scholarly journals The Prolylhydroxylase PHD2 Modulates Centromere Function through the Hydroxylation of CENP-N

2015 ◽  
Author(s):  
Sandra C Moser ◽  
Dalila Bensaddek ◽  
Brian Ortmann ◽  
Sonia Rocha ◽  
Angus I Lamond ◽  
...  
Keyword(s):  
Sister Chromatid ◽  
Protein Complexes ◽  
Histone H3 ◽  
Attachment Site ◽  
Deficient Mutant ◽  
Multiprotein Complex ◽  
Centromere Function ◽  
Spindle Poles ◽  
Histone H3 Variant ◽  
Segregation Of Chromosomes

Successful segregation of chromosomes during mitosis requires that each sister chromatid is captured by microtubules emanating from opposite spindle poles. A multiprotein complex called the kinetochore provides an attachment site on chromosomes for microtubules. We have found that the prolylhydroxylase PHD2 is a critical regulator of the assembly of the kinetochore. PHD2 hydroxylates the kinetochore component CENP-N on P311 and is essential for CENP-N localization to kinetochores. Either depletion of PHD2, or expression of a hydroxylation-deficient mutant, results in loss of the histone H3 variant CENP-A from centromeres. Loss of CENP-N from chromatin bound protein complexes is not due to decreased protein stability but is a consequence of lowered affinity of CENP-N for binding CENP-L. Loss of hydroxylation also results in increased targeting of CENP-L to chromatin. Hydroxylation by PHD2 thus plays an important role in controlling the stoichiometry of mitotic kinetochore components.

The nucleosomes that mark centromere location on chromosomes old and new

2019 ◽  
Vol 63 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Craig W. Gambogi ◽  
Ben E. Black
Keyword(s):  
Dna Sequences ◽  
Critical Role ◽  
Histone H3 ◽  
Centromeric Dna ◽  
Artificial Chromosomes ◽  
Centromere Function ◽  
Histone H3 Variant ◽  
Dna Elements ◽  
Mitosis And Meiosis ◽  
Segregation Of Chromosomes

Abstract Proper segregation of chromosomes is an essential component of cell division. The centromere is the locus at which the kinetochore—the proteinaceous complex that ties chromosomes to microtubules—forms during mitosis and meiosis. Thus, the centromere is critical for equal segregation of chromosomes. The centromere is characterized by both protein and DNA elements: the histone H3 variant CENP-A epigenetically defines the location of the centromere while centromeric DNA sequences are neither necessary nor sufficient for centromere function. Paradoxically, the DNA sequences play a critical role in new centromere formation. In this essay, we discuss the contribution of both epigenetics and genetics at the centromere. Understanding these contributions is vital to efforts to control centromere formation on synthetic/artificial chromosomes and centromere strength on natural ones.

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.

scholarly journals ConnectingGCN5’s centromeric SAGA to the mitotic tension-sensing checkpoint

2018 ◽  
Vol 29 (18) ◽  
pp. 2201-2212 ◽  
Author(s):  
Emily L. Petty ◽  
Masha Evpak ◽  
Lorraine Pillus
Keyword(s):  
Chromosome Segregation ◽  
Sister Chromatid ◽  
Spindle Assembly Checkpoint ◽  
Binding Function ◽  
Chromatid Cohesion ◽  
Histone H3 Variant ◽  
Spindle Microtubules ◽  
Low Tension ◽  
Centromere Histone H3 ◽  
Segregation Of Chromosomes

Multiple interdependent mechanisms ensure faithful segregation of chromosomes during cell division. Among these, the spindle assembly checkpoint monitors attachment of spindle microtubules to the centromere of each chromosome, whereas the tension-sensing checkpoint monitors the opposing forces between sister chromatid centromeres for proper biorientation. We report here a new function for the deeply conserved Gcn5 acetyltransferase in the centromeric localization of Rts1, a key player in the tension-sensing checkpoint. Rts1 is a regulatory component of protein phopshatase 2A, a near universal phosphatase complex, which is recruited to centromeres by the Shugoshin (Sgo) checkpoint component under low-tension conditions to maintain sister chromatid cohesion. We report that loss of Gcn5 disrupts centromeric localization of Rts1. Increased RTS1 dosage robustly suppresses gcn5∆ cell cycle and chromosome segregation defects, including restoration of Rts1 to centromeres. Sgo1’s Rts1-binding function also plays a key role in RTS1 dosage suppression of gcn5∆ phenotypes. Notably, we have identified residues of the centromere histone H3 variant Cse4 that function in these chromosome segregation-related roles of RTS1. Together, these findings expand the understanding of the mechanistic roles of Gcn5 and Cse4 in chromosome segregation.

scholarly journals CENP-A nucleosome—a chromatin-embedded pedestal for the centromere: lessons learned from structural biology

2020 ◽  
Vol 64 (2) ◽  
pp. 205-221
Author(s):  
Ahmad Ali-Ahmad ◽  
Nikolina Sekulić
Keyword(s):  
Cell Division ◽  
Structural Biology ◽  
Histone H3 ◽  
Lessons Learned ◽  
Centromeric Chromatin ◽  
Centromere Proteins ◽  
Molecular Determinants ◽  
Histone H3 Variant ◽  
Segregation Of Chromosomes

Abstract The centromere is a chromosome locus that directs equal segregation of chromosomes during cell division. A nucleosome containing the histone H3 variant CENP-A epigenetically defines the centromere. Here, we summarize findings from recent structural biology studies, including several CryoEM structures, that contributed to elucidate specific features of the CENP-A nucleosome and molecular determinants of its interactions with CENP-C and CENP-N, the only two centromere proteins that directly bind to it. Based on those findings, we propose a role of the CENP-A nucleosome in the organization of centromeric chromatin beyond binding centromeric proteins.

scholarly journals Trans-generational inheritance of centromere identity requires the CENP-A N-terminal tail in the C. elegans maternal germ line

2020 ◽  
Author(s):  
Reinier F. Prosée ◽  
Joanna M. Wenda ◽  
Caroline Gabus ◽  
Kamila Delaney ◽  
Francoise Schwager ◽  
...  
Keyword(s):  
De Novo ◽  
Germ Line ◽  
Protein A ◽  
Histone H3 ◽  
Centromeric Chromatin ◽  
C Elegans ◽  
Centromere Function ◽  
Centromere Protein A ◽  
Histone H3 Variant ◽  
Meiosis I

AbstractCentromere protein A (CENP-A) is a histone H3 variant that defines centromeric chromatin and is essential for centromere function. In most eukaryotes CENP-A-containing chromatin is epigenetically maintained, and centromere identity is inherited from one cell cycle to the next. In the germ line of the holocentric nematode Caenorhabditis elegans, this inheritance cycle is disrupted. CENP-A is removed at the mitosis-to-meiosis transition and is established de novo on chromatin during diplotene of meiosis I. Here we show that the N-terminal tail of CENP-A is required for the de novo establishment of centromeres, but dispensable for centromere maintenance during embryogenesis. Worms homozygous for a CENP-A tail deletion maintain a functional centromere during development, but give rise to inviable offspring because they fail to re-establish centromeres in the maternal germ line. We identify the N-terminal tail of CENP-A as a critical domain for the interaction with the conserved kinetochore protein KNL-2, and argue that this interaction plays an important role in setting centromere identity in the germ line. We conclude that centromere establishment and maintenance are functionally distinct in C. elegans.

scholarly journals The role of heterochromatin in centromere function

2005 ◽  
Vol 360 (1455) ◽  
pp. 569-579 ◽  
Author(s):  
Alison L Pidoux ◽  
Robin C Allshire
Keyword(s):  
Fission Yeast ◽  
Histone H3 ◽  
Centromeric Heterochromatin ◽  
Chromatin Domain ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Centromere Function ◽  
Kinetochore Assembly ◽  
Histone H3 Variant

Chromatin at centromeres is distinct from the chromatin in which the remainder of the genome is assembled. Two features consistently distinguish centromeres: the presence of the histone H3 variant CENP-A and, in most organisms, the presence of heterochromatin. In fission yeast, domains of silent ‘heterochromatin’ flank the CENP-A chromatin domain that forms a platform upon which the kinetochore is assembled. Thus, fission yeast centromeres resemble their metazoan counterparts where the kinetochore is embedded in centromeric heterochromatin. The centromeric outer repeat chromatin is underacetylated on histones H3 and H4, and methylated on lysine 9 of histone H3, which provides a binding site for the chromodomain protein Swi6 (orthologue of Heterochromatin Protein 1, HP1). The remarkable demonstration that the assembly of repressive heterochromatin is dependent on the RNA interference machinery provokes many questions about the mechanisms of this process that may be tractable in fission yeast. Heterochromatin ensures that a high density of cohesin is recruited to centromeric regions, but it could have additional roles in centromere architecture and the prevention of merotely, and it might also act as a trigger for kinetochore assembly. In addition, we discuss an epigenetic model for ensuring that CENP-A is targeted and replenished at the kinetochore domain.

scholarly journals Both tails and the centromere targeting domain of CENP-A are required for centromere establishment

2015 ◽  
Vol 208 (5) ◽  
pp. 521-531 ◽  
Author(s):  
Glennis A. Logsdon ◽  
Evelyne J. Barrey ◽  
Emily A. Bassett ◽  
Jamie E. DeNizio ◽  
Lucie Y. Guo ◽  
...  
Keyword(s):  
Cell Division ◽  
Histone H3 ◽  
Lac Repressor ◽  
Chromosomal Locus ◽  
Gain Of Function ◽  
Lac Operator ◽  
Centromere Proteins ◽  
Histone H3 Variant ◽  
Segregation Of Chromosomes

The centromere—defined by the presence of nucleosomes containing the histone H3 variant, CENP-A—is the chromosomal locus required for the accurate segregation of chromosomes during cell division. Although the sequence determinants of human CENP-A required to maintain a centromere were reported, those that are required for early steps in establishing a new centromere are unknown. In this paper, we used gain-of-function histone H3 chimeras containing various regions unique to CENP-A to investigate early events in centromere establishment. We targeted histone H3 chimeras to chromosomally integrated Lac operator sequences by fusing each of the chimeras to the Lac repressor. Using this approach, we found surprising contributions from a small portion of the N-terminal tail and the CENP-A targeting domain in the initial recruitment of two essential constitutive centromere proteins, CENP-C and CENP-T. Our results indicate that the regions of CENP-A required for early events in centromere establishment differ from those that are required for maintaining centromere identity.

scholarly journals Hap2-Ino80 facilitated transcription promotes de novo establishment of CENP-A chromatin

2019 ◽  
Author(s):  
Puneet P. Singh ◽  
Manu Shukla ◽  
Sharon A. White ◽  
Pin Tong ◽  
Tatsiana Auchynnikava ◽  
...  
Keyword(s):  
Fission Yeast ◽  
De Novo ◽  
Histone H3 ◽  
Chromatin Assembly ◽  
Centromere Function ◽  
Kinetochore Assembly ◽  
Auxiliary Subunit ◽  
Evolutionarily Conserved ◽  
Histone H3 Variant ◽  
Chromatin Integrity

SUMMARYCentromeres 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 facilitates transcription from centromere DNA. These analyses suggest that Hap2-Ino80 destabilises H3 nucleosomes on centromere DNA through transcription-coupled 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.

scholarly journals Transgenerational inheritance of centromere identity requires the CENP-A N-terminal tail in the C. elegans maternal germ line

PLoS Biology ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. e3000968
Author(s):  
Reinier F. Prosée ◽  
Joanna M. Wenda ◽  
Isa Özdemir ◽  
Caroline Gabus ◽  
Kamila Delaney ◽  
...  
Keyword(s):  
De Novo ◽  
Germ Line ◽  
Protein A ◽  
Histone H3 ◽  
Transgenerational Inheritance ◽  
Centromeric Chromatin ◽  
C Elegans ◽  
Centromere Function ◽  
Centromere Protein A ◽  
Histone H3 Variant

Centromere protein A (CENP-A) is a histone H3 variant that defines centromeric chromatin and is essential for centromere function. In most eukaryotes, CENP-A-containing chromatin is epigenetically maintained, and centromere identity is inherited from one cell cycle to the next. In the germ line of the holocentric nematode Caenorhabditis elegans, this inheritance cycle is disrupted. CENP-A is removed at the mitosis-to-meiosis transition and is reestablished on chromatin during diplotene of meiosis I. Here, we show that the N-terminal tail of CENP-A is required for the de novo establishment of centromeres, but then its presence becomes dispensable for centromere maintenance during development. Worms homozygous for a CENP-A tail deletion maintain functional centromeres during development but give rise to inviable offspring because they fail to reestablish centromeres in the maternal germ line. We identify the N-terminal tail of CENP-A as a critical domain for the interaction with the conserved kinetochore protein KNL-2 and argue that this interaction plays an important role in setting centromere identity in the germ line. We conclude that centromere establishment and maintenance are functionally distinct in C. elegans.

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