scholarly journals SWR1 Chromatin Remodeling Complex Prevents Mitotic Slippage during Spindle Position Checkpoint Arrest

2019 ◽  
Author(s):  
Ayse Koca Caydasi ◽  
Anton Khmelinskii ◽  
Zoulfia Darieva ◽  
Bahtiyar Kurtulmus ◽  
Michael Knop ◽  
...  
Keyword(s):  
Cell Division ◽  
Chromatin Remodeling ◽  
Daughter Cell ◽  
Budding Yeast ◽  
Genetic Material ◽  
Chromatin Remodeling Complex ◽  
Mitotic Slippage ◽  
Genome Wide ◽  
Surveillance Mechanism ◽  
Spindle Position

ABSTRACTFaithful chromosome segregation in budding yeast requires correct positioning of the mitotic spindle along the mother to daughter cell polarity axis. When the anaphase spindle is not correctly positioned, a surveillance mechanism, named as the spindle position checkpoint (SPOC), prevents the progression out of mitosis until correct spindle positioning is achieved. How SPOC works on a molecular level is not well-understood. Here, we performed a genome-wide genetic screen to search for components required for SPOC. We identified the SWR1 chromatin-remodeling complex (SWR1-C) among the several novel factors that are essential for SPOC integrity. Cells lacking SWR1-C were able to activate SPOC upon spindle misorientation but underwent mitotic slippage upon prolonged SPOC arrest. This mitotic slippage required the Cdc14-early anaphase release pathway and other factors including the SAGA histone acetyltransferase complex, proteasome components, the mitotic cyclin-dependent kinase inhibitor Sic1 and the mitogen-activated protein kinase Slt2/Mpk1. Together, our data establish a novel link between chromatin remodeling and robust checkpoint arrest in late anaphase.AUTHORS SUMMARYBefore it physically divides into two, the cell must duplicate its genetic material and separate the duplicated copies to the opposite poles of the cell with the help of the spindle machinery. The direction along which the genetic material is separated has different consequences on cell division, especially when the opposite poles of the cell differ from each other, as is the case of asymmetric cell division. Every cell division in budding yeast is asymmetric. The new (daughter) cell grows on the old (mother) cell and pinches of from this location at the end of the cell division, giving rise to a new and an old cell. The daughter and mother cells differ in size and composition, thus the cell division is asymmetric. In order for the daughter cell to receive one copy of the duplicated genetic material, budding yeast has to separate the copies of its genetic material along the mother to daughter cell direction, which is possible by placing the spindle apparatus along this direction.A surveillance mechanism named the Spindle Position Checkpoint (SPOC) in budding yeast monitors the position of the mitotic spindle and prevents cells from dividing if the spindle fails to align in the mother to daughter direction. The cell can resume cell division only after correcting the position of the spindle followed by inactivation of SPOC. This way SPOC prevents multi-nucleation and enucleation, and hence it is a crucial mechanism to maintain the correct ploidy. It has been known that about five proteins play a role in positively supporting the SPOC. Yet, how SPOC works on a molecular level remains ill understood.In this study, we aimed to find out novel components of SPOC. Through an unbiased genome-wide genetic screen, we successfully identified several new components of the SPOC machinery. Among several other novel proteins identified, we investigated the role of the SWR1 chromatin remodeling complex (SWR1-C) in more detail. We show that the SWR1-C has a function in preventing cells with mis-positioned spindles from resuming cell division when the spindle stays mis-positioned for a prolonged time (mitotic slippage). Our data indicated that SWR1-C is not required to start the immediate SPOC response, rather it is important to keep the prolonged SPOC arrest.

scholarly journals Combined effect of cell geometry and polarity domains determines the orientation of unequal division

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Benoit G Godard ◽  
Remi Dumollard ◽  
Carl-Philipp Heisenberg ◽  
Alex McDougall
Keyword(s):  
Cell Division ◽  
Mitotic Spindle ◽  
Cell Shape ◽  
Daughter Cell ◽  
Cleavage Plane ◽  
Mitotic Cell ◽  
Cell Geometry ◽  
Daughter Cells ◽  
Ascidian Embryos ◽  
Spindle Position

Cell division orientation is thought to result from a competition between cell geometry and polarity domains controlling the position of the mitotic spindle during mitosis. Depending on the level of cell shape anisotropy or the strength of the polarity domain, one dominates the other and determines the orientation of the spindle. Whether and how such competition is also at work to determine unequal cell division (UCD), producing daughter cells of different size, remains unclear. Here, we show that cell geometry and polarity domains cooperate, rather than compete, in positioning the cleavage plane during UCDs in early ascidian embryos. We found that the UCDs and their orientation at the ascidian third cleavage rely on the spindle tilting in an anisotropic cell shape, and cortical polarity domains exerting different effects on spindle astral microtubules. By systematically varying mitotic cell shape, we could modulate the effect of attractive and repulsive polarity domains and consequently generate predicted daughter cell size asymmetries and position. We therefore propose that the spindle position during UCD is set by the combined activities of cell geometry and polarity domains, where cell geometry modulates the effect of cortical polarity domain(s).

scholarly journals Different Levels of Bfa1/Bub2 GAP Activity Are Required to Prevent Mitotic Exit of Budding Yeast Depending on the Type of Perturbations

2008 ◽  
Vol 19 (10) ◽  
pp. 4328-4340 ◽  
Author(s):  
Junwon Kim ◽  
Selma Sun Jang ◽  
Kiwon Song
Keyword(s):  
Budding Yeast ◽  
Mitotic Exit ◽  
Nucleotide Exchange ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor ◽  
Surveillance Mechanism ◽  
Spindle Position ◽  
First Time ◽  
Different Levels

In budding yeast, Tem1 is a key regulator of mitotic exit. Bfa1/Bub2 stimulates Tem1 GTPase activity as a GTPase-activating protein (GAP). Lte1 possesses a guanine-nucleotide exchange factor (GEF) domain likely for Tem1. However, recent observations showed that cells may control mitotic exit without either Lte1 or Bfa1/Bub2 GAP activity, obscuring how Tem1 is regulated. Here, we assayed BFA1 mutants with varying GAP activities for Tem1, showing for the first time that Bfa1/Bub2 GAP activity inhibits Tem1 in vivo. A decrease in GAP activity allowed cells to bypass mitotic exit defects. Interestingly, different levels of GAP activity were required to prevent mitotic exit depending on the type of perturbation. Although essential, more Bfa1/Bub2 GAP activity was needed for spindle damage than for DNA damage to fully activate the checkpoint. Conversely, Bfa1/Bub2 GAP activity was insufficient to delay mitotic exit in cells with misoriented spindles. Instead, decreased interaction of Bfa1 with Kin4 was observed in BFA1 mutant cells with a defective spindle position checkpoint. These findings demonstrate that there is a GAP-independent surveillance mechanism of Bfa1/Bub2, which, together with the GTP/GDP switch of Tem1, may be required for the genomic stability of cells with misaligned spindles.

scholarly journals The Genome-Wide Localization of Rsc9, a Component of the RSC Chromatin-Remodeling Complex, Changes in Response to Stress

2002 ◽  
Vol 9 (3) ◽  
pp. 563-573 ◽  
Author(s):  
Marc Damelin ◽  
Itamar Simon ◽  
Terence I. Moy ◽  
Boris Wilson ◽  
Suzanne Komili ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Chromatin Remodeling Complex ◽  
Genome Wide ◽  
Response To Stress

scholarly journals Using Budding Yeast to Identify Molecules That Block Cancer Cell ‘Mitotic Slippage’ Only in the Presence of Mitotic Poisons

2021 ◽  
Vol 22 (15) ◽  
pp. 7985
Author(s):  
Scott C. Schuyler ◽  
Hsin-Yu Chen
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Drug Targets ◽  
Budding Yeast ◽  
Eukaryotic Cell ◽  
Mitotic Checkpoint ◽  
Chemotherapeutic Agents ◽  
Cell Cycle Checkpoints ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mitotic Slippage

Research on the budding yeast Saccharomyces cerevisiae has yielded fundamental discoveries on highly conserved biological pathways and yeast remains the best-studied eukaryotic cell in the world. Studies on the mitotic cell cycle and the discovery of cell cycle checkpoints in budding yeast has led to a detailed, although incomplete, understanding of eukaryotic cell cycle progression. In multicellular eukaryotic organisms, uncontrolled aberrant cell division is the defining feature of cancer. Some of the most successful classes of anti-cancer chemotherapeutic agents are mitotic poisons. Mitotic poisons are thought to function by inducing a mitotic spindle checkpoint-dependent cell cycle arrest, via the assembly of the highly conserved mitotic checkpoint complex (MCC), leading to apoptosis. Even in the presence of mitotic poisons, some cancer cells continue cell division via ‘mitotic slippage’, which may correlate with a cancer becoming refractory to mitotic poison chemotherapeutic treatments. In this review, knowledge about budding yeast cell cycle control is explored to suggest novel potential drug targets, namely, specific regions in the highly conserved anaphase-promoting complex/cyclosome (APC/C) subunits Apc1 and/or Apc5, and in a specific N-terminal region in the APC/C co-factor cell division cycle 20 (Cdc20), which may yield molecules which block ‘mitotic slippage’ only in the presence of mitotic poisons.

scholarly journals ATPase SRCAP is a new player in cell division, uncovering molecular aspects of Floating-Harbor syndrome

2020 ◽  
Author(s):  
Giovanni Messina ◽  
Yuri Prozzillo ◽  
Francesca Delle Monache ◽  
Maria Virginia Santopietro ◽  
Maria Teresa Atterrato ◽  
...  
Keyword(s):  
Cell Division ◽  
Chromatin Remodeling ◽  
Catalytic Subunit ◽  
Current View ◽  
Mitotic Apparatus ◽  
Direct Role ◽  
The Core ◽  
Chromatin Remodeling Complex ◽  
Evolutionarily Conserved ◽  
Floating Harbor Syndrome

AbstractFloating-Harbor syndrome (FHS) is a rare genetic disease affecting human development caused by heterozygous truncating mutations in the Srcap gene, which encodes the ATPase SRCAP, the core catalytic subunit of the homonymous chromatin-remodeling complex. Using a combined approach, we studied the involvement of SRCAP protein in cell cycle progression in HeLa cells. In addition to the canonical localization in interphase nuclei, both SRCAP and its Drosophila orthologue DOMINO-A localized to the mitotic apparatus after nuclear envelope breakdown. Moreover, SRCAP and DOMINO-A depletion impaired mitosis and cytokinesis in human and Drosophila cells, respectively. Importantly, SRCAP interacted with several cytokinesis regulators at telophase, strongly supporting a direct role in cytokinesis, independent of its chromatin remodeling functions. Our results provide clues about previously undetected, evolutionarily conserved roles of SRCAP in ensuring proper mitosis and cytokinesis. We propose that perturbations in cell division contribute to the onset of developmental defects characteristic of FHS.SummarySignificance statementSrcap is the causative gene of the rare Floating Harbor syndrome (FHS). It encodes the ATPase SRCAP, the core catalytic subunit of the homonymous multiprotein chromatin-remodeling complex in humans, which promotes the exchange of canonical histone H2A with the H2A.Z variant. According to the current view on SRCAP protein functions, FHS is caused by chromatin remodeling defects. Our findings suggest that, in addition to the established function as epigenetic regulator, SRCAP plays previously undetected and evolutionarily conserved roles in cell division. Hence, we propose that perturbations in cell division produced by SRCAP mutations are important causative factors co-occurring at the onset of FHS.

scholarly journals Protein Phosphatase 1 in association with Bud14 inhibits mitotic exit in Saccharomyces cerevisiae

2020 ◽  
Author(s):  
Dilara Kocakaplan ◽  
Hüseyin Karabürk ◽  
Cansu Dilege ◽  
Idil Kirdok ◽  
Şeyma Nur Erkan ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitotic Spindle ◽  
Protein Phosphatase ◽  
Budding Yeast ◽  
Mitotic Exit ◽  
Protein Phosphatase 1 ◽  
Inhibitory Function ◽  
Surveillance Mechanism ◽  
Spindle Position

AbstractSaccharomyces cerevisiae, also known as the budding yeast, orients and elongates its mitotic spindle along its polarity axis in order to segregate one copy of its genomic DNA to the daughter cell. When accurate positioning of the mitotic spindle fails, a surveillance mechanism, named the Spindle Position Checkpoint (SPOC), prevents cells from exiting mitosis unless the spindle orientation is corrected. Mutants with a defective SPOC loss their genomic integrity, become multiploid and aneuploid. Thus, SPOC is a crucial checkpoint for the budding yeast. Yet, a comprehensive understanding of how the SPOC mechanism works is missing. In this study, we identified Bud14 as a novel checkpoint protein. We showed that the mitotic exit inhibitory function of Bud14 requires its association with the type 1 protein phosphatase, Glc7. Our data indicate that Glc7-Bud14 promotes dephosphorylation of the SPOC effector protein Bfa1. Our results support a model in which Glc7-Bud14 works parallel to the SPOC kinase Kin4 in inhibiting mitotic exit.

INO80 requires a polycomb subunit to regulate the establishment of poised chromatin in murine spermatocytes

Development ◽  
2022 ◽  
Vol 149 (1) ◽  
Author(s):  
Prabuddha Chakraborty ◽  
Terry Magnuson
Keyword(s):  
Chromatin Remodeling ◽  
Binding Sites ◽  
Strand Break ◽  
Rna Seq ◽  
Genome Wide Analysis ◽  
The Core ◽  
Chromatin Remodeling Complex ◽  
Genome Wide ◽  
Dna Double Strand Break ◽  
Transcription Program

ABSTRACT INO80 is the catalytic subunit of the INO80-chromatin remodeling complex that is involved in DNA replication, repair and transcription regulation. Ino80 deficiency in murine spermatocytes (Ino80cKO) results in pachytene arrest of spermatocytes due to incomplete synapsis and aberrant DNA double-strand break repair, which leads to apoptosis. RNA-seq on Ino80cKO spermatocytes revealed major changes in transcription, indicating that an aberrant transcription program arises upon INO80 depletion. In Ino80WT spermatocytes, genome-wide analysis showed that INO80-binding sites were mostly promoter proximal and necessary for the regulation of spermatogenic gene expression, primarily of premeiotic and meiotic genes. Furthermore, most of the genes poised for activity, as well as those genes that are active, shared INO80 binding. In Ino80cKO spermatocytes, most poised genes demonstrated de-repression due to reduced H3K27me3 enrichment and, in turn, showed increased expression levels. INO80 interacts with the core PRC2 complex member SUZ12 and promotes its recruitment. Furthermore, INO80 mediates H2A.Z incorporation at the poised promoters, which was reduced in Ino80cKO spermatocytes. Taken together, INO80 is emerging as a major regulator of the meiotic transcription program by mediating poised chromatin establishment through SUZ12 binding.

scholarly journals Identification of SWI2/SNF2-Related 1 Chromatin Remodeling Complex (SWR1-C) Subunits in Pineapple and the Role of Pineapple SWR1 COMPLEX 6 (AcSWC6) in Biotic and Abiotic Stress Response

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 364 ◽  
Author(s):  
Jakada ◽  
Aslam ◽  
Fakher ◽  
Greaves ◽  
Li ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Chromatin Remodeling ◽  
Sequence Similarity ◽  
Rna Seq ◽  
Abiotic Stress Response ◽  
Biotic And Abiotic Stress ◽  
Enhanced Resistance ◽  
Chromatin Remodeling Complex ◽  
Genome Wide

Chromatin remodeling complex orchestrates numerous aspects of growth and development in eukaryotes. SWI2/SNF2-Related 1 chromatin remodeling complex (SWR1-C) is a member of the SWI/SNF ATPase-containing chromatin remodeling complex responsible for the exchange of H2A for H2A.Z. In plants, SWR1-C plays a crucial role by transcriptionally regulating numerous biological and developmental processes. However, SWR1-C activity remains obscure in pineapple. Here, we aim to identify the SWR1-C subunits in pineapple. By genome-wide identification, we found a total of 11 SWR1-C subunits in the pineapple. The identified SWR1-C subunits were named and classified based on the sequence similarity and phylogenetic analysis. RNA-Seq analysis showed that pineapple SWR1-C subunits are expressed differentially in different organs and at different stages. Additionally, the qRT-PCR of pineapple SWR1-C subunits during abiotic stress exposure showed significant changes in their expression. We further investigated the functions of pineapple SWR1 COMPLEX 6 (AcSWC6) by ectopically expressing it in Arabidopsis. Interestingly, transgenic plants ectopically expressing AcSWC6 showed susceptibility to fungal infection and enhanced resistance to salt and osmotic stress, revealing its involvement in biotic and abiotic stress. Moreover, the complementation of mutant Arabidopsis swc6 by pineapple SWC6 suggested the conserved function of SWC6 in plants.

scholarly journals The 14-3-3 protein Bmh1 functions in the spindle position checkpoint by breaking Bfa1 asymmetry at yeast centrosomes

2014 ◽  
Vol 25 (14) ◽  
pp. 2143-2151 ◽  
Author(s):  
Ayse Koca Caydasi ◽  
Yagmur Micoogullari ◽  
Bahtiyar Kurtulmus ◽  
Saravanan Palani ◽  
Gislene Pereira
Keyword(s):  
Cell Cycle ◽  
Molecular Mechanism ◽  
Cell Polarity ◽  
Mitotic Spindle ◽  
Budding Yeast ◽  
Docking Site ◽  
Microtubule Organization ◽  
Family Protein ◽  
Surveillance Mechanism ◽  
Spindle Position

In addition to their well-known role in microtubule organization, centrosomes function as signaling platforms and regulate cell cycle events. An important example of such a function is the spindle position checkpoint (SPOC) of budding yeast. SPOC is a surveillance mechanism that ensures alignment of the mitotic spindle along the cell polarity axis. Upon spindle misalignment, phosphorylation of the SPOC component Bfa1 by Kin4 kinase engages the SPOC by changing the centrosome localization of Bfa1 from asymmetric (one centrosome) to symmetric (both centrosomes). Here we show that, unexpectedly, Kin4 alone is unable to break Bfa1 asymmetry at yeast centrosomes. Instead, phosphorylation of Bfa1 by Kin4 creates a docking site on Bfa1 for the 14-3-3 family protein Bmh1, which in turn weakens Bfa1–centrosome association and promotes symmetric Bfa1 localization. Consistently, BMH1-null cells are SPOC deficient. Our work thus identifies Bmh1 as a new SPOC component and refines the molecular mechanism that breaks Bfa1 centrosome asymmetry upon SPOC activation.

scholarly journals Genome-wide CRISPR screen reveals host genes that regulate SARS-CoV-2 infection

2020 ◽  
Author(s):  
Jin Wei ◽  
Mia Madel Alfajaro ◽  
Ruth E. Hanna ◽  
Peter C. DeWeirdt ◽  
Madison S. Strine ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Cathepsin L ◽  
Therapeutic Targets ◽  
Chromatin Remodeling Complex ◽  
Genome Wide ◽  
A Genome ◽  
Viral Genes ◽  
Crispr Screen ◽  
Chaperone Complex ◽  
Host Genes

Identification of host genes essential for SARS-CoV-2 infection may reveal novel therapeutic targets and inform our understanding of COVID-19 pathogenesis. Here we performed a genome-wide CRISPR screen with SARS-CoV-2 and identified known SARS-CoV-2 host factors including the receptor ACE2 and protease Cathepsin L. We additionally discovered novel pro-viral genes and pathways including the SWI/SNF chromatin remodeling complex and key components of the TGF-β signaling pathway. Small molecule inhibitors of these pathways prevented SARS-CoV-2-induced cell death. We also revealed that the alarmin HMGB1 is critical for SARS-CoV-2 replication. In contrast, loss of the histone H3.3 chaperone complex sensitized cells to virus-induced death. Together this study reveals potential therapeutic targets for SARS-CoV-2 and highlights host genes that may regulate COVID-19 pathogenesis.

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