Unexpected conformational variations of the human centromeric chromatin complex
Ontology highlight
ABSTRACT:
OTHER RELATED OMICS DATASETS IN: GSE104805
PROVIDER: PRJNA413913 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Centromeres of most eukaryotes are multi-megabase arrays of satellite DNA that assemble proteinaceous kinetochores to facilitate faithful chromosome segregation. However, the nature of the chromatin landscape at centromeres remains unclear, in part due to the difficulty of isolating intact centromeric chromatin rendered insoluble by megadalton-size kinetochore protein complexes. To address this challenge we combined classical salt fractionation with chromatin immunoprecipitation to recover human centromeric chromatin under native conditions. We found that >85% of the total centromeric chromatin is insoluble under conditions typically used for native chromatin extraction. To map both soluble and insoluble chromatin in situ, we combined CUT&RUN, a targeted nuclease method, with salt fractionation. Using this approach, we found that the strength of Centromere Protein B (CENP-B) binding and the density of CENP-B motifs corresponds to the occupancy of Constitutive Centromere-Assocated Network (CCAN) complexes bound to α-satellite arrays. We also observed unexpected structural variations of CENP-A-containing complexes on different α-satellite dimeric units within highly homogenous arrays. Our results suggest that slight α-satellite sequence differences controls the structure and occupancy of the associated centromeric chromatin complex.
2018-01-31 | GSE104805 | GEO
Project description:We combined classical salt fractionation with chromatin immunoprecipitation to recover human centromeric chromatin under native conditions. We found that >85% of the total centromeric chromatin is insoluble under conditions typically used for native chromatin extraction. To map both soluble and insoluble chromatin in situ, we combined CUT&RUN (cleavage under targets and release using nuclease), a targeted nuclease method, with salt fractionation. Using this approach, we observed unexpected structural and conformational variations of centromere protein A (CENP-A)-containing complexes on different α-satellite dimeric units within highly homogenous arrays. Our results suggest that slight α-satellite sequence differences control the structure and occupancy of the associated centromeric chromatin complex.
| S-EPMC5828391 | biostudies-literature
Project description:Simple and Complex Centromeric Satellites in Drosophila Sibling Species
| PRJNA414639 | ENA
Project description:Centromeres are the chromosomal sites of assembly for kinetochores, the protein complexes that attach to spindle fibers and mediate separation of chromosomes to daughter cells in mitosis and meiosis. In most multicellular organisms, centromeres comprise a single specific family of tandem repeats, often 100-400 bp in length, found on every chromosome, typically in one location within heterochromatin. Drosophila melanogaster is unusual in that the heterochromatin contains many families of mostly short (5-12 bp) tandem repeats, none of which appears to be present at all centromeres, and none of which is found only at centromeres. Although centromere sequences from a minichromosome have been identified and candidate centromere sequences have been proposed, the DNA sequences at native Drosophila centromeres remain unknown. Here we use native chromatin immunoprecipitation to identify the centromeric sequences bound by the foundational kinetochore protein cenH3, known in vertebrates as CENP-A. In D. melanogaster, these sequences include a few families of 5-bp and 10-bp repeats, but in closely related D. simulans, a partially overlapping set of short repeats and more complex repeats comprise the centromeres. The results suggest that a recent expansion of short repeats is replacing more complex centromeric repeats in the melanogaster subgroup of Drosophila.
2018-01-08 | GSE105100 | GEO
Project description:In human cells chromosome specific aneuploidy was measured. Then, using NGS methods, centromeric features were measured for each chromosome (including centromere length and amount of centromeric proteins). The study aims at testing an association between centromeric features and missegregation rate.
2019-11-26 | GSE132193 | GEO
Project description:Centromeric chromatin in Koala
| PRJNA436016 | ENA
Project description:We report high throughput sequencing of DNA associated with centromeric chromatin in the koala genome.
2018-04-26 | GSE111153 | GEO
Project description:Faithful gamete formation during meiosis requires that kinetochores take on new functions that impact homolog pairing/recombination and their attachments to microtubules. We used a proteomics pipeline to determine the global composition of centromeric chromatin and kinetochores at distinct meiotic stages. Our datasets uncover an unanticipated role for the Ctf19CCAN inner kinetochore sub-complex in gametogenesis. We show that components of the Ctf19 complex that are dispensable for mitotic growth become critical for assembly of a functional kinetochore upon meiotic entry. Consequently, in the absence of these factors, chromosomes fail to attach to meiotic spindles and produce inviable gametes due to gross segregation errors. Our evidence suggests that functional kinetochore assembly is driven by Ctf19CCAN complex-dependent Ipl1AURORA B positioning at the inner kinetochore. Thus, our global view of kinetochore composition in meiosis reveals the extent of kinetochore remodelling during gametogenesis and uncovers a kinetochore assembly pathway that becomes critical in meiosis.
2021-02-23 | PXD019754 | Pride
Project description:Functional centromeres are essential for proper cell division. Centromeres are established largely by epigenetic processes resulting in incorporation of the histone H3 variant CENP-A. Here, we demonstrate the direct involvement of H2B monoubiquitination, mediated by RNF20 in humans or Brl1 in Schizosaccharomyces pombe, in centromeric chromatin maintenance. Monoubiquinated H2B (H2Bub1) is needed for this maintenance, promoting noncoding transcription, centromere integrity and accurate chromosomal segregation. A transient pulse of centromeric H2Bub1 leads to RNA polymerase II–mediated transcription of the centromere’s central domain, coupled to decreased H3 stability. H2Bub1-deficient cells have centromere cores that, despite their intact centromeric heterochromatin barriers, exhibit characteristics of heterochromatin, such as silencing histone modifications, reduced nucleosome turnover and reduced levels of transcription. In the H2Bub1-deficient cells, centromere functionality is hampered, thus resulting in unequal chromosome segregation. Therefore, centromeric H2Bub1 is essential for maintaining active centromeric chromatin.
2014-01-29 | GSE49874 | GEO
Project description:Chemical cross-linking coupled to mass spectrometry was used to study the architecture and conformational state(s) of the Drosophila melanogaster origin replication complex (ORC). Two versions of the ORC were subjected to cross-linking with the amine-reactive reagents, disuccinimidyl suberate (DSS). One was a complex with truncated subunits (“core complex”), one with full-length sequences of all six subunits (“full-length complex”).
2018-06-11 | PXD009526 | Pride