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Perales IE, Jones SD, Piaszynski KM, Geyer PK. Developmental changes in nuclear lamina components during germ cell differentiation. Nucleus 2024; 15:2339214. [PMID: 38597409 PMCID: PMC11008544 DOI: 10.1080/19491034.2024.2339214] [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: 02/20/2024] [Accepted: 04/02/2024] [Indexed: 04/11/2024] Open
Abstract
The nuclear lamina (NL) changes composition for regulation of nuclear events. We investigated changes that occur in Drosophila oogenesis, revealing switches in NL composition during germ cell differentiation. Germline stem cells (GSCs) express only LamB and predominantly emerin, whereas differentiating nurse cells predominantly express LamC and emerin2. A change in LamC-specific localization also occurs, wherein phosphorylated LamC redistributes to the nuclear interior only in the oocyte, prior to transcriptional reactivation of the meiotic genome. These changes support existing concepts that LamC promotes differentiation, a premise that was tested. Remarkably ectopic LamC production in GSCs did not promote premature differentiation. Increased LamC levels in differentiating germ cells altered internal nuclear structure, increased RNA production, and reduced female fertility due to defects in eggshell formation. These studies suggest differences between Drosophila lamins are regulatory, not functional, and reveal an unexpected robustness to level changes of a major scaffolding component of the NL.
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Affiliation(s)
- Isabella E. Perales
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
| | - Samuel D. Jones
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
| | | | - Pamela K. Geyer
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
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2
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Lazo PA. Nuclear functions regulated by the VRK1 kinase. Nucleus 2024; 15:2353249. [PMID: 38753965 DOI: 10.1080/19491034.2024.2353249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 05/06/2024] [Indexed: 05/18/2024] Open
Abstract
In the nucleus, the VRK1 Ser-Thr kinase is distributed in nucleoplasm and chromatin, where it has different roles. VRK1 expression increases in response to mitogenic signals. VRK1 regulates cyclin D1 expression at G0 exit and facilitates chromosome condensation at the end of G2 and G2/M progression to mitosis. These effects are mediated by the phosphorylation of histone H3 at Thr3 by VRK1, and later in mitosis by haspin. VRK1 regulates the apigenetic patterns of histones in processes requiring chromating remodeling, such as transcription, replication and DNA repair. VRK1 is overexpressed in tumors, facilitating tumor progression and resistance to genotoxic treatments. VRK1 also regulates the organization of Cajal bodies assembled on coilin, which are necessary for the assembly of different types of RNP complexes. VRK1 pathogenic variants cuase defects in Cajal bodies, functionally altering neurons with long axons and leading to neurological diseases, such as amyotrophic laterla sclerosis, spinal muscular atrophy, distal hereditay motor neuropathies and Charcot-Marie-Tooth.
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Affiliation(s)
- Pedro A Lazo
- Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Salamanca, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
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3
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de Souza Gama FH, Dutra LA, Hawgood M, Dos Reis CV, Serafim RAM, Ferreira MA, Teodoro BVM, Takarada JE, Santiago AS, Balourdas DI, Nilsson AS, Urien B, Almeida VM, Gileadi C, Ramos PZ, Salmazo A, Vasconcelos SNS, Cunha MR, Mueller S, Knapp S, Massirer KB, Elkins JM, Gileadi O, Mascarello A, Lemmens BBLG, Guimarães CRW, Azevedo H, Couñago RM. Novel Dihydropteridinone Derivatives As Potent Inhibitors of the Understudied Human Kinases Vaccinia-Related Kinase 1 and Casein Kinase 1δ/ε. J Med Chem 2024; 67:8609-8629. [PMID: 38780468 DOI: 10.1021/acs.jmedchem.3c02250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Vaccinia-related kinase 1 (VRK1) and the δ and ε isoforms of casein kinase 1 (CK1) are linked to various disease-relevant pathways. However, the lack of tool compounds for these kinases has significantly hampered our understanding of their cellular functions and therapeutic potential. Here, we describe the structure-based development of potent inhibitors of VRK1, a kinase highly expressed in various tumor types and crucial for cell proliferation and genome integrity. Kinome-wide profiling revealed that our compounds also inhibit CK1δ and CK1ε. We demonstrate that dihydropteridinones 35 and 36 mimic the cellular outcomes of VRK1 depletion. Complementary studies with existing CK1δ and CK1ε inhibitors suggest that these kinases may play overlapping roles in cell proliferation and genome instability. Together, our findings highlight the potential of VRK1 inhibition in treating p53-deficient tumors and possibly enhancing the efficacy of existing cancer therapies that target DNA stability or cell division.
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Affiliation(s)
| | - Luiz A Dutra
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Michael Hawgood
- Science for Life Laboratory, Sweden, Tomtebodavägen 23A, 17165 Solna, Sweden
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Caio Vinícius Dos Reis
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Ricardo A M Serafim
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Marcos A Ferreira
- Aché Laboratórios Farmacêuticos S.A., Guarulhos, São Paulo 07034-904, Brazil
| | - Bruno V M Teodoro
- Aché Laboratórios Farmacêuticos S.A., Guarulhos, São Paulo 07034-904, Brazil
| | - Jéssica Emi Takarada
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - André S Santiago
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Dimitrios-Ilias Balourdas
- Institute of Pharmaceutical Chemistry, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, Frankfurt am Main 60438, Germany
- Structural Genomics Consortium (SGC), Buchmann Institute for Life Sciences, Johann Wolfgang Goethe University, Max-von-Laue-Str. 15, Frankfurt am Main 60438, Germany
| | - Ann-Sofie Nilsson
- Science for Life Laboratory, Sweden, Tomtebodavägen 23A, 17165 Solna, Sweden
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Bruno Urien
- Science for Life Laboratory, Sweden, Tomtebodavägen 23A, 17165 Solna, Sweden
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Vitor M Almeida
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Carina Gileadi
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Priscila Z Ramos
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Anita Salmazo
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Stanley N S Vasconcelos
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Micael R Cunha
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Susanne Mueller
- Institute of Pharmaceutical Chemistry, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, Frankfurt am Main 60438, Germany
- Structural Genomics Consortium (SGC), Buchmann Institute for Life Sciences, Johann Wolfgang Goethe University, Max-von-Laue-Str. 15, Frankfurt am Main 60438, Germany
| | - Stefan Knapp
- Institute of Pharmaceutical Chemistry, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, Frankfurt am Main 60438, Germany
- Structural Genomics Consortium (SGC), Buchmann Institute for Life Sciences, Johann Wolfgang Goethe University, Max-von-Laue-Str. 15, Frankfurt am Main 60438, Germany
| | - Katlin B Massirer
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Jonathan M Elkins
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | - Opher Gileadi
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
| | | | - Bennie B L G Lemmens
- Science for Life Laboratory, Sweden, Tomtebodavägen 23A, 17165 Solna, Sweden
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | | | - Hatylas Azevedo
- Aché Laboratórios Farmacêuticos S.A., Guarulhos, São Paulo 07034-904, Brazil
| | - Rafael M Couñago
- Centro de Química Medicinal, Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, São Paulo Brazil
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4
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Navarro-Carrasco E, Monte-Serrano E, Campos-Díaz A, Rolfs F, de Goeij-de Haas R, Pham TV, Piersma SR, González-Alonso P, Jiménez CR, Lazo PA. VRK1 Regulates Sensitivity to Oxidative Stress by Altering Histone Epigenetic Modifications and the Nuclear Phosphoproteome in Tumor Cells. Int J Mol Sci 2024; 25:4874. [PMID: 38732093 PMCID: PMC11084957 DOI: 10.3390/ijms25094874] [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: 03/21/2024] [Revised: 04/24/2024] [Accepted: 04/27/2024] [Indexed: 05/13/2024] Open
Abstract
The chromatin organization and its dynamic remodeling determine its accessibility and sensitivity to DNA damage oxidative stress, the main source of endogenous DNA damage. We studied the role of the VRK1 chromatin kinase in the response to oxidative stress. which alters the nuclear pattern of histone epigenetic modifications and phosphoproteome pathways. The early effect of oxidative stress on chromatin was studied by determining the levels of 8-oxoG lesions and the alteration of the epigenetic modification of histones. Oxidative stress caused an accumulation of 8-oxoG DNA lesions that were increased by VRK1 depletion, causing a significant accumulation of DNA strand breaks detected by labeling free 3'-DNA ends. In addition, oxidative stress altered the pattern of chromatin epigenetic marks and the nuclear phosphoproteome pathways that were impaired by VRK1 depletion. Oxidative stress induced the acetylation of H4K16ac and H3K9 and the loss of H3K4me3. The depletion of VRK1 altered all these modifications induced by oxidative stress and resulted in losses of H4K16ac and H3K9ac and increases in the H3K9me3 and H3K4me3 levels. All these changes were induced by the oxidative stress in the epigenetic pattern of histones and impaired by VRK1 depletion, indicating that VRK1 plays a major role in the functional reorganization of chromatin in the response to oxidative stress. The analysis of the nuclear phosphoproteome in response to oxidative stress detected an enrichment of the phosphorylated proteins associated with the chromosome organization and chromatin remodeling pathways, which were significantly decreased by VRK1 depletion. VRK1 depletion alters the histone epigenetic pattern and nuclear phosphoproteome pathways in response to oxidative stress. The enzymes performing post-translational epigenetic modifications are potential targets in synthetic lethality strategies for cancer therapies.
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Affiliation(s)
- Elena Navarro-Carrasco
- Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, E-37007 Salamanca, Spain; (E.N.-C.); (E.M.-S.); (A.C.-D.); (P.G.-A.)
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, E-37007 Salamanca, Spain
| | - Eva Monte-Serrano
- Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, E-37007 Salamanca, Spain; (E.N.-C.); (E.M.-S.); (A.C.-D.); (P.G.-A.)
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, E-37007 Salamanca, Spain
| | - Aurora Campos-Díaz
- Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, E-37007 Salamanca, Spain; (E.N.-C.); (E.M.-S.); (A.C.-D.); (P.G.-A.)
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, E-37007 Salamanca, Spain
| | - Frank Rolfs
- OncoProteomics Laboratory, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands; (F.R.); (R.d.G.-d.H.); (T.V.P.); (S.R.P.); (C.R.J.)
| | - Richard de Goeij-de Haas
- OncoProteomics Laboratory, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands; (F.R.); (R.d.G.-d.H.); (T.V.P.); (S.R.P.); (C.R.J.)
| | - Thang V. Pham
- OncoProteomics Laboratory, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands; (F.R.); (R.d.G.-d.H.); (T.V.P.); (S.R.P.); (C.R.J.)
| | - Sander R. Piersma
- OncoProteomics Laboratory, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands; (F.R.); (R.d.G.-d.H.); (T.V.P.); (S.R.P.); (C.R.J.)
| | - Paula González-Alonso
- Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, E-37007 Salamanca, Spain; (E.N.-C.); (E.M.-S.); (A.C.-D.); (P.G.-A.)
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, E-37007 Salamanca, Spain
| | - Connie R. Jiménez
- OncoProteomics Laboratory, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands; (F.R.); (R.d.G.-d.H.); (T.V.P.); (S.R.P.); (C.R.J.)
| | - Pedro A. Lazo
- Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, E-37007 Salamanca, Spain; (E.N.-C.); (E.M.-S.); (A.C.-D.); (P.G.-A.)
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, E-37007 Salamanca, Spain
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5
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Fishburn AT, Florio CJ, Lopez NJ, Link NL, Shah PS. Molecular functions of ANKLE2 and its implications in human disease. Dis Model Mech 2024; 17:dmm050554. [PMID: 38691001 PMCID: PMC11103583 DOI: 10.1242/dmm.050554] [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] [Indexed: 05/03/2024] Open
Abstract
Ankyrin repeat and LEM domain-containing 2 (ANKLE2) is a scaffolding protein with established roles in cell division and development, the dysfunction of which is increasingly implicated in human disease. ANKLE2 regulates nuclear envelope disassembly at the onset of mitosis and its reassembly after chromosome segregation. ANKLE2 dysfunction is associated with abnormal nuclear morphology and cell division. It regulates the nuclear envelope by mediating protein-protein interactions with barrier to autointegration factor (BANF1; also known as BAF) and with the kinase and phosphatase that modulate the phosphorylation state of BAF. In brain development, ANKLE2 is crucial for proper asymmetric division of neural progenitor cells. In humans, pathogenic loss-of-function mutations in ANKLE2 are associated with primary congenital microcephaly, a condition in which the brain is not properly developed at birth. ANKLE2 is also linked to other disease pathologies, including congenital Zika syndrome, cancer and tauopathy. Here, we review the molecular roles of ANKLE2 and the recent literature on human diseases caused by its dysfunction.
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Affiliation(s)
- Adam T. Fishburn
- Department of Microbiology and Molecular Genetics, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Cole J. Florio
- Department of Microbiology and Molecular Genetics, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Nick J. Lopez
- Department of Microbiology and Molecular Genetics, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Nichole L. Link
- Department of Neurobiology, University of Utah, 20 South 2030 East, Salt Lake City, UT 84112, USA
| | - Priya S. Shah
- Department of Microbiology and Molecular Genetics, University of California, One Shields Avenue, Davis, CA 95616, USA
- Department of Chemical Engineering, University of California, One Shields Avenue, Davis, CA 95616, USA
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6
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Navarro-Carrasco E, Campos-Díaz A, Monte-Serrano E, Rolfs F, de Goeij-de Haas R, Pham TV, Piersma SR, Jiménez CR, Lazo PA. Loss of VRK1 alters the nuclear phosphoproteome in the DNA damage response to doxorubicin. Chem Biol Interact 2024; 391:110908. [PMID: 38367682 DOI: 10.1016/j.cbi.2024.110908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 01/22/2024] [Accepted: 02/07/2024] [Indexed: 02/19/2024]
Abstract
Dynamic chromatin remodeling requires regulatory mechanisms for its adaptation to different nuclear function, which are likely to be mediated by signaling proteins. In this context, VRK1 is a nuclear Ser-Thr kinase that regulates pathways associated with transcription, replication, recombination, and DNA repair. Therefore, VRK1 is a potential regulatory, or coordinator, molecule in these processes. In this work we studied the effect that VRK1 depletion has on the basal nuclear and chromatin phosphoproteome, and their associated pathways. VRK1 depletion caused an alteration in the pattern of the nuclear phosphoproteome, which is mainly associated with nucleoproteins, ribonucleoproteins, RNA splicing and processing. Next, it was determined the changes in proteins associated with DNA damage that was induced by doxorubicin treatment. Doxorubicin alters the nuclear phosphoproteome affecting proteins implicated in DDR, including DSB repair proteins NBN and 53BP1, cellular response to stress and chromatin organization proteins. In VRK1-depleted cells, the effect of doxorubicin on protein phosphorylation was reverted to basal levels. The nuclear phosphoproteome patterns induced by doxorubicin are altered by VRK1 depletion, and is enriched in histone modification proteins and chromatin associated proteins. These results indicate that VRK1 plays a major role in processes requiring chromatin remodeling in its adaptation to different biological contexts.
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Affiliation(s)
- Elena Navarro-Carrasco
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Salamanca, E-37007, Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, E-37007, Salamanca, Spain.
| | - Aurora Campos-Díaz
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Salamanca, E-37007, Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, E-37007, Salamanca, Spain.
| | - Eva Monte-Serrano
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Salamanca, E-37007, Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, E-37007, Salamanca, Spain.
| | - Frank Rolfs
- OncoProteomics Laboratory, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands.
| | - Richard de Goeij-de Haas
- OncoProteomics Laboratory, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands.
| | - Thang V Pham
- OncoProteomics Laboratory, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands.
| | - Sander R Piersma
- OncoProteomics Laboratory, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands.
| | - Connie R Jiménez
- OncoProteomics Laboratory, Cancer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands.
| | - Pedro A Lazo
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC) - Universidad de Salamanca, E-37007, Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, E-37007, Salamanca, Spain.
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7
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Carrasco Apolinario ME, Umeda R, Teranishi H, Shan M, Phurpa, Sebastian WA, Lai S, Shimizu N, Shiraishi H, Shikano K, Hikida T, Hanada T, Ohta K, Hanada R. Behavioral and neurological effects of Vrk1 deficiency in zebrafish. Biochem Biophys Res Commun 2023; 675:10-18. [PMID: 37429068 DOI: 10.1016/j.bbrc.2023.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 06/16/2023] [Accepted: 07/02/2023] [Indexed: 07/12/2023]
Abstract
Vaccinia-related kinase 1 (VRK1) is a serine/threonine kinase, for which mutations have been reported cause to neurodegenerative diseases, including spinal muscular atrophy, characterized by microcephaly, motor dysfunction, and impaired cognitive function, in humans. Partial Vrk1 knockdown in mice has been associated with microcephaly and impaired motor function. However, the pathophysiological relationship between VRK1 and neurodegenerative disorders and the precise mechanism of VRK1-related microcephaly and motor function deficits have not been fully investigated. To address this, in this study, we established vrk1-deficient (vrk1-/-) zebrafish and found that they show mild microcephaly and impaired motor function with a low brain dopamine content. Furthermore, vrk1-/- zebrafish exhibited decreased cell proliferation, defects in nuclear envelope formation, and heterochromatin formation in the brain. To our knowledge, this is the first report demonstrating the important role of VRK1 in microcephaly and motor dysfunction in vivo using vrk1-/- zebrafish. These findings contribute to elucidating the pathophysiological mechanisms underlying VRK1-mediated neurodegenerative diseases associated with microcephaly.
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Affiliation(s)
| | - Ryohei Umeda
- Department of Neurophysiology, Faculty of Medicine, Oita University, Oita, Japan; Department of Advanced Medical Science, Faculty of Medicine, Oita University, Oita, Japan
| | - Hitoshi Teranishi
- Department of Neurophysiology, Faculty of Medicine, Oita University, Oita, Japan
| | - Mengting Shan
- Department of Neurophysiology, Faculty of Medicine, Oita University, Oita, Japan
| | - Phurpa
- Department of Neurophysiology, Faculty of Medicine, Oita University, Oita, Japan
| | | | - Shaohong Lai
- Department of Cell Biology, Faculty of Medicine, Oita University, Oita, Japan
| | - Nobuyuki Shimizu
- Department of Cell Biology, Faculty of Medicine, Oita University, Oita, Japan
| | - Hiroshi Shiraishi
- Department of Cell Biology, Faculty of Medicine, Oita University, Oita, Japan
| | - Kenshiro Shikano
- Department of Neurophysiology, Faculty of Medicine, Oita University, Oita, Japan
| | - Takatoshi Hikida
- Laboratory for Advanced Brain Functions, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Toshikatsu Hanada
- Department of Cell Biology, Faculty of Medicine, Oita University, Oita, Japan
| | - Keisuke Ohta
- Advanced Imaging Research Center, Kurume University, Kurume, Japan
| | - Reiko Hanada
- Department of Neurophysiology, Faculty of Medicine, Oita University, Oita, Japan.
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8
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Vedanayagam J, Lin CJ, Papareddy R, Nodine M, Flynt AS, Wen J, Lai EC. Regulatory logic of endogenous RNAi in silencing de novo genomic conflicts. PLoS Genet 2023; 19:e1010787. [PMID: 37343034 DOI: 10.1371/journal.pgen.1010787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 05/17/2023] [Indexed: 06/23/2023] Open
Abstract
Although the biological utilities of endogenous RNAi (endo-RNAi) have been largely elusive, recent studies reveal its critical role in the non-model fruitfly Drosophila simulans to suppress selfish genes, whose unchecked activities can severely impair spermatogenesis. In particular, hairpin RNA (hpRNA) loci generate endo-siRNAs that suppress evolutionary novel, X-linked, meiotic drive loci. The consequences of deleting even a single hpRNA (Nmy) in males are profound, as such individuals are nearly incapable of siring male progeny. Here, comparative genomic analyses of D. simulans and D. melanogaster mutants of the core RNAi factor dcr-2 reveal a substantially expanded network of recently-emerged hpRNA-target interactions in the former species. The de novo hpRNA regulatory network in D. simulans provides insight into molecular strategies that underlie hpRNA emergence and their potential roles in sex chromosome conflict. In particular, our data support the existence of ongoing rapid evolution of Nmy/Dox-related networks, and recurrent targeting of testis HMG Box loci by hpRNAs. Importantly, the impact of the endo-RNAi network on gene expression flips the convention for regulatory networks, since we observe strong derepression of targets of the youngest hpRNAs, but only mild effects on the targets of the oldest hpRNAs. These data suggest that endo-RNAi are especially critical during incipient stages of intrinsic sex chromosome conflicts, and that continual cycles of distortion and resolution may contribute to speciation.
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Affiliation(s)
- Jeffrey Vedanayagam
- Developmental Biology Program, Sloan Kettering Institute, New York, New York, United States of America
| | - Ching-Jung Lin
- Developmental Biology Program, Sloan Kettering Institute, New York, New York, United States of America
- Weill Graduate School of Medical Sciences, Weill Cornell Medical College, New York, New York, United States of America
| | - Ranjith Papareddy
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Austria
| | - Michael Nodine
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Austria
| | - Alex S Flynt
- Cellular and Molecular Biology, University of Southern Mississippi, Hattiesburg, Mississippi, United States of America
| | - Jiayu Wen
- Division of Genome Sciences and Cancer, The John Curtin School of Medical Research The Australian National University, Canberra, Australia
| | - Eric C Lai
- Developmental Biology Program, Sloan Kettering Institute, New York, New York, United States of America
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9
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Mendaluk A, Caussinus E, Boutros M, Lehner CF. A genome-wide RNAi screen for genes important for proliferation of cultured Drosophila cells at low temperature identifies the Ball/VRK protein kinase. Chromosoma 2023; 132:31-53. [PMID: 36746786 PMCID: PMC9981717 DOI: 10.1007/s00412-023-00787-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 02/08/2023]
Abstract
A change in ambient temperature is predicted to disrupt cellular homeostasis by affecting all cellular processes in an albeit non-uniform manner. Diffusion is generally less temperature-sensitive than enzymes, for example, and each enzyme has a characteristic individual temperature profile. The actual effects of temperature variation on cells are still poorly understood at the molecular level. Towards an improved understanding, we have performed a genome-wide RNA interference screen with S2R + cells. This Drosophila cell line proliferates over a temperature range comparable to that tolerated by the parental ectothermic organism. Based on effects on cell counts and cell cycle profile after knockdown at 27 and 17 °C, respectively, genes were identified with an apparent greater physiological significance at one or the other temperature. While 27 °C is close to the temperature optimum, the substantially lower 17 °C was chosen to identify genes important at low temperatures, which have received less attention compared to the heat shock response. Among a substantial number of screen hits, we validated a set successfully in cell culture and selected ballchen for further evaluation in the organism. This gene encodes the conserved metazoan VRK protein kinase that is crucial for the release of chromosomes from the nuclear envelope during mitosis. Our analyses in early embryos and larval wing imaginal discs confirmed a higher requirement for ballchen function at temperatures below the optimum. Overall, our experiments validate the genome-wide screen as a basis for future characterizations of genes with increased physiological significance at the lower end of the readily tolerated temperature range.
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Affiliation(s)
- Anna Mendaluk
- Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland
| | - Emmanuel Caussinus
- Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland
| | - Michael Boutros
- Division of Signaling and Functional Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg University, BioQuant, Heidelberg, Germany
| | - Christian F Lehner
- Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland.
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10
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Nieken KJ, O’Brien K, McDonnell A, Zhaunova L, Ohkura H. A large-scale RNAi screen reveals that mitochondrial function is important for meiotic chromosome organization in oocytes. Chromosoma 2023; 132:1-18. [PMID: 36648541 PMCID: PMC9981535 DOI: 10.1007/s00412-023-00784-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/22/2022] [Accepted: 01/03/2023] [Indexed: 01/18/2023]
Abstract
In prophase of the first meiotic division, chromatin forms a compact spherical cluster called the karyosome within the enlarged oocyte nucleus in Drosophila melanogaster. Similar clustering of chromatin has been widely observed in oocytes in many species including humans. It was previously shown that the proper karyosome formation is required for faithful chromosome segregation, but knowledge about its formation and maintenance is limited. To identify genes involved in karyosome formation, we carried out a large-scale cytological screen using Drosophila melanogaster oocytes. This screen comprised 3916 genes expressed in ovaries, of which 106 genes triggered reproducible karyosome defects upon knockdown. The karyosome defects in 24 out of these 106 genes resulted from activation of the meiotic recombination checkpoint, suggesting possible roles in DNA repair or piRNA processing. The other genes identified in this screen include genes with functions linked to chromatin, nuclear envelope, and actin. We also found that silencing of genes with mitochondrial functions, including electron transport chain components, induced a distinct karyosome defect typically with de-clustered chromosomes located close to the nuclear envelope. Furthermore, mitochondrial dysfunction not only impairs karyosome formation and maintenance, but also delays synaptonemal complex disassembly in cells not destined to become the oocyte. These karyosome defects do not appear to be mediated by apoptosis. This large-scale unbiased study uncovered a set of genes required for karyosome formation and revealed a new link between mitochondrial dysfunction and chromatin organization in oocytes.
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Affiliation(s)
- Karen Jule Nieken
- grid.4305.20000 0004 1936 7988Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF UK
| | - Kathryn O’Brien
- grid.4305.20000 0004 1936 7988Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF UK
| | - Alexander McDonnell
- grid.4305.20000 0004 1936 7988Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF UK
| | - Liudmila Zhaunova
- grid.4305.20000 0004 1936 7988Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF UK
| | - Hiroyuki Ohkura
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK.
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11
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Immune and spermatogenesis-related loci are involved in the development of extreme patterns of male infertility. Commun Biol 2022; 5:1220. [PMID: 36357561 PMCID: PMC9649734 DOI: 10.1038/s42003-022-04192-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 10/28/2022] [Indexed: 11/12/2022] Open
Abstract
We conducted a genome-wide association study in a large population of infertile men due to unexplained spermatogenic failure (SPGF). More than seven million genetic variants were analysed in 1,274 SPGF cases and 1,951 unaffected controls from two independent European cohorts. Two genomic regions were associated with the most severe histological pattern of SPGF, defined by Sertoli cell-only (SCO) phenotype, namely the MHC class II gene HLA-DRB1 (rs1136759, P = 1.32E-08, OR = 1.80) and an upstream locus of VRK1 (rs115054029, P = 4.24E-08, OR = 3.14), which encodes a protein kinase involved in the regulation of spermatogenesis. The SCO-associated rs1136759 allele (G) determines a serine in the position 13 of the HLA-DRβ1 molecule located in the antigen-binding pocket. Overall, our data support the notion of unexplained SPGF as a complex trait influenced by common variation in the genome, with the SCO phenotype likely representing an immune-mediated condition. A GWAS in a large case-control cohort of European ancestry identifies two genomic regions, the MHC class II gene HLA-DRB1 and an upstream locus of VRK1, that are associated with the most severe phenotype of spermatogenic failure.
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12
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Dissecting the roles of Haspin and VRK1 in histone H3 phosphorylation during mitosis. Sci Rep 2022; 12:11210. [PMID: 35778595 PMCID: PMC9249732 DOI: 10.1038/s41598-022-15339-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 06/22/2022] [Indexed: 12/12/2022] Open
Abstract
Protein kinases that phosphorylate histones are ideally-placed to influence the behavior of chromosomes during cell division. Indeed, a number of conserved histone phosphorylation events occur prominently during mitosis and meiosis in most eukaryotes, including on histone H3 at threonine-3 (H3T3ph). At least two kinases, Haspin and VRK1 (NHK-1/ballchen in Drosophila), have been proposed to carry out this modification. Phosphorylation of H3 by Haspin has defined roles in mitosis, but the significance of VRK1 activity towards histones in dividing cells has been unclear. Here, using in vitro kinase assays, KiPIK screening, RNA interference, and CRISPR/Cas9 approaches, we were unable to substantiate a direct role for VRK1, or its paralogue VRK2, in the phosphorylation of threonine-3 or serine-10 of Histone H3 in mitosis, although loss of VRK1 did slow cell proliferation. We conclude that the role of VRKs, and their more recently identified association with neuromuscular disease and importance in cancers of the nervous system, are unlikely to involve mitotic histone kinase activity. In contrast, Haspin is required to generate H3T3ph during mitosis.
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13
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Yang S, McAdow J, Du Y, Trigg J, Taghert PH, Johnson AN. Spatiotemporal expression of regulatory kinases directs the transition from mitosis to cellular morphogenesis in Drosophila. Nat Commun 2022; 13:772. [PMID: 35140224 PMCID: PMC8828718 DOI: 10.1038/s41467-022-28322-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 01/17/2022] [Indexed: 02/01/2023] Open
Abstract
Embryogenesis depends on a tightly regulated balance between mitosis, differentiation, and morphogenesis. Understanding how the embryo uses a relatively small number of proteins to transition between growth and morphogenesis is a central question of developmental biology, but the mechanisms controlling mitosis and differentiation are considered to be fundamentally distinct. Here we show the mitotic kinase Polo, which regulates all steps of mitosis in Drosophila, also directs cellular morphogenesis after cell cycle exit. In mitotic cells, the Aurora kinases activate Polo to control a cytoskeletal regulatory module that directs cytokinesis. We show that in the post-mitotic mesoderm, the control of Polo activity transitions from the Aurora kinases to the uncharacterized kinase Back Seat Driver (Bsd), where Bsd and Polo cooperate to regulate muscle morphogenesis. Polo and its effectors therefore direct mitosis and cellular morphogenesis, but the transition from growth to morphogenesis is determined by the spatiotemporal expression of upstream activating kinases. The mechanisms regulating mitosis and differentiation during development are thought to be distinct. Here they show that in Drosophila the mitotic kinase Polo regulates cellular morphogenesis after cell cycle exit.
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Affiliation(s)
- Shuo Yang
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jennifer McAdow
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Yingqiu Du
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jennifer Trigg
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Paul H Taghert
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Aaron N Johnson
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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14
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Khan MHF, Akhtar J, Umer Z, Shaheen N, Shaukat A, Munir MS, Mithani A, Anwar S, Tariq M. Kinome-Wide RNAi Screen Uncovers Role of Ballchen in Maintenance of Gene Activation by Trithorax Group in Drosophila. Front Cell Dev Biol 2021; 9:637873. [PMID: 33748127 PMCID: PMC7973098 DOI: 10.3389/fcell.2021.637873] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/15/2021] [Indexed: 12/19/2022] Open
Abstract
Polycomb group (PcG) and trithorax group (trxG) proteins are evolutionary conserved factors that contribute to cell fate determination and maintenance of cellular identities during development of multicellular organisms. The PcG maintains heritable patterns of gene silencing while trxG acts as anti-silencing factors by conserving activation of cell type specific genes. Genetic and molecular analysis has revealed extensive details about how different PcG and trxG complexes antagonize each other to maintain cell fates, however, the cellular signaling components that contribute to the preservation of gene expression by PcG/trxG remain elusive. Here, we report an ex vivo kinome-wide RNAi screen in Drosophila aimed at identifying cell signaling genes that facilitate trxG in counteracting PcG mediated repression. From the list of trxG candidates, Ballchen (BALL), a histone kinase known to phosphorylate histone H2A at threonine 119 (H2AT119p), was characterized as a trxG regulator. The ball mutant exhibits strong genetic interactions with Polycomb (Pc) and trithorax (trx) mutants and loss of BALL affects expression of trxG target genes. BALL co-localizes with Trithorax on chromatin and depletion of BALL results in increased H2AK118 ubiquitination, a histone mark central to PcG mediated gene silencing. Moreover, BALL was found to substantially associate with known TRX binding sites across the genome. Genome wide distribution of BALL also overlaps with H3K4me3 and H3K27ac at actively transcribed genes. We propose that BALL mediated signaling positively contributes to the maintenance of gene activation by trxG in counteracting the repressive effect of PcG.
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Affiliation(s)
- Muhammad Haider Farooq Khan
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Jawad Akhtar
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Zain Umer
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Najma Shaheen
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Ammad Shaukat
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Muhammad Shahbaz Munir
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Aziz Mithani
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Saima Anwar
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Muhammad Tariq
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
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15
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Campillo-Marcos I, García-González R, Navarro-Carrasco E, Lazo PA. The human VRK1 chromatin kinase in cancer biology. Cancer Lett 2021; 503:117-128. [PMID: 33516791 DOI: 10.1016/j.canlet.2020.12.032] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/30/2020] [Accepted: 12/21/2020] [Indexed: 01/08/2023]
Abstract
VRK1 is a nuclear Ser-Thr chromatin kinase that does not mutate in cancer, and is overexpressed in many types of tumors and associated with a poor prognosis. Chromatin VRK1 phosphorylates several transcription factors, including p53, histones and proteins implicated in DNA damage response pathways. In the context of cell proliferation, VRK1 regulates entry in cell cycle, chromatin condensation in G2/M, Golgi fragmentation, Cajal body dynamics and nuclear envelope assembly in mitosis. This kinase also controls the initial chromatin relaxation associated with histone acetylation, and the non-homologous-end joining (NHEJ) DNA repair pathway, which involves sequential steps such as γH2AX, NBS1 and 53BP1 foci formation, all phosphorylated by VRK1, in response to ionizing radiation or chemotherapy. In addition, VRK1 can be an alternative target for therapies based on synthetic lethality strategies. Therefore, VRK1 roles on proliferation have a pro-tumorigenic effect. Functions regulating chromatin stability and DNA damage responses have a protective anti-tumor role in normal cells, but in tumor cells can also facilitate resistance to genotoxic treatments.
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Affiliation(s)
- Ignacio Campillo-Marcos
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular Del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Salamanca, 37007 Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 37007 Salamanca, Spain.
| | - Raúl García-González
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular Del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Salamanca, 37007 Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 37007 Salamanca, Spain.
| | - Elena Navarro-Carrasco
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular Del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Salamanca, 37007 Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 37007 Salamanca, Spain.
| | - Pedro A Lazo
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular Del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Salamanca, 37007 Salamanca, Spain.
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16
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Barbosa P, Zhaunova L, Debilio S, Steccanella V, Kelly V, Ly T, Ohkura H. SCF-Fbxo42 promotes synaptonemal complex assembly by downregulating PP2A-B56. J Cell Biol 2020; 220:211645. [PMID: 33382409 PMCID: PMC7780726 DOI: 10.1083/jcb.202009167] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/20/2020] [Accepted: 12/02/2020] [Indexed: 12/27/2022] Open
Abstract
Meiosis creates genetic diversity by recombination and segregation of chromosomes. The synaptonemal complex assembles during meiotic prophase I and assists faithful exchanges between homologous chromosomes, but how its assembly/disassembly is regulated remains to be understood. Here, we report how two major posttranslational modifications, phosphorylation and ubiquitination, cooperate to promote synaptonemal complex assembly. We found that the ubiquitin ligase complex SCF is important for assembly and maintenance of the synaptonemal complex in Drosophila female meiosis. This function of SCF is mediated by two substrate-recognizing F-box proteins, Slmb/βTrcp and Fbxo42. SCF-Fbxo42 down-regulates the phosphatase subunit PP2A-B56, which is important for synaptonemal complex assembly and maintenance.
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Affiliation(s)
- Pedro Barbosa
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Liudmila Zhaunova
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Simona Debilio
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK,Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Verdiana Steccanella
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Van Kelly
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Tony Ly
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Hiroyuki Ohkura
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK,Correspondence to Hiroyuki Ohkura:
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17
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Link N, Chung H, Jolly A, Withers M, Tepe B, Arenkiel BR, Shah PS, Krogan NJ, Aydin H, Geckinli BB, Tos T, Isikay S, Tuysuz B, Mochida GH, Thomas AX, Clark RD, Mirzaa GM, Lupski JR, Bellen HJ. Mutations in ANKLE2, a ZIKA Virus Target, Disrupt an Asymmetric Cell Division Pathway in Drosophila Neuroblasts to Cause Microcephaly. Dev Cell 2019; 51:713-729.e6. [PMID: 31735666 DOI: 10.1016/j.devcel.2019.10.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/19/2019] [Accepted: 10/14/2019] [Indexed: 12/12/2022]
Abstract
The apical Par complex, which contains atypical protein kinase C (aPKC), Bazooka (Par-3), and Par-6, is required for establishing polarity during asymmetric division of neuroblasts in Drosophila, and its activity depends on L(2)gl. We show that loss of Ankle2, a protein associated with microcephaly in humans and known to interact with Zika protein NS4A, reduces brain volume in flies and impacts the function of the Par complex. Reducing Ankle2 levels disrupts endoplasmic reticulum (ER) and nuclear envelope morphology, releasing the kinase Ballchen-VRK1 into the cytosol. These defects are associated with reduced phosphorylation of aPKC, disruption of Par-complex localization, and spindle alignment defects. Importantly, removal of one copy of ballchen or l(2)gl suppresses Ankle2 mutant phenotypes and restores viability and brain size. Human mutational studies implicate the above-mentioned genes in microcephaly and motor neuron disease. We suggest that NS4A, ANKLE2, VRK1, and LLGL1 define a pathway impinging on asymmetric determinants of neural stem cell division.
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Affiliation(s)
- Nichole Link
- Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Hyunglok Chung
- Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Angad Jolly
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; MD/PhD Medical Scientist Training Program and MHG Graduate program, BCM, Houston, TX 77030, USA
| | - Marjorie Withers
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Burak Tepe
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, BCM, Houston, TX 77030, USA
| | - Benjamin R Arenkiel
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, BCM, Houston, TX 77030, USA
| | - Priya S Shah
- Department of Chemical Engineering and Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute for Quantitative Biosciences, QB3, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hatip Aydin
- Center of Genetics Diagnosis, Zeynep Kamil Maternity and Children's Training and Research Hospital, Istanbul, Turkey
| | - Bilgen B Geckinli
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul, Turkey
| | - Tulay Tos
- Department of Medical Genetics, Dr. Sami Ulus Research and Training Hospital of Women's and Children's Health and Diseases, Ankara, Turkey
| | - Sedat Isikay
- Department of Physiotherapy and Rehabilitation, Hasan Kalyoncu University, School of Health Sciences, Gaziantep, Turkey
| | - Beyhan Tuysuz
- Department of Pediatrics, Istanbul University-Cerrahpasa, Medical Faculty, Istanbul, Turkey
| | - Ganesh H Mochida
- Division of Genetics and Genomics, Department of Pediatrics and Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Pediatric Neurology Unit, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Ajay X Thomas
- Department of Pediatrics, Section of Neurology and Developmental Neuroscience, BCM, Houston, TX 77030, USA; Section of Child Neurology, Texas Children's Hospital, Houston, TX 77030, USA
| | - Robin D Clark
- Division of Medical Genetics, Department of Pediatrics, Loma Linda University Medical Center, Loma Linda, CA 92354, USA
| | - Ghayda M Mirzaa
- Department of Pediatrics, University of Washington, Seattle, WA 98195, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98105, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Department of Pediatrics, BCM, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hugo J Bellen
- Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; MD/PhD Medical Scientist Training Program and MHG Graduate program, BCM, Houston, TX 77030, USA; Program in Developmental Biology, BCM, Houston, TX 77030, USA.
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18
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Female Meiosis: Synapsis, Recombination, and Segregation in Drosophila melanogaster. Genetics 2018; 208:875-908. [PMID: 29487146 PMCID: PMC5844340 DOI: 10.1534/genetics.117.300081] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 10/18/2017] [Indexed: 12/11/2022] Open
Abstract
A century of genetic studies of the meiotic process in Drosophila melanogaster females has been greatly augmented by both modern molecular biology and major advances in cytology. These approaches, and the findings they have allowed, are the subject of this review. Specifically, these efforts have revealed that meiotic pairing in Drosophila females is not an extension of somatic pairing, but rather occurs by a poorly understood process during premeiotic mitoses. This process of meiotic pairing requires the function of several components of the synaptonemal complex (SC). When fully assembled, the SC also plays a critical role in maintaining homolog synapsis and in facilitating the maturation of double-strand breaks (DSBs) into mature crossover (CO) events. Considerable progress has been made in elucidating not only the structure, function, and assembly of the SC, but also the proteins that facilitate the formation and repair of DSBs into both COs and noncrossovers (NCOs). The events that control the decision to mature a DSB as either a CO or an NCO, as well as determining which of the two CO pathways (class I or class II) might be employed, are also being characterized by genetic and genomic approaches. These advances allow a reconsideration of meiotic phenomena such as interference and the centromere effect, which were previously described only by genetic studies. In delineating the mechanisms by which the oocyte controls the number and position of COs, it becomes possible to understand the role of CO position in ensuring the proper orientation of homologs on the first meiotic spindle. Studies of bivalent orientation have occurred in the context of numerous investigations into the assembly, structure, and function of the first meiotic spindle. Additionally, studies have examined the mechanisms ensuring the segregation of chromosomes that have failed to undergo crossing over.
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19
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Campillo-Marcos I, Lazo PA. Implication of the VRK1 chromatin kinase in the signaling responses to DNA damage: a therapeutic target? Cell Mol Life Sci 2018; 75:2375-2388. [PMID: 29679095 PMCID: PMC5986855 DOI: 10.1007/s00018-018-2811-2] [Citation(s) in RCA: 37] [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: 02/05/2018] [Revised: 03/14/2018] [Accepted: 04/03/2018] [Indexed: 12/19/2022]
Abstract
DNA damage causes a local distortion of chromatin that triggers the sequential processes that participate in specific DNA repair mechanisms. This initiation of the repair response requires the involvement of a protein whose activity can be regulated by histones. Kinases are candidates to regulate and coordinate the connection between a locally altered chromatin and the response initiating signals that lead to identification of the type of lesion and the sequential steps required in specific DNA damage responses (DDR). This initiating kinase must be located in chromatin, and be activated independently of the type of DNA damage. We review the contribution of the Ser-Thr vaccinia-related kinase 1 (VRK1) chromatin kinase as a new player in the signaling of DNA damage responses, at chromatin and cellular levels, and its potential as a new therapeutic target in oncology. VRK1 is involved in the regulation of histone modifications, such as histone phosphorylation and acetylation, and in the formation of γH2AX, NBS1 and 53BP1 foci induced in DDR. Induction of DNA damage by chemotherapy or radiation is a mainstay of cancer treatment. Therefore, novel treatments can be targeted to proteins implicated in the regulation of DDR, rather than by directly causing DNA damage.
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Affiliation(s)
- Ignacio Campillo-Marcos
- Experimental Therapeutics and Translational Oncology Program, Instituto de Biología Molecular y Celular del Cáncer, CSIC-Universidad de Salamanca, 37007, Salamanca, Spain
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 37007, Salamanca, Spain
| | - Pedro A Lazo
- Experimental Therapeutics and Translational Oncology Program, Instituto de Biología Molecular y Celular del Cáncer, CSIC-Universidad de Salamanca, 37007, Salamanca, Spain.
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, 37007, Salamanca, Spain.
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20
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Bogolyubov DS. Karyosphere (Karyosome): A Peculiar Structure of the Oocyte Nucleus. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 337:1-48. [PMID: 29551157 DOI: 10.1016/bs.ircmb.2017.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The karyosphere, aka the karyosome, is a meiosis-specific structure that represents a "knot" of condensed chromosomes joined together in a limited volume of the oocyte nucleus. The karyosphere is an evolutionarily conserved but morphologically rather "multifaceted" structure. It forms at the diplotene stage of meiotic prophase in many animals, from hydra and Drosophila to human. Karyosphere formation is generally linked with transcriptional silencing of the genome. It is believed that karyosphere/karyosome is a prerequisite for proper completion of meiotic divisions and further development. Here, a brief review on the karyosphere features in some invertebrates and vertebrates is provided. Special emphasis is made on terminology, since current discrepancies in this field may lead to confusions. In particular, it is proposed to distinguish the karyosphere with a capsule and the karyosome (a karyosphere devoid of a capsule). The "inverted" karyospheres are also considered, in which the chromosomes situate externally to an extrachromosomal structure (e.g., in human oocytes).
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Affiliation(s)
- Dmitry S Bogolyubov
- Institute of Cytology of the Russian Academy of Science, St. Petersburg, Russia.
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21
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Romé P, Ohkura H. Combining microscopy and biochemistry to study meiotic spindle assembly in Drosophila oocytes. Methods Cell Biol 2018; 145:237-248. [PMID: 29957206 PMCID: PMC6031290 DOI: 10.1016/bs.mcb.2018.03.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Studies using Drosophila have played pivotal roles in advancing our understanding of molecular mechanisms of mitosis throughout the past decades, due to the short generation time and advanced genetic research of this organism. Drosophila is also an excellent model to study female meiosis in oocytes. Pathways such as the acentrosomal assembly of the meiotic spindle in oocytes are conserved from fly to humans. Collecting and manipulating large Drosophila oocytes for microscopy and biochemistry are both time and cost efficient, offering advantages over mouse or human oocytes. Therefore, Drosophila oocytes serve as an excellent platform for molecular studies of female meiosis using a combination of genetics, microscopy, and biochemistry. Here we describe key methods to observe the formation of the meiotic spindle either in fixed or in live oocytes. Moreover, biochemical methods are described to identify protein-protein interactions in vivo.
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Affiliation(s)
- Pierre Romé
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Hiroyuki Ohkura
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom.
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22
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Ilicheva N, Podgornaya O, Bogolyubov D, Pochukalina G. The karyosphere capsule in Rana temporaria oocytes contains structural and DNA-binding proteins. Nucleus 2018; 9:516-529. [PMID: 30272509 PMCID: PMC6244735 DOI: 10.1080/19491034.2018.1530935] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 09/21/2018] [Accepted: 09/26/2018] [Indexed: 12/14/2022] Open
Abstract
During the last stages of oogenesis, oocyte chromosomes condense and come close together, forming the so-called karyosphere. Karyosphere formation is accompanied by an essential decrease in transcriptional activity. In the grass frog Rana temporaria, the karyosphere is surrounded by an extrachromosomal capsule that separates the chromosomes from the rest of the nucleoplasm. The karyosphere capsule (KC) of R. temporaria has been investigated in detail at the ultrastructural level, but its protein composition remained largely unknown. We demonstrate here that nuclear actin, especially F-actin, as well as lamins A/C and B are the most abundant proteins of the KC. Key proteins of nuclear pore complexes, such as Nup93 and Nup35, are also detectable in the KC. New antibodies recognizing the telomere-binding protein TRF2 allowed us to localize TRF2 in nuclear speckles. We also found that the R. temporaria KC contains some proteins involved in chromatin remodeling, including topoisomerase II and ATRX. Thus, we believe that KC isolates the chromosomes from the rest of the nucleoplasm during the final period of oocyte growth (late diplotene) and represents a specialized oocyte nuclear compartment to store a variety of factors involved in nuclear metabolism that can be used in future early development. Abbreviations: BrUTP: 5-bromouridine 5'-triphosphate; CytD: cytochalasin D; IGCs: interchromatin granule clasters; IgG: immunoglobulin G; KC: karyosphere capsule; Mw: molecular weight; NE: nuclear envelope; PBS: phosphate buffered saline; SDS-PAGE: sodium dodecyl sulfate polyacrylamide gel electrophoresis; Topo II: topoisomerase II.
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Affiliation(s)
- Nadya Ilicheva
- Laboratory of Cell Morphology, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg, Russia
| | - Olga Podgornaya
- Laboratory of Cell Morphology, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg, Russia
- Department of Cytology and Histology, Faculty of Biology, Saint Petersburg State University, St. Petersburg, Russia
- Laboratory of Biomedical Cell Technology, School of Biomedicine, Far Eastern Federal University, Vladivostok, Russia
| | - Dmitry Bogolyubov
- Laboratory of Cell Morphology, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg, Russia
| | - Galina Pochukalina
- Laboratory of Cell Morphology, Institute of Cytology of the Russian Academy of Sciences, St. Petersburg, Russia
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23
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Deletion of the Vaccinia Virus B1 Kinase Reveals Essential Functions of This Enzyme Complemented Partly by the Homologous Cellular Kinase VRK2. J Virol 2017; 91:JVI.00635-17. [PMID: 28515294 DOI: 10.1128/jvi.00635-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 05/10/2017] [Indexed: 12/30/2022] Open
Abstract
The vaccinia virus B1 kinase is highly conserved among poxviruses and is essential for the viral life cycle. B1 exhibits a remarkable degree of similarity to vaccinia virus-related kinases (VRKs), a family of cellular kinases, suggesting that the viral enzyme has evolved to mimic VRK activity. Indeed, B1 and VRKs have been demonstrated to target a shared substrate, the DNA binding protein BAF, elucidating a signaling pathway important for both mitosis and the antiviral response. In this study, we further characterize the role of B1 during vaccinia infection to gain novel insights into its regulation and integration with cellular signaling pathways. We begin by describing the construction and characterization of the first B1 deletion virus (vvΔB1) produced using a complementing cell line expressing the viral kinase. Examination of vvΔB1 revealed that B1 is critical for the production of infectious virions in various cell types and is sufficient for BAF phosphorylation. Interestingly, the severity of the defect in DNA replication following the loss of B1 varied between cell types, leading us to posit that cellular VRKs partly complement for the absence of B1 in some cell lines. Using cell lines devoid of either VRK1 or VRK2, we tested this hypothesis and discovered that VRK2 expression facilitates DNA replication and allows later stages of the viral life cycle to proceed in the absence of B1. Finally, we present evidence that the impact of VRK2 on vaccinia virus is largely independent of BAF phosphorylation. These data support a model in which B1 and VRK2 share additional substrates important for the replication of cytoplasmic poxviruses.IMPORTANCE Viral mimicry of cellular signaling modulators provides clear evidence that the pathogen targets an important host pathway during infection. Poxviruses employ numerous viral homologs of cellular proteins, the study of which have yielded insights into signaling pathways used by both virus and cells alike. The vaccinia virus B1 protein is a homolog of cellular vaccinia virus-related kinases (VRKs) and is needed for viral DNA replication and likely other stages of the viral life cycle. However, much remains to be learned about how B1 and VRKs overlap functionally. This study utilizes new tools, including a B1 deletion virus and VRK knockout cells, to further characterize the functional links between the viral and cellular enzymes. As a result, we have discovered that B1 and VRK2 target a common set of substrates vital to productive infection of this large cytoplasmic DNA virus.
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Flora P, McCarthy A, Upadhyay M, Rangan P. Role of Chromatin Modifications in Drosophila Germline Stem Cell Differentiation. Results Probl Cell Differ 2017; 59:1-30. [PMID: 28247044 DOI: 10.1007/978-3-319-44820-6_1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
During Drosophila oogenesis, germline stem cells (GSCs) self-renew and differentiate to give rise to a mature egg. Self-renewal and differentiation of GSCs are regulated by both intrinsic mechanisms such as regulation of gene expression in the germ line and extrinsic signaling pathways from the surrounding somatic niche. Epigenetic mechanisms, including histone-modifying proteins, nucleosome remodeling complexes, and histone variants, play a critical role in regulating intrinsic gene expression and extrinsic signaling cues from the somatic niche. In the GSCs, intrinsic epigenetic modifiers are required to maintain a stem cell fate by promoting expression of self-renewal factors and repressing the differentiation program. Subsequently, in the GSC daughters, epigenetic regulators activate the differentiation program to promote GSC differentiation. During differentiation, the GSC daughter undergoes meiosis to give rise to the developing egg, containing a compacted chromatin architecture called the karyosome. Epigenetic modifiers control the attachment of chromosomes to the nuclear lamina to aid in meiotic recombination and the release from the lamina for karyosome formation. The germ line is in close contact with the soma for the entirety of this developmental process. This proximity facilitates signaling from the somatic niche to the developing germ line. Epigenetic modifiers play a critical role in the somatic niche, modulating signaling pathways in order to coordinate the transition of GSC to an egg. Together, intrinsic and extrinsic epigenetic mechanisms modulate this exquisitely balanced program.
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Affiliation(s)
- Pooja Flora
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Alicia McCarthy
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Maitreyi Upadhyay
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Prashanth Rangan
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA.
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA.
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25
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Radford SJ, Nguyen AL, Schindler K, McKim KS. The chromosomal basis of meiotic acentrosomal spindle assembly and function in oocytes. Chromosoma 2016; 126:351-364. [PMID: 27837282 DOI: 10.1007/s00412-016-0618-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 12/20/2022]
Abstract
Several aspects of meiosis are impacted by the absence of centrosomes in oocytes. Here, we review four aspects of meiosis I that are significantly affected by the absence of centrosomes in oocyte spindles. One, microtubules tend to assemble around the chromosomes. Two, the organization of these microtubules into a bipolar spindle is directed by the chromosomes. Three, chromosome bi-orientation and attachment to microtubules from the correct pole require modification of the mechanisms used in mitotic cells. Four, chromosome movement to the poles at anaphase cannot rely on polar anchoring of spindle microtubules by centrosomes. Overall, the chromosomes are more active participants during acentrosomal spindle assembly in oocytes, compared to mitotic and male meiotic divisions where centrosomes are present. The chromosomes are endowed with information that can direct the meiotic divisions and dictate their own behavior in oocytes. Processes beyond those known from mitosis appear to be required for their bi-orientation at meiosis I. As mitosis occurs without centrosomes in many systems other than oocytes, including all plants, the concepts discussed here may not be limited to oocytes. The study of meiosis in oocytes has revealed mechanisms that are operating in mitosis and will probably continue to do so.
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Affiliation(s)
- Sarah J Radford
- Waksman Institute, 190 Frelinghuysen Rd, Piscataway, NJ, 08854, USA
| | | | - Karen Schindler
- Department of Genetics, Rutgers University, Piscataway, NJ, 08854, USA
| | - Kim S McKim
- Waksman Institute, 190 Frelinghuysen Rd, Piscataway, NJ, 08854, USA.
- Department of Genetics, Rutgers University, Piscataway, NJ, 08854, USA.
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26
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Dobrzynska A, Askjaer P. Vaccinia-related kinase 1 is required for early uterine development in Caenorhabditis elegans. Dev Biol 2016; 411:246-256. [PMID: 26827901 DOI: 10.1016/j.ydbio.2016.01.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 01/15/2016] [Accepted: 01/18/2016] [Indexed: 10/25/2022]
Abstract
Protein kinases regulate a multitude of processes by reversible phosphorylation of target molecules. Induction of cell proliferation and differentiation are fundamental to development and rely on tightly controlled kinase activities. Vaccinia-Related Kinases (VRKs) have emerged as a multifunctional family of kinases with essential functions conserved, from nematodes and fruit flies, to humans. VRK substrates include chromatin and transcription factors, whereas deregulation of VRKs is implicated in sterility, cancer and neurological defects. In contrast to previous observations, we describe here that Caenorhabditis elegans VRK-1 is expressed in all cell types, including proliferating and post-mitotic cells. Despite the ubiquitous expression pattern, we find that vrk-1 mutants are particularly impaired in uterine development. Our data show that VRK-1 is required for uterine cell proliferation and differentiation. Moreover, the anchor cell, a specialized uterine cell, fails to fuse with neighboring cells to form the utse syncytium in vrk-1 mutants, thus providing further insight on the role of VRKs in organogenesis.
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Affiliation(s)
- Agnieszka Dobrzynska
- Andalusian Center for Developmental Biology, CSIC-Junta de Andalucia-Universidad Pablo de Olavide, Carretera de Utrera, km 1, 41013 Seville, Spain
| | - Peter Askjaer
- Andalusian Center for Developmental Biology, CSIC-Junta de Andalucia-Universidad Pablo de Olavide, Carretera de Utrera, km 1, 41013 Seville, Spain.
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27
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Abstract
Breuer and Ohkura propose a negative regulatory loop within the nuclear pore complex (NPC) controlling the chromatin attachment state, in which Nup155 and Nup93 recruit Nup62 to suppress chromatin tethering by Nup155. The nuclear pore complex (NPC) tethers chromatin to create an environment for gene regulation, but little is known about how this activity is regulated to avoid excessive tethering of the genome. Here we propose a negative regulatory loop within the NPC controlling the chromatin attachment state, in which Nup155 and Nup93 recruit Nup62 to suppress chromatin tethering by Nup155. Depletion of Nup62 severely disrupts chromatin distribution in the nuclei of female germlines and somatic cells, which can be reversed by codepleting Nup155. Thus, this universal regulatory system within the NPC is crucial to control large-scale chromatin organization in the nucleus.
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Affiliation(s)
- Manuel Breuer
- The Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
| | - Hiroyuki Ohkura
- The Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
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28
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Nikalayevich E, Ohkura H. The NuRD nucleosome remodelling complex and NHK-1 kinase are required for chromosome condensation in oocytes. J Cell Sci 2015; 128:566-75. [PMID: 25501812 PMCID: PMC4311133 DOI: 10.1242/jcs.158477] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 12/05/2014] [Indexed: 12/31/2022] Open
Abstract
Chromosome condensation during cell division is one of the most dramatic events in the cell cycle. Condensin and topoisomerase II are the most studied factors in chromosome condensation. However, their inactivation leads to only mild defects and little is known about the roles of other factors. Here, we took advantage of Drosophilaoocytes to elucidate the roles of potential condensation factors by performing RNA interference (RNAi). Consistent with previous studies, depletion of condensin I subunits or topoisomerase II in oocytes only mildly affected chromosome condensation. In contrast, we found severe undercondensation of chromosomes after depletion of the Mi-2-containing NuRD nucleosome remodelling complex or the protein kinase NHK-1 (also known as Ballchen in Drosophila). The further phenotypic analysis suggests that Mi-2 and NHK-1 are involved in different pathways of chromosome condensation. We show that the main role of NHK-1 in chromosome condensation is to phosphorylate Barrier-to-autointegration factor (BAF) and suppress its activity in linking chromosomes to nuclear envelope proteins. We further show that NHK-1 is important for chromosome condensation during mitosis as well as in oocytes.
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Affiliation(s)
| | - Hiroyuki Ohkura
- Wellcome Trust Centre for Cell Biology, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JR, UK
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29
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Ohkura H. Meiosis: an overview of key differences from mitosis. Cold Spring Harb Perspect Biol 2015; 7:cshperspect.a015859. [PMID: 25605710 DOI: 10.1101/cshperspect.a015859] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Meiosis is the specialized cell division that generates gametes. In contrast to mitosis, molecular mechanisms and regulation of meiosis are much less understood. Meiosis shares mechanisms and regulation with mitosis in many aspects, but also has critical differences from mitosis. This review highlights these differences between meiosis and mitosis. Recent studies using various model systems revealed differences in a surprisingly wide range of aspects, including cell-cycle regulation, recombination, postrecombination events, spindle assembly, chromosome-spindle interaction, and chromosome segregation. Although a great degree of diversity can be found among organisms, meiosis-specific processes, and regulation are generally conserved.
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Affiliation(s)
- Hiroyuki Ohkura
- The Wellcome Trust Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
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30
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Yamamoto S, Jaiswal M, Charng WL, Gambin T, Karaca E, Mirzaa G, Wiszniewski W, Sandoval H, Haelterman NA, Xiong B, Zhang K, Bayat V, David G, Li T, Chen K, Gala U, Harel T, Pehlivan D, Penney S, Vissers LELM, de Ligt J, Jhangiani SN, Xie Y, Tsang SH, Parman Y, Sivaci M, Battaloglu E, Muzny D, Wan YW, Liu Z, Lin-Moore AT, Clark RD, Curry CJ, Link N, Schulze KL, Boerwinkle E, Dobyns WB, Allikmets R, Gibbs RA, Chen R, Lupski JR, Wangler MF, Bellen HJ. A drosophila genetic resource of mutants to study mechanisms underlying human genetic diseases. Cell 2014; 159:200-214. [PMID: 25259927 PMCID: PMC4298142 DOI: 10.1016/j.cell.2014.09.002] [Citation(s) in RCA: 257] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 06/04/2014] [Accepted: 09/02/2014] [Indexed: 12/31/2022]
Abstract
Invertebrate model systems are powerful tools for studying human disease owing to their genetic tractability and ease of screening. We conducted a mosaic genetic screen of lethal mutations on the Drosophila X chromosome to identify genes required for the development, function, and maintenance of the nervous system. We identified 165 genes, most of whose function has not been studied in vivo. In parallel, we investigated rare variant alleles in 1,929 human exomes from families with unsolved Mendelian disease. Genes that are essential in flies and have multiple human homologs were found to be likely to be associated with human diseases. Merging the human data sets with the fly genes allowed us to identify disease-associated mutations in six families and to provide insights into microcephaly associated with brain dysgenesis. This bidirectional synergism between fly genetics and human genomics facilitates the functional annotation of evolutionarily conserved genes involved in human health.
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Affiliation(s)
- Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Howard Hughes Medical Institute, Houston, TX 77030, USA
| | - Wu-Lin Charng
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Tomasz Gambin
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Institute of Computer Science, Warsaw University of Technology, 00-661 Warsaw, Poland
| | - Ender Karaca
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Ghayda Mirzaa
- Department of Pediatrics, University of Washington, Seattle, WA 98195, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Wojciech Wiszniewski
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Hector Sandoval
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Nele A Haelterman
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Bo Xiong
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Ke Zhang
- Program in Structural and Computational Biology and Molecular Biophysics, BCM, Houston, TX 77030, USA
| | - Vafa Bayat
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Gabriela David
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Tongchao Li
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Kuchuan Chen
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Upasana Gala
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Tamar Harel
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Davut Pehlivan
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Samantha Penney
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Lisenka E L M Vissers
- Department of Human Genetics, Radboudumc, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Joep de Ligt
- Department of Human Genetics, Radboudumc, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | | | - Yajing Xie
- Department of Ophthalmology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Stephen H Tsang
- Department of Ophthalmology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Yesim Parman
- Neurology Department and Neuropathology Laboratory, Istanbul University Medical School, Istanbul 34390, Turkey
| | - Merve Sivaci
- Department of Molecular Biology and Genetics, Bogazici University, Istanbul 34342, Turkey
| | - Esra Battaloglu
- Department of Molecular Biology and Genetics, Bogazici University, Istanbul 34342, Turkey
| | - Donna Muzny
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Human Genome Sequencing Center, BCM, Houston, TX 77030, USA
| | - Ying-Wooi Wan
- Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA; Department of Obstetrics and Gynecology, BCM, Houston, TX 77030, USA
| | - Zhandong Liu
- Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA; Department of Pediatrics, BCM, Houston, TX 77030, USA
| | | | - Robin D Clark
- Division of Medical Genetics, Department of Pediatrics, Loma Linda University Medical Center, Loma Linda, CA 92354, USA
| | - Cynthia J Curry
- Department of Pediatrics, University of California San Francisco, San Francisco, CA 94143, USA; Genetic Medicine Central California, Fresno, CA 93701, USA
| | - Nichole Link
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Karen L Schulze
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Howard Hughes Medical Institute, Houston, TX 77030, USA
| | - Eric Boerwinkle
- Human Genome Sequencing Center, BCM, Houston, TX 77030, USA; Human Genetics Center, University of Texas, Health Science Center, Houston, TX 77030, USA
| | - William B Dobyns
- Department of Pediatrics, University of Washington, Seattle, WA 98195, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Neurology, University of Washington, Seattle WA 98195, USA
| | - Rando Allikmets
- Department of Ophthalmology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Richard A Gibbs
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Human Genome Sequencing Center, BCM, Houston, TX 77030, USA
| | - Rui Chen
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Human Genome Sequencing Center, BCM, Houston, TX 77030, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA; Human Genome Sequencing Center, BCM, Houston, TX 77030, USA
| | - Michael F Wangler
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA.
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Houston, TX 77030, USA; Howard Hughes Medical Institute, Houston, TX 77030, USA; Program in Structural and Computational Biology and Molecular Biophysics, BCM, Houston, TX 77030, USA; Department of Neuroscience, BCM, Houston, TX 77030, USA.
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31
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Yakulov T, Günesdogan U, Jäckle H, Herzig A. Bällchen participates in proliferation control and prevents the differentiation of Drosophila melanogaster neuronal stem cells. Biol Open 2014; 3:881-6. [PMID: 25190057 PMCID: PMC4197436 DOI: 10.1242/bio.20148631] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Stem cells continuously generate differentiating daughter cells and are essential for tissue homeostasis and development. Their capacity to self-renew as undifferentiated and actively dividing cells is controlled by either external signals from a cellular environment, the stem cell niche, or asymmetric distribution of cell fate determinants during cell division. Here we report that the protein kinase Bällchen (BALL) is required to prevent differentiation as well as to maintain normal proliferation of neuronal stem cells of Drosophila melanogaster, called neuroblasts. Our results show that the brains of ball mutant larvae are severely reduced in size, which is caused by a reduced proliferation rate of the neuroblasts. Moreover, ball mutant neuroblasts gradually lose the expression of the neuroblast determinants Miranda and aPKC, suggesting their premature differentiation. Our results indicate that BALL represents a novel cell intrinsic factor with a dual function regulating the proliferative capacity and the differentiation status of neuronal stem cells during development.
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Affiliation(s)
- Toma Yakulov
- Present address: Renal Division, University Hospital Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany
| | - Ufuk Günesdogan
- Present address: Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Herbert Jäckle
- Max-Planck-Institut für biophysikalische Chemie, Abteilung Molekulare Entwicklungsbiologie, Am Fassberg 11, 37077 Göttingen, Germany Present address: Renal Division, University Hospital Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany. Present address: Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK. Present address: Max-Planck-Institut für Infektionsbiologie, Department Cellular Microbiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Alf Herzig
- Present address: Max-Planck-Institut für Infektionsbiologie, Department Cellular Microbiology, Charitéplatz 1, 10117 Berlin, Germany.
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Herzig B, Yakulov TA, Klinge K, Günesdogan U, Jäckle H, Herzig A. Bällchen is required for self-renewal of germline stem cells in Drosophila melanogaster. Biol Open 2014; 3:510-21. [PMID: 24876388 PMCID: PMC4058086 DOI: 10.1242/bio.20147690] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Self-renewing stem cells are pools of undifferentiated cells, which are maintained in cellular niche environments by distinct tissue-specific signalling pathways. In Drosophila melanogaster, female germline stem cells (GSCs) are maintained in a somatic niche of the gonads by BMP signalling. Here we report a novel function of the Drosophila kinase Bällchen (BALL), showing that its cell autonomous role is to maintain the self-renewing capacity of female GSCs independent of BMP signalling. ball mutant GSCs are eliminated from the niche and subsequently differentiate into mature eggs, indicating that BALL is largely dispensable for differentiation. Similar to female GSCs, BALL is required to maintain self-renewal of male GSCs, suggesting a tissue independent requirement of BALL for self-renewal of germline stem cells.
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Affiliation(s)
- Bettina Herzig
- Department of Molecular Developmental Biology, Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany Present address: Renal Division, University Hospital Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany. Present address: Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK. Present address: Department of Cellular Microbiology, Max-Planck-Institut für Infektionsbiologie, Charitéplatz 1, 10117 Berlin, Germany
| | - Toma A Yakulov
- Present address: Renal Division, University Hospital Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany
| | - Kathrin Klinge
- Department of Molecular Developmental Biology, Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany Present address: Renal Division, University Hospital Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany. Present address: Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK. Present address: Department of Cellular Microbiology, Max-Planck-Institut für Infektionsbiologie, Charitéplatz 1, 10117 Berlin, Germany
| | - Ufuk Günesdogan
- Present address: Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Herbert Jäckle
- Department of Molecular Developmental Biology, Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany Present address: Renal Division, University Hospital Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany. Present address: Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK. Present address: Department of Cellular Microbiology, Max-Planck-Institut für Infektionsbiologie, Charitéplatz 1, 10117 Berlin, Germany
| | - Alf Herzig
- Present address: Department of Cellular Microbiology, Max-Planck-Institut für Infektionsbiologie, Charitéplatz 1, 10117 Berlin, Germany.
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López-Sánchez I, Valbuena A, Vázquez-Cedeira M, Khadake J, Sanz-García M, Carrillo-Jiménez A, Lazo PA. VRK1 interacts with p53 forming a basal complex that is activated by UV-induced DNA damage. FEBS Lett 2014; 588:692-700. [PMID: 24492002 DOI: 10.1016/j.febslet.2014.01.040] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 01/09/2014] [Accepted: 01/19/2014] [Indexed: 01/08/2023]
Abstract
DNA damage immediate cellular response requires the activation of p53 by kinases. We found that p53 forms a basal stable complex with VRK1, a Ser-Thr kinase that responds to UV-induced DNA damage by specifically phosphorylating p53. This interaction takes place through the p53 DNA binding domain, and frequent DNA-contact mutants of p53, such as R273H, R248H or R280K, do not disrupt the complex. UV-induced DNA damage activates VRK1, and is accompanied by phosphorylation of p53 at Thr-18 before it accumulates. We propose that the VRK1-p53 basal complex is an early-warning system for immediate cellular responses to DNA damage.
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Affiliation(s)
- Inmaculada López-Sánchez
- Experimental Therapeutics and Translational Oncology Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, Spain
| | - Alberto Valbuena
- Experimental Therapeutics and Translational Oncology Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, Spain
| | - Marta Vázquez-Cedeira
- Experimental Therapeutics and Translational Oncology Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
| | - Jyoti Khadake
- European Bioinformatics Institute-EMBL, Cambridge, England, United Kingdom
| | - Marta Sanz-García
- Experimental Therapeutics and Translational Oncology Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, Spain
| | - Alejandro Carrillo-Jiménez
- Experimental Therapeutics and Translational Oncology Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, Spain
| | - Pedro A Lazo
- Experimental Therapeutics and Translational Oncology Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain.
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Molitor TP, Traktman P. Depletion of the protein kinase VRK1 disrupts nuclear envelope morphology and leads to BAF retention on mitotic chromosomes. Mol Biol Cell 2014; 25:891-903. [PMID: 24430874 PMCID: PMC3952857 DOI: 10.1091/mbc.e13-10-0603] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The VRK1 protein kinase regulates the phosphorylation of BAF, which binds to dsDNA and LEM domain–containing proteins. VRK1 depletion increases the immobile fraction of BAF at the nuclear periphery and disturbs nuclear envelope architecture. It also leads to the retention of BAF on chromosomes as cells enter and progress through mitosis. Barrier to autointegration factor (BAF), which is encoded by the BANF1 gene, binds with high-affinity to double-stranded DNA and LEM domain–containing proteins at the nuclear periphery. A BANF1 mutation has recently been associated with a novel human progeria syndrome, and cells from these patients have aberrant nuclear envelopes. The interactions of BAF with its DNA- and protein-binding partners are known to be regulated by phosphorylation, and previously we validated BAF as a highly efficient substrate for the VRK1 protein kinase. Here we show that depletion of VRK1 in MCF10a and MDA-MB-231 cells results in aberrant nuclear architecture. The immobile fraction of green fluorescent protein (GFP)–BAF at the nuclear envelope (NE) is elevated, suggesting that prolonged interactions of BAF with its binding partners is likely responsible for the aberrant NE architecture. Because detachment of BAF from its binding partners is associated with NE disassembly, we performed live-imaging analysis of control and VRK1-depleted cells to visualize GFP-BAF dynamics during mitosis. In the absence of VRK1, BAF does not disperse but instead remains chromosome bound from the onset of mitosis. VRK1 depletion also increases the number of anaphase bridges and multipolar spindles. Thus phosphorylation of BAF by VRK1 is essential both for normal NE architecture and proper dynamics of BAF–chromosome interactions during mitosis. These results are consistent with previous studies of the VRK/BAF signaling axis in Caenorhabditis elegans and Drosophila melanogaster and validate VRK1 as a key regulator of NE architecture and mitotic chromosome dynamics in mammalian cells.
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Affiliation(s)
- Tyler P Molitor
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI 53226
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35
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Mitotic rounding alters cell geometry to ensure efficient bipolar spindle formation. Dev Cell 2013; 25:270-83. [PMID: 23623611 DOI: 10.1016/j.devcel.2013.03.014] [Citation(s) in RCA: 213] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 02/14/2013] [Accepted: 03/21/2013] [Indexed: 01/07/2023]
Abstract
Accurate animal cell division requires precise coordination of changes in the structure of the microtubule-based spindle and the actin-based cell cortex. Here, we use a series of perturbation experiments to dissect the relative roles of actin, cortical mechanics, and cell shape in spindle formation. We find that, whereas the actin cortex is largely dispensable for rounding and timely mitotic progression in isolated cells, it is needed to drive rounding to enable unperturbed spindle morphogenesis under conditions of confinement. Using different methods to limit mitotic cell height, we show that a failure to round up causes defects in spindle assembly, pole splitting, and a delay in mitotic progression. These defects can be rescued by increasing microtubule lengths and therefore appear to be a direct consequence of the limited reach of mitotic centrosome-nucleated microtubules. These findings help to explain why most animal cells round up as they enter mitosis.
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36
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Jolliffe AK, Derry WB. The TP53 signaling network in mammals and worms. Brief Funct Genomics 2012; 12:129-41. [PMID: 23165352 DOI: 10.1093/bfgp/els047] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The nematode worm Caenorhabditis elegans has been an invaluable model organism for studying the molecular mechanisms that govern cell fate, from fundamental aspects of multicellular development to programmed cell death (apoptosis). The transparency of this organism permits visualization of cells in living animals at high resolution. The powerful genetics and functional genomics tools available in C. elegans allow for detailed analysis of gene function, including genes that are frequently deregulated in human diseases such as cancer. The TP53 protein is a critical suppressor of tumor formation in vertebrates, and the TP53 gene is mutated in over 50% of human cancers. TP53 suppresses malignancy by integrating a variety of cellular stresses that direct it to activate transcription of genes that help to repair the damage or trigger apoptotic death if the damage is beyond repair. The TP53 paralogs, TP63 and TP73, have distinct roles in development as well as overlapping functions with TP53 in apoptosis and repair, which complicates their analysis in vertebrates. C. elegans contains a single TP53 family member, cep-1, that shares properties of all three vertebrate genes and thus offers a simple system in which to study the biological functions of this important gene family. This review summarizes major advances in our understanding of the TP53 family using C. elegans as a model organism.
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Habermann K, Mirgorodskaya E, Gobom J, Lehmann V, Müller H, Blümlein K, Deery MJ, Czogiel I, Erdmann C, Ralser M, von Kries JP, Lange BMH. Functional analysis of centrosomal kinase substrates in Drosophila melanogaster reveals a new function of the nuclear envelope component otefin in cell cycle progression. Mol Cell Biol 2012; 32:3554-69. [PMID: 22751930 PMCID: PMC3422010 DOI: 10.1128/mcb.00814-12] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 06/25/2012] [Indexed: 11/20/2022] Open
Abstract
Phosphorylation is one of the key mechanisms that regulate centrosome biogenesis, spindle assembly, and cell cycle progression. However, little is known about centrosome-specific phosphorylation sites and their functional relevance. Here, we identified phosphoproteins of intact Drosophila melanogaster centrosomes and found previously unknown phosphorylation sites in known and unexpected centrosomal components. We functionally characterized phosphoproteins and integrated them into regulatory signaling networks with the 3 important mitotic kinases, cdc2, polo, and aur, as well as the kinase CkIIβ. Using a combinatorial RNA interference (RNAi) strategy, we demonstrated novel functions for P granule, nuclear envelope (NE), and nuclear proteins in centrosome duplication, maturation, and separation. Peptide microarrays confirmed phosphorylation of identified residues by centrosome-associated kinases. For a subset of phosphoproteins, we identified previously unknown centrosome and/or spindle localization via expression of tagged fusion proteins in Drosophila SL2 cells. Among those was otefin (Ote), an NE protein that we found to localize to centrosomes. Furthermore, we provide evidence that it is phosphorylated in vitro at threonine 63 (T63) through Aurora-A kinase. We propose that phosphorylation of this site plays a dual role in controlling mitotic exit when phosphorylated while dephosphorylation promotes G(2)/M transition in Drosophila SL2 cells.
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Affiliation(s)
- Karin Habermann
- Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Berlin, Germany
| | - Ekaterina Mirgorodskaya
- Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Berlin, Germany
| | - Johan Gobom
- Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Berlin, Germany
| | - Verena Lehmann
- Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Berlin, Germany
| | - Hannah Müller
- Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Berlin, Germany
| | - Katharina Blümlein
- University of Cambridge, Department of Biochemistry and Cambridge Systems Biology Centre, Cambridge, United Kingdom
| | - Michael J. Deery
- University of Cambridge, Department of Biochemistry and Cambridge Systems Biology Centre, Cambridge, United Kingdom
| | - Irina Czogiel
- Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Berlin, Germany
| | - Christoph Erdmann
- Leibniz Institute for Molecular Pharmacology (FMP), Screening Unit, Berlin, Germany
| | - Markus Ralser
- University of Cambridge, Department of Biochemistry and Cambridge Systems Biology Centre, Cambridge, United Kingdom
| | - Jens Peter von Kries
- Leibniz Institute for Molecular Pharmacology (FMP), Screening Unit, Berlin, Germany
| | - Bodo M. H. Lange
- Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Berlin, Germany
- Alacris Theranostics GmbH, Berlin, Germany
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Loh BJ, Cullen CF, Vogt N, Ohkura H. The conserved kinase SRPK regulates karyosome formation and spindle microtubule assembly in Drosophila oocytes. J Cell Sci 2012; 125:4457-62. [PMID: 22854045 PMCID: PMC3500864 DOI: 10.1242/jcs.107979] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In Drosophila oocytes, after the completion of recombination, meiotic chromosomes form a compact cluster called the karyosome within the nucleus, and later assemble spindle microtubules without centrosomes. Although these oocyte-specific phenomena are also observed in humans, their molecular basis is not well understood. Here, we report essential roles for the conserved kinase SRPK in both karyosome formation and spindle microtubule assembly in oocytes. We have identified a female-sterile srpk mutant through a cytological screen for karyosome defects. Unlike most karyosome mutants, the karyosome defect is independent of the meiotic recombination checkpoint. Heterochromatin clustering found within the wild-type karyosome is disrupted in the mutant. Strikingly, a loss of SRPK severely prevents microtubule assembly for acentrosomal spindles in mature oocytes. Subsequently, bi-orientation and segregation of meiotic chromosomes are also defective. Therefore, this study demonstrates new roles of this conserved kinase in two independent meiotic steps specific to oocytes.
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Affiliation(s)
- Benjamin J Loh
- The Wellcome Trust Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JR, UK
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Baillet A, Mandon-Pepin B. Mammalian ovary differentiation - a focus on female meiosis. Mol Cell Endocrinol 2012; 356:13-23. [PMID: 21964319 DOI: 10.1016/j.mce.2011.09.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 09/01/2011] [Accepted: 09/13/2011] [Indexed: 02/03/2023]
Abstract
Over the past 50 years, the ovary development has been subject of fewer studies as compare to the male pathway. Nevertheless due to the advancement of genetics, mouse ES cells and the development of genetic models, studies of ovarian differentiation was boosted. This review emphasizes some of new progresses in the research field of the mammalian ovary differentiation that have occurred in recent years with focuses of the period around prophase I of meiosis and of recent roles of small non-RNAs in the ovarian gene expression.
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Affiliation(s)
- Adrienne Baillet
- Laboratoire de Génétique et Biologie Cellulaire, EA 4589 Université de Versailles Saint-Quentin-en-Yvelines, Ecole Pratique des Hautes Etudes, F-78035 Versailles cedex, France.
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40
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Maslova A, Krasikova A. Nuclear actin depolymerization in transcriptionally active avian and amphibian oocytes leads to collapse of intranuclear structures. Nucleus 2012; 3:300-11. [PMID: 22572951 PMCID: PMC3414407 DOI: 10.4161/nucl.20393] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Actin, which is normally depleted in the nuclei of somatic cells, accumulates in high amounts in giant nuclei of amphibian oocytes. The supramolecular organization and functions of this nuclear pool of actin in growing vertebrate oocyte are controversial. Here, we investigated the role of nuclear actin in the maintenance of the spatial architecture of intranuclear structures in avian and amphibian growing oocytes. A meshwork of filamentous actin was not detected in freshly isolated or fixed oocyte nuclei of Xenopus, chicken or quail. We found that the actin meshwork inside the oocyte nucleus could be induced by phalloidin treatment. Actin polymerization is demonstrated to be required to stabilize the specific spatial organization of nuclear structures in avian and amphibian growing oocytes. In experiments with the actin depolymerizing drugs cytochalasin D and latrunculin A, we showed that disassembly of nuclear actin polymers led to chromosome condensation and their transportation to a limited space within the oocyte nucleus. Experimentally induced "collapsing" of chromosomes and nuclear bodies, together with global inhibition of transcription, strongly resembled the process of karyosphere formation during oocyte growth.
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Affiliation(s)
| | - Alla Krasikova
- Saint-Petersburg State University; Saint Petersburg, Russia
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41
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Valbuena A, Sanz-García M, López-Sánchez I, Vega FM, Lazo PA. Roles of VRK1 as a new player in the control of biological processes required for cell division. Cell Signal 2011; 23:1267-72. [PMID: 21514377 DOI: 10.1016/j.cellsig.2011.04.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 04/04/2011] [Indexed: 11/28/2022]
Abstract
Cell division, in addition to an accurate transmission of genetic information to daughter cells, also requires the temporal and spatial coordination of several biological processes without which cell division would not be feasible. These processes include the temporal coordination of DNA replication and chromosome segregation, regulation of nuclear envelope disassembly and assembly, chromatin condensation and Golgi fragmentation for its redistribution into daughter cells, among others. However, little is known regarding regulatory proteins and signalling pathways that might participate in the coordination of all these different biological functions. Such regulatory players should directly have a role in the processes leading to cell division. VRK1 (Vaccinia-related kinase 1) is an early response gene required for cyclin D1 expression, regulates p53 by a specific Thr18 phosphorylation, controls chromatin condensation by histone phosphorylation, nuclear envelope assembly by phosphorylation of BANF1, and participates in signalling required for Golgi fragmentation late in the G2 phase. We propose that VRK1, a Ser-Thr kinase, might be a candidate to play an important coordinator role in these cell division processes as part of a novel signalling pathway.
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Affiliation(s)
- Alberto Valbuena
- Experimental Therapeutics and Translational Oncology Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Campus Miguel de Unamuno, E-37007 Salamanca, Spain
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42
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Schober CS, Aydiner F, Booth CJ, Seli E, Reinke V. The kinase VRK1 is required for normal meiotic progression in mammalian oogenesis. Mech Dev 2011; 128:178-90. [PMID: 21277975 DOI: 10.1016/j.mod.2011.01.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 01/19/2011] [Accepted: 01/20/2011] [Indexed: 01/02/2023]
Abstract
The kinase VRK1 has been implicated in mitotic and meiotic progression in invertebrate species, but whether it mediates these events during mammalian gametogenesis is not completely understood. Previous work has demonstrated a role for mammalian VRK1 in proliferation of male spermatogonia, yet whether VRK1 plays a role in meiotic progression, as seen in Drosophila, has not been determined. Here, we have established a mouse strain bearing a gene trap insertion in the VRK1 locus that disrupts Vrk1 expression. In addition to the male proliferation defects, we find that reduction of VRK1 activity causes a delay in meiotic progression during oogenesis, results in the presence of lagging chromosomes during formation of the metaphase plate, and ultimately leads to the failure of oocytes to be fertilized. The activity of at least one phosphorylation substrate of VRK1, p53, is not required for these defects. These results are consistent with previously defined functions of VRK1 in meiotic progression in Drosophila oogenesis, and indicate a conserved role for VRK1 in coordinating proper chromosomal configuration in female meiosis.
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Affiliation(s)
- Carolyn S Schober
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
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43
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Choi YH, Park CH, Kim W, Ling H, Kang A, Chang MW, Im SK, Jeong HW, Kong YY, Kim KT. Vaccinia-related kinase 1 is required for the maintenance of undifferentiated spermatogonia in mouse male germ cells. PLoS One 2010; 5:e15254. [PMID: 21179456 PMCID: PMC3001494 DOI: 10.1371/journal.pone.0015254] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 11/02/2010] [Indexed: 11/18/2022] Open
Abstract
Vaccinia-related kinase 1 (VRK1) is a crucial protein kinase for mitotic regulation. VRK1 is known to play a role in germ cell development, and its deficiency results in sterility. Here we describe that VRK1 is essential for the maintenance of spermatogonial stem cells. To determine whether VRK1 plays a role in these cells, we assessed the population size of undifferentiated spermatogonia. Flow cytometry analyses showed that the number of undifferentiated spermatogonia was markedly reduced in VRK1-deficient testes. VRK1 was highly expressed in spermatogonial populations, and approximately 66% of undifferentiated spermatogonia that were sorted as an Ep-CAM+/c-kit−/alpha-6-integrin+ population showed a positive signal for VRK1. Undifferentiated stem cells expressing Plzf and Oct4 but not c-kit also expressed VRK1, suggesting that VRK1 is an intrinsic factor for the maintenance of spermatogonial stem cells. Microarray analyses of the global testicular transcriptome and quantitative RT-PCR of VRK1-deficient testes revealed significantly reduced expression levels of undifferentiated spermatogonial marker genes in early postnatal mice. Together, these results suggest that VRK1 is required for the proliferation and differentiation of undifferentiated spermatogonia, which are essential for spermatogenic cell maintenance.
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Affiliation(s)
- Yoon Ha Choi
- Division of Molecular and Life Science, Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Choon-Ho Park
- Division of Molecular and Life Science, Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Wanil Kim
- Division of Molecular and Life Science, Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Hua Ling
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | - Aram Kang
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | - Matthew Wook Chang
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | - Sun-Kyoung Im
- Division of Molecular and Life Science, Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Hyun-Woo Jeong
- Division of Molecular and Life Science, Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Young-Yun Kong
- Department of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Kyong-Tai Kim
- Division of Molecular and Life Science, Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
- Division of Integrative Bioscience and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
- * E-mail:
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Lancaster OM, Breuer M, Cullen CF, Ito T, Ohkura H. The meiotic recombination checkpoint suppresses NHK-1 kinase to prevent reorganisation of the oocyte nucleus in Drosophila. PLoS Genet 2010; 6:e1001179. [PMID: 21060809 PMCID: PMC2965759 DOI: 10.1371/journal.pgen.1001179] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Accepted: 09/24/2010] [Indexed: 11/19/2022] Open
Abstract
The meiotic recombination checkpoint is a signalling pathway that blocks meiotic progression when the repair of DNA breaks formed during recombination is delayed. In comparison to the signalling pathway itself, however, the molecular targets of the checkpoint that control meiotic progression are not well understood in metazoans. In Drosophila, activation of the meiotic checkpoint is known to prevent formation of the karyosome, a meiosis-specific organisation of chromosomes, but the molecular pathway by which this occurs remains to be identified. Here we show that the conserved kinase NHK-1 (Drosophila Vrk-1) is a crucial meiotic regulator controlled by the meiotic checkpoint. An nhk-1 mutation, whilst resulting in karyosome defects, does so independent of meiotic checkpoint activation. Rather, we find unrepaired DNA breaks formed during recombination suppress NHK-1 activity (inferred from the phosphorylation level of one of its substrates) through the meiotic checkpoint. Additionally DNA breaks induced by X-rays in cultured cells also suppress NHK-1 kinase activity. Unrepaired DNA breaks in oocytes also delay other NHK-1 dependent nuclear events, such as synaptonemal complex disassembly and condensin loading onto chromosomes. Therefore we propose that NHK-1 is a crucial regulator of meiosis and that the meiotic checkpoint suppresses NHK-1 activity to prevent oocyte nuclear reorganisation until DNA breaks are repaired. Meiosis is a specialised form of cell division that produces haploid gametes from diploid cells. Failures or errors in meiosis can lead to infertility, miscarriages, or birth defects. In meiosis, chromosomes first swap genetic information during recombination and then undergo two rounds of segregation. Temporal separation of these distinct meiotic events is essential for successful meiosis. To ensure this correct temporal order, the meiotic recombination checkpoint blocks meiotic progression when recombination is not completed. Adding to our understanding of this process, we here report that the conserved Drosophila protein kinase NHK-1 is a crucial regulator of meiosis that is controlled by the meiotic recombination checkpoint. The meiotic recombination checkpoint suppresses the activity of NHK-1 to block transitional remodelling of meiotic chromosomes in the oocyte nucleus until recombination is completed.
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Affiliation(s)
- Oscar M. Lancaster
- The Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Manuel Breuer
- The Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - C. Fiona Cullen
- The Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Takashi Ito
- Department of Biochemistry, Nagasaki University School of Medicine, Nagasaki, Japan
| | - Hiroyuki Ohkura
- The Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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Waters K, Yang AZ, Reinke V. Genome-wide analysis of germ cell proliferation in C.elegans identifies VRK-1 as a key regulator of CEP-1/p53. Dev Biol 2010; 344:1011-25. [PMID: 20599896 DOI: 10.1016/j.ydbio.2010.06.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 05/28/2010] [Accepted: 06/16/2010] [Indexed: 01/22/2023]
Abstract
Proliferating germ cells in Caenorhabditiselegans provide a useful model system for deciphering fundamental mechanisms underlying the balance between proliferation and differentiation. Using gene expression profiling, we identified approximately 200 genes upregulated in the proliferating germ cells of C. elegans. Functional characterization using RNA-mediated interference demonstrated that over forty of these factors are required for normal germline proliferation and development. Detailed analysis of two of these factors defined an important regulatory relationship controlling germ cell proliferation. We established that the kinase VRK-1 is required for normal germ cell proliferation, and that it acts in part to regulate CEP-1(p53) activity. Loss of cep-1 significantly rescued the proliferation defects of vrk-1 mutants. We suggest that VRK-1 prevents CEP-1 from triggering an inappropriate cell cycle arrest, thereby promoting germ cell proliferation. This finding reveals a previously unsuspected mechanism for negative regulation of p53 activity in germ cells to control proliferation.
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46
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Wiebe MS, Nichols RJ, Molitor TP, Lindgren JK, Traktman P. Mice deficient in the serine/threonine protein kinase VRK1 are infertile due to a progressive loss of spermatogonia. Biol Reprod 2009; 82:182-93. [PMID: 19696012 DOI: 10.1095/biolreprod.109.079095] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The VRK1 protein kinase has been implicated as a pro-proliferative factor. Genetic analyses of mutant alleles of the Drosophila and Caenorhabditis elegans VRK1 homologs have revealed phenotypes ranging from embryonic lethality to mitotic and meiotic defects with resultant sterility. Herein, we describe the first genetic analysis of murine VRK1. Two lines of mice containing distinct gene-trap integrations into the Vrk1 locus were established. Insertion into intron 12 (GT12) spared VRK1 function, enabling the examination of VRK1 expression in situ. Insertion into intron 3 (GT3) disrupted VRK1 function, but incomplete splicing to the gene trap rendered this allele hypomorphic (approximately 15% of wild-type levels of VRK1 remain). GT3/GT3 mice are viable, but both males and females are infertile. In testes, VRK1 is expressed in Sertoli cells and spermatogonia. The infertility of GT3/GT3 male mice results from a progressive defect in spermatogonial proliferation or differentiation, culminating in the absence of mitotic and meiotic cells in adult testis. These data demonstrate an important role for VRK1 in cell proliferation and confirm that the need for VRK1 during gametogenesis is evolutionarily conserved.
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Affiliation(s)
- Matthew S Wiebe
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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47
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Klerkx EPF, Alarcón P, Waters K, Reinke V, Sternberg PW, Askjaer P. Protein kinase VRK-1 regulates cell invasion and EGL-17/FGF signaling in Caenorhabditis elegans. Dev Biol 2009; 335:12-21. [PMID: 19679119 DOI: 10.1016/j.ydbio.2009.08.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 08/03/2009] [Accepted: 08/03/2009] [Indexed: 11/16/2022]
Abstract
The vaccinia-related kinases (VRKs) are highly conserved throughout the animal kingdom and phosphorylate several chromatin proteins and transcription factors. In early Caenorhabditis elegans embryos, VRK-1 is required for proper nuclear envelope formation. In this work, we present the first investigation of the developmental role of VRKs by means of a novel C. elegans vrk-1 mutant allele. We found that VRK-1 is essential in hermaphrodites for formation of the vulva, uterus, and utse and for development and maintenance of the somatic gonad and thus the germ line. VRK-1 regulates anchor cell polarity and the timing of anchor cell invasion through the basement membranes separating vulval and somatic gonadal cells during the L3 larval stage. VRK-1 is also required for proper specification and proliferation of uterine cells and sex myoblasts. Expression of the fibroblast growth factor-like protein EGL-17 and its receptor EGL-15 is reduced in vrk-1 mutants, suggesting that VRK-1 might act at least partially through activation of FGF signaling. Expression of a translational VRK-1Colon, two colonsGFP fusion protein in the ventral nerve cord and vulva precursor cells restores vulva and uterus formation, suggesting both cell autonomous and non-autonomous roles of VRK-1.
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Affiliation(s)
- Elke P F Klerkx
- Centro Andaluz de Biología del Desarrollo (CABD), Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide, Seville 41013, Spain
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48
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Renbaum P, Kellerman E, Jaron R, Geiger D, Segel R, Lee M, King MC, Levy-Lahad E. Spinal muscular atrophy with pontocerebellar hypoplasia is caused by a mutation in the VRK1 gene. Am J Hum Genet 2009; 85:281-9. [PMID: 19646678 DOI: 10.1016/j.ajhg.2009.07.006] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2009] [Revised: 07/05/2009] [Accepted: 07/13/2009] [Indexed: 01/16/2023] Open
Abstract
The spinal muscular atrophies (SMAs) are a genetically and clinically heterogeneous group of disorders characterized by degeneration and loss of anterior horn cells in the spinal cord, leading to muscle weakness and atrophy. Spinal muscular atrophy with pontocerebellar hypoplasia (SMA-PCH, also known as pontocerebellar hypoplasia type 1 [PCH1]) is one of the rare infantile SMA variants that include additional clinical manifestations, and its genetic basis is unknown. We used a homozygosity mapping and positional cloning approach in a consanguineous family of Ashkenazi Jewish origin and identified a nonsense mutation in the vaccinia-related kinase 1 gene (VRK1) as a cause of SMA-PCH. VRK1, one of three members of the mammalian VRK family, is a serine/threonine kinase that phosphorylates p53 and CREB and is essential for nuclear envelope formation. Its identification as a gene involved in SMA-PCH implies new roles for the VRK proteins in neuronal development and maintenance and suggests the VRK genes as candidates for related phenotypes.
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49
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Wignall SM, Villeneuve AM. Lateral microtubule bundles promote chromosome alignment during acentrosomal oocyte meiosis. Nat Cell Biol 2009; 11:839-44. [PMID: 19525937 PMCID: PMC2760407 DOI: 10.1038/ncb1891] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Accepted: 03/23/2009] [Indexed: 12/31/2022]
Abstract
Although centrosomes serve to organize microtubules in most cell types, oocyte spindles form and mediate meiotic chromosome segregation in their absence. Here, we used high-resolution imaging of both bipolar and experimentally generated monopolar spindles in Caenorhabditis elegans to reveal a surprising organization of microtubules and chromosomes within acentrosomal structures. We found that homologous chromosome pairs (bivalents) are surrounded by microtubule bundles running along their sides, whereas microtubule density is extremely low at chromosome ends despite a high concentration of kinetochore proteins at those regions. Furthermore, we found that the chromokinesin KLP-19 (kinesin-like protein 19) is targeted to a ring around the centre of each bivalent and provides a polar ejection force that is required for congression. Together, these observations create a new picture of chromosome-microtubule association in acentrosomal spindles and reveal a mechanism by which metaphase alignment can be achieved using this organization. Specifically, we propose that ensheathment by lateral microtubule bundles places spatial constraints on the chromosomes, thereby promoting biorientation, and that localized motors mediate movement along these bundles, thereby promoting alignment.
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Affiliation(s)
- Sarah M Wignall
- Department of Developmental Biology, Stanford University School of Medicine, CA 94305, USA.
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50
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Meireles AM, Fisher KH, Colombié N, Wakefield JG, Ohkura H. Wac: a new Augmin subunit required for chromosome alignment but not for acentrosomal microtubule assembly in female meiosis. ACTA ACUST UNITED AC 2009; 184:777-84. [PMID: 19289792 PMCID: PMC2699157 DOI: 10.1083/jcb.200811102] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The bipolar spindle forms without centrosomes naturally in female meiosis and by experimental manipulation in mitosis. Augmin is a recently discovered protein complex required for centrosome-independent microtubule generation within the spindle in Drosophilamelanogaster cultured cells. Five subunits of Augmin have been identified so far, but neither their organization within the complex nor their role in developing organisms is known. In this study, we report a new Augmin subunit, wee Augmin component (Wac). Wac directly interacts with another Augmin subunit, Dgt2, via its coiled-coil domain. Wac depletion in cultured cells, especially without functional centrosomes, causes severe defects in spindle assembly. We found that a wac deletion mutant is viable but female sterile and shows only a mild impact on somatic mitosis. Unexpectedly, mutant female meiosis showed robust microtubule assembly of the acentrosomal spindle but frequent chromosome misalignment. For the first time, this study establishes the role of an Augmin subunit in developing organisms and provides an insight into the architecture of the complex.
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Affiliation(s)
- Ana M Meireles
- Wellcome Trust Centre for Cell Biology, The University of Edinburgh, Edinburgh, Scotland, UK
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