIII (U87DK; 2 million copies of kinase dead EGFRvIII per cell). RNA was hybridized to Affymetrix microarrays.
Project description:We present a computational method for building a regulatory network from global phosphoproteomic and transcription profiling data. To recover the critical missing links between signaling events and transcriptional responses, we relate changes in chromatin accessibility to changes in expression and then uses these links to connect proteomic and transcriptome data. We applied our approach to integrate epigenomic, phosphoproteomic and transcriptome changes induced by the variant III mutation of the epidermal growth factor receptor (EGFRvIII) in a cell line model of glioblastoma multiforme (GBM). Genome-wide DNase I hypersensitivity followed by sequencing (DNase-Seq) to measure chromatin accessibility in a cell line derived from the U87MG glioblastoma cell line to express high level of EGFRvIII (U87H; 2 million copies of EGFRvIII per cell) and a control cell line expressing kinase dead EGFRvIII (U87DK; 2 million kinase dead EGFRvIII per cell). A prediction from the computational method, the transcriptional co-regulator p300, was experimentally validated by chromatin immunoprecipitation followed by sequencing (ChIP-Seq).
Project description:EGFRvIII is the most common deletion mutant of EGFR in human cancer and its levels are highly correlated with poor prognosis in GBM. The deletion of exons 2-7 removes most of the extracellular ligand binding domain, so it is unable to bind EGF or other EGFR-binding ligands. Nevertheless, the mutant receptor is constitutively phosphorylated, and is capable of activating downstream signaling pathways at a low level. To comprehensively identify the downstream signaling consequences of the EGFRvIII, we incorporated phosphoproteomic, transcription profiling and DNase-Seq data from U87MG glioblastoma cells expressing titrated levels of this mutant receptor.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs. One-condition experment, gene expression of 3A6