scholarly journals CDK-regulated dimerization of M18BP1 on a Mis18 hexamer is necessary for CENP-A loading

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Dongqing Pan ◽  
Kerstin Klare ◽  
Arsen Petrovic ◽  
Annika Take ◽  
Kai Walstein ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Histone H3 ◽  
G1 Phase ◽  
Cyclin Dependent Kinase ◽  
2A Peptide ◽  
Macromolecular Complexes ◽  
Histone H3 Variant ◽  
Genetic Features ◽  
Spindle Microtubules ◽  
Chromosomal Loci

Centromeres are unique chromosomal loci that promote the assembly of kinetochores, macromolecular complexes that bind spindle microtubules during mitosis. In most organisms, centromeres lack defined genetic features. Rather, they are specified epigenetically by a centromere-specific histone H3 variant, CENP-A. The Mis18 complex, comprising the Mis18α:Mis18β subcomplex and M18BP1, is crucial for CENP-A homeostasis. It recruits the CENP-A-specific chaperone HJURP to centromeres and primes it for CENP-A loading. We report here that a specific arrangement of Yippee domains in a human Mis18α:Mis18β 4:2 hexamer binds two copies of M18BP1 through M18BP1’s 140 N-terminal residues. Phosphorylation by Cyclin-dependent kinase 1 (CDK1) at two conserved sites in this region destabilizes binding to Mis18α:Mis18β, limiting complex formation to the G1 phase of the cell cycle. Using an improved viral 2A peptide co-expression strategy, we demonstrate that CDK1 controls Mis18 complex recruitment to centromeres by regulating oligomerization of M18BP1 through the Mis18α:Mis18β scaffold.

scholarly journals Ccp1-Ndc80 switch at the N terminus of CENP-T regulates kinetochore assembly

2021 ◽  
Vol 118 (48) ◽  
pp. e2104459118
Author(s):  
Qianhua Dong ◽  
Xue-lei Liu ◽  
Xiao-hui Wang ◽  
Yu Zhao ◽  
Yu-hang Chen ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Chromosome Segregation ◽  
Competitive Exclusion ◽  
Histone H3 ◽  
Cyclin Dependent Kinase ◽  
Null Mutant ◽  
Kinetochore Assembly ◽  
N Terminus ◽  
Ndc80 Complex ◽  
Histone H3 Variant

Kinetochores, a protein complex assembled on centromeres, mediate chromosome segregation. In most eukaryotes, centromeres are epigenetically specified by the histone H3 variant CENP-A. CENP-T, an inner kinetochore protein, serves as a platform for the assembly of the outer kinetochore Ndc80 complex during mitosis. How CENP-T is regulated through the cell cycle remains unclear. Ccp1 (counteracter of CENP-A loading protein 1) associates with centromeres during interphase but delocalizes from centromeres during mitosis. Here, we demonstrated that Ccp1 directly interacts with CENP-T. CENP-T is important for the association of Ccp1 with centromeres, whereas CENP-T centromeric localization depends on Mis16, a homolog of human RbAp48/46. We identified a Ccp1-interaction motif (CIM) at the N terminus of CENP-T, which is adjacent to the Ndc80 receptor motif. The CIM domain is required for Ccp1 centromeric localization, and the CIM domain–deleted mutant phenocopies ccp1Δ. The CIM domain can be phosphorylated by CDK1 (cyclin-dependent kinase 1). Phosphorylation of CIM weakens its interaction with Ccp1. Consistent with this, Ccp1 dissociates from centromeres through all stages of the cell cycle in the phosphomimetic mutant of the CIM domain, whereas in the phospho-null mutant of the domain, Ccp1 associates with centromeres during mitosis. We further show that the phospho-null mutant disrupts the positioning of the Ndc80 complex during mitosis, resulting in chromosome missegregation. This work suggests that competitive exclusion between Ccp1 and Ndc80 at the N terminus of CENP-T via phosphorylation ensures precise kinetochore assembly during mitosis and uncovers a previously unrecognized mechanism underlying kinetochore assembly through the cell cycle.

scholarly journals Depletion of KNL2 Results in Altered Expression of Genes Involved in Regulation of the Cell Cycle, Transcription, and Development in Arabidopsis

2019 ◽  
Vol 20 (22) ◽  
pp. 5726 ◽  
Author(s):  
Anastassia Boudichevskaia ◽  
Andreas Houben ◽  
Anne Fiebig ◽  
Klara Prochazkova ◽  
Ales Pecinka ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Critical Role ◽  
Histone H3 ◽  
Global Gene Expression ◽  
Proper Function ◽  
Knockout Mutant ◽  
Flower Bud ◽  
Altered Expression ◽  
Expression Of Genes ◽  
Histone H3 Variant

Centromeres contain specialized nucleosomes at which histone H3 is partially replaced by the centromeric histone H3 variant cenH3 that is required for the assembly, maintenance, and proper function of kinetochores during mitotic and meiotic divisions. Previously, we identified a KINETOCHORE NULL 2 (KNL2) of Arabidopsis thaliana that is involved in the licensing of centromeres for the cenH3 recruitment. We also demonstrated that a knockout mutant for KNL2 shows mitotic and meiotic defects, slower development, reduced growth rate, and fertility. To analyze an effect of KNL2 mutation on global gene transcription of Arabidopsis, we performed RNA-sequencing experiments using seedling and flower bud tissues of knl2 and wild-type plants. The transcriptome data analysis revealed a high number of differentially expressed genes (DEGs) in knl2 plants. The set was enriched in genes involved in the regulation of the cell cycle, transcription, development, and DNA damage repair. In addition to comprehensive information regarding the effects of KNL2 mutation on the global gene expression, physiological changes in plants are also presented, which provides an integrated understanding of the critical role played by KNL2 in plant growth and development.

scholarly journals Imaging the fate of histone Cse4 reveals de novo replacement in S phase and subsequent stable residence at centromeres

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Jan Wisniewski ◽  
Bassam Hajj ◽  
Jiji Chen ◽  
Gaku Mizuguchi ◽  
Hua Xiao ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Elevated Temperatures ◽  
De Novo ◽  
Histone H3 ◽  
S Phase ◽  
Nuclear Accumulation ◽  
Histone H3 Variant ◽  
Functionally Impaired ◽  
Cell Cycle Dynamics ◽  
Cell Lethality

The budding yeast centromere contains Cse4, a specialized histone H3 variant. Fluorescence pulse-chase analysis of an internally tagged Cse4 reveals that it is replaced with newly synthesized molecules in S phase, remaining stably associated with centromeres thereafter. In contrast, C-terminally-tagged Cse4 is functionally impaired, showing slow cell growth, cell lethality at elevated temperatures, and extra-centromeric nuclear accumulation. Recent studies using such strains gave conflicting findings regarding the centromeric abundance and cell cycle dynamics of Cse4. Our findings indicate that internally tagged Cse4 is a better reporter of the biology of this histone variant. Furthermore, the size of centromeric Cse4 clusters was precisely mapped with a new 3D-PALM method, revealing substantial compaction during anaphase. Cse4-specific chaperone Scm3 displays steady-state, stoichiometric co-localization with Cse4 at centromeres throughout the cell cycle, while undergoing exchange with a nuclear pool. These findings suggest that a stable Cse4 nucleosome is maintained by dynamic chaperone-in-residence Scm3.

scholarly journals Ser68 phosphoregulation is essential for CENP-A deposition, centromere function and viability in mice

2021 ◽  
Author(s):  
Yuting Liu ◽  
Kehui Wang ◽  
Li Huang ◽  
Jicheng Zhao ◽  
Xinpeng Chen ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Viability ◽  
Histone H3 ◽  
Dependent Manner ◽  
Centromere Function ◽  
Histone H3 Variant ◽  
A Cell ◽  
Cycle Dependent ◽  
Spatiotemporal Control

Centromere identity is defined by nucleosomes containing CENP-A, a histone H3 variant. The deposition of CENP-A at centromeres is tightly regulated in a cell-cycle-dependent manner. We previously reported that the spatiotemporal control of centromeric CENP-A incorporation is mediated by the phosphorylation of CENP-A Ser68. However, a recent report argued that Ser68 phosphoregulation is dispensable for accurate CENP-A loading. Here, we report that the substitution of Ser68 of endogenous CENP-A with either Gln68 or Glu68 severely impairs CENP-A deposition and cell viability. We also find that mice harboring the corresponding mutations are lethal. Together, these results indicate that the dynamic phosphorylation of Ser68 ensures cell-cycle-dependent CENP-A deposition and cell viability.

An expansion phase precedes terminal erythroid differentiation of hematopoietic progenitor cells from cord blood in vitro and is associated with up-regulation of cyclin E and cyclin-dependent kinase 2

Blood ◽  
2000 ◽  
Vol 96 (12) ◽  
pp. 3985-3987 ◽  
Author(s):  
Mu-Shui Dai ◽  
Charlie R. Mantel ◽  
Zhen-Biao Xia ◽  
Hal E. Broxmeyer ◽  
Li Lu
Keyword(s):  
Cell Cycle ◽  
Cord Blood ◽  
Cyclin E ◽  
Erythroid Differentiation ◽  
S Phase ◽  
Cyclin D3 ◽  
G1 Phase ◽  
Cyclin Dependent Kinase ◽  
Terminal Erythroid Differentiation

The dynamics of cell cycle regulation were investigated during in vitro erythroid proliferation and differentiation of CD34+cord blood cells. An unusual cell cycle profile with a majority of cells in S phase (70.2%) and minority of cells in G1 phase (27.4%) was observed in burst-forming unit-erythrocytes (BFU-E)–derived erythroblasts from a 7-day culture of CD34+ cells stimulated with interleukin 3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), Steel factor, and Epo. Terminal erythroid differentiation was accompanied by a rapid increase of G0/G1 phase cells. Expression of cyclin E and cyclin-dependent kinase 2 (cdk2) correlated with the proportion of S phase cells. Cyclin D3 was moderately up-regulated during the proliferation phase, and both cyclin E and D3 were rapidly down-regulated during terminal differentiation. This suggests that the high proliferation potential of erythroblasts is associated with temporal up-regulation of cyclin E and cdk2.

scholarly journals Subunit interactions and arrangements in the fission yeast Mis16–Mis18–Mis19 complex

2019 ◽  
Vol 2 (4) ◽  
pp. e201900408 ◽  
Author(s):  
Melanie Korntner-Vetter ◽  
Stéphane Lefèvre ◽  
Xiao-Wen Hu ◽  
Roger George ◽  
Martin R Singleton
Keyword(s):  
Cell Cycle ◽  
Binding Site ◽  
Fission Yeast ◽  
Histone H3 ◽  
Histone H4 ◽  
Subunit Interactions ◽  
Centromeric Chromatin ◽  
Partner Protein ◽  
Histone H3 Variant

Centromeric chromatin in fission yeast is distinguished by the presence of nucleosomes containing the histone H3 variant Cnp1CENP-A. Cell cycle–specific deposition of Cnp1 requires the Mis16–Mis18–Mis19 complex, which is thought to direct recruitment of Scm3-chaperoned Cnp1/histone H4 dimers to DNA. Here, we present the structure of the essential Mis18 partner protein Mis19 and describe its interaction with Mis16, revealing a bipartite-binding site. We provide data on the stoichiometry and overall architecture of the complex and provide detailed insights into the Mis18–Mis19 interface.

Inheritance of chromatin modifications through the cell cycle

2019 ◽  
pp. 184-190
Author(s):  
John C. Lucchesi
Keyword(s):  
Cell Cycle ◽  
Histone H3 ◽  
Parent Cell ◽  
Dna Repeats ◽  
Cpg Dinucleotides ◽  
Daughter Cells ◽  
Histone H3 Variant ◽  
Dna Strands ◽  
Non Coding Rnas ◽  
Transcriptional Landscape

Following mitosis, the particular transcriptional landscape of the parent cell must be faithfully transmitted to daughter cells. Although transcription ceases, not all transcription factors are displaced. DNA methylation has been implicated in the inheritance of chromatin characteristics because maintenance DNA methyl transferases methylate CpG dinucleotides on the newly replicated strand if the corresponding GpC on the parent strand is methylated. Nucleosomes that are deposited on the newly synthesized DNA strands are made up of old and new histones, and some marks present on the old histones are maintained. The proper distribution of nucleosomes and the topological organization of the genome into topologically associating domains (TADs) must be transmitted to daughter cells. Following DNA replication, centromeres must be specified on the daughter chromatids. In most eukaryotes, centromeres are identified by the presence of nucleosomes bearing the histone H3 variant CENP-A. An additional number of proteins and non-coding RNAs originating from centric and pericentromeric DNA repeats associate with centromeres and appear to play a role in centromere function.

scholarly journals Cdc28 Activates Exit from Mitosis in Budding Yeast

2000 ◽  
Vol 149 (7) ◽  
pp. 1361-1376 ◽  
Author(s):  
Adam D. Rudner ◽  
Kevin G. Hardwick ◽  
Andrew W. Murray
Keyword(s):  
Cell Cycle ◽  
Kinase Activity ◽  
Budding Yeast ◽  
G1 Phase ◽  
Phosphorylation Sites ◽  
Cyclin Dependent Kinase ◽  
Anaphase Promoting Complex ◽  
Reduced Activity

The activity of the cyclin-dependent kinase 1 (Cdk1), Cdc28, inhibits the transition from anaphase to G1 in budding yeast. CDC28-T18V, Y19F (CDC28-VF), a mutant that lacks inhibitory phosphorylation sites, delays the exit from mitosis and is hypersensitive to perturbations that arrest cells in mitosis. Surprisingly, this behavior is not due to a lack of inhibitory phosphorylation or increased kinase activity, but reflects reduced activity of the anaphase-promoting complex (APC), a defect shared with other mutants that lower Cdc28/Clb activity in mitosis. CDC28-VF has reduced Cdc20- dependent APC activity in mitosis, but normal Hct1- dependent APC activity in the G1 phase of the cell cycle. The defect in Cdc20-dependent APC activity in CDC28-VF correlates with reduced association of Cdc20 with the APC. The defects of CDC28-VF suggest that Cdc28 activity is required to induce the metaphase to anaphase transition and initiate the transition from anaphase to G1 in budding yeast.

scholarly journals Effective Potentials and Orbits in Weyl Conformastatic Slender Disk

2021 ◽  
Author(s):  
Paul Talbert ◽  
Steven Henikoff
Keyword(s):  
Cell Division ◽  
Dna Sequences ◽  
Histone H3 ◽  
Repeated Dna ◽  
Sequencing Technology ◽  
Repeated Dna Sequences ◽  
Effective Potentials ◽  
Histone H3 Variant ◽  
Long Read ◽  
Chromosomal Loci

Centromeres, the chromosomal loci where spindle fibers attach during cell division to segregate chromosomes, are typically found within satellite arrays in plants and animals. Satellite arrays have been difficult to analyze because they comprise megabases of tandem head-to-tail highly repeated DNA sequences. Much evidence suggests that centromeres are epigenetically defined by the location of nucleosomes containing the centromere-specific histone H3 variant cenH3, independently of the DNA sequences where they are located; however, the reason that cenH3 nucleosomes are generally found on rapidly evolving satellite arrays has remained unclear. Recently, long read sequencing technology has clarified the structures of satellite arrays and sparked rethinking of how they evolve, while new experiments and analyses have helped bring both understanding and further speculation about the role these highly repeated sequences play in centromere identification.

scholarly journals Genetic screening identifies a SUMO protease dynamically maintaining centromeric chromatin and the associated centromere complex

2019 ◽  
Author(s):  
Sreyoshi Mitra ◽  
Dani L. Bodor ◽  
Ana F. David ◽  
João F. Mata ◽  
Beate Neumann ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Genetic Screening ◽  
Chromatin Modification ◽  
Histone H3 ◽  
Centromeric Chromatin ◽  
Sumo Protease ◽  
Chromatin Regulators ◽  
Histone H3 Variant ◽  
Key Factor ◽  
Labeling Approach

AbstractCentromeres are defined by a unique self-propagating chromatin structure featuring nucleosomes containing the histone H3 variant CENP-A. CENP-A turns over slower than general chromatin and a key question is whether this unusual stability is intrinsic to CENP-A nucleosomes or rather imposed by external factors. We designed a specific genetic screen to identify proteins involved in CENP-A stability based on SNAP-tag pulse chase labeling. Using a double pulse-labeling approach we simultaneously assay for factors with selective roles in CENP-A chromatin assembly. We discover a series of new proteins involved in CENP-A propagation, including proteins with known roles in DNA replication, repair and chromatin modification and transcription, revealing that a broad set of chromatin regulators impacts in CENP-A transmission through the cell cycle. The key factor we find to strongly affect CENP-A stability is SENP6. This SUMO-protease controls not only the levels of chromatin bound CENP-A but is required for the maintenance of virtually the entire centromere and kinetochore, with the exception of CENP-B. Acute depletion of SENP6 protein reveals its requirement for maintaining centromeric CENP-A levels throughout the cell cycle, suggesting that a dynamic SUMO cycle underlies a continuous surveillance of the centromere complex.

Sign in / Sign up

Export Citation Format

Share Document