Constitutional Trisomy 8 Mosaicism as a Model for Epigenetic Studies of Aneuploidy (DNA methylation)
Ontology highlight
ABSTRACT: To increase our understanding of epigenetic patterns associated with aneuploidy we used constitutional trisomy 8 mosaicism as a model, enabling analyses of single cell clones, harboring either trisomy or disomy 8, from the same patient. We profiled gene and miRNA expression as well as genome-wide and promoter specific DNA methylation and hydroxymethylation patterns in trisomic and disomic fibroblasts, using microarrays and methylated DNA immunoprecipitation. comparison of trisomy 8 cells with disomic as well as reference fibroblasts
Project description:We propose that tetraploidy induces epigentic changes including DNA methylation due to the abnormal chromatin in the cells. To test our hypothesis, we employed methylated CpG island recovery assay (MIRA) assisted microarray to determine the DNA methylation profiles in both diploid and tetraploid cells. First, we conducted a methylated-CpG island recovery assay (MIRA). Briefly, we enriched for methylated CpG islands with methylated DNA binding proteins, MBD2/MBD3L1. The pulled down DNA fragments containing CpG islands and input DNA fragments were amplified with real-time PCR. After labeling, they were hybridized to CpG island promoter array. Data were collected and analyzed.
Project description:Astrocytomas are common and lethal human brain tumors. Here, we have analyzed the methylation status of over 28,000 CpG islands and 18,000 promoters in normal human brain and in astrocytomas of various grades using the methylated-CpG island recovery assay (MIRA). We identified six to seven thousand methylated CpG islands in normal human brain. ~5% of the promoter-associated CpG islands in normal brain are methylated. Promoter CpG island methylation is inversely and intragenic methylation is directly correlated with gene expression levels in brain tissue. In astrocytomas, several hundred CpG islands undergo specific hypermethylation relative to normal brain with 428 methylation peaks common to more than 25% of the tumors. Genes involved in brain development and neuronal differentiation, such as POU4F3, GDNF, OTX2, NEFM, CNTN4, OTP, SIM1, FYN, EN1, CHAT, GSX2, NKX6-1, RAX, PAX6, DLX2, were strongly enriched among genes frequently methylated in tumors. There was an overrepresentation of homeobox genes and 31% of the most commonly methylated genes represent targets of the Polycomb complex. We identified several chromosomal loci in which many (sometimes more than 20) consecutive CpG islands were hypermethylated in tumors. Seven of such loci were near homeobox genes, including the HOXC and HOXD clusters, and the BARHL2, DLX1, and PITX2 genes. Two other clusters of hypermethylated islands were at sequences of recent gene duplication events. Our analysis offers mechanistic insights into brain neoplasia suggesting that methylation of genes involved in neuronal differentiation, perhaps in cooperation with other oncogenic events, may shift the balance from regulated differentiation towards gliomagenesis. Comparison of methylation patterns of 30 astrocytomas and 6 controls
Project description:This SuperSeries is composed of the following subset Series: GSE18802: Comparison of gene expression profiles in diploid and transformed tetraploid MEF cells GSE18814: Comparison of DNA methylation profiles in diploid and transformed tetraploid MEF cells Refer to individual Series
Project description:Methylated modifications of genome are common events in carcinogenesis and is involved in the tumorigenesis and progression of various cancers including gastric cancer Methylated DNA immunoprecipitation (MeDIP) combined with a human miRNA tiling microarray analysis demonstrated that there are much methylation differention between gastric cancers and adjacent controls microRNA gene methylation comparison of 3 pairs of gastric cancer and controls
Project description:The transcription factor HIF-2a play an important role in the tumor progress, the aim is to explore the target genes of HIF-2a in liver cancer cell line. Chromatin immunoprecipitation (ChIP) of HIF-2a together with chromatin profiling by ChIP-on-chip analysis demonstrated that HIF-2a directly activates many target genes. Analyze the target genes in a liver cancer cell line MHCC97H
Project description:To further our understanding of the role of DNA methylation in development, Methylated DNA Immunoprecipitation (MeDIP) was used in conjunction with a NimbleGen promoter plus CpG island array to identify Tissue and Developmental Stage specific Differentially Methylated DNA Regions (T-DMRs and DS-DMRs) on a genome-wide basis. Four tissues (brain, heart, liver, and testis) from C57BL/6J mice were analyzed at three developmental stages (15 day embryo, E15; new born, NB; 12 week adult, AD). Almost 5,000 adult T-DMRs and 10,000 DS-DMRs were identified. Surprisingly, almost all DS-DMRs were tissue specific (i.e., methylated and ummenthylated in one or more non-overlapping tissues), indicating that the vast majority of unique sequence DNA methylation has tissue specificity. Also, many DS-DMRs were methylated at early development stages (E15 and NB) but unmethylated in adult, indicating “demethylation” has a prominent role in tissue differentiation. The pattern of DNA methylation in adult testis was dramatically different from somatic tissues in many aspects, mostly notably with a very strong bias of methylation in non-CpGi (CpG island) promoter regions (94%). Although the majority of T-DMRs and DS-DMRs tended to be in non-CpGi promoter regions, a relatively large number were also located in CpGi in promoter, intra-genic and inter-genic regions (>15% of all CpGi). Gene Ontology analysis of genes with methylation in non-CpGi promoters indicates enrichment of genes related to membrane proteins and G-protein coupled receptors. Our data also suggest regulatory roles of DNA methylation outside of promoter regions and in alternative promoter selection. Overall, our studies indicate that change in DNA methylation during development is a dynamic, widespread and tissue-specific process involving both DNA methylation and demethylation. Comparison of DNA methylation across 3 developmental stages (15 day embryo, newborn, and adult) for four tissues (brain, heart, liver and testis)
Project description:Emerging evidences indicate that microRNAs (miRNAs) are often deregulated and have fundamental roles in hepatocellular carcinoma (HCC). However, the mechanism underlying miRNA dysregulation in HCC is still elusive. In this report, we used an integrated analysis strategy combining methylated DNA immunoprecipitation chip (MeDIP-chip) and miRNA expression microarray data to study the correlation between aberrant methylation and dysregulation of miRNA in HCC. In all, we showed that global miRNA methylation profiles were significantly different between cancerous and normal hepatocytes, and abnormal methylation was an important mechanism governing miRNA expression in HCC. MeDIP-chip was processed in cancerous hepatocytes SK-HEP-1, HepG2, MHCC97-H and normal hepatocytes PHHC-4-1, PHHC-4-2, PHHC-4-3 (3 technical repeat of PHHC-4). MiRNA microarray were processed for cancerous hepatocytes SK-HEP-1, HepG2, Hep3B, Huh7, MHCC97-H, MHCC97-L, SMMC-7721 and normal hepatocytes PHHC-1, PHHC-2, PHHC-3. Then an integrated analysis strategy combining MeDIP-chip and miRNA expression microarray [GSE20077] were used to study the correlation of aberrant DNA methylation and dysregulation of miRNAs.
Project description:A large-scale analysis of histone acetylation as well as RNA polymerase II and GATA 1 interactions on chromosome 6q in human erythroid progenitor cells. Human erythroid progenitors from day 10 erythroid cultures were used for ChIP-chip analysis. For this purpose, the NimbleGen array system was used, following manufacturer's protocols. Samples for ChIP were taken from the same individual and processed for use with each of the following antibodies: GATA1, PolII, AcH3 and AcH4.
Project description:E2F2 is essential for the maintenance of T lymphocyte quiescence. To identify the full set of E2F2 target genes, and to gain further understanding of the role of E2F2 in transcriptional regulation, we have performed ChIP-chip analyses across the genome of lymph node-derived T lymphocytes. Here we show that during quiescence, E2F2 binds the promoters of a large number of genes involved in DNA metabolism and cell cycle regulation, concomitant with their transcriptional silencing. We performed 3 ChIP-chip experiments with an antibody against E2F2 and another 3 ChIP-chip experiments with an antibody against SV40TAg (irrelevant antibody).