Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Ccp1 homodimer mediates chromatin integrity by antagonizing CENP-A loading

ABSTRACT: CENP-A is a centromere-specific histone 3 variant essential for centromere specification. CENP-A partially replaces canonical histone H3 at the centromeres. How the particular CENP-A/H3 ratio at centromeres is precisely maintained is unknown. It also remains unclear how CENP-A is excluded from non-centromeric chromatin. Here we identify Ccp1, an uncharacterized NAP family protein in fission yeast that antagonizes CENP-A loading at both centromeric and non-centromeric regions. Like the CENP-A loading factor HJURP, Ccp1 interacts with CENP-A, and is recruited to centromeres at the end of mitosis in a Mis16-dependent manner. These data indicate that factors with opposing CENP-A loading activities are recruited to centromeres. Furthermore, Ccp1 also cooperates with H2A.Z to evict CENP-A assembled in euchromatin. Structural analyses indicate that Ccp1 forms a homodimer that is required for its anti-CENP-A loading activity. Our study establishes mechanisms for maintenance of CENP-A homeostasis at centromeres and the prevention of ectopic assembly of centromeres.

ORGANISM(S): Schizosaccharomyces pombe

PROVIDER: GSE85166 | GEO | 2016/08/04

SECONDARY ACCESSION(S): PRJNA336376

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Similar Datasets

Ccp1 homodimer mediates chromatin integrity by antagonizing CENP-A loading

Project description:CENP-A is a centromere-specific histone 3 variant essential for centromere specification. CENP-A partially replaces canonical histone H3 at the centromeres. How the particular CENP-A/H3 ratio at centromeres is precisely maintained is unknown. It also remains unclear how CENP-A is excluded from non-centromeric chromatin. Here we identify Ccp1, an uncharacterized NAP family protein in fission yeast that antagonizes CENP-A loading at both centromeric and non-centromeric regions. Like the CENP-A loading factor HJURP, Ccp1 interacts with CENP-A, and is recruited to centromeres at the end of mitosis in a Mis16-dependent manner. These data indicate that factors with opposing CENP-A loading activities are recruited to centromeres. Furthermore, Ccp1 also cooperates with H2A.Z to evict CENP-A assembled in euchromatin. Structural analyses indicate that Ccp1 forms a homodimer that is required for its anti-CENP-A loading activity. Our study establishes mechanisms for maintenance of CENP-A homeostasis at centromeres and the prevention of ectopic assembly of centromeres. Examination of cnp1 distribution in one wild type (wt) and two ccp1 mutants.

2016-08-04 | E-GEOD-85166 | biostudies-arrayexpress

DNA replication-mediated error correction of ectopic CENP-A deposition maintains centromere identity

Project description:Chromatin assembled with histone H3 variant CENP-A is the heritable epigenetic determinant of human centromere identity. Using genome-wide mapping and reference models for 23 human centromeres, CENP-A is shown in early G1 to be assembled into nucleosomes within megabase, repetitive a-satellite DNAs at each centromere and onto 11,390 sites on the chromosome arms. Centromere-bound CENP-A is found to be quantitatively maintained during DNA replication by coordinated action of the MCM2 helicase, CAF1, HJURP, and the CCAN network of constitutive centromere components. CCAN serves to tether CENP-A removed by MCM2, thereby enabling local reassembly onto both daughter centromeres with identical DNA sequence preferences and nucleosome phasing as the loading in G1 and independent of CENP-B. Conversely, without CCAN-mediated tethering, DNA replication removes CENP-A from sites on the chromosome arms. Our data identify an MCM2/CAF1/HJURP- and CCAN-dependent error correction mechanism that acts in S-phase to maintain CENP-A-dependent centromere identity.

2019-03-20 | GSE111381 | GEO

Direct recruitment of Mis18 to interphase spindle poles promotes CENP-A chromatin assembly.

Project description:CENP-A chromatin specifies mammalian centromere identity, and its chaperone HJURP replenishes CENP-A when recruited by the Mis18 complex (Mis18C) via M18BP/KNL2 to CENP-C at kinetochores during interphase. However, the Mis18C recruitment mechanism remains unresolved in species lacking M18BP1, such as fission yeast. Fission yeast centromeres cluster at G2 spindle pole bodies (SPBs) when CENP-ACnp1 is replenished and where Mis18C also localizes. We show that SPBs play an unexpected role in concentrating Mis18C near centromeres through the recruitment of Mis18 by direct binding to the major SPB LInker of Nucleoskeleton and Cytoskeleton (LINC) complex component Sad1. Mis18 recruitment by Sad1 is important for CENP-ACnp1 chromatin establishment and acts in parallel with a CENP-C-mediated Mis18C recruitment pathway to maintain centromeric CENP-ACnp1, but is independent of Sad1-mediated centromere clustering. SPBs therefore provide a non-chromosomal scaffold for both Mis18C recruitment and centromere clustering during G2. This centromere-independent Mis18-SPB recruitment provides a mechanism that governs de novo CENP-ACnp1 chromatin assembly by the proximity of appropriate sequences to SPBs and highlights how nuclear spatial organization influences centromere identity.

2023-09-18 | PXD045191 | Pride

The Ino80 complex mediates epigenetic centromere propagation via active removal of histone H3

Project description:Centromere is the chromosomal locus at which kinetochore is assembled to direct chromosome segregation. Histone H3 variant CENP-A epigenetically marks active centromeres; however, the mechanism by which CENP-A propagates at the centromere, replacing histone H3, remains poorly understood. Using fission yeast, we find that CENP-ACnp1 chromatin assembly at the centromere requires the Ino80 ATP-dependent chromatin remodeling complex which removes histone H3-containing nucleosomes from associated chromatin. CENP-ACnp1 chromatin actively recruits the Ino80 complex to centromeres to elicit eviction of histone H3-containing nucleosomes. Artificial targeting of Ino80 subunits to a non-centromeric DNA placed in a native centromere enhances the spreading of CENP-ACnp1 chromatin into the non-centromeric DNA. Based on these results, we propose that CENP-ACnp1 chromatin employs the Ino80 complex to mediate replacement of histone H3 with CENP-ACnp1, and thereby reinforces itself.

2017-07-14 | GSE99589 | GEO

Identification of HJURP binding determinants on the Mis18 complex using photo-cross-linking and mass spectrometry

Project description:In the early G1 phase of the cell cycle, human HJURP is recruited to centromeres by the Mis18 complex, which consists of Mis18α, Mis18β and M18BP1. This interaction of HJURP with the Mis18 complex is essential for CENP-A deposition and the preservation of centromere identity. To identify the binding site of HJURP on the Mis18 complex, we used the amber-codon suppression method to incorporate unnatural photo-cross-linking amino acids (Bpa, p-benzoyl-L-phenylalanine; AbK, 3’-azibutyl-N-carbamoyl-lysine) and performed UV-cross-linking and mass spectrometry (MS) experiments.

2019-08-01 | PXD013339 | Pride

The N-terminal Tail of CENP-A Confers Epigenetic Stability to Centromeres via the CENP-T Branch of the CCAN in Fission Yeast

Project description:We employ the well-studied fission yeast centromere to investigate the function of the CENP-A (Cnp1) N-tail. We show that alteration of the N-tail did not affect Cnp1 loading at centromeres, outer kinetochore formation, or spindle checkpoint signaling, but nevertheless elevated chromosome loss. N-Tail mutants exhibited synthetic lethality with an altered centromeric DNA sequence, with rare survivors harboring chromosomal fusions in which the altered centromere was epigenetically inactivated. Elevated centromere inactivation was also observed for N-tail mutants with unaltered centromeric DNA sequences. N-tail mutants specifically reduced localization of the CCAN proteins Cnp20/CENP-T and Mis6/CENP-I, but not Cnp3/CENP-C. Overexpression of Cnp20/CENP-T suppressed defects in an N-tail mutant, suggesting a causal link between reduced CENP-T recruitment and the observed centromere inactivation phenotype. Thus, the Cnp1 N-tail promotes epigenetic stability of centromeres via recruitment of the CENP-T branch of the CCAN. Genome-wide localization of GFP-tagged N-tail Cnp1 variant tailswap versus wt control in cnp1 deletion background

2015-04-16 | E-GEOD-63350 | biostudies-arrayexpress

CENP-A chaperone Scm3HJURP contains a cysteine-rich domain required for centromere targeting and kinetochore integrity

Project description:Centromeric chromatin is crucial for supporting kinetochore assembly and chromosome segregation. To specify centromeres, the histone H3 variant CENP-A is loaded by the conserved chaperone Scm3/HJURP. The amino-terminus of Scm3/HJURP interacts with CENP-A, while the carboxyl-terminus contains a small domain that interacts with the Mis18 holocomplex, which facilitates centromere localization. Fungal Scm3 proteins contain an additional conserved cysteine-rich domain (CYS) with unknown function. In this study, we found that CYS is essential for the localization and function of fission yeast Scm3. Disrupting CYS prevents Scm3 from localizing to the centromere and results in cell lethality. Moreover, introducing point mutations in a predicted zinc-binding motif within CYS hinders Scm3 centromere targeting and kinetochore integrity, consistent with structural evidence that CYS binds zinc. We find that expressing only the Scm3 carboxyl-terminus is harmful as it localizes to centromeres and causes defective kinetochores. Remarkably, mutating the CYS zinc-binding motif in this construct eliminates the observed centromere localization and toxicity. Together, our findings establish this cysteine-rich domain with predicted zinc-binding capability as an essential feature of fungal Scm3 proteins and shed new light on the molecular mechanism for targeting Scm3 to centromeres.

2024-03-06 | GSE231729 | GEO

Swr1 mediated H2A.ZPht1 incorporation designates centromere DNA for de novo CENP-ACnp1 assembly

Project description:The centromere is the location on each chromosome that directs the assembly of the kinetochore. The underlying hallmark of centromeres in most eukaryotes is the presence of specialised nucleosomes in which canonical histone H3 is replaced by the histone H3 variant CENP-A. The molecular events that mediate a programme to install CENP-A in place of histone H3, at centromeres and how the centromeric chromatin is reorganised for CENP-A assembly during cell cycle remain poorly characterised. Histone H2A variant, H2A.Z is linked to transcriptional competence, in maintaining heterochromatin silencing and enriched in CENP-A chromatin. Our analyses demonstrate that H2A.ZPht1 and the Swr1 complex are associated with CENP-ACnp1 chromatin in fission yeast. Swr1 and Msc1 regulate H2A.ZPht1 deposition at centromeres and along with H2A.ZPht1 maintain CENP-ACnp1 chromatin integrity. Additionally, they coordinate the deposition of CENP-ACnp1 through the cell cycle, coupled with eviction of histone H3 from centromeres. Based on our results, we propose that the centromere is programmed to the widespread incorporation of H2A.ZPht1 via Swr1, and that H2A.ZPht1 dynamics likely play a role in regulating centromeric chromatin by influencing CENP-A incorporation.

2020-12-01 | GSE106585 | GEO

Epigenetically induced paucity of histone H2A.Z stabilizes fission yeast ectopic centromeres

Project description:In most eukaryotes, the centromere is epigenetically defined by nucleosomes that contain the histone H3 variant centromere protein A (CENP-A). Specific targeting of the CENP-A-loading chaperone to the centromere is vital for stable centromere propagation; however, the existence of ectopic centromeres (neocentromeres) indicates that this chaperone can function in different chromatin environments. The mechanism responsible for accommodating the CENP-A chaperone at novel chromatin regions is poorly understood. Here, we report the identification of transient, immature neocentromeres in Schizosaccharomyces pombe, which show reduced association with the CENP-A chaperone Scm3 attributable to persistence of the histone H2A variant H2A.Z. Following acquisition of adjacent heterochromatin or relocation of the immature neocentromeres to subtelomeric regions, H2A.Z was depleted and Scm3 was replenished, leading to subsequent stabilization of the neocentromeres. These findings provide novel insights into histone variant-mediated epigenetic control of neocentromere establishment. Comparison of chromosomal distributions of centromeric proteins and heterochromatin proteins between the NC survivors and their derivatives.

2013-11-03 | E-GEOD-37094 | biostudies-arrayexpress

Hap2-Ino80 mediated transcription facilitates de novo establishment of CENP-A chromatin

Project description:Centromeres are maintained epigenetically by the presence of CENP-A, an evolutionarily-conserved histone H3 variant, which directs kinetochore assembly and hence, centromere function. To identify factors that promote assembly of CENP-A chromatin, we affinity selected solubilised fission yeast CENP-ACnp1 chromatin. All subunits of the Ino80 complex were enriched, including the auxiliary subunit Hap2. In addition to a role in maintenance of CENP-ACnp1 chromatin integrity at endogenous centromeres, Hap2 is required for de novo assembly of CENP-ACnp1 chromatin on naïve centromere DNA and promotes H3 turnover on centromere regions and other loci prone to CENP-ACnp1 deposition. Prior to CENP-ACnp1 chromatin assembly, Hap2 is required for transcription from centromere DNA. These analyses suggest that Hap2-Ino80 destabilises H3 nucleosomes on centromere DNA through transcription-mediated histone H3 turnover, driving the replacement of resident H3 nucleosomes with CENP-ACnp1 nucleosomes. These inherent properties define centromere DNA by directing a program that mediates CENP-ACnp1 assembly on appropriate sequences.

2020-05-27 | PXD016602 | Pride

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data