Three-dimensional connectivity and chromatin environment mediate the activation efficiency of mammalian DNA replication origins
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE131699 | GEO | 2022/08/24
REPOSITORIES: GEO
Similar Datasets
Project description:Because of the lack of information, regulation of DNA replication initiation in mammals is still poorly understood. In order to identify general rules, we have mapped replication origins along 1% of the human genome in HeLa cells. We found large gene-poor regions lacking origin and G+C rich regions containing clusters of closely spaced origins. Half of the 283 origins mapped are within or near CpG islands. The connection with gene expression is further reinforced by the observation that most origins overlap with DNAseI hypersensitive sites found at transcriptional regulatory elements. We show, however, that this association is independent of chromatin structure and transcriptional activity. Replication timing analyses coupled to our origin mapping demonstrate that origin dense regions and isolated origins are replicated at every moment in S phase. All together, our data suggest that a relatively strict origin-timing programme regulates DNA replication of the human genome. Keywords: Nascent strands, ENCODE project, HeLAS3 cells, SNS-Chip Four independent preparations of Short Nascent Strands (SNS) were performed. In order to have enough material for microarray hybridisation, we coupled the stringent preparation of SNS with the TLAD method, a technique of linear amplification that can generate several µg of amplified material from 10-20 ng of DNA (Liu et al., 2003).Two were amplified by TLAD (experiments A and B) and hybridized on DNA microarrays, and the other two (experiments C and D) were used for the validation by real-time quantitative PCR (qPCR) of results obtained on micro-arrays. We performed also a gDNA/gDNA hybridization where gDNA are also amplified by TLAD to order to do a control.
2010-05-18 | E-GEOD-10217 | biostudies-arrayexpress
Project description:At every cell cycle, faithful inheritance of metazoan genomes requires the concerted activation of thousands of DNA replication origins. However, which genetic and chromatin features define metazoan replication start sites remains largely unknown. Here, we delineate the origin repertoire of the Drosophila genome at high resolution. We address the role of origin-proximal G-quadruplexes and show their ability to transiently stall replication forks in vivo. We dissect the chromatin configuration of replication origins and identify a rich spatial organization of chromatin features at initiation sites. DNA shape and chromatin configurations, not strict sequence specificity, mark and predict replication origins in higher eukaryotes. We further examine the link between transcription and origin firing and reveal that modulation of origin activity across cell types is intimately linked to cell-type-specific transcriptional programs. Our study unravels conserved origin features and provides unique insights into the relationship between DNA topology, chromatin, transcription and replication initiation across metazoa. Our dataset consists of SNS-Seq profiles in Drosophila S2 and Bg3 cells. Small nascent leading strands (SNS) have been purified with an enhanced sensitivity SNS purification protocol. For standard SNS-Seq experiments (from pooled gradient fractions, denoted as "pool"), SNS were purified from two biological replicates. For single-fraction SNS-Seq experiments, two libraries were prepared for each fraction. The genomic coordinates of S2 and Bg3 replication origins are also provided.
2015-04-23 | E-GEOD-65692 | biostudies-arrayexpress
Project description:Because of the lack of information, regulation of DNA replication initiation in mammals is still poorly understood. In order to identify general rules, we have mapped replication origins along 1% of the human genome in HeLa cells. We found large gene-poor regions lacking origin and G+C rich regions containing clusters of closely spaced origins. Half of the 283 origins mapped are within or near CpG islands. The connection with gene expression is further reinforced by the observation that most origins overlap with DNAseI hypersensitive sites found at transcriptional regulatory elements. We show, however, that this association is independent of chromatin structure and transcriptional activity. Replication timing analyses coupled to our origin mapping demonstrate that origin dense regions and isolated origins are replicated at every moment in S phase. All together, our data suggest that a relatively strict origin-timing programme regulates DNA replication of the human genome. Keywords: Nascent strands, ENCODE project, HeLAS3 cells, SNS-Chip
2008-10-22 | GSE10217 | GEO
Project description:We report the application of single-molecule-based sequencing technology for high-throughput profiling of DNA replication origins in K562 mammalian cells. We have optimized a specific method of peak detection adapted to the signal produced by the sequencing of short nascent strands (SNS) that are specific of replication initiation, with the aim to have both a good sensitivity and specificity. We demonstrated the existence of the spatiao-temporal program of DNA replication driven by a specific epigenetic signature. K562 human cells; five samples subjected to SNS-Seq.
2014-05-01 | E-GEOD-46189 | biostudies-arrayexpress
Project description:Lamins are the major structural components of the nuclear lamina (NL) beneath the inner nuclear membrane. Although lamins are believed to regulate genome organization and transcription, how they perform these functions remains poorly understood. Combining Hi-C with fluorescence in situ hybridization (FISH) and Histone and Lamina landscape (HiLands) analyses of chromatin domains, we show that lamins differentially regulate the NL-associated HiLands-P and -B domains in mouse ES cells (mESCs). Lamin loss leads to HiLands-P expansion at the NL, detachment of HiLands-B from the NL, and genome-wide changes of 3D chromatin interactions in NL-associated and interior HiLands in mESCs. Further epigenome and transcriptome analyses show that lamins can function from the NL to maintain the boundaries of active and repressive chromatin domains, thereby influencing gene expression throughout the genome. These findings should provide the basis to further understand how changes in the NL-associated chromatin influence transcription in development and NL-associated diseases.
2017-11-01 | GSE89520 | GEO
Project description:Here, we precisely determined MCM7 binding sites inHeLa cells by ChIP-Seq, classified them into firing and dormant replication origins using SNS data deposited, and analyzed their association with various chromatin signatures.
2017-11-23 | GSE107248 | GEO
Project description:Here, we identify DNA replication initiation sites from 19 human samples, representing three untransformed and three immortalized cell types using SNS-seq protocol.
2020-09-28 | GSE128477 | GEO
Project description:Short nascent strands purification coupled to next-generation sequencing allowed us to identify replication origins on human genome in an extensive way, by mapping replication origins in 4 different cell types, IMR-90 fibroblasts, hESC H9 cells, iPSC Th Cl-4 cells and HeLa cells. We demonstrated the existence of a cell type-specific reprogrammable signature of the cell identity revealed by specific efficiencies of conserved origin positions and not by the selection of cell-type specific subsets of origins. 4 different cell types were analyzed. For each cell types, 2 different biological replicates of short nascent strands at replication origins were purified. Each SNS sample was sequencing at least one time.
2012-07-01 | E-GEOD-37757 | biostudies-arrayexpress
Project description:The aerial performance of flying insects ultimately depends on how flapping wings interact with the surrounding air. It has previously been suggested that the wing's three-dimensional camber and corrugation help to stiffen the wing against aerodynamic and inertial loading during flapping motion. Their contribution to aerodynamic force production, however, is under debate. Here, we investigated the potential benefit of three-dimensional wing shape in three different-sized species of flies using models of micro-computed tomography-scanned natural wings and models in which we removed either the wing's camber, corrugation, or both properties. Forces and aerodynamic power requirements during root flapping were derived from three-dimensional computational fluid dynamics modelling. Our data show that three-dimensional camber has no benefit for lift production and attenuates Rankine-Froude flight efficiency by up to approximately 12% compared to a flat wing. Moreover, we did not find evidence for lift-enhancing trapped vortices in corrugation valleys at Reynolds numbers between 137 and 1623. We found, however, that in all tested insect species, aerodynamic pressure distribution during flapping is closely aligned to the wing's venation pattern. Altogether, our study strongly supports the assumption that the wing's three-dimensional structure provides mechanical support against external forces rather than improving lift or saving energetic costs associated with active wing flapping.
| S-EPMC7115228 | biostudies-literature
Project description:Genome segregation is a fundamental step in the life cycle of every cell. Most bacteria rely on dedicated DNA partition proteins to actively segregate chromosomes and low copy-number plasmids. Here, by employing super resolution microscopy, we establish that the ParF DNA partition protein of the ParA family assembles into a three-dimensional meshwork that uses the nucleoid as a scaffold and periodically shuttles between its poles. Whereas ParF specifies the territory for plasmid trafficking, the ParG partner protein dictates the tempo of ParF assembly cycles and plasmid segregation events by stimulating ParF adenosine triphosphate hydrolysis. Mutants in which this ParG temporal regulation is ablated show partition deficient phenotypes as a result of either altered ParF structure or dynamics and indicate that ParF nucleoid localization and dynamic relocation, although necessary, are not sufficient per se to ensure plasmid segregation. We propose a Venus flytrap model that merges the concepts of ParA polymerization and gradient formation and speculate that a transient, dynamic network of intersecting polymers that branches into the nucleoid interior is a widespread mechanism to distribute sizeable cargos within prokaryotic cells.
| S-EPMC5389482 | biostudies-literature