bims-micesi 2022-06-26 papers

bims-micesi

Biomed News

on Mitotic cell signalling

Issue of 2022–06–26
fourteen papers selected by
Valentina Piano, Max Planck Institute of Molecular Physiology

Centromere Identity and the Regulation of Chromosome Segregation.
Wnt signalling in cell division: from mechanisms to tissue engineering.
A CDK activity buffer ensures mitotic completion.
Cytotoxicity of 9,10-Phenanthrenequinone Impairs Mitotic Progression and Spindle Assembly Independent of ROS Production in HeLa Cells.
CENP-A Regulation and Cancer.
DDK: The Outsourced Kinase of Chromosome Maintenance.
Pathogenic mutations in the chromokinesin KIF22 disrupt anaphase chromosome segregation.
Centromere drive: model systems and experimental progress.
Spindle reorientation in response to mechanical stress is an emergent property of the spindle positioning mechanisms.
The Highest Density of Phosphorylated Histone H1 Appeared in Prophase and Prometaphase in Parallel with Reduced H3K9me3, and HDAC1 Depletion Increased H1.2/H1.3 and H1.4 Serine 38 Phosphorylation.
Paradox lost: Concerted evolution and centromeric instability: Centromeres are hospitable habitats for repeats that evolve adaptations for proliferation within the nucleus sometimes at organismal cost.: Centromeres are hospitable habitats for repeats that evolve adaptations for proliferation within the nucleus sometimes at organismal cost.
Cell biology: How to short-circuit the cell cycle.
ROS-independent cytotoxicity of 9,10-phenanthrenequinone inhibits cell cycle progression and spindle assembly during meiotic maturation in mouse oocytes.
Investigating Mitotic Inheritance of Histone Posttranslational Modifications by Triple pSILAC Coupled to Nascent Chromatin Capture.

Front Cell Dev Biol. 2022 ;10 914249

Centromere Identity and the Regulation of Chromosome Segregation.

Kousik Sundararajan, Aaron F Straight.

  Eukaryotes segregate their chromosomes during mitosis and meiosis by attaching chromosomes to the microtubules of the spindle so that they can be distributed into daughter cells. The complexity of centromeres ranges from the point centromeres of yeast that attach to a single microtubule to the more complex regional centromeres found in many metazoans or holocentric centromeres of some nematodes, arthropods and plants, that bind to dozens of microtubules per kinetochore. In vertebrates, the centromere is defined by a centromere specific histone variant termed Centromere Protein A (CENP-A) that replaces histone H3 in a subset of centromeric nucleosomes. These CENP-A nucleosomes are distributed on long stretches of highly repetitive DNA and interspersed with histone H3 containing nucleosomes. The mechanisms by which cells control the number and position of CENP-A nucleosomes is unknown but likely important for the organization of centromeric chromatin in mitosis so that the kinetochore is properly oriented for microtubule capture. CENP-A chromatin is epigenetically determined thus cells must correct errors in CENP-A organization to prevent centromere dysfunction and chromosome loss. Recent improvements in sequencing complex centromeres have paved the way for defining the organization of CENP-A nucleosomes in centromeres. Here we discuss the importance and challenges in understanding CENP-A organization and highlight new discoveries and advances enabled by recent improvements in the human genome assembly.

Keywords:  CENP-A; alpha satellite; centromere; chromatin; epigenetics

DOI:  https://doi.org/10.3389/fcell.2022.914249
Trends Cell Biol. 2022 Jun 15. pii: S0962-8924(22)00137-4. [Epub ahead of print]

Wnt signalling in cell division: from mechanisms to tissue engineering.

Shukry J Habib, Sergio P Acebrón.

  Wnt signalling is an essential player in tissue formation, notably in the regulation of stem cell function. Wnt signalling is best known for its roles in G1/S progression. However, a complex Wnt programme that also mediates mitotic progression and asymmetric cell division (ACD) is emerging. Recent developments in this area have provided mechanistic insights as well as tools to engineer or target Wnt signalling for translational and therapeutic purposes. Here, we discuss the bidirectional relationship between Wnt activity and mitosis. We emphasise how various Wnt-dependent mechanisms control spindle dynamics, chromosome segregation, and ACD. Finally, we illustrate how knowledge about these mechanisms has been successfully employed in tissue engineering for regenerative medicine applications.

Keywords:  asymmetric cell division; bioengineering; chromosome segregation; localised Wnt signalling; spindle orientation; stem cells

DOI:  https://doi.org/10.1016/j.tcb.2022.05.006
J Cell Sci. 2022 Jun 15. pii: jcs259626. [Epub ahead of print]135(12):

A CDK activity buffer ensures mitotic completion.

Souradeep Basu, James O Patterson, Theresa U Zeisner, Paul Nurse.

  The eukaryotic cell cycle is driven by the activity of cyclin-dependent kinases (CDKs). CDK activity rises over 50-fold during the cell cycle, from a low level in G1 to a high level in mitosis. However, it is not known whether the entire range of CDK activity is necessary for cell cycle progression, or whether cells can tolerate a reduction in CDK activity level. Here, in fission yeast, we show that sublethal CDK inhibition lengthens the time cells spend in mitosis but does not cause misordering of mitotic events. Maximum attainable CDK activity exceeds the amount necessary for mitosis, and thus forms a CDK activity buffer between sufficient and maximal possible CDK activities. This CDK activity buffer is needed for mitotic completion when CDK activity is compromised, and CDK inhibition only becomes lethal to cells when this buffer is exhausted. Finally, we explore what factors influence this CDK activity buffer, and find that it is influenced by CDK-counteracting phosphatases. Therefore, maximum attainable CDK activity is not necessary for mitosis but provides robustness to CDK activity reduction to ensure mitotic completion.

Keywords:   Schizosaccharomyces pombe ; CDK inhibitor; Cdk1; Cyclin-dependent kinase; Kinase activity; Mitosis

DOI:  https://doi.org/10.1242/jcs.259626
Toxics. 2022 Jun 16. pii: 327. [Epub ahead of print]10(6):

Cytotoxicity of 9,10-Phenanthrenequinone Impairs Mitotic Progression and Spindle Assembly Independent of ROS Production in HeLa Cells.

Seul Kim, Jiyeon Leem, Jeong Su Oh, Jae-Sung Kim.

  The polycyclic aromatic hydrocarbon quinone derivative 9,10-phenanthrenequinone (9,10-PQ) is one of the most abundant and toxic components found in diesel exhaust particles (DEPs). These DEPs are created during diesel fuel combustion and are considered the main source of urban air pollution. As 9,10-PQ can produce excessive reactive oxygen species (ROS) through redox cycling, it has been shown to exert potent cytotoxic effects against various cell types. However, the mechanisms underlying this cytotoxicity remain unclear. In this study, we showed that 9,10-PQ exerts cytotoxicity by impairing mitotic progression and spindle assembly in HeLa cells. Exposure to 9,10-PQ impaired spindle assembly and chromosome alignment, resulting in delayed mitotic entry and progression in HeLa cells. Furthermore, 9,10-PQ exposure decreased the CEP192 and p-Aurora A levels at the spindle poles. Notably, these mitotic defects induced by 9,10-PQ were not rescued by scavenging ROS, implying the ROS-independent activity of 9,10-PQ. Therefore, our results provide the first evidence that 9,10-PQ exerts its cytotoxicity through specific inhibition of mitotic progression and spindle assembly, independent of ROS.

Keywords:  9,10-phenanthrenanquinone; HeLa cells; mitosis; reactive oxidative stress; spindle assembly

DOI:  https://doi.org/10.3390/toxics10060327
Front Cell Dev Biol. 2022 ;10 907120

CENP-A Regulation and Cancer.

Charlène Renaud-Pageot, Jean-Pierre Quivy, Marina Lochhead, Geneviève Almouzni.

  In mammals, CENP-A, a histone H3 variant found in the centromeric chromatin, is critical for faithful chromosome segregation and genome integrity maintenance through cell divisions. Specifically, it has dual functions, enabling to define epigenetically the centromere position and providing the foundation for building up the kinetochore. Regulation of its dynamics of synthesis and deposition ensures to propagate proper centromeres on each chromosome across mitosis and meiosis. However, CENP-A overexpression is a feature identified in many cancers. Importantly, high levels of CENP-A lead to its mislocalization outside the centromere. Recent studies in mammals have begun to uncover how CENP-A overexpression can affect genome integrity, reprogram cell fate and impact 3D nuclear organization in cancer. Here, we summarize the mechanisms that orchestrate CENP-A regulation. Then we review how, beyond its centromeric function, CENP-A overexpression is linked to cancer state in mammalian cells, with a focus on the perturbations that ensue at the level of chromatin organization. Finally, we review the clinical interest for CENP-A in cancer treatment.

Keywords:  CENP-A histone variant; cancer; centromere; chromatin organization; chromosome instability

DOI:  https://doi.org/10.3389/fcell.2022.907120
Biology (Basel). 2022 Jun 07. pii: 877. [Epub ahead of print]11(6):

DDK: The Outsourced Kinase of Chromosome Maintenance.

Peter J Gillespie, J Julian Blow.

  The maintenance of genomic stability during the mitotic cell-cycle not only demands that the DNA is duplicated and repaired with high fidelity, but that following DNA replication the chromatin composition is perpetuated and that the duplicated chromatids remain tethered until their anaphase segregation. The coordination of these processes during S phase is achieved by both cyclin-dependent kinase, CDK, and Dbf4-dependent kinase, DDK. CDK orchestrates the activation of DDK at the G1-to-S transition, acting as the 'global' regulator of S phase and cell-cycle progression, whilst 'local' control of the initiation of DNA replication and repair and their coordination with the re-formation of local chromatin environments and the establishment of chromatid cohesion are delegated to DDK. Here, we discuss the regulation and the multiple roles of DDK in ensuring chromosome maintenance. Regulation of replication initiation by DDK has long been known to involve phosphorylation of MCM2-7 subunits, but more recent results have indicated that Treslin:MTBP might also be important substrates. Molecular mechanisms by which DDK regulates replisome stability and replicated chromatid cohesion are less well understood, though important new insights have been reported recently. We discuss how the 'outsourcing' of activities required for chromosome maintenance to DDK allows CDK to maintain outright control of S phase progression and the cell-cycle phase transitions whilst permitting ongoing chromatin replication and cohesion establishment to be completed and achieved faithfully.

Keywords:  CDK; DDK; DNA repair; DNA replication; chromatid cohesion; epigenetic inheritance; replication fork stability

DOI:  https://doi.org/10.3390/biology11060877
Elife. 2022 Jun 22. pii: e78653. [Epub ahead of print]11

Pathogenic mutations in the chromokinesin KIF22 disrupt anaphase chromosome segregation.

Alex F Thompson, Patrick R Blackburn, Noah S Arons, Sarah N Stevens, Dusica Babovic-Vuksanovic, Jane B Lian, Eric W Klee, Jason Stumpff.

  The chromokinesin KIF22 generates forces that contribute to mitotic chromosome congression and alignment. Mutations in the a2 helix of the motor domain of KIF22 have been identified in patients with abnormal skeletal development, and we report the identification of a patient with a novel mutation in the KIF22 tail. We demonstrate that pathogenic mutations do not result in a loss of KIF22's functions in early mitosis. Instead, mutations disrupt chromosome segregation in anaphase, resulting in reduced proliferation, abnormal daughter cell nuclear morphology, and, in a subset of cells, cytokinesis failure. This phenotype could be explained by a failure of KIF22 to inactivate in anaphase. Consistent with this model, constitutive activation of the motor via a known site of phosphoregulation in the tail phenocopied the effects of pathogenic mutations. These results suggest the motor domain a2 helix may be an important site for regulation of KIF22 activity at the metaphase to anaphase transition. In support of this conclusion, mimicking phosphorylation of a2 helix residue T158 also prevents inactivation of KIF22 in anaphase. These findings demonstrate the importance of both the head and tail of the motor in regulating the activity of KIF22 and offer insight into the cellular consequences of preventing KIF22 inactivation and disrupting force balance in anaphase.

Keywords:  cell biology; human

DOI:  https://doi.org/10.7554/eLife.78653
Chromosome Res. 2022 Jun 22.

Centromere drive: model systems and experimental progress.

Damian Dudka, Michael A Lampson.

  Centromeres connect chromosomes and spindle microtubules to ensure faithful chromosome segregation. Paradoxically, despite this conserved function, centromeric DNA evolves rapidly and centromeric proteins show signatures of positive selection. The centromere drive hypothesis proposes that centromeric DNA can act like a selfish genetic element and drive non-Mendelian segregation during asymmetric female meiosis. Resulting fitness costs lead to genetic conflict with the rest of the genome and impose a selective pressure for centromeric proteins to adapt by suppressing the costs. Here, we describe experimental model systems for centromere drive in yellow monkeyflowers and mice, summarize key findings demonstrating centromere drive, and explain molecular mechanisms. We further discuss efforts to test if centromeric proteins are involved in suppressing drive-associated fitness costs, highlight a model for centromere drive and suppression in mice, and put forth outstanding questions for future research.

Keywords:  centromere; centromere drive; meiosis; molecular evolution; non-Mendelian chromosome segregation; positive selection

DOI:  https://doi.org/10.1007/s10577-022-09696-3
Proc Natl Acad Sci U S A. 2022 Jun 28. 119(26): e2121868119

Spindle reorientation in response to mechanical stress is an emergent property of the spindle positioning mechanisms.

Manasi Kelkar, Pierre Bohec, Matthew B Smith, Varun Sreenivasan, Ana Lisica, Léo Valon, Emma Ferber, Buzz Baum, Guillaume Salbreux, Guillaume Charras.

  Proper orientation of the mitotic spindle plays a crucial role in embryos, during tissue development, and in adults, where it functions to dissipate mechanical stress to maintain tissue integrity and homeostasis. While mitotic spindles have been shown to reorient in response to external mechanical stresses, the subcellular cues that mediate spindle reorientation remain unclear. Here, we used a combination of optogenetics and computational modeling to investigate how mitotic spindles respond to inhomogeneous tension within the actomyosin cortex. Strikingly, we found that the optogenetic activation of RhoA only influences spindle orientation when it is induced at both poles of the cell. Under these conditions, the sudden local increase in cortical tension induced by RhoA activation reduces pulling forces exerted by cortical regulators on astral microtubules. This leads to a perturbation of the balance of torques exerted on the spindle, which causes it to rotate. Thus, spindle rotation in response to mechanical stress is an emergent phenomenon arising from the interaction between the spindle positioning machinery and the cell cortex.

Keywords:  RhoA; cell cortex; mechanics; optogenetics; spindle orientation

DOI:  https://doi.org/10.1073/pnas.2121868119
Life (Basel). 2022 May 27. pii: 798. [Epub ahead of print]12(6):

The Highest Density of Phosphorylated Histone H1 Appeared in Prophase and Prometaphase in Parallel with Reduced H3K9me3, and HDAC1 Depletion Increased H1.2/H1.3 and H1.4 Serine 38 Phosphorylation.

Soňa Legartová, Gabriela Lochmanová, Eva Bártová.

   BACKGROUND: Variants of linker histone H1 are tissue-specific and are responsible for chromatin compaction accompanying cell differentiation, mitotic chromosome condensation, and apoptosis. Heterochromatinization, as the main feature of these processes, is also associated with pronounced trimethylation of histones H3 at the lysine 9 position (H3K9me3).
METHODS: By confocal microscopy, we analyzed cell cycle-dependent levels and distribution of phosphorylated histone H1 (H1ph) and H3K9me3. By mass spectrometry, we studied post-translational modifications of linker histones.
RESULTS: Phosphorylated histone H1, similarly to H3K9me3, has a comparable level in the G1, S, and G2 phases of the cell cycle. A high density of phosphorylated H1 was inside nucleoli of mouse embryonic stem cells (ESCs). H1ph was also abundant in prophase and prometaphase, while H1ph was absent in anaphase and telophase. H3K9me3 surrounded chromosomal DNA in telophase. This histone modification was barely detectable in the early phases of mitosis. Mass spectrometry revealed several ESC-specific phosphorylation sites of H1. HDAC1 depletion did not change H1 acetylation but potentiated phosphorylation of H1.2/H1.3 and H1.4 at serine 38 positions.
CONCLUSIONS: Differences in the level and distribution of H1ph and H3K9me3 were revealed during mitotic phases. ESC-specific phosphorylation sites were identified in a linker histone.

Keywords:  chromatin; epigenetic; histone H1; histone H3; mass spectrometry; nucleolus

DOI:  https://doi.org/10.3390/life12060798
Bioessays. 2022 Jun 24. e2200023

Paradox lost: Concerted evolution and centromeric instability: Centromeres are hospitable habitats for repeats that evolve adaptations for proliferation within the nucleus sometimes at organismal cost.: Centromeres are hospitable habitats for repeats that evolve adaptations for proliferation within the nucleus sometimes at organismal cost.

David Haig.

  Homologous centromeres compete for segregation to the secondary oocyte nucleus at female meiosis I. Centromeric repeats also compete with each other to populate centromeres in mitotic cells of the germline and have become adapted to use the recombinational machinery present at centromeres to promote their own propagation. Repeats are not needed at centromeres, rather centromeres appear to be hospitable habitats for the colonization and proliferation of repeats. This is probably an indirect consequence of two distinctive features of centromeric DNA. Centromeres are subject to breakage by the mechanical forces exerted by microtubules and meiotic crossing-over is suppressed. Centromeric proteins acting in trans are under selection to mitigate the costs of centromeric repeats acting in cis. Collateral costs of mitotic competition at centromeres may help to explain the high rates of aneuploidy observed in early human embryos.

Keywords:  CENP-B; aneuploidy; centromere; centromeric drive; concerted evolution; intragenomic conflict

DOI:  https://doi.org/10.1002/bies.202200023
Curr Biol. 2022 Jun 20. pii: S0960-9822(22)00772-2. [Epub ahead of print]32(12): R561-R563

Cell biology: How to short-circuit the cell cycle.

Michael L Goldberg, Gemunu H Gunaratne.

Although the cell cycle normally progresses from G1toStoG2toM and then back to G1, certain manipulations have been found to 'short circuit' the cycle, causing repetitions of some stages while skipping others. A new study suggests how these changes limit the actions of molecular 'latches' that normally ensure orderly cell cycle progression.

DOI: https://doi.org/10.1016/j.cub.2022.05.013
J Hazard Mater. 2022 Aug 15. pii: S0304-3894(22)01038-X. [Epub ahead of print]436 129248

ROS-independent cytotoxicity of 9,10-phenanthrenequinone inhibits cell cycle progression and spindle assembly during meiotic maturation in mouse oocytes.

Jiyeon Leem, Seul Kim, Jae-Sung Kim, Jeong Su Oh.

  Diesel exhaust particles (DEPs) are major components of ambient particulate matter and are associated with various adverse health effects. Typically, DEPs contain a vast number of organic compounds, among which 9,10-phenanthrenequinone (9,10-PQ), the quinone derivative of the polycyclic aromatic hydrocarbon phenanthrene, is one of the most abundant and toxic. 9,10-PQ can produce excessive reactive oxygen species (ROS) via redox cycling and exhibit cytotoxicity in various cells. However, the underlying mechanisms involved in cytotoxicity of 9,10-PQ remain elusive. In this study, we investigated the effects of exposure to 9,10-PQ using mouse oocytes as a model system. We found that 9,10-PQ compromised meiotic maturation by impairing acentriolar microtubule organizing center (MTOC) assembly and subsequent spindle formation during meiotic maturation. Moreover, 9,10-PQ exposure prevented cell cycle progression by inhibiting Cdk1 activation via disturbance of cyclin B1 accumulation. Importantly, meiotic defects induced by 9,10-PQ exposure were not rescued by decreasing ROS levels, revealing that 9,10-PQ has ROS-independent activity that regulates cell cycle progression and spindle assembly. Therefore, our findings reveal that 9,10-PQ has novel activity that regulates cell-cycle progression and spindle formation in an ROS-independent manner during meiotic maturation in mouse oocytes.

Keywords:  9,10-phenanthrenanquinone; Cell cycle progression; MTOC; Oocyte maturation; Spindle formation

DOI:  https://doi.org/10.1016/j.jhazmat.2022.129248
Methods Mol Biol. 2022 ;2529 407-417

Investigating Mitotic Inheritance of Histone Posttranslational Modifications by Triple pSILAC Coupled to Nascent Chromatin Capture.

Kyosuke Nakamura, Anja Groth, Constance Alabert.

  Pulse stable isotope labeling with amino acids in cell culture (pSILAC) coupled to mass spectrometric analysis is a powerful tool to study propagation of histone post-translational modifications (PTMs). We describe the combination of triple pSILAC with pulse-chase labeling of newly replicated DNA by nascent chromatin capture (NCC). This technology tracks newly synthesized and recycled old histones, from deposition to transmission to daughter cells, unveiling principles of histone-based inheritance.

Keywords:  Chromatin assembly; DNA replication; Histone; Mass spectrometry; Nascent Chromatin Capture; Posttranslational modifications; Pulse-chase; SILAC

DOI:  https://doi.org/10.1007/978-1-0716-2481-4_17