Project description:Glioblastoma, the most aggressive and least treatable form of malignant glioma, is the most common human brain tumor. Although many regions of allelic loss occur in glioblastomas, relatively few tumor suppressor genes have been found mutated at such loci. To address the possibility that epigenetic alterations are an alternative means of glioblastoma gene inactivation, we coupled pharmacological manipulation of methylation with gene profiling to identify potential methylation-regulated, tumor-related genes. Triplicates of three short-term cultured glioblastomas were exposed to 5?M 5-aza-dC for 96 hours followed by cRNA hybridization to an oligonucleotide microarray (Affymetrix U133A). We based candidate gene selection on bioinformatics, RT-PCR, bisulfite sequencing, methylation-specific PCR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Two genes identified in this manner, RUNX3 and Testin (TES), were subsequently shown to harbor frequent tumor-specific epigenetic alterations in primary glioblastomas. This overall approach therefore provides a powerful means to identify candidate tumor suppressor genes for subsequent evaluation and may lead to the identification of genes whose epigenetic dysregulation is integral to glioblastoma tumorigenesis. Duplicates of three short term cultured glioblastoma cell lines (internal IDs: GLI56;GLI60;GLI72) were either exposed to 5umol 5`aza-dC for 96h or left untreated. Total RNA was extracted of treated and untreated cells after 96h and hybridized to U133A chip. Gene expression profiles of treated and untreated cells were compared. Upregulation of gene expression in the treated (demethylated) samples was interpreted as potentially being regulated by methylation - pointing towards hypermethylation in the related cell line. Identification of novel tumor suppressor genes, regulated by methylation, was the overall goal.
Project description:Glioblastoma, the most aggressive and least treatable form of malignant glioma, is the most common human brain tumor. Although many regions of allelic loss occur in glioblastomas, relatively few tumor suppressor genes have been found mutated at such loci. To address the possibility that epigenetic alterations are an alternative means of glioblastoma gene inactivation, we coupled pharmacological manipulation of methylation with gene profiling to identify potential methylation-regulated, tumor-related genes. Triplicates of three short-term cultured glioblastomas were exposed to 5μM 5-aza-dC for 96 hours followed by cRNA hybridization to an oligonucleotide microarray (Affymetrix U133A). We based candidate gene selection on bioinformatics, RT-PCR, bisulfite sequencing, methylation-specific PCR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Two genes identified in this manner, RUNX3 and Testin (TES), were subsequently shown to harbor frequent tumor-specific epigenetic alterations in primary glioblastomas. This overall approach therefore provides a powerful means to identify candidate tumor suppressor genes for subsequent evaluation and may lead to the identification of genes whose epigenetic dysregulation is integral to glioblastoma tumorigenesis. Keywords: expression profile following global demethylation
Project description:Analysis of 2 cultured normal lung cell lines, Normal Human Bronchial Epithelial (NHBE) and Human Small Airway Epithelial (SAEC) cells (Lonza, Walkersville, MD), following treatment with 5-aza-dC to induce DNA demethylation. These results provide insight into the role of epigenetic alterations, specifically demethylation, in differential gene expression in various lung neoplasms.
Project description:Decitabine (5-aza-dC) is a DNMT1-DPC inducing agent used to treat several hematological cancers. However, response rates vary, relapse is common, and predictive biomarkers are unknown. Here, we develop an adaptation of identification of proteins on nascent DNA (iPOND) by combining EdU with 5-aza-dC incorporation by itself or the presence of either ubiquitin E1 or SUMO E1 inhibitor which we term iPOND-DPC. The purpose of this experiments is to identify proteins that are recruited to DNMT1-DPCs and categorize whether their recruitment is dependent on SUMOylation or ubiquitylation.
Project description:Promoter hypermethylation and transcriptional silencing is a common epigenetic mechanism of tumour suppressor inactivation in cancer, including malignant brain tumours. To identify targets of epigenetic silencing mediated by CpG island methylation in paediatric ependymoma, we used a pharmacological unmasking approach through treatment with the demethylating agent 5-Aza-2M-bM-^@M-^Y-deoxycytidine followed by global expression microarray analysis. Three short-term ependymoma cell cultures were used for whole genome expression analysis following treatment with the demethylating agent 5-Aza-dC (5 M-BM-5mol/L) or mock-treated with DMSO (M-bM-^IM-$0.1% v/v) for 96-hrs.
Project description:Analysis of 2 cultured normal lung cell lines, Normal Human Bronchial Epithelial (NHBE) and Human Small Airway Epithelial (SAEC) cells (Lonza, Walkersville, MD), following treatment with 5-aza-dC to induce DNA demethylation. These results provide insight into the role of epigenetic alterations, specifically demethylation, in differential gene expression in various lung neoplasms. Two normal lung cell lines, NHBE and SAEC, were treated with 5uM 5-aza deoxycytidine for 72 hours and Trichostatin A for 24 hours prior to harvesting total RNA for expression array analysis using the Affymetrix Human Genome U133 Plus 2.0 expression platform. Signal intensity and statistical significance was established for each transcript using dChip version 2005. Two-fold increase based on the 90% confidence interval of the result and expression minus baseline >50 was used as the statistical cutoff value after 5Aza-dC and/or TSA treatment to identify upregulated candidate genes.
Project description:Single-nucleus RNA sequencing (snRNA-seq) was used to profile the transcriptome of 16,015 nuclei in human adult testis. This dataset includes five samples from two different individuals. This dataset is part of a larger evolutionary study of adult testis at the single-nucleus level (97,521 single-nuclei in total) across mammals including 10 representatives of the three main mammalian lineages: human, chimpanzee, bonobo, gorilla, gibbon, rhesus macaque, marmoset, mouse (placental mammals); grey short-tailed opossum (marsupials); and platypus (egg-laying monotremes). Corresponding data were generated for a bird (red junglefowl, the progenitor of domestic chicken), to be used as an evolutionary outgroup.
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.