1
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Min H, Spaulding EL, Sharp CS, Garg P, Jeon E, Miranda Portillo LS, Lind NA, Updike DL. A role for BYN-1/bystin in cellular uptake and clearance of residual bodies in the Caenorhabditis elegans germline. Development 2024; 151:dev202694. [PMID: 39377446 PMCID: PMC11488650 DOI: 10.1242/dev.202694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 08/02/2024] [Indexed: 10/09/2024]
Abstract
GLH/Vasa/DDX4 helicases are core germ-granule proteins that promote germline development and fertility. A yeast-two-hybrid screen using Caenorhabditis elegans GLH-1 as bait identified BYN-1, the homolog of human bystin/BYSL. In humans, bystin promotes cell adhesion and invasion in gliomas, and, with its binding partner trophinin, triggers embryonic implantation into the uterine wall. C. elegans embryos do not implant and lack a homolog of trophinin, but both trophinin and GLH-1 contain unique decapeptide phenylalanine-glycine (FG)-repeat domains. In germ cells, we find endogenous BYN-1 in the nucleolus, partitioned away from cytoplasmic germ granules. However, BYN-1 enters the cytoplasm during spermatogenesis to colocalize with GLH-1. Both proteins become deposited in residual bodies (RBs), which are then engulfed and cleared by the somatic gonad. We show that BYN-1 acts upstream of CED-1 to drive RB engulfment, and that removal of the FG-repeat domains from GLH-1 and GLH-2 can partially phenocopy byn-1 defects in RB clearance. These results point to an evolutionarily conserved pathway whereby cellular uptake is triggered by the cytoplasmic mobilization of bystin/BYN-1 to interact with proteins harboring FG-repeats.
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Affiliation(s)
- Hyemin Min
- Davis Center for Regenerative Biology and Aging, The Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA
| | - Emily L. Spaulding
- Davis Center for Regenerative Biology and Aging, The Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA
| | - Catherine S. Sharp
- Davis Center for Regenerative Biology and Aging, The Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA
| | - Pankaj Garg
- Davis Center for Regenerative Biology and Aging, The Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA
| | - Esther Jeon
- Davis Center for Regenerative Biology and Aging, The Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA
| | - Lyn S. Miranda Portillo
- Davis Center for Regenerative Biology and Aging, The Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA
| | - Noah A. Lind
- Davis Center for Regenerative Biology and Aging, The Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA
| | - Dustin L. Updike
- Davis Center for Regenerative Biology and Aging, The Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA
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2
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Elaswad MT, Gao M, Tice VE, Bright CG, Thomas GM, Munderloh C, Trombley NJ, Haddad CN, Johnson UG, Cichon AN, Schisa JA. The CCT chaperonin and actin modulate the ER and RNA-binding protein condensation during oogenesis and maintain translational repression of maternal mRNA and oocyte quality. Mol Biol Cell 2024; 35:ar131. [PMID: 39167497 PMCID: PMC11481691 DOI: 10.1091/mbc.e24-05-0216] [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: 07/01/2024] [Revised: 08/12/2024] [Accepted: 08/14/2024] [Indexed: 08/23/2024] Open
Abstract
The regulation of maternal mRNAs is essential for proper oogenesis, the production of viable gametes, and to avoid birth defects and infertility. Many oogenic RNA-binding proteins have been identified with roles in mRNA metabolism, some of which localize to dynamic ribonucleoprotein granules and others that appear dispersed. Here, we use a combination of in vitro condensation assays and the in vivo Caenorhabditis elegans oogenesis model to characterize the properties of the conserved KH-domain MEX-3 protein and to identify novel regulators of MEX-3 and three other translational regulators. We demonstrate that MEX-3 undergoes phase separation and appears to have intrinsic gel-like properties in vitro. We also identify novel roles for the chaperonin-containing tailless complex polypeptide 1 (CCT) chaperonin and actin in preventing ectopic RNA-binding protein condensates in maturing oocytes that appear to be independent of MEX-3 folding. The CCT chaperonin and actin also oppose the expansion of endoplasmic reticulum sheets that may promote ectopic condensation of RNA-binding proteins. These novel regulators of condensation are also required for the translational repression of maternal mRNA which is essential for oocyte quality and fertility. The identification of this regulatory network may also have implications for understanding the role of hMex3 phase transitions in cancer.
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Affiliation(s)
- Mohamed T. Elaswad
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859
- Biochemistry Cell and Molecular Biology Program, Central Michigan University, Mount Pleasant, MI 48859
| | - Mingze Gao
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859
- Biochemistry Cell and Molecular Biology Program, Central Michigan University, Mount Pleasant, MI 48859
| | - Victoria E. Tice
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859
- Biochemistry Cell and Molecular Biology Program, Central Michigan University, Mount Pleasant, MI 48859
| | - Cora G. Bright
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859
| | - Grace M. Thomas
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859
| | - Chloe Munderloh
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859
| | | | - Christya N. Haddad
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859
| | - Ulysses G. Johnson
- Biochemistry Cell and Molecular Biology Program, Central Michigan University, Mount Pleasant, MI 48859
- Department of Chemistry and Biochemistry, Central Michigan University, Mount Pleasant, MI 48859
| | - Ashley N. Cichon
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859
| | - Jennifer A. Schisa
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859
- Biochemistry Cell and Molecular Biology Program, Central Michigan University, Mount Pleasant, MI 48859
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3
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Elaswad MT, Gao M, Tice VE, Bright CG, Thomas GM, Munderloh C, Trombley NJ, Haddad CN, Johnson UG, Cichon AN, Schisa JA. The CCT chaperonin and actin modulate the ER and RNA-binding protein condensation during oogenesis to maintain translational repression of maternal mRNA and oocyte quality. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.01.601596. [PMID: 39005301 PMCID: PMC11244991 DOI: 10.1101/2024.07.01.601596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
The regulation of maternal mRNAs is essential for proper oogenesis, the production of viable gametes, and to avoid birth defects and infertility. Many oogenic RNA-binding proteins have been identified with roles in mRNA metabolism, some of which localize to dynamic ribonucleoprotein granules and others that appear dispersed. Here, we use a combination of in vitro condensation assays and the in vivo C. elegans oogenesis model to determine the intrinsic properties of the conserved KH-domain MEX-3 protein and to identify novel regulators of MEX-3 and the Lsm protein, CAR-1. We demonstrate that MEX-3 undergoes liquid-liquid phase separation and appears to have intrinsic gel-like properties in vitro . We also identify novel roles for the CCT chaperonin and actin in preventing ectopic RNA-binding protein condensates in maturing oocytes that appear to be independent of MEX-3 folding. CCT and actin also oppose the expansion of ER sheets that may promote ectopic condensation of RNA-binding proteins that are associated with de-repression of maternal mRNA. This regulatory network is essential to preserve oocyte quality, prevent infertility, and may have implications for understanding the role of hMex3 phase transitions in cancer. Significance statement The molecular mechanisms that regulate phase transitions of oogenic RNA-binding proteins are critical to elucidate but are not fully understood.We identify novel regulators of RNA-binding protein phase transitions in maturing oocytes that are required to maintain translational repression of maternal mRNAs and oocyte quality.This study is the first to elucidate a regulatory network involving the CCT chaperonin, actin, and the ER for phase transitions of RNA-binding proteins during oogenesis. Our findings for the conserved MEX-3 protein may also be applicable to better understanding the role of hMex3 phase transitions in cancer.
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4
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Tang Y, Yang X, Huang A, Seong K, Ye M, Li M, Zhao Q, Krasileva K, Gu Y. Proxiome assembly of the plant nuclear pore reveals an essential hub for gene expression regulation. NATURE PLANTS 2024; 10:1005-1017. [PMID: 38773271 DOI: 10.1038/s41477-024-01698-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 04/11/2024] [Indexed: 05/23/2024]
Abstract
The nuclear pore complex (NPC) is vital for nucleocytoplasmic communication. Recent evidence emphasizes its extensive association with proteins of diverse functions, suggesting roles beyond cargo transport. Yet, our understanding of NPC's composition and functionality at this extended level remains limited. Here, through proximity-labelling proteomics, we uncover both local and global NPC-associated proteome in Arabidopsis, comprising over 500 unique proteins, predominantly associated with NPC's peripheral extension structures. Compositional analysis of these proteins revealed that the NPC concentrates chromatin remodellers, transcriptional regulators and mRNA processing machineries in the nucleoplasmic region while recruiting translation regulatory machinery on the cytoplasmic side, achieving a remarkable orchestration of the genetic information flow by coupling RNA transcription, maturation, transport and translation regulation. Further biochemical and structural modelling analyses reveal that extensive interactions with nucleoporins, along with phase separation mediated by substantial intrinsically disordered proteins, may drive the formation of the unexpectedly large nuclear pore proteome assembly.
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Affiliation(s)
- Yu Tang
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
- Institute of Advanced Agricultural Sciences, Peking University, Weifang, Shandong, China
| | - Xiangyun Yang
- Institute of Advanced Agricultural Sciences, Peking University, Weifang, Shandong, China
| | - Aobo Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Kyungyong Seong
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Mao Ye
- Institute of Advanced Agricultural Sciences, Peking University, Weifang, Shandong, China
| | - Mengting Li
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Qiao Zhao
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Ksenia Krasileva
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Yangnan Gu
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.
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5
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Osterli E, Ellenbecker M, Wang X, Terzo M, Jacobson K, Cuello D, Voronina E. COP9 signalosome component CSN-5 stabilizes PUF proteins FBF-1 and FBF-2 in Caenorhabditis elegans germline stem and progenitor cells. Genetics 2024; 227:iyae033. [PMID: 38427913 PMCID: PMC11075551 DOI: 10.1093/genetics/iyae033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/16/2024] [Accepted: 02/17/2024] [Indexed: 03/03/2024] Open
Abstract
RNA-binding proteins FBF-1 and FBF-2 (FBFs) are required for germline stem cell maintenance and the sperm/oocyte switch in Caenorhabditis elegans, although the mechanisms controlling FBF protein levels remain unknown. We identified an interaction between both FBFs and CSN-5), a component of the constitutive photomorphogenesis 9 (COP9) signalosome best known for its role in regulating protein degradation. Here, we find that the Mpr1/Pad1 N-terminal metalloprotease domain of CSN-5 interacts with the Pumilio and FBF RNA-binding domain of FBFs and the interaction is conserved for human homologs CSN5 and PUM1. The interaction between FBF-2 and CSN-5 can be detected in vivo by proximity ligation. csn-5 mutation results in the destabilization of FBF proteins, which may explain previously observed decrease in the numbers of germline stem and progenitor cells, and disruption of oogenesis. The loss of csn-5 does not decrease the levels of a related PUF protein PUF-3, and csn-5(lf) phenotype is not enhanced by fbf-1/2 knockdown, suggesting that the effect is specific to FBFs. The effect of csn-5 on oogenesis is largely independent of the COP9 signalosome and is cell autonomous. Surprisingly, the regulation of FBF protein levels involves a combination of COP9-dependent and COP9-independent mechanisms differentially affecting FBF-1 and FBF-2. This work supports a previously unappreciated role for CSN-5 in the stabilization of germline stem cell regulatory proteins FBF-1 and FBF-2.
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Affiliation(s)
- Emily Osterli
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Mary Ellenbecker
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Xiaobo Wang
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Mikaya Terzo
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Ketch Jacobson
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - DeAnna Cuello
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Ekaterina Voronina
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
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6
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Waddell BM, Wu CW. A role for the C. elegans Argonaute protein CSR-1 in small nuclear RNA 3' processing. PLoS Genet 2024; 20:e1011284. [PMID: 38743783 PMCID: PMC11125478 DOI: 10.1371/journal.pgen.1011284] [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: 10/11/2023] [Revised: 05/24/2024] [Accepted: 05/02/2024] [Indexed: 05/16/2024] Open
Abstract
The Integrator is a multi-subunit protein complex that catalyzes the maturation of snRNA transcripts via 3' cleavage, a step required for snRNA incorporation with snRNP for spliceosome biogenesis. Here we developed a GFP based in vivo snRNA misprocessing reporter as a readout of Integrator function and performed a genome-wide RNAi screen for Integrator regulators. We found that loss of the Argonaute encoding csr-1 gene resulted in widespread 3' misprocessing of snRNA transcripts that is accompanied by a significant increase in alternative splicing. Loss of the csr-1 gene down-regulates the germline expression of Integrator subunits 4 and 6 and is accompanied by a reduced protein translation efficiency of multiple Integrator catalytic and non-catalytic subunits. Through isoform and motif mutant analysis, we determined that CSR-1's effect on snRNA processing is dependent on its catalytic slicer activity but does not involve the CSR-1a isoform. Moreover, mRNA-sequencing revealed high similarity in the transcriptome profile between csr-1 and Integrator subunit knockdown via RNAi. Together, our findings reveal CSR-1 as a new regulator of the Integrator complex and implicate a novel role of this Argonaute protein in snRNA 3' processing.
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Affiliation(s)
- Brandon M. Waddell
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Cheng-Wei Wu
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Biochemistry, Microbiology and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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7
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Kapoor S, Adhikary K, Kotak S. PP2A-B55 SUR-6 promotes nuclear envelope breakdown in C. elegans embryos. Cell Rep 2023; 42:113495. [PMID: 37995185 DOI: 10.1016/j.celrep.2023.113495] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/25/2023] [Accepted: 11/09/2023] [Indexed: 11/25/2023] Open
Abstract
Nuclear envelope (NE) disassembly during mitosis is critical to ensure faithful segregation of the genetic material. NE disassembly is a phosphorylation-dependent process wherein mitotic kinases hyper-phosphorylate lamina and nucleoporins to initiate nuclear envelope breakdown (NEBD). In this study, we uncover an unexpected role of the PP2A phosphatase B55SUR-6 in NEBD during the first embryonic division of Caenorhabditis elegans embryo. B55SUR-6 depletion delays NE permeabilization and stabilizes lamina and nucleoporins. As a result, the merging of parental genomes and chromosome segregation is impaired. NEBD defect upon B55SUR-6 depletion is not due to delayed mitotic onset or mislocalization of mitotic kinases. Importantly, we demonstrate that microtubule-dependent mechanical forces synergize with B55SUR-6 for efficient NEBD. Finally, our data suggest that the lamin LMN-1 is likely a bona fide target of PP2A-B55SUR-6. These findings establish a model highlighting biochemical crosstalk between kinases, PP2A-B55SUR-6 phosphatase, and microtubule-generated mechanical forces in timely NE dissolution.
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Affiliation(s)
- Sukriti Kapoor
- Department of Microbiology and Cell Biology (MCB), Indian Institute of Science (IISc), Bangalore 560012, India
| | - Kuheli Adhikary
- Department of Microbiology and Cell Biology (MCB), Indian Institute of Science (IISc), Bangalore 560012, India
| | - Sachin Kotak
- Department of Microbiology and Cell Biology (MCB), Indian Institute of Science (IISc), Bangalore 560012, India.
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8
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Nkombo Nkoula S, Velez-Aguilera G, Ossareh-Nazari B, Van Hove L, Ayuso C, Legros V, Chevreux G, Thomas L, Seydoux G, Askjaer P, Pintard L. Mechanisms of nuclear pore complex disassembly by the mitotic Polo-like kinase 1 (PLK-1) in C. elegans embryos. SCIENCE ADVANCES 2023; 9:eadf7826. [PMID: 37467327 PMCID: PMC10355831 DOI: 10.1126/sciadv.adf7826] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/16/2023] [Indexed: 07/21/2023]
Abstract
The nuclear envelope, which protects and organizes the genome, is dismantled during mitosis. In the Caenorhabditis elegans zygote, nuclear envelope breakdown (NEBD) of the parental pronuclei is spatially and temporally regulated during mitosis to promote the unification of the maternal and paternal genomes. Nuclear pore complex (NPC) disassembly is a decisive step of NEBD, essential for nuclear permeabilization. By combining live imaging, biochemistry, and phosphoproteomics, we show that NPC disassembly is a stepwise process that involves Polo-like kinase 1 (PLK-1)-dependent and -independent steps. PLK-1 targets multiple NPC subcomplexes, including the cytoplasmic filaments, central channel, and inner ring. PLK-1 is recruited to and phosphorylates intrinsically disordered regions (IDRs) of several multivalent linker nucleoporins. Notably, although the phosphosites are not conserved between human and C. elegans nucleoporins, they are located in IDRs in both species. Our results suggest that targeting IDRs of multivalent linker nucleoporins is an evolutionarily conserved driver of NPC disassembly during mitosis.
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Affiliation(s)
- Sylvia Nkombo Nkoula
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
- Programme Équipe Labellisée Ligue contre le Cancer, Paris, France
| | - Griselda Velez-Aguilera
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
- Programme Équipe Labellisée Ligue contre le Cancer, Paris, France
| | - Batool Ossareh-Nazari
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
- Programme Équipe Labellisée Ligue contre le Cancer, Paris, France
| | - Lucie Van Hove
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
- Programme Équipe Labellisée Ligue contre le Cancer, Paris, France
| | - Cristina Ayuso
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, Seville, Spain
| | - Véronique Legros
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
| | - Guillaume Chevreux
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
| | - Laura Thomas
- HHMI and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Géraldine Seydoux
- HHMI and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter Askjaer
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, Seville, Spain
| | - Lionel Pintard
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
- Programme Équipe Labellisée Ligue contre le Cancer, Paris, France
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9
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Nkoula SN, Velez-Aguilera G, Ossareh-Nazari B, Hove LV, Ayuso C, Legros V, Chevreux G, Thomas L, Seydoux G, Askjaer P, Pintard L. Mechanisms of Nuclear Pore Complex disassembly by the mitotic Polo-Like Kinase 1 (PLK-1) in C. elegans embryos. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.21.528438. [PMID: 36865292 PMCID: PMC9980100 DOI: 10.1101/2023.02.21.528438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The nuclear envelope, which protects and organizes the interphase genome, is dismantled during mitosis. In the C. elegans zygote, nuclear envelope breakdown (NEBD) of the parental pronuclei is spatially and temporally regulated during mitosis to promote the unification of the parental genomes. During NEBD, Nuclear Pore Complex (NPC) disassembly is critical for rupturing the nuclear permeability barrier and removing the NPCs from the membranes near the centrosomes and between the juxtaposed pronuclei. By combining live imaging, biochemistry, and phosphoproteomics, we characterized NPC disassembly and unveiled the exact role of the mitotic kinase PLK-1 in this process. We show that PLK-1 disassembles the NPC by targeting multiple NPC sub-complexes, including the cytoplasmic filaments, the central channel, and the inner ring. Notably, PLK-1 is recruited to and phosphorylates intrinsically disordered regions of several multivalent linker nucleoporins, a mechanism that appears to be an evolutionarily conserved driver of NPC disassembly during mitosis. (149/150 words). One-Sentence Summary PLK-1 targets intrinsically disordered regions of multiple multivalent nucleoporins to dismantle the nuclear pore complexes in the C. elegans zygote.
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10
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Ellenbecker M, Voronina E. Disruption of C. elegans embryonic P granules upon dlc-1(RNAi) is not associated with P granule component loss. MICROPUBLICATION BIOLOGY 2022; 2022:10.17912/micropub.biology.000700. [PMID: 36568482 PMCID: PMC9772925 DOI: 10.17912/micropub.biology.000700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/21/2022] [Accepted: 12/03/2022] [Indexed: 12/27/2022]
Abstract
Dynein light chain (DLC-1) is a light chain component of the dynein motor complex, it functions as an allosteric regulator of multi-subunit protein complexes and promotes P granule integrity in the C. elegans embryo. P granules are RNA-protein complexes located in the C. elegans germline that are important for RNA regulation and fertility. To further study the role of DLC-1 during C. elegans embryogenesis we performed quantitative tandem mass tag mass spectrometry on embryos after dlc-1 knock down. The amount of core P granule components and nucleoporin proteins did not change after dlc-1(RNAi). These results show that DLC-1 does not help regulate P granule protein levels and support the model that DLC-1 facilitates phase separation of P granule components in vivo .
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11
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Miwa T, Ohtani K, Inoue K, Sakamoto H. The germ cell-specific TAP-like protein NXF-2 forms a novel granular structure and is required for tra-2 3'UTR-dependent mRNA export in Caenorhabditis elegans. Genes Cells 2022; 27:621-628. [PMID: 35950937 DOI: 10.1111/gtc.12978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/04/2022] [Accepted: 08/07/2022] [Indexed: 11/29/2022]
Abstract
TAP is a general mRNA export receptor and is highly conserved among eukaryotes. The nematode Caenorhabditis elegans has another TAP-like protein, NXF-2, but little is known about its function. In this study, we show that NXF-2 is specifically expressed in germ cells and forms a novel granular structure that is different from that of P granules and that NXF-2 granules are anchored to the nuclear periphery in the mitotic region of the hermaphrodite gonad. In contrast, NXF-2 granules are released within the whole cytoplasm in the meiotic region, where the feminization gene tra-2 starts to function. Both inhibition of XPO-1 (an ortholog of the export receptor CRM1) and mutation of the nuclear export signal of NXF-2 caused the release of NXF-2 granules from the nuclear periphery, indicating that anchoring of NXF-2 granules depends on XPO-1 function. Moreover, inhibition of NXF-2 resulted in a substantial nuclear accumulation of the reporter mRNA carrying the tra-2 3'UTR. These results suggest that, together with XPO-1, NXF-2 exports and anchors tra-2 mRNA to the nuclear periphery to avoid precocious translation until the germ cells reach the meiotic region, thereby contributing to the regulation of tra-2 mRNA expression. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Takashi Miwa
- Biology, Kobe University Graduate School of Science Faculty of Science, Grad. Sch. Sci. Tech.1-1 Rokkodai, Nada-ku, Kobe Hyogo, Japan
| | - Keigo Ohtani
- Biology, Kobe University Graduate School of Science Faculty of Science, Grad. Sch. Sci. Tech.1-1 Rokkodai, Nada-ku, Kobe Hyogo, Japan
| | - Kunio Inoue
- Biology, Kobe University Graduate School of Science Faculty of Science, Grad. Sch. Sci. Tech.1-1 Rokkodai, Nada-ku, Kobe Hyogo, Japan
| | - Hiroshi Sakamoto
- Biology, Kobe University Graduate School of Science Faculty of Science, Grad. Sch. Sci. Tech.1-1 Rokkodai, Nada-ku, Kobe Hyogo, Japan
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12
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Nag N, Sasidharan S, Uversky VN, Saudagar P, Tripathi T. Phase separation of FG-nucleoporins in nuclear pore complexes. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119205. [PMID: 34995711 DOI: 10.1016/j.bbamcr.2021.119205] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/14/2021] [Accepted: 12/23/2021] [Indexed: 12/11/2022]
Abstract
The nuclear envelope (NE) is a bilayer membrane that separates and physically isolates the genetic material from the cytoplasm. Nuclear pore complexes (NPCs) are cylindrical structures embedded in the NE and remain the sole channel of communication between the nucleus and the cytoplasm. The interior of NPCs contains densely packed intrinsically disordered FG-nucleoporins (FG-Nups), consequently forming a permeability barrier. This barrier facilitates the selection and specificity of the cargoes that are imported, exported, or shuttled through the NPCs. Recent studies have revealed that FG-Nups undergo the process of liquid-liquid phase separation into liquid droplets. Moreover, these liquid droplets mimic the permeability barrier observed in the interior of NPCs. This review highlights the phase separation of FG-Nups occurring inside the NPCs rooted in the NE. We discuss the phase separation of FG-Nups and compare the different aspects contributing to their phase separation. Furthermore, several diseases caused by the aberrant phase separation of the proteins are examined with respect to NEs. By understanding the fundamental process of phase separation at the nuclear membrane, the review seeks to explore the parameters influencing this phenomenon as well as its importance, ultimately paving the way for better research on the structure-function relationship of biomolecular condensates.
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Affiliation(s)
- Niharika Nag
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India
| | - Santanu Sasidharan
- Department of Biotechnology, National Institute of Technology Warangal, Warangal 506004, India
| | - Vladimir N Uversky
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33620, United States; Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy pereulok, 9, Dolgoprudny, Moscow Region 141700, Russia
| | - Prakash Saudagar
- Department of Biotechnology, National Institute of Technology Warangal, Warangal 506004, India.
| | - Timir Tripathi
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India.
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13
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Phillips CM, Updike DL. Germ granules and gene regulation in the Caenorhabditis elegans germline. Genetics 2022; 220:6541922. [PMID: 35239965 PMCID: PMC8893257 DOI: 10.1093/genetics/iyab195] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/10/2021] [Indexed: 01/27/2023] Open
Abstract
The transparency of Caenorhabditis elegans provides a unique window to observe and study the function of germ granules. Germ granules are specialized ribonucleoprotein (RNP) assemblies specific to the germline cytoplasm, and they are largely conserved across Metazoa. Within the germline cytoplasm, they are positioned to regulate mRNA abundance, translation, small RNA production, and cytoplasmic inheritance to help specify and maintain germline identity across generations. Here we provide an overview of germ granules and focus on the significance of more recent observations that describe how they further demix into sub-granules, each with unique compositions and functions.
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Affiliation(s)
- Carolyn M Phillips
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA,Corresponding author: (C.M.P.); (D.L.U.)
| | - Dustin L Updike
- The Mount Desert Island Biological Laboratory, Bar Harbor, ME 04672, USA,Corresponding author: (C.M.P.); (D.L.U.)
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14
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de la Cruz Ruiz P, Romero-Bueno R, Askjaer P. Analysis of Nuclear Pore Complexes in Caenorhabditis elegans by Live Imaging and Functional Genomics. Methods Mol Biol 2022; 2502:161-182. [PMID: 35412238 DOI: 10.1007/978-1-0716-2337-4_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Nuclear pore complexes (NPCs) are essential to communication of macromolecules between the cell nucleus and the surrounding cytoplasm. RNA synthesized in the nucleus is exported through NPCs to function in the cytoplasm, whereas transcription factors and other proteins are selectively and actively imported. In addition, many NPC constituents, known as nuclear pore proteins (nucleoporins or nups), also play critical roles in other processes, such as genome organization, gene expression, and kinetochore function. Thanks to its genetic amenability and transparent body, the nematode Caenorhabditis elegans is an attractive model to study NPC dynamics. We provide here an overview of available genome engineered strains and FLP/Frt-based tools to study tissue-specific functions of individual nucleoporins. We also present protocols for live imaging of fluorescently tagged nucleoporins in intact tissues of embryos, larvae, and adult and for analysis of interactions between nucleoporins and chromatin by DamID.
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Affiliation(s)
- Patricia de la Cruz Ruiz
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, Seville, Spain
| | - Raquel Romero-Bueno
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, Seville, Spain
| | - Peter Askjaer
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, Seville, Spain.
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15
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Price IF, Hertz HL, Pastore B, Wagner J, Tang W. Proximity labeling identifies LOTUS domain proteins that promote the formation of perinuclear germ granules in C. elegans. eLife 2021; 10:e72276. [PMID: 34730513 PMCID: PMC8616582 DOI: 10.7554/elife.72276] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 11/01/2021] [Indexed: 11/30/2022] Open
Abstract
The germ line produces gametes that transmit genetic and epigenetic information to the next generation. Maintenance of germ cells and development of gametes require germ granules-well-conserved membraneless and RNA-rich organelles. The composition of germ granules is elusive owing to their dynamic nature and their exclusive expression in the germ line. Using Caenorhabditis elegans germ granule, called P granule, as a model system, we employed a proximity-based labeling method in combination with mass spectrometry to comprehensively define its protein components. This set of experiments identified over 200 proteins, many of which contain intrinsically disordered regions (IDRs). An RNA interference-based screen identified factors that are essential for P granule assembly, notably EGGD-1 and EGGD-2, two putative LOTUS-domain proteins. Loss of eggd-1 and eggd-2 results in separation of P granules from the nuclear envelope, germline atrophy, and reduced fertility. We show that IDRs of EGGD-1 are required to anchor EGGD-1 to the nuclear periphery while its LOTUS domains are required to promote the perinuclear localization of P granules. Taken together, our work expands the repertoire of P granule constituents and provides new insights into the role of LOTUS-domain proteins in germ granule organization.
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Affiliation(s)
- Ian F Price
- Department of Biological Chemistry and PharmacologyColumbusUnited States
- Center for RNA BiologyColumbusUnited States
- Ohio State Biochemistry ProgramColumbusUnited States
| | - Hannah L Hertz
- Department of Biological Chemistry and PharmacologyColumbusUnited States
- Center for RNA BiologyColumbusUnited States
| | - Benjamin Pastore
- Department of Biological Chemistry and PharmacologyColumbusUnited States
- Center for RNA BiologyColumbusUnited States
- Ohio State Biochemistry ProgramColumbusUnited States
| | - Jillian Wagner
- Department of Biological Chemistry and PharmacologyColumbusUnited States
- Department of Molecular Genetics, Ohio State UniversityColumbusUnited States
| | - Wen Tang
- Department of Biological Chemistry and PharmacologyColumbusUnited States
- Center for RNA BiologyColumbusUnited States
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16
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Multifunctionality of F-rich nucleoporins. Biochem Soc Trans 2021; 48:2603-2614. [PMID: 33336681 DOI: 10.1042/bst20200357] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/13/2020] [Accepted: 12/01/2020] [Indexed: 01/11/2023]
Abstract
Nucleoporins (Nups) represent a range of proteins most known for composing the macromolecular assembly of the nuclear pore complex (NPC). Among them, the family of intrinsically disordered proteins (IDPs) phenylalanine-glycine (FG) rich Nups, form the permeability barrier and coordinate the high-speed nucleocytoplasmic transport in a selective way. Those FG-Nups have been demonstrated to participate in various biological processes besides nucleocytoplasmic transport. The high number of accessible hydrophobic motifs of FG-Nups potentially gives rise to this multifunctionality, enabling them to form unique microenvironments. In this review, we discuss the multifunctionality of disordered and F-rich Nups and the diversity of their localizations, emphasizing the important roles of those Nups in various regulatory and metabolic processes.
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17
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Shinkai Y, Kuramochi M, Miyafusa T. New Family Members of FG Repeat Proteins and Their Unexplored Roles During Phase Separation. Front Cell Dev Biol 2021; 9:708702. [PMID: 34322491 PMCID: PMC8311347 DOI: 10.3389/fcell.2021.708702] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 06/17/2021] [Indexed: 12/26/2022] Open
Abstract
The condensation and compartmentalization of biomacromolecules in the cell are driven by the process of phase separation. The main effectors of phase separation are intrinsically disordered proteins, which include proteins with a phenylalanine-glycine (FG) repeat domain. Our understanding of the biological function of FG repeat proteins during phase separation has been mainly derived from recent research on a member of the nuclear pore complex proteins, nucleoporins containing FG repeat domain (FG-NUPs). FG-NUPs form meshwork structures by inter- and intra-molecular FG domain interactions, which confine the nucleo-cytoplasmic exchange. Whereas FG-NUPs localize in the nuclear membrane, other FG repeat proteins reside in the cytoplasm and the nucleoplasm, and the biological function of the FG repeat domain of these proteins is not well described. In the present review, we list the FG repeat proteins that are known to phase separate in the cell, and review their biological functions. We extract the unraveled features of FG repeat proteins as an activator of barrier formation and homotypic cell-cell interactions. Understanding the regulatory mechanisms of FG repeat proteins will provide a potential delivery tool for therapeutic reagents.
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Affiliation(s)
- Yoichi Shinkai
- Molecular Neurobiology Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Masahiro Kuramochi
- Graduate School of Science and Engineering, Ibaraki University, Hitachi, Japan
| | - Takamitsu Miyafusa
- Bio-System Research Group, Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
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18
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Cipriani PG, Bay O, Zinno J, Gutwein M, Gan HH, Mayya VK, Chung G, Chen JX, Fahs H, Guan Y, Duchaine TF, Selbach M, Piano F, Gunsalus KC. Novel LOTUS-domain proteins are organizational hubs that recruit C. elegans Vasa to germ granules. eLife 2021; 10:60833. [PMID: 34223818 PMCID: PMC8331183 DOI: 10.7554/elife.60833] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 06/27/2021] [Indexed: 12/16/2022] Open
Abstract
We describe MIP-1 and MIP-2, novel paralogous C. elegans germ granule components that interact with the intrinsically disordered MEG-3 protein. These proteins promote P granule condensation, form granules independently of MEG-3 in the postembryonic germ line, and balance each other in regulating P granule growth and localization. MIP-1 and MIP-2 each contain two LOTUS domains and intrinsically disordered regions and form homo- and heterodimers. They bind and anchor the Vasa homolog GLH-1 within P granules and are jointly required for coalescence of MEG-3, GLH-1, and PGL proteins. Animals lacking MIP-1 and MIP-2 show temperature-sensitive embryonic lethality, sterility, and mortal germ lines. Germline phenotypes include defects in stem cell self-renewal, meiotic progression, and gamete differentiation. We propose that these proteins serve as scaffolds and organizing centers for ribonucleoprotein networks within P granules that help recruit and balance essential RNA processing machinery to regulate key developmental transitions in the germ line.
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Affiliation(s)
- Patricia Giselle Cipriani
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, United States.,NYU Abu Dhabi Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Olivia Bay
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, United States
| | - John Zinno
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, United States
| | - Michelle Gutwein
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, United States
| | - Hin Hark Gan
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, United States
| | - Vinay K Mayya
- Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Canada
| | - George Chung
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, United States
| | - Jia-Xuan Chen
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Hala Fahs
- NYU Abu Dhabi Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Yu Guan
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, United States
| | - Thomas F Duchaine
- Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Canada
| | | | - Fabio Piano
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, United States.,NYU Abu Dhabi Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Kristin C Gunsalus
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, United States.,NYU Abu Dhabi Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
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19
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Tikhomirova MA, Sheval EV. Formation of Biomolecular Condensates: Regulation of Embryogenesis at the Cellular Level. Russ J Dev Biol 2021. [DOI: 10.1134/s1062360421020077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Mukherjee N, Mukherjee C. Germ cell ribonucleoprotein granules in different clades of life: From insects to mammals. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 12:e1642. [PMID: 33555143 DOI: 10.1002/wrna.1642] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 01/04/2021] [Accepted: 01/05/2021] [Indexed: 12/12/2022]
Abstract
Ribonucleoprotein (RNP) granules are no newcomers in biology. Found in all life forms, ranging across taxa, these membrane-less "organelles" have been classified into different categories based on their composition, structure, behavior, function, and localization. Broadly, they can be listed as stress granules (SGs), processing bodies (PBs), neuronal granules (NGs), and germ cell granules (GCGs). Keeping in line with the topic of this review, RNP granules present in the germ cells have been implicated in a wide range of cellular functions including cellular specification, differentiation, proliferation, and so forth. The mechanisms used by them can be diverse and many of them remain partly obscure and active areas of research. GCGs can be of different types in different organisms and at different stages of development, with multiple types coexisting in the same cell. In this review, the different known subcategories of GCGs have been studied with respect to five distinct model organisms, namely, Drosophila, Caenorhabditis elegans, Xenopus, Zebrafish, and mammals. Of them, the cytoplasmic polar granules in Drosophila, P granules in C. elegans, balbiani body in Xenopus and Zebrafish, and chromatoid bodies in mammals have been specifically emphasized upon. A descriptive account of the same has been provided along with insights into our current understanding of their functional significance with respect to cellular events relating to different developmental and reproductive processes. This article is categorized under: RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Export and Localization > RNA Localization RNA in Disease and Development > RNA in Disease.
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21
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Sundby AE, Molnar RI, Claycomb JM. Connecting the Dots: Linking Caenorhabditis elegans Small RNA Pathways and Germ Granules. Trends Cell Biol 2021; 31:387-401. [PMID: 33526340 DOI: 10.1016/j.tcb.2020.12.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/28/2020] [Accepted: 12/30/2020] [Indexed: 12/15/2022]
Abstract
Germ granules are non-membrane bound, phase-separated organelles, composed of RNAs and proteins. Germ granules are present only within the germ cells of animals, including model systems such as Caenorhabditis elegans, Drosophila, mice, and zebrafish, where they play critical roles in specifying the germ lineage, the inheritance of epigenetic information, and post-transcriptional gene regulation. Across species, conserved germ granule proteins reflect these essential functions. A significant proportion of proteins that localize to germ granules are components of RNA metabolism and small RNA (sRNA) gene regulatory pathways. Here we synthesize our current knowledge of the roles that germ granules and their components play in sRNA pathway functions, transgenerational inheritance, and fertility in the C. elegans germline.
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Affiliation(s)
- Adam E Sundby
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Ruxandra I Molnar
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Julie M Claycomb
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
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22
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Vishnupriya R, Thomas L, Wahba L, Fire A, Subramaniam K. PLP-1 is essential for germ cell development and germline gene silencing in Caenorhabditis elegans. Development 2020; 147:dev.195578. [PMID: 33051256 DOI: 10.1242/dev.195578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/06/2020] [Indexed: 12/12/2022]
Abstract
The germline genome is guarded against invading foreign genetic elements by small RNA-dependent gene-silencing pathways. Components of these pathways localize to, or form distinct aggregates in the vicinity of, germ granules. These components and their dynamics in and out of granules are currently being intensively studied. Here, we report the identification of PLP-1, a Caenorhabditis elegans protein related to the human single-stranded nucleic acid-binding protein Pur-alpha, as a component of germ granules in C. elegans We show that PLP-1 is essential for silencing different types of transgenes in the germ line and for suppressing the expression of several endogenous genes controlled by the germline gene-silencing pathways. Our results reveal that PLP-1 functions downstream of small RNA biogenesis during initiation of gene silencing. Based on these results and the earlier findings that Pur-alpha proteins interact with both RNA and protein, we propose that PLP-1 couples certain RNAs with their protein partners in the silencing complex. PLP-1 orthologs localized on RNA granules may similarly contribute to germline gene silencing in other organisms.
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Affiliation(s)
- Rajaram Vishnupriya
- Department of Biotechnology, Indian Institute of Technology-Madras, Chennai 600036, India
| | - Linitha Thomas
- Department of Biological Sciences & Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Lamia Wahba
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.,Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Andrew Fire
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.,Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kuppuswamy Subramaniam
- Department of Biotechnology, Indian Institute of Technology-Madras, Chennai 600036, India
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23
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Dodson AE, Kennedy S. Phase Separation in Germ Cells and Development. Dev Cell 2020; 55:4-17. [PMID: 33007213 DOI: 10.1016/j.devcel.2020.09.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/28/2020] [Accepted: 09/05/2020] [Indexed: 12/20/2022]
Abstract
The animal germline is an immortal cell lineage that gives rise to eggs and/or sperm each generation. Fusion of an egg and sperm, or fertilization, sets off a cascade of developmental events capable of producing an array of different cell types and body plans. How germ cells develop, function, and eventually give rise to entirely new organisms is an important question in biology. A growing body of evidence suggests that phase separation events likely play a significant and multifaceted role in germ cells and development. Here, we discuss the organization, dynamics, and potential functions of phase-separated compartments in germ cells and examine the various ways in which phase separation might contribute to the development of multicellular organisms.
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Affiliation(s)
- Anne E Dodson
- Department of Genetics, Blavatnik Institute at Harvard Medical School, Boston, MA 02115, USA.
| | - Scott Kennedy
- Department of Genetics, Blavatnik Institute at Harvard Medical School, Boston, MA 02115, USA
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24
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Phase Separation in Membrane Biology: The Interplay between Membrane-Bound Organelles and Membraneless Condensates. Dev Cell 2020; 55:30-44. [PMID: 32726575 DOI: 10.1016/j.devcel.2020.06.033] [Citation(s) in RCA: 156] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/14/2020] [Accepted: 06/26/2020] [Indexed: 12/13/2022]
Abstract
In eukaryotic cells, various membrane-bound organelles compartmentalize diverse cellular activities in a spatially and temporally controlled manner. Numerous membraneless organelles assembled via liquid-liquid phase separation (LLPS), known as condensates, also facilitate compartmentalization of cellular functions. Emerging evidence shows that these two organelle types interact in many biological processes. Membranes modulate the biogenesis and dynamics of phase-separated condensates by serving as assembly platforms or by forming direct contacts. Phase separation of membrane-associated proteins participates in various trafficking events, such as clustering of vesicles for temporally controlled fusion and storage, and transport of membraneless condensates on membrane-bound organelles. Phase separation also acts in cargo trafficking pathways by sorting and docking cargos for translocon-mediated transport across membranes, by shuttling cargos through the nuclear pore complex, and by triggering the formation of surrounding autophagosomes for delivery to lysosomes. The coordinated actions of membrane-bound and membraneless organelles ensure spatiotemporal control of various cellular functions.
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25
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Tian S, Curnutte HA, Trcek T. RNA Granules: A View from the RNA Perspective. Molecules 2020; 25:E3130. [PMID: 32650583 PMCID: PMC7397151 DOI: 10.3390/molecules25143130] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/29/2020] [Accepted: 07/07/2020] [Indexed: 12/17/2022] Open
Abstract
RNA granules are ubiquitous. Composed of RNA-binding proteins and RNAs, they provide functional compartmentalization within cells. They are inextricably linked with RNA biology and as such are often referred to as the hubs for post-transcriptional regulation. Much of the attention has been given to the proteins that form these condensates and thus many fundamental questions about the biology of RNA granules remain poorly understood: How and which RNAs enrich in RNA granules, how are transcripts regulated in them, and how do granule-enriched mRNAs shape the biology of a cell? In this review, we discuss the imaging, genetic, and biochemical data, which have revealed that some aspects of the RNA biology within granules are carried out by the RNA itself rather than the granule proteins. Interestingly, the RNA structure has emerged as an important feature in the post-transcriptional control of granule transcripts. This review is part of the Special Issue in the Frontiers in RNA structure in the journal Molecules.
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Affiliation(s)
| | | | - Tatjana Trcek
- Homewood Campus, Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA; (S.T.); (H.A.C.)
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26
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Chen W, Hu Y, Lang CF, Brown JS, Schwabach S, Song X, Zhang Y, Munro E, Bennett K, Zhang D, Lee HC. The Dynamics of P Granule Liquid Droplets Are Regulated by the Caenorhabditis elegans Germline RNA Helicase GLH-1 via Its ATP Hydrolysis Cycle. Genetics 2020; 215:421-434. [PMID: 32245789 PMCID: PMC7268986 DOI: 10.1534/genetics.120.303052] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/12/2020] [Indexed: 02/06/2023] Open
Abstract
P granules are phase-separated liquid droplets that play important roles in the maintenance of germ cell fate in Caenorhabditis elegans Both the localization and formation of P granules are highly dynamic, but mechanisms that regulate such processes remain poorly understood. Here, we show evidence that the VASA-like germline RNA helicase GLH-1 couples distinct steps of its ATPase hydrolysis cycle to control the formation and disassembly of P granules. In addition, we found that the phenylalanine-glycine-glycine repeats in GLH-1 promote its localization at the perinucleus. Proteomic analyses of the GLH-1 complex with a GLH-1 mutation that interferes with P granule disassembly revealed transient interactions of GLH-1 with several Argonautes and RNA-binding proteins. Finally, we found that defects in recruiting the P granule component PRG-1 to perinuclear foci in the adult germline correlate with the fertility defects observed in various GLH-1 mutants. Together, our results highlight the versatile roles of an RNA helicase in controlling the formation of liquid droplets in space and time.
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Affiliation(s)
- Wenjun Chen
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637
| | - Yabing Hu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China 430074
| | - Charles F Lang
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637
| | - Jordan S Brown
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637
| | - Sierra Schwabach
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637
| | - Xiaoyan Song
- Department of Clinical Laboratory, The Third Affiliated Hospital of Zhengzhou University, China 450052
| | - Ying Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China 430074
| | - Edwin Munro
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637
| | - Karen Bennett
- Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Columbia, Missouri 65212
| | - Donglei Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China 430074
| | - Heng-Chi Lee
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637
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27
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Marnik EA, Fuqua JH, Sharp CS, Rochester JD, Xu EL, Holbrook SE, Updike DL. Germline Maintenance Through the Multifaceted Activities of GLH/Vasa in Caenorhabditis elegans P Granules. Genetics 2019; 213:923-939. [PMID: 31506335 PMCID: PMC6827368 DOI: 10.1534/genetics.119.302670] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 09/03/2019] [Indexed: 02/07/2023] Open
Abstract
Vasa homologs are ATP-dependent DEAD-box helicases, multipotency factors, and critical components that specify and protect the germline. They regulate translation, amplify piwi-interacting RNAs (piRNAs), and act as RNA solvents; however, the limited availability of mutagenesis-derived alleles and their wide range of phenotypes have complicated their analysis. Now, with clustered regularly interspaced short palindromic repeats (CRISPR/Cas9), these limitations can be mitigated to determine why protein domains have been lost or retained throughout evolution. Here, we define the functional motifs of GLH-1/Vasa in Caenorhabditis elegans using 28 endogenous, mutant alleles. We show that GLH-1's helicase activity is required to retain its association with P granules. GLH-1 remains in P granules when changes are made outside of the helicase and flanking domains, but fertility is still compromised. Removal of the glycine-rich repeats from GLH proteins progressively diminishes P-granule wetting-like interactions at the nuclear periphery. Mass spectrometry of GLH-1-associated proteins implies conservation of a transient piRNA-amplifying complex, and reveals a novel affinity between GLH-1 and three structurally conserved PCI (26S Proteasome Lid, COP9, and eIF3) complexes or "zomes," along with a reciprocal aversion for assembled ribosomes and the 26S proteasome. These results suggest that P granules compartmentalize the cytoplasm to exclude large protein assemblies, effectively shielding associated transcripts from translation and associated proteins from turnover. Within germ granules, Vasa homologs may act as solvents, ensuring mRNA accessibility by small RNA surveillance and amplification pathways, and facilitating mRNA export through germ granules to initiate translation.
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Affiliation(s)
| | - J Heath Fuqua
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine 04672
- The College of the Atlantic, Bar Harbor, Maine 04609
| | - Catherine S Sharp
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine 04672
| | - Jesse D Rochester
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine 04672
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine 04469
| | - Emily L Xu
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine 04672
- The College of William and Mary, Williamsburg, Virginia 23185
| | - Sarah E Holbrook
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine 04672
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine 04469
- The Jackson Laboratory, Bar Harbor, Maine 04609
| | - Dustin L Updike
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine 04672
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28
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De Graeve F, Debreuve E, Rahmoun S, Ecsedi S, Bahri A, Hubstenberger A, Descombes X, Besse F. Detecting and quantifying stress granules in tissues of multicellular organisms with the Obj.MPP analysis tool. Traffic 2019; 20:697-711. [PMID: 31314165 DOI: 10.1111/tra.12678] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 07/15/2019] [Accepted: 07/15/2019] [Indexed: 12/11/2022]
Abstract
Stress granules (SGs) are macromolecular assemblies induced by stress and composed of proteins and mRNAs stalled in translation initiation. SGs play an important role in the response to stress and in the modulation of signaling pathways. Furthermore, these structures are related to the pathological ribonucleoprotein (RNP) aggregates found in neurodegenerative disease contexts, highlighting the need to understand how they are formed and recycled in normal and pathological contexts. Although genetically tractable multicellular organisms have been key in identifying modifiers of RNP aggregate toxicity, in vivo analysis of SG properties and regulation has lagged behind, largely due to the difficulty of detecting SG from images of intact tissues. Here, we describe the object detector software Obj.MPP and show how it overcomes the limits of classical object analyzers to extract the properties of SGs from wide-field and confocal images of Caenorhabditis elegans and Drosophila tissues, respectively. We demonstrate that Obj.MPP enables the identification of genes modulating the assembly of endogenous and pathological SGs, and thus that it will be useful in the context of future genetic screens and in vivo studies.
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Affiliation(s)
- Fabienne De Graeve
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - Eric Debreuve
- Université Côte d'Azur, CNRS, INRIA, I3S, Sophia-Antipolis, France
| | - Somia Rahmoun
- Université Coôte d'Azur, INRIA, CNRS, I3S, Sophia-Antipolis, France
| | - Szilvia Ecsedi
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - Alia Bahri
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - Arnaud Hubstenberger
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - Xavier Descombes
- Université Coôte d'Azur, INRIA, CNRS, I3S, Sophia-Antipolis, France
| | - Florence Besse
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
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29
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Min H, Lee YU, Shim YH, Kawasaki I. Autophagy of germ-granule components, PGL-1 and PGL-3, contributes to DNA damage-induced germ cell apoptosis in C. elegans. PLoS Genet 2019; 15:e1008150. [PMID: 31125345 PMCID: PMC6534287 DOI: 10.1371/journal.pgen.1008150] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 04/23/2019] [Indexed: 12/19/2022] Open
Abstract
Germ granules, termed P granules in nematode C. elegans, are the germline-specific cytoplasmic structures widely observed from worms to humans. P granules are known to have critical functions for postembryonic germline development likely through regulating RNA metabolism. They are localized at the perinuclear region of germ cells during most of the developmental stages. However, the biological significance of this specific localization remains elusive. PGL-1 and PGL-3, the defining components of P granules, were shown to be lost from the perinuclear region prior to germ cell apoptosis. Furthermore, this loss was shown to be significantly enhanced upon DNA damage. Here, we show that the removal of PGL-1 and PGL-3 from the perinuclear region following UV-induced DNA damage is significantly reduced in autophagy mutants. Autophagy was previously shown to be required for DNA damage-induced germ cell apoptosis. We show that the apoptosis defect of autophagy mutants is bypassed by depletion of pgl-1 or pgl-3. These findings are consistent with time-lapse observations of LGG-1 foci formation, showing that autophagy is activated following UV irradiation and that maximal accumulation of LGG-1 foci occurs before PGL-1 removal. We also show that some of the autophagy genes are transcriptionally activated following UV irradiation by CEP-1, the worm p53-like protein. Taken together, our results indicate that autophagy is required to remove the major P granule components, PGL-1 and PGL-3, and that their removal is required for the full induction of DNA damage-induced germ cell apoptosis. Our study contributes to a better understanding of germ cell apoptosis, a process that leads to the elimination of the vast majority of germ cells in various animals from worms to mammals.
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Affiliation(s)
- Hyemin Min
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea
| | - Yong-Uk Lee
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea
| | - Yhong-Hee Shim
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea
| | - Ichiro Kawasaki
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea
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30
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Marnik EA, Updike DL. Membraneless organelles: P granules in Caenorhabditis elegans. Traffic 2019; 20:373-379. [PMID: 30924287 DOI: 10.1111/tra.12644] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 03/27/2019] [Accepted: 03/27/2019] [Indexed: 12/22/2022]
Abstract
Membraneless organelles are distinct compartments within a cell that are not enclosed by a traditional lipid membrane and instead form through a process called liquid-liquid phase separation. Examples of these non-membrane-bound organelles include nucleoli, stress granules, P bodies, pericentriolar material and germ granules. Many recent studies have used Caenorhabditis elegans germ granules, known as P granules, to expand our understanding of the formation of these unique cellular compartments. From this work, we know that proteins with intrinsically disordered regions (IDRs) play a critical role in the process of phase separation. IDR phase separation is further tuned through their interactions with RNA and through protein modifications such as phosphorylation and methylation. These findings from C elegans, combined with work done in other model organisms, continue to provide insight into the formation of membraneless organelles and the important role they play in compartmentalizing cellular processes.
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Affiliation(s)
- Elisabeth A Marnik
- Center for Regenerative Biology and Medicine, The Mount Desert Island Biological Laboratory, Bar Harbor, Maine
| | - Dustin L Updike
- Center for Regenerative Biology and Medicine, The Mount Desert Island Biological Laboratory, Bar Harbor, Maine
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31
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Seydoux G. The P Granules of C. elegans: A Genetic Model for the Study of RNA-Protein Condensates. J Mol Biol 2018; 430:4702-4710. [PMID: 30096346 DOI: 10.1016/j.jmb.2018.08.007] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 07/26/2018] [Accepted: 08/01/2018] [Indexed: 01/25/2023]
Abstract
P granules are RNA/protein condensates in the germline of Caenorhabditis elegans. Genetic analyses have begun to identify the proteins that regulate P granule assembly in the cytoplasm of zygotes. Among them, the RGG-domain protein PGL-3, the intrinsically disordered protein MEG-3, and the RNA helicase LAF-1 all bind and phase separate with RNA in vitro. We discuss how RNA-induced phase separation, competition with other RNA-binding proteins, and reversible phosphorylation contribute to the asymmetric localization of P granules in the cytoplasm of newly fertilized embryos. P granules contain RNA silencing complexes that monitor the germline transcriptome and may provide an RNA memory of germline gene expression across generations.
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Affiliation(s)
- Geraldine Seydoux
- Department of Molecular Biology and Genetics, HHMI, Johns Hopkins University, School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA.
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32
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Kato M, McKnight SL. A Solid-State Conceptualization of Information Transfer from Gene to Message to Protein. Annu Rev Biochem 2018; 87:351-390. [DOI: 10.1146/annurev-biochem-061516-044700] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this review, we describe speculative ideas and early stage research concerning the flow of genetic information from the nuclear residence of genes to the disparate, cytoplasmic sites of protein synthesis. We propose that this process of information transfer is meticulously guided by transient structures formed from protein segments of low sequence complexity/intrinsic disorder. These low complexity domains are ubiquitously associated with regulatory proteins that control gene expression and RNA biogenesis, but they are also found in the central channel of nuclear pores, the nexus points of intermediate filament assembly, and the locations of action of other well-studied cellular proteins and pathways. Upon being organized into localized cellular positions via mechanisms utilizing properly folded protein domains, thereby facilitating elevated local concentration, certain low complexity domains adopt cross-β interactions that are both structurally specific and labile to disassembly. These weakly tethered assemblies, we propose, are built to relay the passage of genetic information from one site to another within a cell, ensuring that the process is of extreme fidelity.
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Affiliation(s)
- Masato Kato
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9152, USA
| | - Steven L. McKnight
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9152, USA
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33
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Tosato V, West N, Zrimec J, Nikitin DV, Del Sal G, Marano R, Breitenbach M, Bruschi CV. Bridge-Induced Translocation between NUP145 and TOP2 Yeast Genes Models the Genetic Fusion between the Human Orthologs Associated With Acute Myeloid Leukemia. Front Oncol 2017; 7:231. [PMID: 29034209 PMCID: PMC5626878 DOI: 10.3389/fonc.2017.00231] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 09/07/2017] [Indexed: 01/03/2023] Open
Abstract
In mammalian organisms liquid tumors such as acute myeloid leukemia (AML) are related to spontaneous chromosomal translocations ensuing in gene fusions. We previously developed a system named bridge-induced translocation (BIT) that allows linking together two different chromosomes exploiting the strong endogenous homologous recombination system of the yeast Saccharomyces cerevisiae. The BIT system generates a heterogeneous population of cells with different aneuploidies and severe aberrant phenotypes reminiscent of a cancerogenic transformation. In this work, thanks to a complex pop-out methodology of the marker used for the selection of translocants, we succeeded by BIT technology to precisely reproduce in yeast the peculiar chromosome translocation that has been associated with AML, characterized by the fusion between the human genes NUP98 and TOP2B. To shed light on the origin of the DNA fragility within NUP98, an extensive analysis of the curvature, bending, thermostability, and B-Z transition aptitude of the breakpoint region of NUP98 and of its yeast ortholog NUP145 has been performed. On this basis, a DNA cassette carrying homologous tails to the two genes was amplified by PCR and allowed the targeted fusion between NUP145 and TOP2, leading to reproduce the chimeric transcript in a diploid strain of S. cerevisiae. The resulting translocated yeast obtained through BIT appears characterized by abnormal spherical bodies of nearly 500 nm of diameter, absence of external membrane and defined cytoplasmic localization. Since Nup98 is a well-known regulator of the post-transcriptional modification of P53 target genes, and P53 mutations are occasionally reported in AML, this translocant yeast strain can be used as a model to test the constitutive expression of human P53. Although the abnormal phenotype of the translocant yeast was never rescued by its expression, an exogenous P53 was recognized to confer increased vitality to the translocants, in spite of its usual and well-documented toxicity to wild-type yeast strains. These results obtained in yeast could provide new grounds for the interpretation of past observations made in leukemic patients indicating a possible involvement of P53 in cell transformation toward AML.
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Affiliation(s)
- Valentina Tosato
- Ulisse Biomed S.r.l., AREA Science Park, Trieste, Italy.,Faculty of Health Sciences, University of Primorska, Izola, Slovenia.,Yeast Molecular Genetics, ICGEB, AREA Science Park, Trieste, Italy
| | - Nicole West
- Clinical Pathology, Hospital Maggiore, Trieste, Italy
| | - Jan Zrimec
- Faculty of Health Sciences, University of Primorska, Izola, Slovenia
| | - Dmitri V Nikitin
- Biology Faculty, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Giannino Del Sal
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Roberto Marano
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Michael Breitenbach
- Genetics Division, Department of Cell Biology, University of Salzburg, Salzburg, Austria
| | - Carlo V Bruschi
- Yeast Molecular Genetics, ICGEB, AREA Science Park, Trieste, Italy.,Genetics Division, Department of Cell Biology, University of Salzburg, Salzburg, Austria
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34
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Andralojc KM, Campbell AC, Kelly AL, Terrey M, Tanner PC, Gans IM, Senter-Zapata MJ, Khokhar ES, Updike DL. ELLI-1, a novel germline protein, modulates RNAi activity and P-granule accumulation in Caenorhabditis elegans. PLoS Genet 2017; 13:e1006611. [PMID: 28182654 PMCID: PMC5325599 DOI: 10.1371/journal.pgen.1006611] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 02/24/2017] [Accepted: 01/31/2017] [Indexed: 12/13/2022] Open
Abstract
Germ cells contain non-membrane bound cytoplasmic organelles that help maintain germline integrity. In C. elegans they are called P granules; without them, the germline undergoes partial masculinization and aberrant differentiation. One key P-granule component is the Argonaute CSR-1, a small-RNA binding protein that antagonizes accumulation of sperm-specific transcripts in developing oocytes and fine-tunes expression of proteins critical to early embryogenesis. Loss of CSR-1 complex components results in a very specific, enlarged P-granule phenotype. In a forward screen to identify mutants with abnormal P granules, ten alleles were recovered with a csr-1 P-granule phenotype, eight of which contain mutations in known components of the CSR-1 complex (csr-1, ego-1, ekl-1, and drh-3). The remaining two alleles are in a novel gene now called elli-1 (enlarged germline granules). ELLI-1 is first expressed in primordial germ cells during mid-embryogenesis, and continues to be expressed in the adult germline. While ELLI-1 forms cytoplasmic aggregates, they occasionally dock, but do not co-localize with P granules. Instead, the majority of ELLI-1 aggregates accumulate in the shared germline cytoplasm. In elli-1 mutants, several genes that promote RNAi and P-granule accumulation are upregulated, and embryonic lethality, sterility, and RNAi resistance in a hypomorphic drh-3 allele is enhanced, suggesting that ELLI-1 functions with CSR-1 to modulate RNAi activity, P-granule accumulation, and post-transcriptional expression in the germline.
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Affiliation(s)
- Karolina M. Andralojc
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine, United States of America
| | - Anne C. Campbell
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine, United States of America
| | - Ashley L. Kelly
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine, United States of America
| | - Markus Terrey
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine, United States of America
| | - Paige C. Tanner
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine, United States of America
| | - Ian M. Gans
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine, United States of America
| | | | - Eraj S. Khokhar
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine, United States of America
| | - Dustin L. Updike
- The Mount Desert Island Biological Laboratory, Bar Harbor, Maine, United States of America
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35
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Cohen-Fix O, Askjaer P. Cell Biology of the Caenorhabditis elegans Nucleus. Genetics 2017; 205:25-59. [PMID: 28049702 PMCID: PMC5216270 DOI: 10.1534/genetics.116.197160] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 11/09/2016] [Indexed: 12/25/2022] Open
Abstract
Studies on the Caenorhabditis elegans nucleus have provided fascinating insight to the organization and activities of eukaryotic cells. Being the organelle that holds the genetic blueprint of the cell, the nucleus is critical for basically every aspect of cell biology. The stereotypical development of C. elegans from a one cell-stage embryo to a fertile hermaphrodite with 959 somatic nuclei has allowed the identification of mutants with specific alterations in gene expression programs, nuclear morphology, or nuclear positioning. Moreover, the early C. elegans embryo is an excellent model to dissect the mitotic processes of nuclear disassembly and reformation with high spatiotemporal resolution. We review here several features of the C. elegans nucleus, including its composition, structure, and dynamics. We also discuss the spatial organization of chromatin and regulation of gene expression and how this depends on tight control of nucleocytoplasmic transport. Finally, the extensive connections of the nucleus with the cytoskeleton and their implications during development are described. Most processes of the C. elegans nucleus are evolutionarily conserved, highlighting the relevance of this powerful and versatile model organism to human biology.
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Affiliation(s)
- Orna Cohen-Fix
- Laboratory of Molecular and Cellular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Peter Askjaer
- Andalusian Center for Developmental Biology, Consejo Superior de Investigaciones Científicas/Junta de Andalucia/Universidad Pablo de Olavide, 41013 Seville, Spain
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36
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Wang X, Olson JR, Rasoloson D, Ellenbecker M, Bailey J, Voronina E. Dynein light chain DLC-1 promotes localization and function of the PUF protein FBF-2 in germline progenitor cells. Development 2016; 143:4643-4653. [PMID: 27864381 DOI: 10.1242/dev.140921] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 11/04/2016] [Indexed: 11/20/2022]
Abstract
PUF family translational repressors are conserved developmental regulators, but the molecular function provided by the regions flanking the PUF RNA-binding domain is unknown. In C. elegans, the PUF proteins FBF-1 and FBF-2 support germline progenitor maintenance by repressing production of meiotic proteins and use distinct mechanisms to repress their target mRNAs. We identify dynein light chain DLC-1 as an important regulator of FBF-2 function. DLC-1 directly binds to FBF-2 outside of the RNA-binding domain and promotes FBF-2 localization and function. By contrast, DLC-1 does not interact with FBF-1 and does not contribute to FBF-1 activity. Surprisingly, we find that the contribution of DLC-1 to FBF-2 activity is independent of the dynein motor. Our findings suggest that PUF protein localization and activity are mediated by sequences flanking the RNA-binding domain that bind specific molecular partners. Furthermore, these results identify a new role for DLC-1 in post-transcriptional regulation of gene expression.
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Affiliation(s)
- Xiaobo Wang
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Jenessa R Olson
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Dominique Rasoloson
- Department of Molecular Biology and Genetics, Johns Hopkins School of Medicine, HHMI, Baltimore, MD 21205, USA
| | - Mary Ellenbecker
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Jessica Bailey
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Ekaterina Voronina
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
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37
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Fickentscher R, Struntz P, Weiss M. Setting the Clock for Fail-Safe Early Embryogenesis. PHYSICAL REVIEW LETTERS 2016; 117:188101. [PMID: 27835015 DOI: 10.1103/physrevlett.117.188101] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Indexed: 06/06/2023]
Abstract
The embryogenesis of the small nematode Caenorhabditis elegans is a remarkably robust self-organization phenomenon. Cell migration trajectories in the early embryo, for example, are well explained by mechanical cues that push cells into positions where they experience the least repulsive forces. Yet, how this mechanically guided progress in development is properly timed has remained elusive so far. Here, we show that cell volumes and division times are strongly anticorrelated during the early embryogenesis of C. elegans with significant differences between somatic cells and precursors of the germline. Our experimental findings are explained by a simple model that in conjunction with mechanical guidance can account for the fail-safe early embryogenesis of C. elegans.
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Affiliation(s)
- Rolf Fickentscher
- Experimental Physics I, University of Bayreuth, Universitätsstrasse 30, D-95447 Bayreuth, Germany
| | - Philipp Struntz
- Experimental Physics I, University of Bayreuth, Universitätsstrasse 30, D-95447 Bayreuth, Germany
| | - Matthias Weiss
- Experimental Physics I, University of Bayreuth, Universitätsstrasse 30, D-95447 Bayreuth, Germany
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38
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Chen JX, Cipriani PG, Mecenas D, Polanowska J, Piano F, Gunsalus KC, Selbach M. In Vivo Interaction Proteomics in Caenorhabditis elegans Embryos Provides New Insights into P Granule Dynamics. Mol Cell Proteomics 2016; 15:1642-57. [PMID: 26912668 PMCID: PMC4858945 DOI: 10.1074/mcp.m115.053975] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 02/24/2016] [Indexed: 01/20/2023] Open
Abstract
Studying protein interactions in whole organisms is fundamental to understanding development. Here, we combine in vivo expressed GFP-tagged proteins with quantitative proteomics to identify protein-protein interactions of selected key proteins involved in early C. elegans embryogenesis. Co-affinity purification of interaction partners for eight bait proteins resulted in a pilot in vivo interaction map of proteins with a focus on early development. Our network reflects known biology and is highly enriched in functionally relevant interactions. To demonstrate the utility of the map, we looked for new regulators of P granule dynamics and found that GEI-12, a novel binding partner of the DYRK family kinase MBK-2, is a key regulator of P granule formation and germline maintenance. Our data corroborate a recently proposed model in which the phosphorylation state of GEI-12 controls P granule dynamics. In addition, we find that GEI-12 also induces granule formation in mammalian cells, suggesting a common regulatory mechanism in worms and humans. Our results show that in vivo interaction proteomics provides unique insights into animal development.
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Affiliation(s)
- Jia-Xuan Chen
- From the ‡Max Delbrück Center for Molecular Medicine, D-13092 Berlin, Germany; §Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003
| | - Patricia G Cipriani
- §Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003; ¶New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Desirea Mecenas
- §Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003
| | - Jolanta Polanowska
- §Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003; ‖INSERM, U1104, 13288 Marseille, France
| | - Fabio Piano
- §Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003; ¶New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Kristin C Gunsalus
- §Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003; ¶New York University Abu Dhabi, Abu Dhabi, United Arab Emirates;
| | - Matthias Selbach
- From the ‡Max Delbrück Center for Molecular Medicine, D-13092 Berlin, Germany; **Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany.
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39
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Transport Selectivity of Nuclear Pores, Phase Separation, and Membraneless Organelles. Trends Biochem Sci 2015; 41:46-61. [PMID: 26705895 DOI: 10.1016/j.tibs.2015.11.001] [Citation(s) in RCA: 292] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/30/2015] [Accepted: 11/03/2015] [Indexed: 12/21/2022]
Abstract
Nuclear pore complexes (NPCs) provide a selective passageway for receptor-mediated active transport between nucleus and cytoplasm, while maintaining the distinct molecular compositions of both compartments at large. In this review we discuss how NPCs gain a remarkable sorting selectivity from non-globular FG domains and their phase separation into dense polymer meshworks. The resulting sieve-like FG hydrogels are effective barriers to normal macromolecules but are at the same time highly permeable to shuttling nuclear transport receptors, which bind to FG motifs as well as to their designated cargoes. Phase separation driven by disordered protein domains was recently also recognized as being pivotal to the formation of membraneless organelles, making it an important emerging principle in cell biology.
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40
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Hubstenberger A, Cameron C, Noble SL, Keenan S, Evans TC. Modifiers of solid RNP granules control normal RNP dynamics and mRNA activity in early development. J Cell Biol 2015; 211:703-16. [PMID: 26527741 PMCID: PMC4639854 DOI: 10.1083/jcb.201504044] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 09/25/2015] [Indexed: 12/13/2022] Open
Abstract
Modifiers of aberrant solid RNP granules suggest new insights into pathways that control dynamics of large-scale RNP bodies and mRNAs during C. elegans oogenesis. Ribonucleoproteins (RNPs) often coassemble into supramolecular bodies with regulated dynamics. The factors controlling RNP bodies and connections to RNA regulation are unclear. During Caenorhabditis elegans oogenesis, cytoplasmic RNPs can transition among diffuse, liquid, and solid states linked to mRNA regulation. Loss of CGH-1/Ddx6 RNA helicase generates solid granules that are sensitive to mRNA regulators. Here, we identified 66 modifiers of RNP solids induced by cgh-1 mutation. A majority of genes promote or suppress normal RNP body assembly, dynamics, or metabolism. Surprisingly, polyadenylation factors promote RNP coassembly in vivo, suggesting new functions of poly(A) tail regulation in RNP dynamics. Many genes carry polyglutatmine (polyQ) motifs or modulate polyQ aggregation, indicating possible connections with neurodegenerative disorders induced by CAG/polyQ expansion. Several RNP body regulators repress translation of mRNA subsets, suggesting that mRNAs are repressed by multiple mechanisms. Collectively, these findings suggest new pathways of RNP modification that control large-scale coassembly and mRNA activity during development.
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Affiliation(s)
- Arnaud Hubstenberger
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Pierre-and-Marie-Curie University, University Paris 06, 75005 Paris, France
| | - Cristiana Cameron
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Scott L Noble
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 Graduate Program in Molecular Biology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Sean Keenan
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Thomas C Evans
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
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41
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Abstract
Germ cells are the special cells in the body that undergo meiosis to generate gametes and subsequently entire new organisms after fertilization, a process that continues generation after generation. Recent studies have expanded our understanding of the factors and mechanisms that specify germ cell fate, including the partitioning of maternally supplied 'germ plasm', inheritance of epigenetic memory and expression of transcription factors crucial for primordial germ cell (PGC) development. Even after PGCs are specified, germline fate is labile and thus requires protective mechanisms, such as global transcriptional repression, chromatin state alteration and translation of only germline-appropriate transcripts. Findings from diverse species continue to provide insights into the shared and divergent needs of these special reproductive cells.
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Affiliation(s)
- Susan Strome
- Molecular, Cell &Developmental Biology, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - Dustin Updike
- Kathryn W. Davis Center for Regenerative Biology &Medicine, Mount Desert Island Biological Laboratory, Bar Harbor, Maine 04672, USA
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42
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Asakawa H, Mori C, Ohtsuki C, Iwamoto M, Hiraoka Y, Haraguchi T. Uncleavable Nup98-Nup96 is functional in the fission yeast Schizosaccharomyces pombe. FEBS Open Bio 2015; 5:508-14. [PMID: 26137436 PMCID: PMC4483485 DOI: 10.1016/j.fob.2015.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 05/18/2015] [Accepted: 06/07/2015] [Indexed: 11/19/2022] Open
Abstract
Essential nucleoporins Nup98 and Nup96 are coded by a single open reading frame, and produced by autopeptidase cleavage. The autocleavage site of Nup98-Nup96 is highly conserved in a wide range of organisms. To understand the importance of autocleavage, we examined a mutant that produces the Nup98-Nup96 joint molecule as a sole protein product of the nup189 (+) gene in the fission yeast Schizosaccharomyces pombe. Cells expressing only the joint molecule were found to be viable. This result indicates that autocleavage of Nup98-Nup96 is dispensable for cell growth, at least under normal culture conditions in S. pombe.
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Affiliation(s)
- Haruhiko Asakawa
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan
| | - Chie Mori
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan
| | - Chizuru Ohtsuki
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan
| | - Masaaki Iwamoto
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan
- Corresponding authors at: Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan. Tel.: +81 668794620; fax: +81 668794622 (Y. Hiraoka), Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan. Tel.: +81 789692241; fax: +81 789692249 (T. Haraguchi).
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan
- Corresponding authors at: Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan. Tel.: +81 668794620; fax: +81 668794622 (Y. Hiraoka), Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan. Tel.: +81 789692241; fax: +81 789692249 (T. Haraguchi).
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43
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Talamas JA, Capelson M. Nuclear envelope and genome interactions in cell fate. Front Genet 2015; 6:95. [PMID: 25852741 PMCID: PMC4365743 DOI: 10.3389/fgene.2015.00095] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 02/22/2015] [Indexed: 12/14/2022] Open
Abstract
The eukaryotic cell nucleus houses an organism’s genome and is the location within the cell where all signaling induced and development-driven gene expression programs are ultimately specified. The genome is enclosed and separated from the cytoplasm by the nuclear envelope (NE), a double-lipid membrane bilayer, which contains a large variety of trans-membrane and associated protein complexes. In recent years, research regarding multiple aspects of the cell nucleus points to a highly dynamic and coordinated concert of efforts between chromatin and the NE in regulation of gene expression. Details of how this concert is orchestrated and how it directs cell differentiation and disease are coming to light at a rapid pace. Here we review existing and emerging concepts of how interactions between the genome and the NE may contribute to tissue specific gene expression programs to determine cell fate.
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Affiliation(s)
- Jessica A Talamas
- Program in Epigenetics, Department of Cell and Developmental Biology, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA
| | - Maya Capelson
- Program in Epigenetics, Department of Cell and Developmental Biology, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA
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44
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VanGompel MJW, Nguyen KCQ, Hall DH, Dauer WT, Rose LS. A novel function for the Caenorhabditis elegans torsin OOC-5 in nucleoporin localization and nuclear import. Mol Biol Cell 2015; 26:1752-63. [PMID: 25739455 PMCID: PMC4436785 DOI: 10.1091/mbc.e14-07-1239] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 02/24/2015] [Indexed: 12/03/2022] Open
Abstract
Mutation in the human AAA+ protein torsinA leads to DYT1 dystonia. Loss of a Caenorhabditis elegans torsin, OOC-5, leads to defects in nucleoporin localization and nuclear import, a novel phenotype for a torsin mutant. NE ultrastructural defects similar to those in mouse and fly torsin mutants are also found, showing conservation of function. Torsin proteins are AAA+ ATPases that localize to the endoplasmic reticular/nuclear envelope (ER/NE) lumen. A mutation that markedly impairs torsinA function causes the CNS disorder DYT1 dystonia. Abnormalities of NE membranes have been linked to torsinA loss of function and the pathogenesis of DYT1 dystonia, leading us to investigate the role of the Caenorhabditis elegans torsinA homologue OOC-5 at the NE. We report a novel role for torsin in nuclear pore biology. In ooc-5–mutant germ cell nuclei, nucleoporins (Nups) were mislocalized in large plaques beginning at meiotic entry and persisted throughout meiosis. Moreover, the KASH protein ZYG-12 was mislocalized in ooc-5 gonads. Nups were mislocalized in adult intestinal nuclei and in embryos from mutant mothers. EM analysis revealed vesicle-like structures in the perinuclear space of intestinal and germ cell nuclei, similar to defects reported in torsin-mutant flies and mice. Consistent with a functional disruption of Nups, ooc-5–mutant embryos displayed impaired nuclear import kinetics, although the nuclear pore-size exclusion barrier was maintained. Our data are the first to demonstrate a requirement for a torsin for normal Nup localization and function and suggest that these functions are likely conserved.
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Affiliation(s)
- Michael J W VanGompel
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616
| | - Ken C Q Nguyen
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, New York, NY 10461
| | - David H Hall
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, New York, NY 10461
| | - William T Dauer
- Departments of Neurology and Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Lesilee S Rose
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616
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45
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Schmidt HB, Görlich D. Nup98 FG domains from diverse species spontaneously phase-separate into particles with nuclear pore-like permselectivity. eLife 2015; 4. [PMID: 25562883 PMCID: PMC4283134 DOI: 10.7554/elife.04251] [Citation(s) in RCA: 224] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 11/20/2014] [Indexed: 01/28/2023] Open
Abstract
Nuclear pore complexes (NPCs) conduct massive transport mediated by shuttling nuclear transport receptors (NTRs), while keeping nuclear and cytoplasmic contents separated. The NPC barrier in Xenopus relies primarily on the intrinsically disordered FG domain of Nup98. We now observed that Nup98 FG domains of mammals, lancelets, insects, nematodes, fungi, plants, amoebas, ciliates, and excavates spontaneously and rapidly phase-separate from dilute (submicromolar) aqueous solutions into characteristic 'FG particles'. This required neither sophisticated experimental conditions nor auxiliary eukaryotic factors. Instead, it occurred already during FG domain expression in bacteria. All Nup98 FG phases rejected inert macromolecules and yet allowed far larger NTR cargo complexes to rapidly enter. They even recapitulated the observations that large cargo-domains counteract NPC passage of NTR⋅cargo complexes, while cargo shielding and increased NTR⋅cargo surface-ratios override this inhibition. Their exquisite NPC-typical sorting selectivity and strong intrinsic assembly propensity suggest that Nup98 FG phases can form in authentic NPCs and indeed account for the permeability properties of the pore.
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Affiliation(s)
- Hermann Broder Schmidt
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dirk Görlich
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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Abstract
Nuclear pore complexes (NPCs) are the sole gateways between the nucleus and the cytoplasm of eukaryotic cells and they mediate all macromolecular trafficking between these cellular compartments. Nucleocytoplasmic transport is highly selective and precisely regulated and as such an important aspect of normal cellular function. Defects in this process or in its machinery have been linked to various human diseases, including cancer. Nucleoporins, which are about 30 proteins that built up NPCs, are critical players in nucleocytoplasmic transport and have also been shown to be key players in numerous other cellular processes, such as cell cycle control and gene expression regulation. This review will focus on the three nucleoporins Nup98, Nup214, and Nup358. Common to them is their significance in nucleocytoplasmic transport, their multiple other functions, and being targets for chromosomal translocations that lead to haematopoietic malignancies, in particular acute myeloid leukaemia. The underlying molecular mechanisms of nucleoporin-associated leukaemias are only poorly understood but share some characteristics and are distinguished by their poor prognosis and therapy outcome.
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47
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Updike DL, Knutson AK, Egelhofer TA, Campbell AC, Strome S. Germ-granule components prevent somatic development in the C. elegans germline. Curr Biol 2014; 24:970-5. [PMID: 24746798 DOI: 10.1016/j.cub.2014.03.015] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 02/05/2014] [Accepted: 03/04/2014] [Indexed: 12/12/2022]
Abstract
Specialized ribonucleoprotein organelles collectively known as germ granules are found in the germline cytoplasm from worms to humans [1]. In Drosophila, germ granules have been implicated in germline determination [2]. C. elegans germ granules, known as P granules, do not appear to be required for primordial germ cell (PGC) determination [3], but their components are still needed for fertility [4-6]. One potential role for P granules is to maintain germline fate and totipotency. This is suggested by the loss of P granules from germ cells that transform into somatic cell types, e.g., in germlines lacking MEX-3 and GLD-1 or upon neuronal induction by CHE-1 [7, 8]. However, it has not been established whether loss of P granules is the cause or effect of cell fate transformation. To test cause and effect, we severely compromised P granules by simultaneously knocking down factors that nucleate granule formation (PGL-1 and PGL-3) and promote their perinuclear localization (GLH-1 and GLH-4) [9] and investigated whether this causes germ cells to lose totipotency and initiate somatic reprogramming. We found that compromising P granules causes germ cells to express neuronal and muscle markers and send out neurite-like projections, suggesting that P granules maintain totipotency and germline identity by antagonizing somatic fate.
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Affiliation(s)
- Dustin L Updike
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA; Kathryn W. Davis Center for Regenerative Biology and Medicine, Mount Desert Island Biological Laboratory, Salisbury Cove, ME 04672, USA.
| | - Andrew Kekūpa'a Knutson
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Thea A Egelhofer
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Anne C Campbell
- Kathryn W. Davis Center for Regenerative Biology and Medicine, Mount Desert Island Biological Laboratory, Salisbury Cove, ME 04672, USA
| | - Susan Strome
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
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48
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Rahman MM, Rosu S, Joseph-Strauss D, Cohen-Fix O. Down-regulation of tricarboxylic acid (TCA) cycle genes blocks progression through the first mitotic division in Caenorhabditis elegans embryos. Proc Natl Acad Sci U S A 2014; 111:2602-7. [PMID: 24550289 PMCID: PMC3932911 DOI: 10.1073/pnas.1311635111] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The cell cycle is a highly regulated process that enables the accurate transmission of chromosomes to daughter cells. Here we uncover a previously unknown link between the tricarboxylic acid (TCA) cycle and cell cycle progression in the Caenorhabditis elegans early embryo. We found that down-regulation of TCA cycle components, including citrate synthase, malate dehydrogenase, and aconitase, resulted in a one-cell stage arrest before entry into mitosis: pronuclear meeting occurred normally, but nuclear envelope breakdown, centrosome separation, and chromosome condensation did not take place. Mitotic entry is controlled by the cyclin B-cyclin-dependent kinase 1 (Cdk1) complex, and the inhibitory phosphorylation of Cdk1 must be removed in order for the complex to be active. We found that following down-regulation of the TCA cycle, cyclin B levels were normal but CDK-1 remained inhibitory-phosphorylated in one-cell stage-arrested embryos, indicative of a G2-like arrest. Moreover, this was not due to an indirect effect caused by checkpoint activation by DNA damage or replication defects. These observations suggest that CDK-1 activation in the C. elegans one-cell embryo is sensitive to the metabolic state of the cell, and that down-regulation of the TCA cycle prevents the removal of CDK-1 inhibitory phosphorylation. The TCA cycle was previously shown to be necessary for the development of the early embryo in mammals, but the molecular processes affected were not known. Our study demonstrates a link between the TCA cycle and a specific cell cycle transition in the one-cell stage embryo.
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Affiliation(s)
- Mohammad M. Rahman
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Simona Rosu
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Daphna Joseph-Strauss
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Orna Cohen-Fix
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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49
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How might flukes and tapeworms maintain genome integrity without a canonical piRNA pathway? Trends Parasitol 2014; 30:123-9. [PMID: 24485046 DOI: 10.1016/j.pt.2014.01.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 12/29/2013] [Accepted: 01/06/2014] [Indexed: 12/31/2022]
Abstract
Surveillance by RNA interference is central to controlling the mobilization of transposable elements (TEs). In stem cells, Piwi argonaute (Ago) proteins and associated proteins repress mobilization of TEs to maintain genome integrity. This defense mechanism targeting TEs is termed the Piwi-interacting RNA (piRNA) pathway. In this opinion article, we draw attention to the situation that the genomes of cestodes and trematodes have lost the piwi and vasa genes that are hallmark characters of the germline multipotency program. This absence of Piwi-like Agos and Vasa helicases prompts the question: how does the germline of these flatworms withstand mobilization of TEs? Here, we present an interpretation of mechanisms likely to defend the germline integrity of parasitic flatworms.
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50
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Askjaer P, Galy V, Meister P. Modern Tools to Study Nuclear Pore Complexes and Nucleocytoplasmic Transport in Caenorhabditis elegans. Methods Cell Biol 2014; 122:277-310. [DOI: 10.1016/b978-0-12-417160-2.00013-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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