DNA replication timing of Arabidopsis thaliana chromosome 4
Ontology highlight
ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE103321 | GEO | 2017/08/31
SECONDARY ACCESSION(S): PRJNA401874
REPOSITORIES: GEO
Similar Datasets
Project description:DNA replication programs have been studied extensively in yeast and animal systems, where they have been shown to correlate with gene expression and certain epigenetic modifications. Despite the conservation of core DNA replication proteins, little is known about replication programs in plants. We used flow cytometry and tiling microarrays to profile DNA replication of Arabidopsis thaliana chromosome 4 (chr4) during early, mid, and late S phase. Replication profiles for early and mid S phase were similar and encompassed the majority of the euchromatin. Late S phase exhibited a distinctly different profile that includes the remaining euchromatin and essentially all of the heterochromatin. Termination zones were consistent between experiments, allowing us to define 163 putative replicons on chr4 that clustered into larger domains of predominately early or late replication. Early-replicating sequences, especially the initiation zones of early replicons, displayed a pattern of epigenetic modifications specifying an open chromatin conformation. Late replicons, and the termination zones of early replicons, showed an opposite pattern. Histone H3 acetylated on lysine 56 (H3K56ac) was enriched in early replicons, as well as the initiation zones of both early and late replicons. H3K56ac was also associated with expressed genes, but this effect was local whereas replication time correlated with H3K56ac over broad regions. The similarity of the replication profiles for early and mid S phase cells indicates that replication origin activation in euchromatin is stochastic. Replicon organization in Arabidopsis is strongly influenced by epigenetic modifications to histones and DNA. The domain organization of Arabidopsis is more similar to that in Drosophila than that in mammals, which may reflect genome size and complexity. The distinct patterns of association of H3K56ac with gene expression and early replication provide evidence that H3K56ac may be associated with initiation zones and replication origins.
2011-07-06 | GSE30433 | GEO
Project description:DNA replication programs have been studied extensively in yeast and animal systems, where they have been shown to correlate with gene expression and certain epigenetic modifications. Despite the conservation of core DNA replication proteins, little is known about replication programs in plants. We used flow cytometry and tiling microarrays to profile DNA replication of Arabidopsis thaliana chromosome 4 (chr4) during early, mid, and late S phase. Replication profiles for early and mid S phase were similar and encompassed the majority of the euchromatin. Late S phase exhibited a distinctly different profile that includes the remaining euchromatin and essentially all of the heterochromatin. Termination zones were consistent between experiments, allowing us to define 163 putative replicons on chr4 that clustered into larger domains of predominately early or late replication. Early-replicating sequences, especially the initiation zones of early replicons, displayed a pattern of epigenetic modifications specifying an open chromatin conformation. Late replicons, and the termination zones of early replicons, showed an opposite pattern. Histone H3 acetylated on lysine 56 (H3K56ac) was enriched in early replicons, as well as the initiation zones of both early and late replicons. H3K56ac was also associated with expressed genes, but this effect was local whereas replication time correlated with H3K56ac over broad regions. The similarity of the replication profiles for early and mid S phase cells indicates that replication origin activation in euchromatin is stochastic. Replicon organization in Arabidopsis is strongly influenced by epigenetic modifications to histones and DNA. The domain organization of Arabidopsis is more similar to that in Drosophila than that in mammals, which may reflect genome size and complexity. The distinct patterns of association of H3K56ac with gene expression and early replication provide evidence that H3K56ac may be associated with initiation zones and replication origins. Replicating DNA in cultured Arabidopsis cells was labeled with BrdU for 1 hour. Cells were harvested, nuclei extracted, and the nuclei were sorted by FACS as Early, Mid or Late S phase based on DNA content (DAPI signal). Newly replicated DNA was isolated by immunoprecipitation to BrdU, amplified, and labeled with Cy5/Cy3. Input DNA served as a reference and was labeled with Cy3/Cy5. Equal amounts of DNA was hybridized to a spotted cDNA that covers Arabidopsis chr4. Each S phase sample has 3 biological replicates with a dye swap serving as a technical replicate for a total of 18 arrays.
2011-07-06 | E-GEOD-30433 | biostudies-arrayexpress
Project description:DNA replication is spatially and temporally regulated during S-phase. DNA replication timing is established in early G1-phase at a point referred to as TDP (timing decision point). We show that Rif1 (Rap1-interacting-factor1), originally identified as a telomere binding factor in yeast, is a critical determinant of the replication timing program in human cells. Depletion of Rif1 results in specific loss of mid-S replication foci profiles, stimulation of initiation events in early S-phase and changes in long-range replication timing domain structures. Overall replication timing is shifted toward mid-S in both directions, suggesting that replication timing regulation is abrogated in the absence of Rif1. Rif1 tightly binds to nuclear insoluble structures at late-M to early-G1 and regulates the chromatin-loop sizes. Furthermore, Rif1 colocalizes specifically with the mid-S replication foci. Thus, Rif1 establishes the mid-S replication domains that are restrained from being activated at early S-phase. Our results indicate that Rif1 plays crucial roles in determining the replication timing domain structures through regulating higher-order chromatin architecture.
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Project description:Duplication of mammalian genomes requires replisomes to overcome numerous impediments during passage through open (eu) and condensed (hetero) chromatin. Typically, studies of replication stress characterize mixed populations of challenged and unchallenged replication forks, averaged across S phase, and model a single species of “stressed” replisome. However, in cells containing potent obstacles to replication, we find two different lesion proximal replisomes. One is bound by the DONSON protein and is more frequent in early S phase, in regions marked by euchromatin. The other interacts with the FANCM DNA translocase, is more prominent in late S phase, and favors heterochromatin. The two forms can also be detected in unstressed cells. CHIP-seq of DNA associated with DONSON or FANCM confirms the bias of the former towards regions that replicate early and the skew of the latter towards regions that replicate late
2020-05-15 | GSE150550 | GEO
Project description:DNA replication is spatially and temporally regulated during S-phase. DNA replication timing is established in early G1-phase at a point referred to as TDP (timing decision point). We show that Rif1 (Rap1-interacting-factor1), originally identified as a telomere binding factor in yeast, is a critical determinant of the replication timing program in human cells. Depletion of Rif1 results in specific loss of mid-S replication foci profiles, stimulation of initiation events in early S-phase and changes in long-range replication timing domain structures. Overall replication timing is shifted toward mid-S in both directions, suggesting that replication timing regulation is abrogated in the absence of Rif1. Rif1 tightly binds to nuclear insoluble structures at late-M to early-G1 and regulates the chromatin-loop sizes. Furthermore, Rif1 colocalizes specifically with the mid-S replication foci. Thus, Rif1 establishes the mid-S replication domains that are restrained from being activated at early S-phase. Our results indicate that Rif1 plays crucial roles in determining the replication timing domain structures through regulating higher-order chromatin architecture. HeLa cells (ATCC), with a total of 4 individual replicates
2012-05-14 | E-GEOD-37971 | biostudies-arrayexpress
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Project description:In this study we report that B. melitensis at the late logarithmic phase of growth are more invasive for HeLa cells than at mid logarithmic or stationary growth phases. Microarray analysis of B. melitensis gene expression identified 414 up- and 40 down-regulated genes in late-log growth phase compared to the stationary growth phase. The vast majority of the up-regulated genes in late-log cultures were those associated with DNA replication, transcription and translation, intermediate metabolism, energy production and conversion, membrane transport and cell envelope, biogenesis and outer membrane, while the down-regulated genes were distributed among several functional categories. This first Brucella global gene expression study provides novel information on growth phase-specific gene regulation important not only for understanding Brucella physiology but also the initial molecular interactions between Brucella and its host. Keywords: Comparison bacterial growth phase normalized to genomic DNA There are two kind of samples consisting of RNA isolated from Brucella melitensis grown logarithmically or at stationary phase. There are four biological replicates of each sample. Every Brucella melitensis open reading frame was printed in triplicate on each microarray, thereby providing three technical replicates for each biological replicates. Each replicate was normalized against labeled Brucella melitensis genomic DNA.
2010-05-19 | E-GEOD-11192 | biostudies-arrayexpress
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