DNA methylation analysis of normal and cancer cells
ABSTRACT: DNA methylation of prostatic normal cells (PrEC), normal mammary epithelial cells (HMEC), prostate cancer cell line (MDA-PCa-2b), and breast cancer cell lines (BT474 and MDA-MB-231) was analyzed by MeDIP-on-chip analysis. DNA obtained from each cells was immunoprecipitated by anti 5-methylcytidine antibody. IP DNA and input DNA were labeled with Cy5 and Cy3, respectively, and then analyzed by using human CpG island microarray provided by Agilent Technologies.
Project description:Instructive mechanisms are present for induction of DNA methylation, as shown by methylation of specific CpG islands (CGIs) by specific inducers and in specific cancers. However, instructive factors involved are poorly understood, except for involvement of low transcription and trimethylation of histone H3 lysine 27 (H3K27me3). Here, we used methylated DNA immunoprecipitation (MeDIP) combined with a CGI oligonucleotide microarray analysis, and identified 5510 and 521 genes with promoter CGIs resistant and susceptible, respectively, to DNA methylation in prostate cancer cell lines. Expression analysis revealed that the susceptible genes had low transcription in a normal prostatic epithelial cell line. Chromatin immunoprecipitation with microarray hybridization (CHiP-chip) analysis of RNA polymerase II (Pol II) and histone modifications showed that, even among the genes with low transcription, the presence of Pol II was associated with marked resistance to DNA methylation (OR = 0.22; 95% CI = 0.12-0.38), and H3K27me3 was associated with increased susceptibility (OR = 11.20; 95% CI = 7.14-17.55). The same was true in normal human mammary epithelial cells for 5430 and 733 genes resistant and susceptible, respectively, to DNA methylation in breast cancer cell lines. These results showed that the presence of Pol II, active or stalled, and H3K27me3 can predict the epigenetic fate of promoter CGIs independently of transcription levels. To analyze DNA methylation status in normal and cancer cells, MeDIP-CGI oligonucleotide microarray analysis was performed. To analyze expression and histone modification status in normal cells, GeneChip analysis and ChIP-oligonucleotide microarray analysis were performed.
Project description:Genomic imprinting describes the expression of a subset of mammalian genes from one parental chromosome. The parent-of-origin specific expression of imprinted genes relies on DNA methylation of CpG-dinucleotides at differentially methylated regions (DMRs) during gametogenesis. We identified the paternally methylated DMR at human chromosome 2 near the imprinted ZDBF2 gene using a methylated-DNA immunoprecipitation-on-chip (meDIP-on-chip) method applied to DNA from sperm. To analyze whether or not the GPR1-ZDBF2 DMR is conserved in human genome, methylation analysis of human sperm sample was performed using MeDIP and genome tiling array.
Project description:Genomic imprinting describes the expression of a subset of mammalian genes from one parental chromosome. The parent-of-origin specific expression of imprinted genes relies on DNA methylation of CpG-dinucleotides at differentially methylated regions (DMRs) during gametogenesis. We identified the paternally methylated DMRs at mouse chromosome 1 near the imprinted Zdbf2 gene using a methylated-DNA immunoprecipitation-on-chip (meDIP-on-chip) method applied to DNA from parthenogenetic (PG)- and androgenetic (AG)-derived cells and sperm. To identify novel DMRs, genome-wide methylation analysis of three samples were performed using MeDIP and whole genome tiling array.
Project description:The interferon-producing plasmacytoid dendritic cells (PDC) share common progenitors with antigen-presenting classical dendritic cells (cDC), yet they possess distinct morphology and molecular features resembling those of lymphocytes. It is unclear whether the unique cell fate of PDC is actively maintained in the steady state. We report that the deletion of transcription factor E2-2 from mature peripheral PDC caused their spontaneous differentiation into cells with cDC properties. This included the loss of PDC markers, increase in MHC class II expression and T cell priming capacity, acquisition of dendritic morphology and induction of cDC signature genes. Genome-wide chromatin immunoprecipitation revealed direct binding of E2-2 to key PDC-specific and lymphoid genes, as well as to certain genes enriched in cDC. Thus, E2-2 actively maintains the cell fate of mature PDC and opposes the “default” cDC fate, in part through direct regulation of lineage-specific gene expression programs. Cells of the human PDC lymphoma line CAL-1 (Maeda et al., Int J Hematol 2005) were crosslinked with formaldehyde, sonicated, and subjected to immunoprecipitation with anti-E2-2 mAb (Bain et al., Mol Cell Biol 1993) or mouse IgG control as described (Cisse et al., Cell 2008). After crosslink reversal, the isolated chromatin was amplified, labeled and hybridized to Human Promoter ChIP-on-chip Microarray Set (Agilent Technologies). Hybridized microarrays were scanned and analyzed using DNA Analytics software (Agilent Technologies).
Project description:This SuperSeries is composed of the following subset Series: GSE18126: Methylation status in AG- and PG-derived cells and sperm GSE18178: Methylation status in human sperm Refer to individual Series
Project description:This SuperSeries is composed of the following subset Series: GSE24726: Gene expression profile of mature plasmacytoid dendritic cells (PDC) after the deletion of transcription factor E2-2 GSE24740: Binding targets of transcription factor E2-2 in human plasmacytoid dendritic cells Refer to individual Series
Project description:Cyclin D1 belongs to the core cell cycle machinery1, and it is frequently overexpressed in human cancers2. The full repertoire of cyclin D1 functions in normal development and in cancer cells is currently unknown. To address this question, here we introduce a novel approach that allows one to determine the set of cyclin D1-interacting proteins (D1 “interactome”) and cyclin D1-bound genomic fragments (D1 “cistrome”) in essentially any mouse organ, at any point of development or at any stage of cancer progression. Using this approach, we detected several novel tissue-specific interactors of cyclin D1. A significant number of these partners represent proteins involved in transcription. We show, using genome-wide location analysis3, that cyclin D1 occupies promoters of a very large number of genes in the developing mouse, where it binds in close proximity to transcription start sites. Bioinformatics analyses of cyclin D1-bound genomic segments in the developing embryo revealed DNA recognition sequences for several transcription factors. By querying SAGE libraries4, promoter CpG content5 and gene expression profiles of cyclin D1-null organs, we demonstrate that cyclin D1 binds promoters of highly expressed genes, and that it functions to activate or to repress gene expression in vivo. Analyses of cyclin D1 transcriptional targets reveal that cyclin D1 contributes to cell proliferation by upregulating genes required for S-phase entry and progression. Hence, cyclin D1 plays a broad transcriptional regulatory function in vivo during normal mouse development. We hypothesized that cyclin D1 may play role in transcription by interacting with transcriptional machinery at the promoters of target genes. To test this possibility, we employed chromatin immunoprecipitation coupled to DNA microarray analysis (genome-wide location analysis or ChIP-chip) to study association of cyclin D1 with genomic DNA sequences. In this procedure, a protein of interest is crosslinked to DNA, immunoprecipitated, and the bound DNA is hybridized to an array containing probes that span the genome. Since anti-FLAG antibodies have been successfully used for ChIP-chip in several different systems including murine cells, knock-in mice expressing tagged cyclin D1 provided us with a novel tool to query the association of cyclin D1 with the genome in vivo, in a living mouse.
Project description:HIV-1 Tat is a multifunctional protein, that in addition to its primary function of transactivating viral transcription also tends to modulate cellular gene expression, the molecular mechanism of which remains to be clearly elucidated. We have reported earlier NFκB enhancer binding activity of Tat and proposed its potential role in regulation of cellular gene expression. In the present study, we have analysed genome wide occupancy of Tat protein in HIV-1 infected cells. Our results identify an entire spectrum of binding sites of Tat protein on chromatin and also reveal that Tat is recruited majorly on gene promoters indicating its possible involvement in the regulation of cellular gene expression. Agilent two-color ChIP-on-Chip experiment, Organism: Homo sapiens ,Genotypic Technology designed Custom Human Promoter 244k ChIP-on-chip Array (AMADID-019469)
Project description:BACKGROUND & AIMS: C/EBPbeta is involved in numerous process as carcinogenesis but its role is still not clear due to the existence of an active form (LAP) and an inhibitory form (LIP) of this transcription factor. The main goals of the present research were (i) the identification of genes inversely regulated by LAP and LIP i-e the genuine C/EBPbeta molecular signature in the Hep3B human hepatoma cell line (ii) a better understanding of LAP and LIP respective role in hepatic cells survival and proliferation (iii) the search of the C/EBPbeta signature among hepatocellular carcinomas. METHODS: Using Tet-off expression system we engineered Hep3BLAP and Hep3BLIP cells, in which LAP and LIP were over-expressed respectively. Then, using both expression profiling (DNA arrays) and ChIP-on-chip analysis, we identified genes inversely and/or directly regulated by each of the C/EBPbeta isoforms. The expression levels of these genes regulated by LAP/LIP were compared in controls and HCCs patients. RESULTS: We identified 676 genes inversely regulated by LAP and LIP and among these, 45 are direct targets. Using functional studies, we displayed the opposite role of LAP and LIP in staurosporine-induced cell death and the implication of LAP in the repression of Hep3B cells proliferation. Finally we identified a subgroup of HCCs with a deregulation of 165 genes belonging to C/EBPbeta signature and coding for proteins involved in chemoresistance and metastasis formation. CONCLUSIONS: Our study increases knowledge on LAP and LIP functions and provides first evidence that their molecular signature in the HCCs could predict tumor evolution. Total genomic DNA were extracted from 3 Hep3BLAP expressing LAP and were labelled Cy3 fluorochrome. Genomic DNA were extracted from 3 Hep3BLAP expressing LAP, were immunoprecipited with anti-CEBPbeta antibody and were labelled with Cy5 fluorochrome. Each sample was hybridized on an Agilent two-color microarray G4489A (Human Promoter ChIP-on-Chip Set 244K).
Project description:Hox proteins are transcription factors and key regulators of segmental identity along the anterior posterior axis across all bilateral animals. Despite decades of research, mechanism by which Hox proteins select their targets and specify segmental identity remains elusive. To address this question we carried out whole genome ChIP-chip experiments to identify direct targets of Hox protein Ultrabithorax (Ubx) during haltere development in Drosophila. When mis-expressed in wing segment (T2) Ubx converts its identity to that of haltere segment (T3). We used CbxHm/+ wing discs ectopically expressing Ubx in the pouch region of discs to obtain chromatin. This helped us focus on targets of Ubx involved in pouch development without mixing with the targets involved in notum development. Polyclonal Ubx antibodies against N-terminal region (excluding homeodomain) were generated in our lab and used to pull down Ubx bound regions from CbxHm/+ wing discs. Mock DNA (No antibody) was used as control. Test Vs. Mock experiment. CbxHm/+ discs for Chromatin source. Biological replicates: 3 [Agilent two-color ChIP-on-Chip experiment,Organism: Drosophila melanogaster ,Drosophila Whole Genome ChIP-on-Chip Set 244K Microarray 1 of 2 (AMADID: 014816 and 014817)]