Project description:Bloom Syndrome (BS) is a recessive genetic disorder characterized by hyper-recombination and genome instability. It is caused by mutations in the conserved RecQ helicase gene, BLM, which is essential in maintaining genome integrity and unwinds various aberrant DNA structures. One such structure is DNA G-quadruplexes (G4s), which have broad regulatory functions. Although putative G4-forming sequences have been previously implicated in BS, it remains unclear what (dys)regulatory role, if any, endogenous G4 structures may play in BS. Here, we profiled chromatin accessibility and gene expression via ATAC-seq and RNA-seq and mapped endogenous G4 via ChIP-seq in wild-type (WT) vs. BS cell lines. We observed that in BS, differential G4 formation positively correlated with both chromatin accessibility and gene expression. Stabilizing G4 in WT cells with pyridostatin partially phenocopied BS. Additionally, data from a BS family showed that regions with increased chromatin accessibility in BS individuals were also enriched for G4-forming sequences. Our data showed that G4 formation is associated with higher chromatin accessibility and gene expression; likely in BS, unresolved G4 increases focal chromatin accessibility, thereby upregulating gene expression. In summary, our results revealed a central role of G4 in the molecular etiology of BS and provide a new perspective on BLM’s regulatory function through G4s.
Project description:Bloom Syndrome (BS) is a recessive genetic disorder characterized by hyper-recombination and genome instability. It is caused by mutations in the conserved RecQ helicase gene, BLM, which is essential in maintaining genome integrity and unwinds various aberrant DNA structures. One such structure is DNA G-quadruplexes (G4s), which have broad regulatory functions. Although putative G4-forming sequences have been previously implicated in BS, it remains unclear what (dys)regulatory role, if any, endogenous G4 structures may play in BS. Here, we profiled chromatin accessibility and gene expression via ATAC-seq and RNA-seq and mapped endogenous G4 via ChIP-seq in wild-type (WT) vs. BS cell lines. We observed that in BS, differential G4 formation positively correlated with both chromatin accessibility and gene expression. Stabilizing G4 in WT cells with pyridostatin partially phenocopied BS. Additionally, data from a BS family showed that regions with increased chromatin accessibility in BS individuals were also enriched for G4-forming sequences. Our data showed that G4 formation is associated with higher chromatin accessibility and gene expression; likely in BS, unresolved G4 increases focal chromatin accessibility, thereby upregulating gene expression. In summary, our results revealed a central role of G4 in the molecular etiology of BS and provide a new perspective on BLM’s regulatory function through G4s.
Project description:Bloom Syndrome (BS) is a recessive genetic disorder characterized by hyper-recombination and genome instability. It is caused by mutations in the conserved RecQ helicase gene, BLM, which is essential in maintaining genome integrity and unwinds various aberrant DNA structures. One such structure is DNA G-quadruplexes (G4s), which have broad regulatory functions. Although putative G4-forming sequences have been previously implicated in BS, it remains unclear what (dys)regulatory role, if any, endogenous G4 structures may play in BS. Here, we profiled chromatin accessibility and gene expression via ATAC-seq and RNA-seq and mapped endogenous G4 via ChIP-seq in wild-type (WT) vs. BS cell lines. We observed that in BS, differential G4 formation positively correlated with both chromatin accessibility and gene expression. Stabilizing G4 in WT cells with pyridostatin partially phenocopied BS. Additionally, data from a BS family showed that regions with increased chromatin accessibility in BS individuals were also enriched for G4-forming sequences. Our data showed that G4 formation is associated with higher chromatin accessibility and gene expression; likely in BS, unresolved G4 increases focal chromatin accessibility, thereby upregulating gene expression. In summary, our results revealed a central role of G4 in the molecular etiology of BS and provide a new perspective on BLM’s regulatory function through G4s.
Project description:Cross-talk between DNA methylation and histone modifications drives the establishment of composite epigenetic signatures and is traditionally studied using correlative rather than direct approaches. Here we present sequential ChIP-bisulfite-sequencing (ChIP- BS-seq) as an approach to quantitatively assess DNA methylation patterns associated with chromatin modifications or chromatin-associated factors directly. A chromatin- immunoprecipitation (ChIP)-capturing step is used to obtain a restricted representation of the genome occupied by the epigenetic feature of interest, for which a single-base resolution DNA methylation map is then generated. When applied to H3 lysine 27 tri- methylation (H3K27me3), we found that H3K27me3 and DNA methylation are compatible throughout most of the genome, except for CpG islands, where these two marks are mutually exclusive. Further ChIP-BS-seq-based analysis in Dnmt triple- knock-out (TKO) embryonic stem cells revealed that total loss of CpG methylation is associated with alteration of H3K27me3 levels throughout the genome: H3K27me3 in localized peaks is decreased while broad local enrichments (BLOCs) of H3K27me3 are formed. At an even broader scale, these BLOCs correspond to regions of high DNA methylation in wild-type ES cells, suggesting that DNA methylation prevents H3K27me3 deposition locally and at megabase scale. Our strategy provides an unique way of investigating global interdependencies between DNA methylation and other chromatin features. ChIP (chromatin immunoprecipitation) is followed by bisulfite conversion and deep sequencing to directly assess DNA methylation levels in captured chromatin fragments (ChIP-BS-seq). We used ChIP-BS-seq to study the potential global cross-talk between H3K27me3 and DNA methylation, which are both linked to repression. First, we used capturing of methylated DNA, followed by bisulfite-deep sequencing (MethylCap-BS-seq). Genomic DNA isolated from normal and tumor colon tissues was used for MethylCap-BS-seq as well as for conventional MethylCap-seq experiments. Second, we performed ChIP-BS-seq on H3K27me3, using HCT116 colon carcinoma cells. Third, to further study the relevance of the observations, we generated genome-wide profiles for H3K27me3 and DNA methylation by conventional ChIP-seq and MethylCap-seq, and RNA-seq, respectively. Finally, we performed H3K27me3-ChIP-BS-seq and MethylCap-seq on wild-type mouse ES cells as well as Dnmt-triple-knockout (TKO) mouse ES cells.
Project description:To investigate the function of FEM2 in regulation of 24-nt siRNA accumulation, 18-day-old seedlings wer used for RNA-seq, BS-seq and sRNA-seq.
Project description:We report the ChIP-seq of several histone modification markers for BS cells and H3K36me3 ChIP-seq for M cells, we found that BS-specific gene module trend to be regulated by histone acetylation.
Project description:This SuperSeries is composed of the following subset Series: GSE36129: An IDN2-containing complex involved in RNA-directed DNA methylation in Arabidopsis [leaves RNA-seq] GSE36143: An IDN2-containing complex involved in RNA-directed DNA methylation in Arabidopsis [BS-seq] GSE37206: An IDN2-containing complex involved in RNA-directed DNA methylation in Arabidopsis [flowers RNA-seq] Refer to individual Series
Project description:Bloom Syndrome (BS) is a recessive genetic disorder characterized by hyper-recombination and genome instability. It is caused by mutations in the conserved RecQ helicase gene, BLM, which acts to unwind various aberrant DNA structures. One such structure is DNA G-quadruplexes (G4s), which have broad regulatory functions. Despite previous association between putative G4-forming sequences and BS, it remains unclear what (dys)regulatory role, if any, endogenous G4 structures may play in BS. Here, we profiled chromatin accessibility and gene expression via ATAC-seq and RNA-seq and mapped endogenous G4 via ChIP-seq in wild-type (WT) vs. BS cell lines. We observed that in BS, differential G4 formation positively correlated with both differential chromatin accessibility and gene expression. To test the direct involvement of G4s in the molecular phenotypes in BS, we applied pyridostatin, a G4-stabilizing molecule, in WT cells and showed that G4 stabilization partially phenocopied BS. Additionally, data from a BS family showed that regions with increased chromatin accessibility in BS individuals were also enriched for G4-forming sequences. Our data showed that G4 formation promotes chromatin accessibility and gene expression; likely in BS, unresolved G4 increases focal chromatin accessibility, thereby upregulating gene expression. In summary, our results revealed a central role of G4 in the molecular etiology of BS and provide a new perspective on BLM’s regulatory function through G4s.
Project description:This model was reconstructed from single-nucleus RNA-seq (snRNA-seq) data of human postmortem brain and curated using published metabolomics data from human iPSC-derived neurons and cerebrospinal fluid (CSF), together with gene expression data from the Human Protein Atlas. It more accurately simulates human neuronal metabolic flux in neurodegenerative conditions such as Alzheimer's disease (AD).