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Lee KY, Green RA, Gutierrez E, Gomez-Cavazos JS, Kolotuev I, Wang S, Desai A, Groisman A, Oegema K. CYK-4 functions independently of its centralspindlin partner ZEN-4 to cellularize oocytes in germline syncytia. eLife 2018; 7:36919. [PMID: 29989548 PMCID: PMC6056237 DOI: 10.7554/elife.36919] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 07/09/2018] [Indexed: 12/15/2022] Open
Abstract
Throughout metazoans, germ cells undergo incomplete cytokinesis to form syncytia connected by intercellular bridges. Gamete formation ultimately requires bridge closure, yet how bridges are reactivated to close is not known. The most conserved bridge component is centralspindlin, a complex of the Rho family GTPase-activating protein (GAP) CYK-4/MgcRacGAP and the microtubule motor ZEN-4/kinesin-6. Here, we show that oocyte production by the syncytial Caenorhabditis elegans germline requires CYK-4 but not ZEN-4, which contrasts with cytokinesis, where both are essential. Longitudinal imaging after conditional inactivation revealed that CYK-4 activity is important for oocyte cellularization, but not for the cytokinesis-like events that generate syncytial compartments. CYK-4’s lipid-binding C1 domain and the GTPase-binding interface of its GAP domain were both required to target CYK-4 to intercellular bridges and to cellularize oocytes. These results suggest that the conserved C1-GAP region of CYK-4 constitutes a targeting module required for closure of intercellular bridges in germline syncytia.
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Affiliation(s)
- Kian-Yong Lee
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
| | - Rebecca A Green
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
| | - Edgar Gutierrez
- Department of Physics, University of California, San Diego, La Jolla, United States
| | - J Sebastian Gomez-Cavazos
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
| | - Irina Kolotuev
- Microscopy Rennes Imaging Center and Biosit, University of Rennes 1, Rennes, France
| | - Shaohe Wang
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
| | - Arshad Desai
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
| | - Alex Groisman
- Department of Physics, University of California, San Diego, La Jolla, United States
| | - Karen Oegema
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
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Khaliullin RN, Green RA, Shi LZ, Gomez-Cavazos JS, Berns MW, Desai A, Oegema K. A positive-feedback-based mechanism for constriction rate acceleration during cytokinesis in Caenorhabditis elegans. eLife 2018; 7:36073. [PMID: 29963981 PMCID: PMC6063732 DOI: 10.7554/elife.36073] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 07/01/2018] [Indexed: 12/23/2022] Open
Abstract
To ensure timely cytokinesis, the equatorial actomyosin contractile ring constricts at a relatively constant rate despite its progressively decreasing size. Thus, the per-unit-length constriction rate increases as ring perimeter decreases. To understand this acceleration, we monitored cortical surface and ring component dynamics during the first cytokinesis of the Caenorhabditis elegans embryo. We found that, per unit length, the amount of ring components (myosin, anillin) and the constriction rate increase with parallel exponential kinetics. Quantitative analysis of cortical flow indicated that the cortex within the ring is compressed along the axis perpendicular to the ring, and the per-unit-length rate of cortical compression increases during constriction in proportion to ring myosin. We propose that positive feedback between ring myosin and compression-driven flow of cortex into the ring drives an exponential increase in the per-unit-length amount of ring myosin to maintain a high ring constriction rate and support this proposal with an analytical mathematical model.
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Affiliation(s)
- Renat N Khaliullin
- Department of Cellular and Molecular Medicine, Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States
| | - Rebecca A Green
- Department of Cellular and Molecular Medicine, Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States
| | - Linda Z Shi
- Department of Bioengineering and Institute of Engineering in Medicine, University of California, San Diego, San Diego, United States
| | - J Sebastian Gomez-Cavazos
- Department of Cellular and Molecular Medicine, Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States
| | - Michael W Berns
- Department of Bioengineering and Institute of Engineering in Medicine, University of California, San Diego, San Diego, United States
| | - Arshad Desai
- Department of Cellular and Molecular Medicine, Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States
| | - Karen Oegema
- Department of Cellular and Molecular Medicine, Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States
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Hattersley N, Lara-Gonzalez P, Cheerambathur D, Gomez-Cavazos JS, Kim T, Prevo B, Khaliullin R, Lee KY, Ohta M, Green R, Oegema K, Desai A. Employing the one-cell C. elegans embryo to study cell division processes. Methods Cell Biol 2018; 144:185-231. [PMID: 29804670 DOI: 10.1016/bs.mcb.2018.03.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The one-cell Caenorhabditis elegans embryo offers many advantages for mechanistic analysis of cell division processes. Conservation of key genes and pathways involved in cell division makes findings in C. elegans broadly relevant. A key technical advantage of this system is the ability to penetrantly deplete essential gene products by RNA interference (RNAi) and replace them with wild-type or mutant versions expressed at endogenous levels from single copy RNAi-resistant transgene insertions. This ability to precisely perturb essential genes is complemented by the inherently highly reproducible nature of the zygotic division that facilitates development of quantitative imaging assays. Here, we detail approaches to generate targeted single copy transgene insertions that are RNAi-resistant, to engineer variants of individual genes employing transgene insertions as well as at the endogenous locus, and to in situ tag genes with fluorophores/purification tags. We also describe imaging assays and common image analysis tools employed to quantitatively monitor phenotypic effects of specific perturbations on meiotic and mitotic chromosome segregation, centrosome assembly/function, and cortical dynamics/cytokinesis.
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Affiliation(s)
- Neil Hattersley
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Pablo Lara-Gonzalez
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Dhanya Cheerambathur
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - J Sebastian Gomez-Cavazos
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Taekyung Kim
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Bram Prevo
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Renat Khaliullin
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Kian-Yong Lee
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Midori Ohta
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Rebecca Green
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Karen Oegema
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States
| | - Arshad Desai
- Ludwig Institute for Cancer Research, La Jolla, CA, United States; Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States.
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Abstract
The luminal domain of Nup210 that lacks NPC sorting signals is sufficient for myogenesis, which suggests that Nup210 may operate within the nuclear envelope/ER lumen during differentiation. Previously, we identified the nucleoporin gp210/Nup210 as a critical regulator of muscle and neuronal differentiation, but how this nucleoporin exerts its function and whether it modulates nuclear pore complex (NPC) activity remain unknown. Here, we show that gp210/Nup210 mediates muscle cell differentiation in vitro via its conserved N-terminal domain that extends into the perinuclear space. Removal of the C-terminal domain, which partially mislocalizes gp210/Nup210 away from NPCs, efficiently rescues the differentiation defect caused by the knockdown of endogenous gp210/Nup210. Unexpectedly, a gp210/Nup210 mutant lacking the NPC-targeting transmembrane and C-terminal domains is sufficient for C2C12 myoblast differentiation. We demonstrate that the endoplasmic reticulum (ER) stress-specific caspase cascade is exacerbated during Nup210 depletion and that blocking ER stress-mediated apoptosis rescues differentiation of Nup210-deficient cells. Our results suggest that the role of gp210/Nup210 in cell differentiation is mediated by its large luminal domain, which can act independently of NPC association and appears to play a pivotal role in the maintenance of nuclear envelope/ER homeostasis.
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Affiliation(s)
- J Sebastian Gomez-Cavazos
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037 Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093
| | - Martin W Hetzer
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037
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Gomez-Cavazos JS, Hetzer MW. Outfits for different occasions: tissue-specific roles of Nuclear Envelope proteins. Curr Opin Cell Biol 2012; 24:775-83. [PMID: 22995343 DOI: 10.1016/j.ceb.2012.08.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/07/2012] [Accepted: 08/20/2012] [Indexed: 11/29/2022]
Abstract
The Nuclear Envelope (NE) contains over 100 different proteins that associate with nuclear components such as chromatin, the lamina and the transcription machinery. Mutations in genes encoding NE proteins have been shown to result in tissue-specific defects and disease, suggesting cell-type specific differences in NE composition and function. Consistent with these observations, recent studies have revealed unexpected functions for numerous NE associated proteins during cell differentiation and development. Here we review the latest insights into the roles played by the NE in cell differentiation, development, disease and aging, focusing primarily on inner nuclear membrane (INM) proteins and nuclear pore components.
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Affiliation(s)
- J Sebastian Gomez-Cavazos
- Salk Institute for Biological Studies, Molecular and Cell Biology Laboratory, 10010N. Torrey Pines Road, La Jolla, 92037 CA, United States
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D'Angelo MA, Gomez-Cavazos JS, Mei A, Lackner DH, Hetzer MW. A change in nuclear pore complex composition regulates cell differentiation. Dev Cell 2012; 22:446-58. [PMID: 22264802 DOI: 10.1016/j.devcel.2011.11.021] [Citation(s) in RCA: 174] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 10/06/2011] [Accepted: 11/14/2011] [Indexed: 12/11/2022]
Abstract
Nuclear pore complexes (NPCs) are built from ∼30 different proteins called nucleoporins or Nups. Previous studies have shown that several Nups exhibit cell-type-specific expression and that mutations in NPC components result in tissue-specific diseases. Here we show that a specific change in NPC composition is required for both myogenic and neuronal differentiation. The transmembrane nucleoporin Nup210 is absent in proliferating myoblasts and embryonic stem cells (ESCs) but becomes expressed and incorporated into NPCs during cell differentiation. Preventing Nup210 production by RNAi blocks myogenesis and the differentiation of ESCs into neuroprogenitors. We found that the addition of Nup210 to NPCs does not affect nuclear transport but is required for the induction of genes that are essential for cell differentiation. Our results identify a single change in NPC composition as an essential step in cell differentiation and establish a role for Nup210 in gene expression regulation and cell fate determination.
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Affiliation(s)
- Maximiliano A D'Angelo
- Salk Institute for Biological Studies, Molecular and Cell Biology Laboratory, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA.
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