Detecting chromatin interactions along and between sister chromatids with SisterC
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE145695 | GEO | 2020/06/17
REPOSITORIES: GEO
Similar Datasets
Project description:Detecting chromatin interactions along and between sister chromatids with SisterC
| PRJNA607964 | ENA
Project description:The three-dimensional organization of the genome supports regulated gene expression, recombination, DNA repair, and chromosome segregation during mitosis. Chromosome conformation capture (Hi-C) has revealed a complex genomic landscape of internal chromosome structures in vertebrate cells yet how sister chromatids topologically interact in replicated chromosomes has remained elusive due to their identical sequences. Here, we present sister-chromatid-sensitive Hi-C (scsHi-C) based on nascent DNA labeling with 4-thio-thymidine. Genome-wide conformation maps of human chromosomes revealed that sister chromatid pairs interact most frequently at the boundaries of topologically associating domains (TADs). Continuous loading of a dynamic cohesin pool separates sister-chromatid pairs inside TADs and is required to focus sister chromatid contacts at TAD boundaries. We identified a subset of TADs that are overall highly paired, characterized by facultative heterochromatin, as well as insulated topological domains that form separately within individual sister chromatids. The rich pattern of sister chromatid topologies and our scsHi-C technology will make it possible to dissect how physical interactions between identical DNA molecules contribute to DNA repair, gene expression, chromosome segregation, and potentially other biological processes.
2020-06-12 | GSE152373 | GEO
Project description:Conformation of sister chromatids in the replicated human genome
| PRJNA639130 | ENA
Project description:The extreme length of chromosomal DNA requires organizing mechanisms to both promote functional genetic interactions and ensure faithful chromosome segregation when cells divide. Microscopy and genome wide contact frequency (Hi-C) analyses indicate that intra-chromosomal looping of DNA is a primary pathway of chromosomal organization during all stages of the cell cycle (Dekker, J. & Mirny, L. . Cell 164, 1110–1121 (2016). Although the enzymatic pathways required for DNA loop formation are yet to be fully characterized, the activity of the SMC family of proteins has been consistently associated with this process in interphase and mitosis. Here we use Hi-C to study the reorganization of budding yeast chromosome conformation in early mitosis and the role of SMCs in this process. Using polymer simulations, we find that the differences between interphase and mitotic Hi-C maps can be explained by the formation of intra-chromosomal (cis-) loops in mitotic chromosomes. We demonstrate that mitotic SMC cohesin activity is required for formation of cis-loops, independently of sister-chromatid cohesion. In contrast, SMC condensin is not required for loop formation in these early mitotic cells. Rather condensin activity promotes distinct higher order structures in the chromosomes at centromeres and in the rDNA proximal regions. Thus we demonstrate that cohesin-dependent cis-loops provide the primary higher order organization of budding yeast mitotic chromosomes, independently of condensin and sister chromatid cohesion.
2017-03-22 | GSE87311 | GEO
Project description:The fidelity of chromosome duplication through cell divisions requires timely binding and release of the cohesin. Cohesin is a ring-shaped protein complex linking newly replicated sister chromatids to ensure their appropriate transmission through mitosis. Upon commencement of mitosis cohesin is removed from DNA in two steps: first, from chromosome arms resulting in sister chromatid resolution, and, second, from centromers leading to sister chromatid segregation. As DNA of eukaryotic chromosomes is assembled into chromatin, regulation of sister chromatid cohesion-segregation may involve chromatin modifying machinery, but this link is not well understood. Here we report that H2A-H2B histone chaperone NAP1, a factor, which is primarily implicated in chromatin assembly, is required for cohesin release from mitotic chromosome arms. NAP1 and cohesin protein complex interact directly and share multiple binding sites on chromatin. Depletion of the NAP1 hinders cohesin removal during mitosis resulting in accumulation of unresolved sister chromatids. Thus, in addition to its well established functions in chromatin dynamics, histone chaperone NAP1 coordinates cell cycle dependent cohesin release. These results reveal a novel molecular pathway for sister chromatid resolution and emphasizes a role for histone chaperones in control of eukaryotic genome replication and transmission.
2012-07-26 | GSE30938 | GEO
Project description:The fidelity of chromosome duplication through cell divisions requires timely binding and release of the cohesin. Cohesin is a ring-shaped protein complex linking newly replicated sister chromatids to ensure their appropriate transmission through mitosis. Upon commencement of mitosis cohesin is removed from DNA in two steps: first, from chromosome arms resulting in sister chromatid resolution, and, second, from centromers leading to sister chromatid segregation. As DNA of eukaryotic chromosomes is assembled into chromatin, regulation of sister chromatid cohesion-segregation may involve chromatin modifying machinery, but this link is not well understood. Here we report that H2A-H2B histone chaperone NAP1, a factor, which is primarily implicated in chromatin assembly, is required for cohesin release from mitotic chromosome arms. NAP1 and cohesin protein complex interact directly and share multiple binding sites on chromatin. Depletion of the NAP1 hinders cohesin removal during mitosis resulting in accumulation of unresolved sister chromatids. Thus, in addition to its well established functions in chromatin dynamics, histone chaperone NAP1 coordinates cell cycle dependent cohesin release. These results reveal a novel molecular pathway for sister chromatid resolution and emphasizes a role for histone chaperones in control of eukaryotic genome replication and transmission. Genome-wide NAP1 and Cohesin ChIP-chip profiling in Drosophila S2 cells. The supplementary bed file S2_cohesin_sites.bed contains cohesin binding sites obtained by intersecting the sets of significant ChIP-chip peaks for SA (a cohesin subunit; stromalin) and SMC1.
2012-07-25 | E-GEOD-30938 | biostudies-arrayexpress
Project description:Sister chromatid exchanges (SCEs) are a product of joint DNA molecules resolution, and are considered to require homologous recombination (HR). Canonical HR factors BRCA1, BRCA2 and RAD51 were indeed essential for SCE induction in response to irradiation-induced DNA breaks. By contrast, replication-blocking agents, including PARP inhibitors, induced SCEs independently of BRCA1, BRCA2 or RAD51. HR-independent SCEs were associated with incomplete DNA replication, as evidenced by post-replicative single-stranded DNA (ssDNA) accumulation and enrichment of PARP inhibitor-induced SCEs at common fragile sites (CFSs). Importantly, PARP-induced DNA lesions were transmitted into mitosis, pointing towards SCEs originating from mitotic processing of underreplicated DNA. We found polymerase theta to be associated to mitotic DNA lesions, to be required for SCE formation and to prevent chromosome fragmentation upon PARP inhibition in HR-defective cells. Combined, our data show that replication-blocking agents lead to underreplicated DNA in mitosis, which is processed into SCEs independently of canonical HR factors.
2023-03-11 | PXD028670 | Pride
Project description:Following fertilization in mammals, it is generally accepted that totipotent cells are exclusive to the zygote and to each of the two blastomeres originating from the first mitotic division. We counter that this classic view needs to be revised, because we have presented compelling evidence that the sister blastomeres are both totipotent in only a subset of 2-cell stage mouse embryos (PMID 28811525). Building on our previous findings, we here ask the question if the interblastomere differences depend - at least in part - on the contribution of sperm, since the area of sperm entry is inherited preferentially by one blastomere. To this end, we created sister 2-cell stage blastomeres without sperm entry point, by parthenogenesis. We compare the transcriptomes of the sister blastomeres, to see if the interblastomere mRNA differences observed after fertilization (GSE94050) are still there when the sperm entry point is missing.
2019-07-10 | GSE111589 | GEO
Project description:The biorientation of sister chromatids on the mitotic spindle, essential for accurate sister chromatid segregation, relies on critical centromere components including cohesin, the centromere-specific H3 variant CENP-A, and centromeric DNA. Centromeric DNA is highly variable between chromosomes yet must accomplish a similar function. Moreover, how the 50 nm cohesin ring, proposed to encircle sister chromatids, accommodates inter-sister centromeric distances of hundreds of nanometers on the metaphase spindle is a conundrum. Insight into the 3D organization of centromere components would help resolve how centromeres function on the mitotic spindle. We used ChIP-seq and super-resolution microscopy to examine the geometry of essential centromeric components on human chromosomes. ChIP-seq of SA1, SA2, and Rad21 in human cells demonstrates that cohesin subunits are depleted in -satellite arrays where CENP-A nucleosomes and kinetochores assemble. Cohesin is instead enriched at pericentromeric DNA. Structured illumination microscopy of sister centromeres is consistent, revealing a non-overlapping pattern of CENP-A and cohesin.
2023-10-11 | GSE240957 | GEO
Project description:Cohesion between sister chromatids depends on the chromosomal cohesin complex and allows the spindle apparatus in mitosis to recognize replicated chromosomes for segregation into daughter cells. Sister chromatid cohesion is established concomitant with DNA replication, and requires the essential Eco1 protein, a replication fork-associated acetyl transferase. The mechanism by which Eco1 establishes sister chromatid cohesion is not known. Here, we show that the cohesin subunit Smc3 is acetylated in an Eco1-dependent manner during S phase to establish sister chromatid cohesion. We isolated spontaneous suppressors of the thermosensitive eco1-1 allele in budding yeast, and identified the suppressor mutations from the hybridization pattern of genomic DNA on oligonucleotide tiling arrays. An acetylation mimicking mutation of a conserved lysine in Smc3 to asparagine (K113N) makes Eco1 dispensable for cell growth, indicating that Smc3 acetylation is Eco1’s only essential function. We identified a second set of eco1-1 suppressor mutations in the budding yeast ortholog of the cohesin regulator Wapl (Wpl1/Rad61). Wapl destabilizes cohesin on chromosomes, and Eco1-dependent Smc3 acetylation during S-phase might render cohesin resistant to Wapl. Our results clarify the role of Eco1 in the establishment of sister chromatid cohesion, and suggest that Eco1 modifies cohesin to stabilize an Eco1-independent cohesion establishment reaction.
2008-07-24 | GSE11527 | GEO