Browse
Submit Data
Databases
API
Help

Dataset Information

19 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Screening for human epigenetic variation at CpG islands

ABSTRACT: Many human characteristics, including susceptibility to disease, are determined genetically. An unexplored alternative to such genetic determination concerns epigenetic mechanisms such as DNA methylation. CpG islands (CGIs) are generally constitutively hypomethylated, however there are circumstances in which they become heavily methylated and, when coincident with a gene promoter, this invariably causes transcriptional silencing. CGI methylation occurs in normal tissues during processes such as X-inactivation, but abnormal patterns of methylation have also been implicated in disease. The vast majority of evidence relates to cancer, where silencing of multiple genes in this way appears to be a causal contributor to the cancer state. To address the role and extent of CGI methylation in ‘normal’ and diseased cells we applied MBD-affinity purification in conjunction with next generation sequencing in a panel of human brain autopsy samples. These samples represent a panel of individuals as well as specific brain regions and neurological pathologies.

INSTRUMENT(S): Illumina Genome Analyzer II

ORGANISM(S): Homo sapiens

SUBMITTER:

PROVIDER: E-ERAD-10 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Json Xml

Similar Datasets

Functional characterisation of CpG islands in human and mouse tissues

Project description:Tissue-specific methylation patterns suggest a role for CpG island (CGI) methylation in differentiation and cell-type-specific gene regulation. We have applied CXXC affinity purification (CAP), MBD affinity purification (MAP) and chromatin immunoprecipitation (ChIP) in combination with solexa sequencing to investigate the extent and functional significance of CGI methylation in sperm, blood, cerebellum and ES cells for both human and mouse.

2014-01-21 | E-ERAD-11 | biostudies-arrayexpress

Screening for human epigenetic variation at CpG islands

Project description:Many human characteristics, including susceptibility to disease, are determined genetically. An unexplored alternative to such genetic determination concerns epigenetic mechanisms such as DNA methylation. CpG islands (CGIs) are generally constitutively hypomethylated, however there are circumstances in which they become heavily methylated and, when coincident with a gene promoter, this invariably causes transcriptional silencing. CGI methylation occurs in normal tissues during processes such as X-inactivation, but abnormal patterns of methylation have also been implicated in disease. The vast majority of evidence relates to cancer, where silencing of multiple genes in this way appears to be a causal contributor to the cancer state. To address the role and extent of CGI methylation in ‘normal’ and diseased cells we applied MBD-affinity purification in conjunction with next generation sequencing in a panel of human brain autopsy samples. These samples represent a panel of individuals as well as specific brain regions and neurological pathologies.

| EGAS00001000074 | EGA

Cell Type-Specific DNA Methylation at Intragenic CpG Islands in the Immune System (MAP-Seq and ChIP-Seq data)

Project description:Human and mouse genomes contain a similar number of CpG islands (CGIs), which are discrete CpG-rich DNA sequences associated with transcription start sites. In both species, about 50% of all CGIs are remote from annotated promoters, but nevertheless often have promoter-like features. To document the role of CGI methylation in cell differentiation, we analysed DNA methylation at a comprehensive CGI set in cells of the mouse hematopoietic lineage. Using a method that potentially detects ~33% of genomic CpGs in the methylated state (>7 million) we found that large differences in gene expression were accompanied by surprisingly few DNA methylation changes. There were, however, many DNA methylation differences between hematopoietic cells and a distantly related tissue, brain. Altered DNA methylation occurred predominantly at CGIs within gene bodies, which have the properties of cell type-restricted promoters, but infrequently at annotated gene promoters or CGI flanking sequences. Elevated intragenic CGI methylation correlated with silencing of the associated gene. Differentially methylated intragenic CGIs tended to lack H3K4me3 and associate with a transcriptionally repressive environment regardless of methylation state. Our results indicate that DNA methylation changes play a relatively minor role in the late stages of differentiation, but point to a distinct role for intragenic CGIs. Mouse immune cells (dendritic cells, B cells, CD4 T cells, Th1 and Th2 cells) were isolated and DNA methylation and gene expression profiled. Methylation and expression patterns were compared to those in brain. DNA methylation was profiled using MAP-seq and two replicates were carried out for each cell type of interest.

2011-05-23 | E-GEOD-25688 | biostudies-arrayexpress

MBD-Seq of human primary colorectal tumours to explore abnormal CGI methylation

Project description:A common hallmark of neoplastic cells is abnormal acquisition of CpG island (CGI) methylation and the silencing of associated gene promoters. To determine the extent and distribution of CGI methylation in colorectal cancer, we solexa sequenced MBD affinity purified DNA prepared from five colorectal tumours and matched colon mucosa from the same individuals.

2012-08-01 | E-ERAD-12 | biostudies-arrayexpress

Smchd1 dependent and independent pathways determine developmental dynamics of CpG island methylation on the inactive X chromosome.

Project description:X chromosome inactivation involves multiple levels of chromatin modification, established progressively and in a stepwise manner during early development. The chromosomal protein Smchd1 has recently been shown to play an important role in DNA methylation of CpG islands (CGIs), a late step in the X inactivation pathway required for long-term stability of gene silencing. Here we show that inactive X chromosome (Xi) CGI methylation can occur via either Smchd1 dependent or independent pathways. Smchd1 dependent CGI methylation, the primary pathway, is acquired gradually over an extended period, whereas Smchd1 independent CGI methylation occurs rapidly after the onset of X inactivation. The de novo methyltransferase Dnmt3b is required for methylation of both classes of CGI, whereas Dnmt3a and Dnmt3L are dispensable. Xi CGIs methylated by these distinct pathways differ in respect to their sequence characteristics and immediate chromosomal environment. We discuss the implications of these results for understanding CGI methylation during development. Examination of CpG methylated DNA from wild type and smchd1 null male and female somatic cells and female ES cells differentiated for either 7 or 10 days. Duplicate samples of each type were generated.

2012-10-15 | E-GEOD-37333 | biostudies-arrayexpress

Cell Type-Specific DNA Methylation at Intragenic CpG Islands in the Immune System (gene expression data)

Project description:Human and mouse genomes contain a similar number of CpG islands (CGIs), which are discrete CpG-rich DNA sequences associated with transcription start sites. In both species, about 50% of all CGIs are remote from annotated promoters, but nevertheless often have promoter-like features. To document the role of CGI methylation in cell differentiation, we analysed DNA methylation at a comprehensive CGI set in cells of the mouse hematopoietic lineage. Using a method that potentially detects ~33% of genomic CpGs in the methylated state (>7 million) we found that large differences in gene expression were accompanied by surprisingly few DNA methylation changes. There were, however, many DNA methylation differences between hematopoietic cells and a distantly related tissue, brain. Altered DNA methylation occurred predominantly at CGIs within gene bodies, which have the properties of cell type-restricted promoters, but infrequently at annotated gene promoters or CGI flanking sequences. Elevated intragenic CGI methylation correlated with silencing of the associated gene. Differentially methylated intragenic CGIs tended to lack H3K4me3 and associate with a transcriptionally repressive environment regardless of methylation state. Our results indicate that DNA methylation changes play a relatively minor role in the late stages of differentiation, but point to a distinct role for intragenic CGIs. Mouse immune cells (dendritic cells, B cells, CD4 T cells, Th1 and Th2 cells) were isolated and DNA methylation and gene expression profiled. Methylation and expression patterns were compared to those in brain. For gene expression analysis three biological replicates were used for each cell type.

2011-05-23 | E-GEOD-25578 | biostudies-arrayexpress

Cell Type-Specific DNA Methylation at Intragenic CpG Islands in the Immune System (gene expression data)

2011-05-23 | GSE25578 | GEO

Cell Type-Specific DNA Methylation at Intragenic CpG Islands in the Immune System (MAP-Seq and ChIP-Seq data)

2011-05-23 | GSE25688 | GEO

Functional characterisation of CpG islands in mouse tissues

2012-07-02 | E-ERAD-53 | biostudies-arrayexpress

5-hydroxymethylcytosine: the sixth DNA base

Project description:We performed a meta analysis of publicly available TET1, 5mC, 5hmC and genome wide bisulfite profiling data mostly from mouse embryonic stem cells (ESC). Genome wide chromatin immunoprecipitation combined with deep sequencing (ChIP-seq) has revealed binding of the TET1 protein at CpG-island (CGI) promoters and at bivalent promoters. We show that TET1 also coincides with DNAseI hypersensitive sites (HS). Presence of TET1 at these THREE locations suggests that it may play a dual role: an active role at CpG-islands and DNAseI hypersensitive sites and a repressive role at bivalent loci. In line with the presence of TET1, significant enrichment of 5hmC but not 5mC is detected at bivalent promoters and DNaseI HS. Surprisingly, 5hmC is not detected or present at very low levels at CGI promoters notwithstanding the presence of TET1 at these loci. Our meta analysis suggest that asymmetric methylation is present at CA- and CT-repeats in the genome of some human ESC. Examination of the distribution of 5-methylcytosine and 5-hydroxymethylcytosine in the genome of mouse embryonic stem cells.

2011-11-24 | E-GEOD-31343 | biostudies-arrayexpress

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data