Project description:Imprinted genes are critical for normal human growth and neurodevelopment. We developed a strategy to identify new DNA differentially methylated regions (DMRs), a hallmark of imprinted genes. Using genome-wide methylation profiling, candidate DMRs were selected by identifying CpGs with putative allelic differential methylation in normal biparental tissues. In parallel, we looked for parent of origin-specific DNA methylation patterns in paternally derived human androgenetic complete hydatidiform mole (AnCHM), and maternally derived mature cystic ovarian teratoma (MCT). Using this approach, we found known DMRs associated with imprinted genomic regions as well as new DMRs for known imprinted genes, NAP1L5 and ZNF597. Most importantly, novel candidate imprinted genes were identified. The paternally methylated DMR for one candidate, AXL, a receptor tyrosine kinase, was validated by methylation analyses in humans. Further validation in mouse embryos showed that Axl was expressed preferentially from the maternal allele in a DNA methylation–dependent manner. We have analyzed 3 androgenetic complete hydatidiform mole (AnCHM), 16 white blood cell (WBC), 1 mature cystic ovarian teratoma (MCT), 5 placenta, and 1 lymphoblastoid cell line paternal UPD4 sample
Project description:Imprinted genes are critical for normal human growth and neurodevelopment. We developed a strategy to identify new DNA differentially methylated regions (DMRs), a hallmark of imprinted genes. Using genome-wide methylation profiling, candidate DMRs were selected by identifying CpGs with putative allelic differential methylation in normal biparental tissues. In parallel, we looked for parent of origin-specific DNA methylation patterns in paternally derived human androgenetic complete hydatidiform mole (AnCHM), and maternally derived mature cystic ovarian teratoma (MCT). Using this approach, we found known DMRs associated with imprinted genomic regions as well as new DMRs for known imprinted genes, NAP1L5 and ZNF597. Most importantly, novel candidate imprinted genes were identified. The paternally methylated DMR for one candidate, AXL, a receptor tyrosine kinase, was validated by methylation analyses in humans. Further validation in mouse embryos showed that Axl was expressed preferentially from the maternal allele in a DNA methylation–dependent manner.
Project description:Utilizing reciprocal genome-wide uniparental disomy samples presenting with Beckwith-Wiedemann and Silver-Russell syndrome-like phenotypes, we have analyzed ~0.1% of CpG dinucleotides present in the human genome for imprinted differentially methylated regions (DMRs) using the Illumina Infinium HumanMethylation27 BeadChip microarray. This approach identified 15 imprinted DMRs associated with previously characterized imprinted domains, and confirmed the maternal methylation of the RB1 DMR. In addition, we discovered two novel DMRs: a maternally methylated region overlapping the FAM50B promoter CpG island, which results in paternal expression of this retrotransposon, and a paternally methylated region located between maternally expressed ZNF597 and NAT15 genes.
Project description:Utilizing reciprocal genome-wide uniparental disomy samples presenting with Beckwith-Wiedemann and Silver-Russell syndrome-like phenotypes, we have analyzed ~0.1% of CpG dinucleotides present in the human genome for imprinted differentially methylated regions (DMRs) using the Illumina Infinium HumanMethylation27 BeadChip microarray. This approach identified 15 imprinted DMRs associated with previously characterized imprinted domains, and confirmed the maternal methylation of the RB1 DMR. In addition, we discovered two novel DMRs: a maternally methylated region overlapping the FAM50B promoter CpG island, which results in paternal expression of this retrotransposon, and a paternally methylated region located between maternally expressed ZNF597 and NAT15 genes. We analyzed reciprocal genome-wide uniparental disomy samples (one maternal UPD and three paternal UPD samples) and six different normal somatic tissues derived from the three germinal layers (lymphocytes, buccal cells, placenta, brain, muscle, and fat) .
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:Genomic imprinting is a mechanism in which the expression of genes varies depending on their parent-of-origin. Imprinting occurs through differential DNA methylation and histone modifications on the two parental alleles, with most imprinted genes marked by CpG-rich differentially methylated regions (DMRs). DNA methylation profiling in cases of uniparental disomy (UPD) provides a unique system permitting the study of DNA derived from a single parent (PMID: 20631049). Approximately 70 human imprinted genes have been described, and imprinted loci have been associated with diseases such as diabetes and cancer. We profiled parent of origin DNA methylation marks to find novel imprinted loci. Methods: We have an unprecedented collection of whole blood DNA from XX patients with UPD covering 18 different chromosomes, allowing for the efficient detection of DMRs associated with imprinted genes for 84% of the human genome. Our study is complimented with Ovarian Teratoma DNA (maternal DNA) and Complete hydatidiform Mole (paternal DNA). DNA methylation was profiled using Illumina Infinium 450K Methylation BeadArrays. Imprinted DMRs were defined by sites at which the maternal and paternal methylation levels diverged significantly from the biparental average. We confirmed novel DMRs by bisulfite sequencing of informative trios and SequenomEpiTYPER assays. Allelic specific gene expression studies were also performed by RNA sequencing in independent biparental controls. Findings: Our results provide for the first comprehensive map of the human imprintome, doubling the number of known imprinted regions. We identified a total of 71 DMRs, 41 of which were novel. 27 novel DMRs were maternally methylated and 14 were paternally methylated. We identified DMRs on chromosomes 5, 21 and 22 previously considered devoid of imprinting, highlighting potential parent-of-origin effects in chromosomal aneuploidies such as Down syndrome. We also found DMRs in genes associated with Schizophrenia and epilepsy. Interpretation: Our data provide the first comprehensive genome-wide map of imprinted sites in the human genome, and provide novel insights into potential parent-of-origin effects in human disorders. 66 UPD samples analyzed in total, From each individual, whole bllod DNA was extracted and global DNA methylation levels were assessed using Illumina Infinium HumanMethylation450 BeadChip.
Project description:Genomic imprinting is a form of epigenetic regulation that results in expression of either the maternally or paternally inherited allele of a subset of genes. Imprinted loci contain differentially methylated regions (DMRs) where cytosine methylation marks one of the parental alleles, providing cis-acting regulatory elements that influence the allelic expression of surrounding genes, however to date the total number of imprinted loci within the human genome is unknown. To characterize known imprinted DMRS and identify novel imprinted loci we have performed whole-genome bisulphite sequencing and high-resolution DNA methylation array analysis of healthy tissues. Sequencing of bisulfite converted DNA analysis of normal brain (white matter), liver and term placenta tissue
Project description:Genomic imprinting is a form of epigenetic regulation that results in expression of either the maternally or paternally inherited allele of a subset of genes. Imprinted loci contain differentially methylated regions (DMRs) where cytosine methylation marks one of the parental alleles, providing cis-acting regulatory elements that influence the allelic expression of surrounding genes, however to date the total number of imprinted loci within the human genome is unknown. To characterize known imprinted DMRS and identify novel imprinted loci we have performed whole-genome bisulphite sequencing and high-resolution DNA methylation array analysis of healthy tissues. Sequencing of bisulfite converted DNA and array based analysis of normal tissues, human embryonic stem cells, androgenetic hydatidiform moles and leukocytes from reciprocal genome-wide uniparental disomies.
Project description:Genomic imprinting is a form of epigenetic regulation that results in expression of either the maternally or paternally inherited allele of a subset of genes. Imprinted loci contain differentially methylated regions (DMRs) where cytosine methylation marks one of the parental alleles, providing cis-acting regulatory elements that influence the allelic expression of surrounding genes, however to date the total number of imprinted loci within the human genome is unknown. To characterize known imprinted DMRS and identify novel imprinted loci we have performed whole-genome bisulphite sequencing and high-resolution DNA methylation array analysis of healthy tissues.
Project description:Genomic imprinting is a form of epigenetic regulation that results in expression of either the maternally or paternally inherited allele of a subset of genes. Imprinted loci contain differentially methylated regions (DMRs) where cytosine methylation marks one of the parental alleles, providing cis-acting regulatory elements that influence the allelic expression of surrounding genes, however to date the total number of imprinted loci within the human genome is unknown. To characterize known imprinted DMRS and identify novel imprinted loci we have performed whole-genome bisulphite sequencing and high-resolution DNA methylation array analysis of healthy tissues.