1
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Talavera RA, Prichard BE, Sommer RA, Leitao RM, Sarabia CJ, Hazir S, Paulo JA, Gygi SP, Kellogg DR. Cell growth and nutrient availability control the mitotic exit signaling network in budding yeast. J Cell Biol 2024; 223:e202305008. [PMID: 38722822 PMCID: PMC11082370 DOI: 10.1083/jcb.202305008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 01/03/2024] [Accepted: 04/04/2024] [Indexed: 05/13/2024] Open
Abstract
Cell growth is required for cell cycle progression. The amount of growth required for cell cycle progression is reduced in poor nutrients, which leads to a reduction in cell size. In budding yeast, nutrients can influence cell size by modulating the extent of bud growth, which occurs predominantly in mitosis. However, the mechanisms are unknown. Here, we used mass spectrometry to identify proteins that modulate bud growth in response to nutrient availability. This led to the discovery that nutrients regulate numerous components of the mitotic exit network (MEN), which controls exit from mitosis. A key component of the MEN undergoes gradual multisite phosphorylation during bud growth that is dependent upon bud growth and correlated with the extent of growth. Furthermore, activation of the MEN is sufficient to override a growth requirement for mitotic exit. The data suggest a model in which the MEN ensures that mitotic exit occurs only when an appropriate amount of bud growth has occurred.
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Affiliation(s)
- Rafael A. Talavera
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA, USA
| | - Beth E. Prichard
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA, USA
| | - Robert A. Sommer
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA, USA
| | - Ricardo M. Leitao
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA, USA
| | - Christopher J. Sarabia
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA, USA
| | - Semin Hazir
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA, USA
| | - Joao A. Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Steven P. Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Douglas R. Kellogg
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, CA, USA
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2
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Dai S, Liu S, Zhou C, Yu F, Zhu G, Zhang W, Deng H, Burlingame A, Yu W, Wang T, Li N. Capturing the hierarchically assorted modules of protein-protein interactions in the organized nucleome. MOLECULAR PLANT 2023; 16:930-961. [PMID: 36960533 DOI: 10.1016/j.molp.2023.03.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 02/16/2023] [Accepted: 03/21/2023] [Indexed: 05/04/2023]
Abstract
Nuclear proteins are major constituents and key regulators of nucleome topological organization and manipulators of nuclear events. To decipher the global connectivity of nuclear proteins and the hierarchically organized modules of their interactions, we conducted two rounds of cross-linking mass spectrometry (XL-MS) analysis, one of which followed a quantitative double chemical cross-linking mass spectrometry (in vivoqXL-MS) workflow, and identified 24,140 unique crosslinks in total from the nuclei of soybean seedlings. This in vivo quantitative interactomics enabled the identification of 5340 crosslinks that can be converted into 1297 nuclear protein-protein interactions (PPIs), 1220 (94%) of which were non-confirmative (or novel) nuclear PPIs compared with those in repositories. There were 250 and 26 novel interactors of histones and the nucleolar box C/D small nucleolar ribonucleoprotein complex, respectively. Modulomic analysis of orthologous Arabidopsis PPIs produced 27 and 24 master nuclear PPI modules (NPIMs) that contain the condensate-forming protein(s) and the intrinsically disordered region-containing proteins, respectively. These NPIMs successfully captured previously reported nuclear protein complexes and nuclear bodies in the nucleus. Surprisingly, these NPIMs were hierarchically assorted into four higher-order communities in a nucleomic graph, including genome and nucleolus communities. This combinatorial pipeline of 4C quantitative interactomics and PPI network modularization revealed 17 ethylene-specific module variants that participate in a broad range of nuclear events. The pipeline was able to capture both nuclear protein complexes and nuclear bodies, construct the topological architectures of PPI modules and module variants in the nucleome, and probably map the protein compositions of biomolecular condensates.
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Affiliation(s)
- Shuaijian Dai
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Shichang Liu
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Chen Zhou
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Fengchao Yu
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Guang Zhu
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Wenhao Zhang
- Tsinghua-Peking Joint Centre for Life Sciences, Centre for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Haiteng Deng
- Tsinghua-Peking Joint Centre for Life Sciences, Centre for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Al Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Weichuan Yu
- The HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute, Futian, Shenzhen, Guangdong 518057, China; Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China.
| | - Tingliang Wang
- Tsinghua-Peking Joint Centre for Life Sciences, Centre for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.
| | - Ning Li
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong SAR, China; Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Hong Kong, China; The HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute, Futian, Shenzhen, Guangdong 518057, China.
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3
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Buskirk S, Skibbens RV. G1-Cyclin2 (Cln2) promotes chromosome hypercondensation in eco1/ctf7 rad61 null cells during hyperthermic stress in Saccharomyces cerevisiae. G3 (BETHESDA, MD.) 2022; 12:6613937. [PMID: 35736360 PMCID: PMC9339302 DOI: 10.1093/g3journal/jkac157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 06/13/2022] [Indexed: 11/16/2022]
Abstract
Eco1/Ctf7 is a highly conserved acetyltransferase that activates cohesin complexes and is critical for sister chromatid cohesion, chromosome condensation, DNA damage repair, nucleolar integrity, and gene transcription. Mutations in the human homolog of ECO1 (ESCO2/EFO2), or in genes that encode cohesin subunits, result in severe developmental abnormalities and intellectual disabilities referred to as Roberts syndrome and Cornelia de Lange syndrome, respectively. In yeast, deletion of ECO1 results in cell inviability. Codeletion of RAD61 (WAPL in humans), however, produces viable yeast cells. These eco1 rad61 double mutants, however, exhibit a severe temperature-sensitive growth defect, suggesting that Eco1 or cohesins respond to hyperthermic stress through a mechanism that occurs independent of Rad61. Here, we report that deletion of the G1 cyclin CLN2 rescues the temperature-sensitive lethality otherwise exhibited by eco1 rad61 mutant cells, such that the triple mutant cells exhibit robust growth over a broad range of temperatures. While Cln1, Cln2, and Cln3 are functionally redundant G1 cyclins, neither CLN1 nor CLN3 deletions rescue the temperature-sensitive growth defects otherwise exhibited by eco1 rad61 double mutants. We further provide evidence that CLN2 deletion rescues hyperthermic growth defects independent of START and impacts the state of chromosome condensation. These findings reveal novel roles for Cln2 that are unique among the G1 cyclin family and appear critical for cohesin regulation during hyperthermic stress.
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Affiliation(s)
- Sean Buskirk
- Department of Biology, West Chester University, West Chester, PA 19383, USA
| | - Robert V Skibbens
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015, USA
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4
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The N-Terminal Domain of Bfa1 Coordinates Mitotic Exit Independent of GAP Activity in Saccharomyces cerevisiae. Cells 2022; 11:cells11142179. [PMID: 35883622 PMCID: PMC9316867 DOI: 10.3390/cells11142179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 12/10/2022] Open
Abstract
The spindle position checkpoint (SPOC) of budding yeast delays mitotic exit in response to misaligned spindles to ensure cell survival and the maintenance of genomic stability. The GTPase-activating protein (GAP) complex Bfa1–Bub2, a key SPOC component, inhibits the GTPase Tem1 to induce mitotic arrest in response to DNA and spindle damage, as well as spindle misorientation. However, previous results strongly suggest that Bfa1 exerts a GAP-independent function in blocking mitotic exit in response to misaligned spindles. Thus, the molecular mechanism by which Bfa1 controls mitotic exit in response to misaligned spindles remains unclear. Here, we observed that overexpression of the N-terminal domain of Bfa1 (Bfa1-D16), which lacks GAP activity and cannot localize to the spindle pole body (SPB), induced cell cycle arrest along with hyper-elongation of astral microtubules (aMTs) as Bfa1 overexpression in Δbub2. We found that Δbub2 cells overexpressing Bfa1 or Bfa1-D16 inhibited activation of Mob1, which is responsible for mitotic exit. In anaphase-arrested cells, Bfa1-D16 overexpression inhibited Tem1 binding to the SPB as well as Bfa1 overexpression. Additionally, endogenous levels of Bfa1-D16 showed minor SPOC activity that was not regulated by Kin4. These results suggested that Bfa1-D16 may block mitotic exit through inhibiting Tem1 activity outside of SPBs. Alternatively, Bfa1-D16 dispersed out of SPBs may block Tem1 binding to SPBs by physically interacting with Tem1 as previously reported. Moreover, we observed hyper-elongated aMTs in tem1-3, cdc15-2, and dbf2-2 mutants that induce anaphase arrest and cannot undergo mitotic exit at restrictive temperatures, suggesting that aMT dynamics are closely related to the regulation of mitotic exit. Altogether, these observations suggest that Bfa1 can control the SPOC independent of its GAP activity and SPB localization.
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5
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Baldini L, Charpentier B, Labialle S. Emerging Data on the Diversity of Molecular Mechanisms Involving C/D snoRNAs. Noncoding RNA 2021; 7:ncrna7020030. [PMID: 34066559 PMCID: PMC8162545 DOI: 10.3390/ncrna7020030] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 04/28/2021] [Accepted: 04/30/2021] [Indexed: 12/15/2022] Open
Abstract
Box C/D small nucleolar RNAs (C/D snoRNAs) represent an ancient family of small non-coding RNAs that are classically viewed as housekeeping guides for the 2′-O-methylation of ribosomal RNA in Archaea and Eukaryotes. However, an extensive set of studies now argues that they are involved in mechanisms that go well beyond this function. Here, we present these pieces of evidence in light of the current comprehension of the molecular mechanisms that control C/D snoRNA expression and function. From this inventory emerges that an accurate description of these activities at a molecular level is required to let the snoRNA field enter in a second age of maturity.
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Affiliation(s)
| | - Bruno Charpentier
- Correspondence: (B.C.); (S.L.); Tel.: +33-3-72-74-66-27 (B.C.); +33-3-72-74-66-51 (S.L.)
| | - Stéphane Labialle
- Correspondence: (B.C.); (S.L.); Tel.: +33-3-72-74-66-27 (B.C.); +33-3-72-74-66-51 (S.L.)
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6
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The box C/D snoRNP assembly factor Bcd1 interacts with the histone chaperone Rtt106 and controls its transcription dependent activity. Nat Commun 2021; 12:1859. [PMID: 33767140 PMCID: PMC7994586 DOI: 10.1038/s41467-021-22077-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 02/26/2021] [Indexed: 12/25/2022] Open
Abstract
Biogenesis of eukaryotic box C/D small nucleolar ribonucleoproteins initiates co-transcriptionally and requires the action of the assembly machinery including the Hsp90/R2TP complex, the Rsa1p:Hit1p heterodimer and the Bcd1 protein. We present genetic interactions between the Rsa1p-encoding gene and genes involved in chromatin organization including RTT106 that codes for the H3-H4 histone chaperone Rtt106p controlling H3K56ac deposition. We show that Bcd1p binds Rtt106p and controls its transcription-dependent recruitment by reducing its association with RNA polymerase II, modulating H3K56ac levels at gene body. We reveal the 3D structures of the free and Rtt106p-bound forms of Bcd1p using nuclear magnetic resonance and X-ray crystallography. The interaction is also studied by a combination of biophysical and proteomic techniques. Bcd1p interacts with a region that is distinct from the interaction interface between the histone chaperone and histone H3. Our results are evidence for a protein interaction interface for Rtt106p that controls its transcription-associated activity. Biogenesis of small nucleolar RNAs ribonucleoproteins (snoRNPs) requires dedicated assembly machinery. Here, the authors show that a subset of snoRNP assembly factors interacts, genetically or directly, with factors modulating chromatin architecture, suggesting a link between ribosome formation and chromatin functions.
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7
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Matellán L, Manzano-López J, Monje-Casas F. Polo-like kinase acts as a molecular timer that safeguards the asymmetric fate of spindle microtubule-organizing centers. eLife 2020; 9:61488. [PMID: 33135999 PMCID: PMC7669271 DOI: 10.7554/elife.61488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/20/2020] [Indexed: 12/27/2022] Open
Abstract
The microtubules that form the mitotic spindle originate from microtubule-organizing centers (MTOCs) located at either pole. After duplication, spindle MTOCs can be differentially inherited during asymmetric cell division in organisms ranging from yeast to humans. Problems with establishing predetermined spindle MTOC inheritance patterns during stem cell division have been associated with accelerated cellular aging and the development of both cancer and neurodegenerative disorders. Here, we expand the repertoire of functions Polo-like kinase family members fulfill in regulating pivotal cell cycle processes. We demonstrate that the Plk1 homolog Cdc5 acts as a molecular timer that facilitates the timely and sequential recruitment of two key determinants of spindle MTOCs distribution, that is the γ-tubulin complex receptor Spc72 and the protein Kar9, and establishes the fate of these structures, safeguarding their asymmetric inheritance during Saccharomyces cerevisiae mitosis.
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Affiliation(s)
- Laura Matellán
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
| | - Javier Manzano-López
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
| | - Fernando Monje-Casas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
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8
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Howell RSM, Klemm C, Thorpe PH, Csikász-Nagy A. Unifying the mechanism of mitotic exit control in a spatiotemporal logical model. PLoS Biol 2020; 18:e3000917. [PMID: 33180788 PMCID: PMC7685450 DOI: 10.1371/journal.pbio.3000917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 11/24/2020] [Accepted: 10/09/2020] [Indexed: 11/18/2022] Open
Abstract
The transition from mitosis into the first gap phase of the cell cycle in budding yeast is controlled by the Mitotic Exit Network (MEN). The network interprets spatiotemporal cues about the progression of mitosis and ensures that release of Cdc14 phosphatase occurs only after completion of key mitotic events. The MEN has been studied intensively; however, a unified understanding of how localisation and protein activity function together as a system is lacking. In this paper, we present a compartmental, logical model of the MEN that is capable of representing spatial aspects of regulation in parallel to control of enzymatic activity. We show that our model is capable of correctly predicting the phenotype of the majority of mutants we tested, including mutants that cause proteins to mislocalise. We use a continuous time implementation of the model to demonstrate that Cdc14 Early Anaphase Release (FEAR) ensures robust timing of anaphase, and we verify our findings in living cells. Furthermore, we show that our model can represent measured cell-cell variation in Spindle Position Checkpoint (SPoC) mutants. This work suggests a general approach to incorporate spatial effects into logical models. We anticipate that the model itself will be an important resource to experimental researchers, providing a rigorous platform to test hypotheses about regulation of mitotic exit.
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Affiliation(s)
- Rowan S M Howell
- The Francis Crick Institute, London, United Kingdom.,Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Cinzia Klemm
- School of Biological and Chemical Sciences, Queen Mary University, London, United Kingdom
| | - Peter H Thorpe
- School of Biological and Chemical Sciences, Queen Mary University, London, United Kingdom
| | - Attila Csikász-Nagy
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom.,Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
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9
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Jiménez J, Queralt E, Posas F, de Nadal E. The regulation of Net1/Cdc14 by the Hog1 MAPK upon osmostress unravels a new mechanism regulating mitosis. Cell Cycle 2020; 19:2105-2118. [PMID: 32794416 PMCID: PMC7513861 DOI: 10.1080/15384101.2020.1804222] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
During evolution, cells have developed a plethora of mechanisms to optimize survival in a changing and unpredictable environment. In this regard, they have evolved networks that include environmental sensors, signaling transduction molecules and response mechanisms. Hog1 (yeast) and p38 (mammals) stress-activated protein kinases (SAPKs) are activated upon stress and they drive a full collection of cell adaptive responses aimed to maximize survival. SAPKs are extensively used to learn about the mechanisms through which cells adapt to changing environments. In addition to regulating gene expression and metabolism, SAPKs control cell cycle progression. In this review, we will discuss the latest findings related to the SAPK-driven regulation of mitosis upon osmostress in yeast.
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Affiliation(s)
- Javier Jiménez
- Departament De Ciències Experimentals I De La Salut, Universitat Pompeu Fabra (UPF) , Barcelona, Spain.,Department of Ciències Bàsiques, Facultat De Medicina I Ciències De La Salut, Universitat Internacional De Catalunya , Barcelona, Spain
| | - Ethel Queralt
- Cell Cycle Group, Institut d'Investigacions Biomèdica De Bellvitge (IDIBELL), L'Hospitalet De Llobregat , Barcelona, Spain
| | - Francesc Posas
- Departament De Ciències Experimentals I De La Salut, Universitat Pompeu Fabra (UPF) , Barcelona, Spain.,Institute for Research in Biomedicine (IRB Barcelona), the Barcelona Institute of Science and Technology , 08028 Barcelona, Spain
| | - Eulàlia de Nadal
- Departament De Ciències Experimentals I De La Salut, Universitat Pompeu Fabra (UPF) , Barcelona, Spain.,Institute for Research in Biomedicine (IRB Barcelona), the Barcelona Institute of Science and Technology , 08028 Barcelona, Spain
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10
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Abstract
Proper chromosome segregation is critical for the maintenance of genomic information in every cell division, which is required for cell survival. Cells have orchestrated a myriad of control mechanisms to guarantee proper chromosome segregation. Upon stress, cells induce a number of adaptive responses to maximize survival that range from regulation of gene expression to control of cell-cycle progression. We have found here that in response to osmostress, cells also regulate mitosis to ensure proper telomeric and rDNA segregation during adaptation. Osmostress induces a Hog1-dependent delay of cell-cycle progression in early mitosis by phosphorylating Net1, thereby impairing timely nucleolar release and activation of Cdc14, core elements of mitosis regulation. Thus, Hog1 activation prevents segregation defects to maximize survival. Adaptation to environmental changes is crucial for cell fitness. In Saccharomyces cerevisiae, variations in external osmolarity trigger the activation of the stress-activated protein kinase Hog1 (high-osmolarity glycerol 1), which regulates gene expression, metabolism, and cell-cycle progression. The activation of this kinase leads to the regulation of G1, S, and G2 phases of the cell cycle to prevent genome instability and promote cell survival. Here we show that Hog1 delays mitotic exit when cells are stressed during metaphase. Hog1 phosphorylates the nucleolar protein Net1, altering its affinity for the phosphatase Cdc14, whose activity is essential for mitotic exit and completion of the cell cycle. The untimely release of Cdc14 from the nucleolus upon activation of Hog1 is linked to a defect in ribosomal DNA (rDNA) and telomere segregation, and it ultimately delays cell division. A mutant of Net1 that cannot be phosphorylated by Hog1 displays reduced viability upon osmostress. Thus, Hog1 contributes to maximizing cell survival upon stress by regulating mitotic exit.
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11
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Shen D, Skibbens RV. Promotion of Hyperthermic-Induced rDNA Hypercondensation in Saccharomyces cerevisiae. Genetics 2020; 214:589-604. [PMID: 31980450 PMCID: PMC7054013 DOI: 10.1534/genetics.119.302994] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 12/29/2019] [Indexed: 12/11/2022] Open
Abstract
Ribosome biogenesis is tightly regulated through stress-sensing pathways that impact genome stability, aging and senescence. In Saccharomyces cerevisiae, ribosomal RNAs are transcribed from rDNA located on the right arm of chromosome XII. Numerous studies reveal that rDNA decondenses into a puff-like structure during interphase, and condenses into a tight loop-like structure during mitosis. Intriguingly, a novel and additional mechanism of increased mitotic rDNA compaction (termed hypercondensation) was recently discovered that occurs in response to temperature stress (hyperthermic-induced) and is rapidly reversible. Here, we report that neither changes in condensin binding or release of DNA during mitosis, nor mutation of factors that regulate cohesin binding and release, appear to play a critical role in hyperthermic-induced rDNA hypercondensation. A candidate genetic approach revealed that deletion of either HSP82 or HSC82 (Hsp90 encoding heat shock paralogs) result in significantly reduced hyperthermic-induced rDNA hypercondensation. Intriguingly, Hsp inhibitors do not impact rDNA hypercondensation. In combination, these findings suggest that Hsp90 either stabilizes client proteins, which are sensitive to very transient thermic challenges, or directly promotes rDNA hypercondensation during preanaphase. Our findings further reveal that the high mobility group protein Hmo1 is a negative regulator of mitotic rDNA condensation, distinct from its role in promoting premature condensation of rDNA during interphase upon nutrient starvation.
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Affiliation(s)
- Donglai Shen
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania 18015
| | - Robert V Skibbens
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania 18015
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12
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The Multiple Roles of the Cdc14 Phosphatase in Cell Cycle Control. Int J Mol Sci 2020; 21:ijms21030709. [PMID: 31973188 PMCID: PMC7038166 DOI: 10.3390/ijms21030709] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/17/2020] [Accepted: 01/20/2020] [Indexed: 12/20/2022] Open
Abstract
The Cdc14 phosphatase is a key regulator of mitosis in the budding yeast Saccharomyces cerevisiae. Cdc14 was initially described as playing an essential role in the control of cell cycle progression by promoting mitotic exit on the basis of its capacity to counteract the activity of the cyclin-dependent kinase Cdc28/Cdk1. A compiling body of evidence, however, has later demonstrated that this phosphatase plays other multiple roles in the regulation of mitosis at different cell cycle stages. Here, we summarize our current knowledge about the pivotal role of Cdc14 in cell cycle control, with a special focus in the most recently uncovered functions of the phosphatase.
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13
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PP2A Functions during Mitosis and Cytokinesis in Yeasts. Int J Mol Sci 2019; 21:ijms21010264. [PMID: 31906018 PMCID: PMC6981662 DOI: 10.3390/ijms21010264] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 12/23/2019] [Accepted: 12/24/2019] [Indexed: 12/13/2022] Open
Abstract
Protein phosphorylation is a common mechanism for the regulation of cell cycle progression. The opposing functions of cell cycle kinases and phosphatases are crucial for accurate chromosome segregation and exit from mitosis. Protein phosphatases 2A are heterotrimeric complexes that play essential roles in cell growth, proliferation, and regulation of the cell cycle. Here, we review the function of the protein phosphatase 2A family as the counteracting force for the mitotic kinases. We focus on recent findings in the regulation of mitotic exit and cytokinesis by PP2A phosphatases in S. cerevisiae and other fungal species.
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14
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Crane MM, Russell AE, Schafer BJ, Blue BW, Whalen R, Almazan J, Hong MG, Nguyen B, Goings JE, Chen KL, Kelly R, Kaeberlein M. DNA damage checkpoint activation impairs chromatin homeostasis and promotes mitotic catastrophe during aging. eLife 2019; 8:e50778. [PMID: 31714209 PMCID: PMC6850777 DOI: 10.7554/elife.50778] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 10/30/2019] [Indexed: 02/01/2023] Open
Abstract
Genome instability is a hallmark of aging and contributes to age-related disorders such as cancer and Alzheimer's disease. The accumulation of DNA damage during aging has been linked to altered cell cycle dynamics and the failure of cell cycle checkpoints. Here, we use single cell imaging to study the consequences of increased genomic instability during aging in budding yeast and identify striking age-associated genome missegregation events. This breakdown in mitotic fidelity results from the age-related activation of the DNA damage checkpoint and the resulting degradation of histone proteins. Disrupting the ability of cells to degrade histones in response to DNA damage increases replicative lifespan and reduces genomic missegregations. We present several lines of evidence supporting a model of antagonistic pleiotropy in the DNA damage response where histone degradation, and limited histone transcription are beneficial to respond rapidly to damage but reduce lifespan and genomic stability in the long term.
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Affiliation(s)
- Matthew M Crane
- Department of PathologyUniversity of WashingtonSeattleUnited States
| | - Adam E Russell
- Department of PathologyUniversity of WashingtonSeattleUnited States
| | - Brent J Schafer
- Department of PathologyUniversity of WashingtonSeattleUnited States
| | - Ben W Blue
- Department of PathologyUniversity of WashingtonSeattleUnited States
| | - Riley Whalen
- Department of PathologyUniversity of WashingtonSeattleUnited States
| | - Jared Almazan
- Department of PathologyUniversity of WashingtonSeattleUnited States
| | - Mung Gi Hong
- Department of PathologyUniversity of WashingtonSeattleUnited States
| | - Bao Nguyen
- Department of PathologyUniversity of WashingtonSeattleUnited States
| | - Joslyn E Goings
- Department of PathologyUniversity of WashingtonSeattleUnited States
| | - Kenneth L Chen
- Department of PathologyUniversity of WashingtonSeattleUnited States
- Department of Genome SciencesUniversity of WashingtonSeattleUnited States
- Medical Scientist Training ProgramUniversity of WashingtonSeattleUnited States
| | - Ryan Kelly
- Department of PathologyUniversity of WashingtonSeattleUnited States
| | - Matt Kaeberlein
- Department of PathologyUniversity of WashingtonSeattleUnited States
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15
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Manzano-López J, Matellán L, Álvarez-Llamas A, Blanco-Mira JC, Monje-Casas F. Asymmetric inheritance of spindle microtubule-organizing centres preserves replicative lifespan. Nat Cell Biol 2019; 21:952-965. [DOI: 10.1038/s41556-019-0364-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 06/23/2019] [Indexed: 12/19/2022]
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16
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Matos-Perdomo E, Machín F. Nucleolar and Ribosomal DNA Structure under Stress: Yeast Lessons for Aging and Cancer. Cells 2019; 8:cells8080779. [PMID: 31357498 PMCID: PMC6721496 DOI: 10.3390/cells8080779] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/15/2019] [Accepted: 07/24/2019] [Indexed: 02/06/2023] Open
Abstract
Once thought a mere ribosome factory, the nucleolus has been viewed in recent years as an extremely sensitive gauge of diverse cellular stresses. Emerging concepts in nucleolar biology include the nucleolar stress response (NSR), whereby a series of cell insults have a special impact on the nucleolus. These insults include, among others, ultra-violet radiation (UV), nutrient deprivation, hypoxia and thermal stress. While these stresses might influence nucleolar biology directly or indirectly, other perturbances whose origin resides in the nucleolar biology also trigger nucleolar and systemic stress responses. Among the latter, we find mutations in nucleolar and ribosomal proteins, ribosomal RNA (rRNA) processing inhibitors and ribosomal DNA (rDNA) transcription inhibition. The p53 protein also mediates NSR, leading ultimately to cell cycle arrest, apoptosis, senescence or differentiation. Hence, NSR is gaining importance in cancer biology. The nucleolar size and ribosome biogenesis, and how they connect with the Target of Rapamycin (TOR) signalling pathway, are also becoming important in the biology of aging and cancer. Simple model organisms like the budding yeast Saccharomyces cerevisiae, easy to manipulate genetically, are useful in order to study nucleolar and rDNA structure and their relationship with stress. In this review, we summarize the most important findings related to this topic.
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Affiliation(s)
- Emiliano Matos-Perdomo
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain
- Escuela de Doctorado y Estudios de Postgrado, Universidad de La Laguna, 38200 Tenerife, Spain
| | - Félix Machín
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain.
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, 38200 Tenerife, Spain.
- Facultad de Ciencias de la Salud, Universidad Fernando Pessoa Canarias, 35450 Santa María de Guía, Gran Canaria, Spain.
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17
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Chen Y, Li J, Cao F, Lam J, Cheng CC, Yu CH, Huen MS. Nucleolar residence of the seckel syndrome protein TRAIP is coupled to ribosomal DNA transcription. Nucleic Acids Res 2019; 46:10119-10131. [PMID: 30165463 PMCID: PMC6212796 DOI: 10.1093/nar/gky775] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Accepted: 08/16/2018] [Indexed: 12/30/2022] Open
Abstract
The RING finger protein TRAIP protects genome integrity and its mutation causes Seckel syndrome. TRAIP encodes a nucleolar protein that migrates to UV-induced DNA lesions via a direct interaction with the DNA replication clamp PCNA. Thus far, mechanistically how UV mobilizes TRAIP from the nucleoli remains unknown. We found that PCNA binding is dispensable for the nucleolus-nucleoplasm shuttling of TRAIP following cell exposure to UV irradiation, and that its redistribution did not rely on the master DNA damage kinases ATM and ATR. Interestingly, I-PpoI-induced ribosomal DNA damage led to TRAIP exclusion from the nucleoli, raising the possibility that active ribosomal DNA transcription may underlie TRAIP retention in the nuclear sub-compartments. Accordingly, chemical inhibition of RNA polymerase I activity led to TRAIP diffusion into the nucleoplasm, and was coupled with marked reduction of DNA/RNA hybrids in the nucleoli, suggesting that TRAIP may be sequestered via binding to nucleic acid structures in the nucleoli. Consistently, cell pre-treatment with DNase/RNase effectively released TRAIP from the nucleoli. Taken together, our study defines a bipartite mechanism that drives TRAIP trafficking in response to UV damage, and highlights the nucleolus as a stress sensor that contributes to orchestrating DNA damage responses.
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Affiliation(s)
- Yangzi Chen
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R
| | - Junshi Li
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R
| | - Fakun Cao
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R
| | - Jason Lam
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R
| | - Clooney Cy Cheng
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R
| | - Cheng-Han Yu
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R
| | - Michael Sy Huen
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong S.A.R.,Center for Synthetic Biology Engineering Research, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, PR China.,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong S.A.R
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18
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Girke P, Seufert W. Compositional reorganization of the nucleolus in budding yeast mitosis. Mol Biol Cell 2019; 30:591-606. [PMID: 30625028 PMCID: PMC6589692 DOI: 10.1091/mbc.e18-08-0524] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 01/02/2019] [Accepted: 01/04/2019] [Indexed: 11/26/2022] Open
Abstract
The nucleolus is a membraneless organelle of the nucleus and the site of rRNA synthesis, maturation, and assembly into preribosomal particles. The nucleolus, organized around arrays of rRNA genes (rDNA), dissolves during prophase of mitosis in metazoans, when rDNA transcription ceases, and reforms in telophase, when rDNA transcription resumes. No such dissolution and reformation cycle exists in budding yeast, and the precise course of nucleolar segregation remains unclear. By quantitative live-cell imaging, we observed that the yeast nucleolus is reorganized in its protein composition during mitosis. Daughter cells received equal shares of preinitiation factors, which bind the RNA polymerase I promoter and the rDNA binding barrier protein Fob1, but only about one-third of RNA polymerase I and the processing factors Nop56 and Nsr1. The distribution bias was diminished in nonpolar chromosome segregation events observable in dyn1 mutants. Unequal distribution, however, was enhanced by defects in RNA polymerase I, suggesting that rDNA transcription supports nucleolar segregation. Indeed, quantification of pre-rRNA levels indicated ongoing rDNA transcription in yeast mitosis. These data, together with photobleaching experiments to measure nucleolar protein dynamics in anaphase, consolidate a model that explains the differential partitioning of nucleolar components in budding yeast mitosis.
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Affiliation(s)
- Philipp Girke
- Department of Genetics, University of Regensburg, D-93040 Regensburg, Germany
| | - Wolfgang Seufert
- Department of Genetics, University of Regensburg, D-93040 Regensburg, Germany
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19
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Ditlev JA, Case LB, Rosen MK. Who's In and Who's Out-Compositional Control of Biomolecular Condensates. J Mol Biol 2018; 430:4666-4684. [PMID: 30099028 PMCID: PMC6204295 DOI: 10.1016/j.jmb.2018.08.003] [Citation(s) in RCA: 221] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/01/2018] [Accepted: 08/05/2018] [Indexed: 02/06/2023]
Abstract
Biomolecular condensates are two- and three-dimensional compartments in eukaryotic cells that concentrate specific collections of molecules without an encapsulating membrane. Many condensates behave as dynamic liquids and appear to form through liquid-liquid phase separation driven by weak, multivalent interactions between macromolecules. In this review, we discuss current models and data regarding the control of condensate composition, and we describe our current understanding of the composition of representative condensates including PML nuclear bodies, P-bodies, stress granules, the nucleolus, and two-dimensional membrane localized LAT and nephrin clusters. Specific interactions, such as interactions between modular binding domains, weaker interactions between intrinsically disorder regions and nucleic acid base pairing, and nonspecific interactions, such as electrostatic interactions and hydrophobic interactions, influence condensate composition. Understanding how specific condensate composition is determined is essential to understanding condensates as biochemical entities and ultimately discerning their cellular and organismic functions.
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Affiliation(s)
- Jonathon A Ditlev
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Lindsay B Case
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Michael K Rosen
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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20
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Condensin action and compaction. Curr Genet 2018; 65:407-415. [PMID: 30361853 DOI: 10.1007/s00294-018-0899-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 10/18/2018] [Accepted: 10/20/2018] [Indexed: 12/20/2022]
Abstract
Condensin is a multi-subunit protein complex that belongs to the family of structural maintenance of chromosomes (SMC) complexes. Condensins regulate chromosome structure in a wide range of processes including chromosome segregation, gene regulation, DNA repair and recombination. Recent research defined the structural features and molecular activities of condensins, but it is unclear how these activities are connected to the multitude of phenotypes and functions attributed to condensins. In this review, we briefly discuss the different molecular mechanisms by which condensins may regulate global chromosome compaction, organization of topologically associated domains, clustering of specific loci such as tRNA genes, rDNA segregation, and gene regulation.
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21
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Núñez Villacís L, Wong MS, Ferguson LL, Hein N, George AJ, Hannan KM. New Roles for the Nucleolus in Health and Disease. Bioessays 2018; 40:e1700233. [PMID: 29603296 DOI: 10.1002/bies.201700233] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 02/02/2018] [Indexed: 12/31/2022]
Abstract
Over the last decade, our appreciation of the importance of the nucleolus for cellular function has progressed from the ordinary to the extraordinary. We no longer think of the nucleolus as simply the site of ribosome production, or a dynamic subnuclear body noted by pathologists for its changes in size and shape with malignancy. Instead, the nucleolus has emerged as a key controller of many cellular processes that are fundamental to normal cell homeostasis and the target for dysregulation in many human diseases; in some cases, independent of its functions in ribosome biogenesis. These extra-nucleolar or new functions, which we term "non-canonical" to distinguish them from the more traditional role of the nucleolus in ribosome synthesis, are the focus of this review. In particular, we explore how these non-canonical functions may provide novel insights into human disease and in some cases new targets for therapeutic development.
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Affiliation(s)
- Lorena Núñez Villacís
- ACRF Department of Cancer Biology and Therapeutics, John Curtin School of Medical Research, The Australian National University, Acton, 2601, Australia
| | - Mei S Wong
- ACRF Department of Cancer Biology and Therapeutics, John Curtin School of Medical Research, The Australian National University, Acton, 2601, Australia.,Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Center, Melbourne, 3000, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, 3010, Australia
| | - Laura L Ferguson
- ACRF Department of Cancer Biology and Therapeutics, John Curtin School of Medical Research, The Australian National University, Acton, 2601, Australia
| | - Nadine Hein
- ACRF Department of Cancer Biology and Therapeutics, John Curtin School of Medical Research, The Australian National University, Acton, 2601, Australia
| | - Amee J George
- ACRF Department of Cancer Biology and Therapeutics, John Curtin School of Medical Research, The Australian National University, Acton, 2601, Australia.,School of Biomedical Sciences, University of Queensland, St Lucia, 4067, Australia.,Department of Clinical Pathology, The University of Melbourne, Parkville, 3010, Australia
| | - Katherine M Hannan
- ACRF Department of Cancer Biology and Therapeutics, John Curtin School of Medical Research, The Australian National University, Acton, 2601, Australia.,Department of Biochemistry, The University of Melbourne, Parkville, 3010, Australia
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22
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Matos-Perdomo E, Machín F. The ribosomal DNA metaphase loop of Saccharomyces cerevisiae gets condensed upon heat stress in a Cdc14-independent TORC1-dependent manner. Cell Cycle 2018; 17:200-215. [PMID: 29166821 PMCID: PMC5884360 DOI: 10.1080/15384101.2017.1407890] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Chromosome morphology in Saccharomyces cerevisiae is only visible at the microscopic level in the ribosomal DNA array (rDNA). The rDNA has been thus used as a model to characterize condensation and segregation of sister chromatids in mitosis. It has been established that the metaphase structure ("loop") depends, among others, on the condensin complex; whereas its segregation also depends on that complex, the Polo-like kinase Cdc5 and the cell cycle master phosphatase Cdc14. In addition, Cdc14 also drives rDNA hypercondensation in telophase. Remarkably, since all these components are essential for cell survival, their role on rDNA condensation and segregation was established by temperature-sensitive (ts) alleles. Here, we show that the heat stress (HS) used to inactivate ts alleles (25 ºC to 37 ºC shift) causes rDNA loop condensation in metaphase-arrested wild type cells, a result that can also be mimicked by other stresses that inhibit the TORC1 pathway. Because this condensation might challenge previous findings with ts alleles, we have repeated classical experiments of rDNA condensation and segregation, yet using instead auxin-driven degradation alleles (aid alleles). We have undertaken the protein degradation at lower temperatures (25 ºC) and concluded that the classical roles for condensin, Cdc5, Cdc14 and Cdc15 still prevailed. Thus, condensin degradation disrupts rDNA higher organization, Cdc14 and Cdc5 degradation precludes rDNA segregation and Cdc15 degradation still allows rDNA hypercompaction in telophase. Finally, we provide direct genetic evidence that this HS-mediated rDNA condensation is dependent on TORC1 but, unlike the one observed in anaphase, is independent of Cdc14.
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Affiliation(s)
- Emiliano Matos-Perdomo
- a Unidad de Investigación , Hospital Universitario Ntra Sra de Candelaria , Ctra del Rosario 145, 38010 , Santa Cruz de Tenerife , Spain.,b Universidad de La Laguna , Tenerife , Spain
| | - Félix Machín
- a Unidad de Investigación , Hospital Universitario Ntra Sra de Candelaria , Ctra del Rosario 145, 38010 , Santa Cruz de Tenerife , Spain
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23
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Abstract
The nucleolus in Saccharomyces cerevisiae is one of the last genomic regions to be condensed in mitosis. A new study shows that this extended nucleolar relaxation state is fundamental for the timely execution of mitotic exit.
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