1
|
Seregin AA, Smirnova LP, Dmitrieva EM, Zavialova MG, Simutkin GG, Ivanova SA. Differential Expression of Proteins Associated with Bipolar Disorder as Identified Using the PeptideShaker Software. Int J Mol Sci 2023; 24:15250. [PMID: 37894929 PMCID: PMC10607299 DOI: 10.3390/ijms242015250] [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: 07/28/2023] [Revised: 09/29/2023] [Accepted: 10/06/2023] [Indexed: 10/29/2023] Open
Abstract
The prevalence of bipolar disorder (BD) in modern society is growing rapidly, but due to the lack of paraclinical criteria, its differential diagnosis with other mental disorders is somewhat challenging. In this regard, the relevance of proteomic studies is increasing due to the development of methods for processing large data arrays; this contributes to the discovery of protein patterns of pathological processes and the creation of new methods of diagnosis and treatment. It seems promising to search for proteins involved in the pathogenesis of BD in an easily accessible material-blood serum. Sera from BD patients and healthy individuals were purified via affinity chromatography to isolate 14 major proteins and separated using 1D SDS-PAGE. After trypsinolysis, the proteins in the samples were identified via HPLC/mass spectrometry. Mass spectrometric data were processed using the OMSSA and X!Tandem search algorithms using the UniProtKB database, and the results were analyzed using PeptideShaker. Differences in proteomes were assessed via an unlabeled NSAF-based analysis using a two-tailed Bonferroni-adjusted t-test. When comparing the blood serum proteomes of BD patients and healthy individuals, 10 proteins showed significant differences in NSAF values. Of these, four proteins were predominantly present in BD patients with the maximum NSAF value: 14-3-3 protein zeta/delta; ectonucleoside triphosphate diphosphohydrolase 7; transforming growth factor-beta-induced protein ig-h3; and B-cell CLL/lymphoma 9 protein. Further exploration of the role of these proteins in BD is warranted; conducting such studies will help develop new paraclinical criteria and discover new targets for BD drug therapy.
Collapse
Affiliation(s)
- Alexander A. Seregin
- Mental Health Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk 634014, Russia; (A.A.S.)
| | - Liudmila P. Smirnova
- Mental Health Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk 634014, Russia; (A.A.S.)
| | - Elena M. Dmitrieva
- Mental Health Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk 634014, Russia; (A.A.S.)
| | | | - German G. Simutkin
- Mental Health Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk 634014, Russia; (A.A.S.)
| | - Svetlana A. Ivanova
- Mental Health Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk 634014, Russia; (A.A.S.)
| |
Collapse
|
2
|
Garner KE, Salter A, Lau CK, Gurusaran M, Villemant CM, Granger EP, McNee G, Woodman PG, Davies OR, Burke BE, Allan VJ. The meiotic LINC complex component KASH5 is an activating adaptor for cytoplasmic dynein. J Cell Biol 2023; 222:e202204042. [PMID: 36946995 PMCID: PMC10071310 DOI: 10.1083/jcb.202204042] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 12/15/2022] [Accepted: 02/10/2023] [Indexed: 03/23/2023] Open
Abstract
Cytoplasmic dynein-driven movement of chromosomes during prophase I of mammalian meiosis is essential for synapsis and genetic exchange. Dynein connects to chromosome telomeres via KASH5 and SUN1 or SUN2, which together span the nuclear envelope. Here, we show that KASH5 promotes dynein motility in vitro, and cytosolic KASH5 inhibits dynein's interphase functions. KASH5 interacts with a dynein light intermediate chain (DYNC1LI1 or DYNC1LI2) via a conserved helix in the LIC C-terminal, and this region is also needed for dynein's recruitment to other cellular membranes. KASH5's N-terminal EF-hands are essential as the interaction with dynein is disrupted by mutation of key calcium-binding residues, although it is not regulated by cellular calcium levels. Dynein can be recruited to KASH5 at the nuclear envelope independently of dynactin, while LIS1 is essential for dynactin incorporation into the KASH5-dynein complex. Altogether, we show that the transmembrane protein KASH5 is an activating adaptor for dynein and shed light on the hierarchy of assembly of KASH5-dynein-dynactin complexes.
Collapse
Affiliation(s)
- Kirsten E.L. Garner
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Anna Salter
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- A*STAR Institute of Medical Biology, Singapore, Singapore
| | - Clinton K. Lau
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, UK
| | - Manickam Gurusaran
- Wellcome Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Cécile M. Villemant
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Elizabeth P. Granger
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Gavin McNee
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Philip G. Woodman
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Owen R. Davies
- Wellcome Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Brian E. Burke
- A*STAR Institute of Medical Biology, Singapore, Singapore
| | - Victoria J. Allan
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- A*STAR Institute of Medical Biology, Singapore, Singapore
| |
Collapse
|
3
|
Torisawa T, Kimura A. Sequential accumulation of dynein and its regulatory proteins at the spindle region in the Caenorhabditis elegans embryo. Sci Rep 2022; 12:11740. [PMID: 35817834 PMCID: PMC9273622 DOI: 10.1038/s41598-022-15042-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 06/16/2022] [Indexed: 11/09/2022] Open
Abstract
Cytoplasmic dynein is responsible for various cellular processes during the cell cycle. The mechanism by which its activity is regulated spatially and temporarily inside the cell remains elusive. There are various regulatory proteins of dynein, including dynactin, NDEL1/NUD-2, and LIS1. Characterizing the spatiotemporal localization of regulatory proteins in vivo will aid understanding of the cellular regulation of dynein. Here, we focused on spindle formation in the Caenorhabditis elegans early embryo, wherein dynein and its regulatory proteins translocated from the cytoplasm to the spindle region upon nuclear envelope breakdown (NEBD). We found that (i) a limited set of dynein regulatory proteins accumulated in the spindle region, (ii) the spatial localization patterns were distinct among the regulators, and (iii) the regulatory proteins did not accumulate in the spindle region simultaneously but sequentially. Furthermore, the accumulation of NUD-2 was unique among the regulators. NUD-2 started to accumulate before NEBD (pre-NEBD accumulation), and exhibited the highest enrichment compared to the cytoplasmic concentration. Using a protein injection approach, we revealed that the C-terminal helix of NUD-2 was responsible for pre-NEBD accumulation. These findings suggest a fine temporal control of the subcellular localization of regulatory proteins.
Collapse
Affiliation(s)
- Takayuki Torisawa
- Cell Architecture Laboratory, National Institute of Genetics, Mishima, Japan.,Department of Genetics, The Graduate University for Advanced Studies, Sokendai, Mishima, Japan
| | - Akatsuki Kimura
- Cell Architecture Laboratory, National Institute of Genetics, Mishima, Japan. .,Department of Genetics, The Graduate University for Advanced Studies, Sokendai, Mishima, Japan.
| |
Collapse
|
4
|
Li-Leger E, Feichtinger R, Flibotte S, Holzkamp H, Schnabel R, Moerman DG. Identification of essential genes in Caenorhabditis elegans through whole genome sequencing of legacy mutant collections. G3-GENES GENOMES GENETICS 2021; 11:6373896. [PMID: 34550348 PMCID: PMC8664450 DOI: 10.1093/g3journal/jkab328] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/27/2021] [Indexed: 01/23/2023]
Abstract
It has been estimated that 15%–30% of the ∼20,000 genes in C. elegans are essential, yet many of these genes remain to be identified or characterized. With the goal of identifying unknown essential genes, we performed whole-genome sequencing on complementation pairs from legacy collections of maternal-effect lethal and sterile mutants. This approach uncovered maternal genes required for embryonic development and genes with apparent sperm-specific functions. In total, 58 putative essential genes were identified on chromosomes III–V, of which 52 genes are represented by novel alleles in this collection. Of these 52 genes, 19 (40 alleles) were selected for further functional characterization. The terminal phenotypes of embryos were examined, revealing defects in cell division, morphogenesis, and osmotic integrity of the eggshell. Mating assays with wild-type males revealed previously unknown male-expressed genes required for fertilization and embryonic development. The result of this study is a catalog of mutant alleles in essential genes that will serve as a resource to guide further study toward a more complete understanding of this important model organism. As many genes and developmental pathways in C. elegans are conserved and essential genes are often linked to human disease, uncovering the function of these genes may also provide insight to further our understanding of human biology.
Collapse
Affiliation(s)
- Erica Li-Leger
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
| | - Richard Feichtinger
- Department of Developmental Genetics, Institute of Genetics, Technische Universität Braunschweig, 38106, Germany
| | - Stephane Flibotte
- UBC/LSI Bioinformatics Facility, University of British Columbia, Vancouver, British Columbia, Canada
| | - Heinke Holzkamp
- Department of Developmental Genetics, Institute of Genetics, Technische Universität Braunschweig, 38106, Germany
| | - Ralf Schnabel
- Department of Developmental Genetics, Institute of Genetics, Technische Universität Braunschweig, 38106, Germany
| | - Donald G Moerman
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
| |
Collapse
|
5
|
Torisawa T, Kimura A. The Generation of Dynein Networks by Multi-Layered Regulation and Their Implication in Cell Division. Front Cell Dev Biol 2020; 8:22. [PMID: 32083077 PMCID: PMC7004958 DOI: 10.3389/fcell.2020.00022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/13/2020] [Indexed: 12/13/2022] Open
Abstract
Cytoplasmic dynein-1 (hereafter referred to as dynein) is a major microtubule-based motor critical for cell division. Dynein is essential for the formation and positioning of the mitotic spindle as well as the transport of various cargos in the cell. A striking feature of dynein is that, despite having a wide variety of functions, the catalytic subunit is coded in a single gene. To perform various cellular activities, there seem to be different types of dynein that share a common catalytic subunit. In this review, we will refer to the different kinds of dynein as “dyneins.” This review attempts to classify the mechanisms underlying the emergence of multiple dyneins into four layers. Inside a cell, multiple dyneins generated through the multi-layered regulations interact with each other to form a network of dyneins. These dynein networks may be responsible for the accurate regulation of cellular activities, including cell division. How these networks function inside a cell, with a focus on the early embryogenesis of Caenorhabditis elegans embryos, is discussed, as well as future directions for the integration of our understanding of molecular layering to understand the totality of dynein’s function in living cells.
Collapse
Affiliation(s)
- Takayuki Torisawa
- Cell Architecture Laboratory, National Institute of Genetics, Mishima, Japan.,Department of Genetics, The Graduate University for Advanced Studies, SOKENDAI, Mishima, Japan
| | - Akatsuki Kimura
- Cell Architecture Laboratory, National Institute of Genetics, Mishima, Japan.,Department of Genetics, The Graduate University for Advanced Studies, SOKENDAI, Mishima, Japan
| |
Collapse
|
6
|
Boudreau V, Chen R, Edwards A, Sulaimain M, Maddox PS. PP2A-B55/SUR-6 collaborates with the nuclear lamina for centrosome separation during mitotic entry. Mol Biol Cell 2019; 30:876-886. [PMID: 30840554 PMCID: PMC6589783 DOI: 10.1091/mbc.e18-10-0631] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Across most sexually reproducing animals, centrosomes are provided to the oocyte through fertilization and must be positioned properly to establish the zygotic mitotic spindle. How centrosomes are positioned in space and time through the concerted action of key mitotic entry biochemical regulators, including protein phosphatase 2A (PP2A-B55/SUR-6), biophysical regulators, including dynein, and the nuclear lamina is unclear. Here, we uncover a role for PP2A-B55/SUR-6 in regulating centrosome separation. Mechanistically, PP2A-B55/SUR-6 regulates nuclear size before mitotic entry, in turn affecting nuclear envelope–based dynein density and motor capacity. Computational simulations predicted the requirement of PP2A-B55/SUR-6 regulation of nuclear size and nuclear-envelope dynein density for proper centrosome separation. Conversely, compromising nuclear lamina integrity led to centrosome detachment from the nuclear envelope and migration defects. Removal of PP2A-B55/SUR-6 and the nuclear lamina simultaneously further disrupted centrosome separation, leading to unseparated centrosome pairs dissociated from the nuclear envelope. Taking these combined results into consideration, we propose a model in which centrosomes migrate and are positioned through the concerted action of PP2A-B55/SUR-6–regulated nuclear envelope–based dynein pulling forces and centrosome–nuclear envelope tethering. Our results add critical precision to models of centrosome separation relative to the nucleus during spindle formation in cell division.
Collapse
Affiliation(s)
- Vincent Boudreau
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514
| | - Richard Chen
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514
| | - Alan Edwards
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514
| | - Muhammad Sulaimain
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514
| | - Paul S Maddox
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514
| |
Collapse
|
7
|
Heppert JK, Pani AM, Roberts AM, Dickinson DJ, Goldstein B. A CRISPR Tagging-Based Screen Reveals Localized Players in Wnt-Directed Asymmetric Cell Division. Genetics 2018; 208:1147-1164. [PMID: 29348144 PMCID: PMC5844328 DOI: 10.1534/genetics.117.300487] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/08/2018] [Indexed: 11/18/2022] Open
Abstract
Oriented cell divisions are critical to establish and maintain cell fates and tissue organization. Diverse extracellular and intracellular cues have been shown to provide spatial information for mitotic spindle positioning; however, the molecular mechanisms by which extracellular signals communicate with cells to direct mitotic spindle positioning are largely unknown. In animal cells, oriented cell divisions are often achieved by the localization of force-generating motor protein complexes to discrete cortical domains. Disrupting either these force-generating complexes or proteins that globally affect microtubule stability results in defects in mitotic positioning, irrespective of whether these proteins function as spatial cues for spindle orientation. This poses a challenge to traditional genetic dissection of this process. Therefore, as an alternative strategy to identify key proteins that act downstream of intercellular signaling, we screened the localization of many candidate proteins by inserting fluorescent tags directly into endogenous gene loci, without overexpressing the proteins. We tagged 23 candidate proteins in Caenorhabditis elegans and examined each protein's localization in a well-characterized, oriented cell division in the four-cell-stage embryo. We used cell manipulations and genetic experiments to determine which cells harbor key localized proteins and which signals direct these localizations in vivo We found that Dishevelled and adenomatous polyposis coli homologs are polarized during this oriented cell division in response to a Wnt signal, but two proteins typically associated with mitotic spindle positioning, homologs of NuMA and Dynein, were not detectably polarized. These results suggest an unexpected mechanism for mitotic spindle positioning in this system, they pinpoint key proteins of interest, and they highlight the utility of a screening approach based on analyzing the localization of endogenously tagged proteins.
Collapse
Affiliation(s)
- Jennifer K Heppert
- Department of Biology, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Ariel M Pani
- Department of Biology, University of North Carolina at Chapel Hill, North Carolina 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Allyson M Roberts
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Daniel J Dickinson
- Department of Biology, University of North Carolina at Chapel Hill, North Carolina 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Bob Goldstein
- Department of Biology, University of North Carolina at Chapel Hill, North Carolina 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, North Carolina 27599
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, North Carolina 27599
| |
Collapse
|
8
|
Simões PA, Celestino R, Carvalho AX, Gassmann R. NudE regulates dynein at kinetochores but is dispensable for other dynein functions in the C. elegans early embryo. J Cell Sci 2018; 131:jcs.212159. [PMID: 29192061 PMCID: PMC5818066 DOI: 10.1242/jcs.212159] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 11/27/2017] [Indexed: 12/12/2022] Open
Abstract
In mitosis, the molecular motor dynein is recruited to kinetochores by the Rod-Zw10-Zwilch complex (RZZ) and Spindly to control spindle assembly checkpoint (SAC) signaling and microtubule attachment. How the ubiquitous dynein co-factors Lis1 and NudE contribute to these functions remains poorly understood. Here, we show that the C. elegans NudE homolog NUD-2 is dispensable for dynein- and LIS-1-dependent mitotic spindle assembly in the zygote. This facilitates functional characterization of kinetochore-localized NUD-2, which is recruited by the CENP-F-like proteins HCP-1 and HCP-2 independently of RZZ-Spindly and dynein-LIS-1. Kinetochore dynein levels are reduced in Δnud-2 embryos, and, as occurs upon RZZ inhibition, loss of NUD-2 delays the formation of load-bearing kinetochore-microtubule attachments and causes chromatin bridges in anaphase. Survival of Δnud-2 embryos requires a functional SAC, and kinetochores without NUD-2 recruit an excess of SAC proteins. Consistent with this, SAC signaling in early Δnud-2 embryos extends mitotic duration and prevents high rates of chromosome mis-segregation. Our results reveal that both NUD-2 and RZZ-Spindly are essential for dynein function at kinetochores, and that the gain in SAC strength during early embryonic development is relevant under conditions that mildly perturb mitosis.
Collapse
Affiliation(s)
- Patrícia A Simões
- Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal
| | - Ricardo Celestino
- Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal
| | - Ana X Carvalho
- Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal
| | - Reto Gassmann
- Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal .,Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal
| |
Collapse
|
9
|
Sustained centrosome-cortical contact ensures robust polarization of the one-cell C. elegans embryo. Dev Biol 2017; 422:135-145. [PMID: 28065742 DOI: 10.1016/j.ydbio.2016.12.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 12/09/2016] [Accepted: 12/28/2016] [Indexed: 12/28/2022]
Abstract
In C. elegans, the anterior-posterior axis is established at the one-cell stage when the embryo polarizes along its long axis. One model suggests that a cue from the centrosome triggers symmetry breaking and is then dispensable for further steps in the process. In the absence of the initial centrosome cue, a redundant mechanism, reliant on the centrosome's microtubules, can polarize the cell. Despite this model, data from multiple sources suggest that direct centrosome-contact with the cortex may play a role in ensuring robust polarization. Some of this past work includes analysis of pam-1 mutants, which lack a functional puromycin-sensitive aminopeptidase and have aberrant centrosome positioning and variable polarization defects. To better understand the role of centrosome dynamics in polarization, we looked in detail at centrosome behavior in relation to key polarity landmarks in pam-1 mutants as well as those lacking cortical flows. We provide evidence for a model in which sustained direct contact between the centrosome and the cortex acts to reinforce both the actomyosin and the microtubule-dependent pathways. This contact is necessary for polarization when flows are inhibited.
Collapse
|
10
|
Cohen-Fix O, Askjaer P. Cell Biology of the Caenorhabditis elegans Nucleus. Genetics 2017; 205:25-59. [PMID: 28049702 PMCID: PMC5216270 DOI: 10.1534/genetics.116.197160] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 11/09/2016] [Indexed: 12/25/2022] Open
Abstract
Studies on the Caenorhabditis elegans nucleus have provided fascinating insight to the organization and activities of eukaryotic cells. Being the organelle that holds the genetic blueprint of the cell, the nucleus is critical for basically every aspect of cell biology. The stereotypical development of C. elegans from a one cell-stage embryo to a fertile hermaphrodite with 959 somatic nuclei has allowed the identification of mutants with specific alterations in gene expression programs, nuclear morphology, or nuclear positioning. Moreover, the early C. elegans embryo is an excellent model to dissect the mitotic processes of nuclear disassembly and reformation with high spatiotemporal resolution. We review here several features of the C. elegans nucleus, including its composition, structure, and dynamics. We also discuss the spatial organization of chromatin and regulation of gene expression and how this depends on tight control of nucleocytoplasmic transport. Finally, the extensive connections of the nucleus with the cytoskeleton and their implications during development are described. Most processes of the C. elegans nucleus are evolutionarily conserved, highlighting the relevance of this powerful and versatile model organism to human biology.
Collapse
Affiliation(s)
- Orna Cohen-Fix
- Laboratory of Molecular and Cellular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Peter Askjaer
- Andalusian Center for Developmental Biology, Consejo Superior de Investigaciones Científicas/Junta de Andalucia/Universidad Pablo de Olavide, 41013 Seville, Spain
| |
Collapse
|
11
|
Sharif SR, Islam A, Moon IS. N-Acetyl-D-Glucosamine Kinase Interacts with Dynein-Lis1-NudE1 Complex and Regulates Cell Division. Mol Cells 2016; 39:669-79. [PMID: 27646688 PMCID: PMC5050531 DOI: 10.14348/molcells.2016.0119] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 08/02/2016] [Accepted: 08/09/2016] [Indexed: 01/30/2023] Open
Abstract
N-acetyl-D-glucosamine kinase (GlcNAc kinase or NAGK) primarily catalyzes phosphoryl transfer to GlcNAc during amino sugar metabolism. Recently, it was shown NAGK interacts with dynein light chain roadblock type 1 (DYNLRB1) and upregulates axo-dendritic growth, which is an enzyme activity-independent, non-canonical structural role. The authors examined the distributions of NAGK and NAGK-dynein complexes during the cell cycle in HEK293T cells. NAGK was expressed throughout different stages of cell division and immunocytochemistry (ICC) showed NAGK was localized at nuclear envelope, spindle microtubules (MTs), and kinetochores (KTs). A proximity ligation assay (PLA) for NAGK and DYNLRB1 revealed NAGK-dynein complex on nuclear envelopes in prophase cells and on chromosomes in metaphase cells. NAGK-DYNLRB1 PLA followed by Lis1/NudE1 immunostaining showed NAGK-dynein complexes were colocalized with Lis1 and NudE1 signals, and PLA for NAGK-Lis1 showed similar signal patterns, suggesting a functional link between NAGK and dynein-Lis1 complex. Subsequently, NAGK-dynein complexes were found in KTs and on nuclear membranes where KTs were marked with CENP-B ICC and nuclear membrane with lamin ICC. Furthermore, knockdown of NAGK by small hairpin (sh) RNA was found to delay cell division. These results indicate that the NAGK-dynein interaction with the involvements of Lis1 and NudE1 plays an important role in prophase nuclear envelope breakdown (NEB) and metaphase MT-KT attachment during eukaryotic cell division.
Collapse
Affiliation(s)
- Syeda Ridita Sharif
- Department of Anatomy, Dongguk Medical Institute, Dongguk University Graduate School of Medicine, Gyeongju 38066,
Korea
| | - Ariful Islam
- Department of Anatomy, Dongguk Medical Institute, Dongguk University Graduate School of Medicine, Gyeongju 38066,
Korea
| | - Il Soo Moon
- Department of Anatomy, Dongguk Medical Institute, Dongguk University Graduate School of Medicine, Gyeongju 38066,
Korea
- Section of Neuroscience, Dongguk Medical Institute, Dongguk University Graduate School of Medicine, Gyeongju 38066,
Korea
| |
Collapse
|
12
|
Yao GD, Shi SL, Song WY, Jin HX, Peng ZF, Yang HY, Wang EY, Sun YP. Role of PAFAH1B1 in human spermatogenesis, fertilization and early embryonic development. Reprod Biomed Online 2015; 31:613-24. [DOI: 10.1016/j.rbmo.2015.07.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 07/16/2015] [Accepted: 07/16/2015] [Indexed: 11/16/2022]
|
13
|
Cianfrocco MA, DeSantis ME, Leschziner AE, Reck-Peterson SL. Mechanism and regulation of cytoplasmic dynein. Annu Rev Cell Dev Biol 2015; 31:83-108. [PMID: 26436706 DOI: 10.1146/annurev-cellbio-100814-125438] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Until recently, dynein was the least understood of the cytoskeletal motors. However, a wealth of new structural, mechanistic, and cell biological data is shedding light on how this complicated minus-end-directed, microtubule-based motor works. Cytoplasmic dynein-1 performs a wide array of functions in most eukaryotes, both in interphase, in which it transports organelles, proteins, mRNAs, and viruses, and in mitosis and meiosis. Mutations in dynein or its regulators are linked to neurodevelopmental and neurodegenerative diseases. Here, we begin by providing a synthesis of recent data to describe the current model of dynein's mechanochemical cycle. Next, we discuss regulators of dynein, with particular focus on those that directly interact with the motor to modulate its recruitment to microtubules, initiate cargo transport, or activate minus-end-directed motility.
Collapse
Affiliation(s)
- Michael A Cianfrocco
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, California 92093;
| | - Morgan E DeSantis
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, California 92093;
| | - Andres E Leschziner
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, California 92093;
| | - Samara L Reck-Peterson
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, California 92093;
| |
Collapse
|
14
|
Callejas-Negrete OA, Plamann M, Schnittker R, Bartnicki-García S, Roberson RW, Pimienta G, Mouriño-Pérez RR. Two microtubule-plus-end binding proteins LIS1-1 and LIS1-2, homologues of human LIS1 in Neurospora crassa. Fungal Genet Biol 2015; 82:213-27. [PMID: 26231681 DOI: 10.1016/j.fgb.2015.07.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 07/26/2015] [Accepted: 07/27/2015] [Indexed: 11/17/2022]
Abstract
LIS1 is a microtubule (Mt) plus-end binding protein that interacts with the dynein/dynactin complex. In humans, LIS1 is required for proper nuclear and organelle migration during cell growth. Although gene duplication is absent from Neurospora crassa, we found two paralogues of human LIS1. We named them LIS1-1 and LIS1-2 and studied their dynamics and function by fluorescent tagging. At the protein level, LIS1-1 and LIS1-2 were very similar. Although, the characteristic coiled-coil motif was not present in LIS1-2. LIS1-1-GFP and LIS1-2-GFP showed the same cellular distribution and dynamics, but LIS1-2-GFP was less abundant. Both LIS1 proteins were found in the subapical region as single fluorescent particles traveling toward the cell apex, they accumulated in the apical dome forming prominent short filament-like structures, some of which traversed the Spitzenkörper (Spk). The fluorescent structures moved exclusively in anterograde fashion along straight paths suggesting they traveled on Mts. There was no effect in the filament behavior of LIS1-1-GFP in the Δlis1-2 mutant but the dynamics of LIS1-2-GFP was affected in the Δlis1-1 mutant. Microtubular integrity and the dynein-dynactin complex were necessary for the formation of filament-like structures of LIS1-1-GFP in the subapical and apical regions; however, conventional kinesin (KIN-1) was not. Deletion mutants showed that the lack of lis1-1 decreased cell growth by ∼75%; however, the lack of lis1-2 had no effect on growth. A Δlis1-1;Δlis1-2 double mutant showed slower growth than either single mutant. Conidia production was reduced but branching rate increased in Δlis1-1 and the Δlis1-1;Δlis1-2 double mutants. The absence of LIS1-1 had a strong effect on Mt organization and dynamics and indirectly affected nuclear and mitochondrial distribution. The absence of LIS1-1 filaments in dynein mutants (ropy mutants) or in benomyl treated hyphae indicates the strong association between this protein and the regulation of the dynein-dynactin complex and Mt organization. LIS1-1 and LIS1-2 had a high amino acid homology, nevertheless, the absence of the coiled-coil motif in LIS1-2 suggests that its function or regulation may be distinct from that of LIS1-1.
Collapse
Affiliation(s)
- Olga A Callejas-Negrete
- Departamento de Microbiología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, B.C., Mexico
| | - Michael Plamann
- School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Robert Schnittker
- School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Salomon Bartnicki-García
- Departamento de Microbiología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, B.C., Mexico
| | | | - Genaro Pimienta
- Departamento de Microbiología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, B.C., Mexico
| | - Rosa R Mouriño-Pérez
- Departamento de Microbiología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, B.C., Mexico.
| |
Collapse
|
15
|
Dix CI, Soundararajan HC, Dzhindzhev NS, Begum F, Suter B, Ohkura H, Stephens E, Bullock SL. Lissencephaly-1 promotes the recruitment of dynein and dynactin to transported mRNAs. ACTA ACUST UNITED AC 2013; 202:479-94. [PMID: 23918939 PMCID: PMC3734092 DOI: 10.1083/jcb.201211052] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lissencephaly-1 promotes the interaction of dynein with dynactin and facilitates motor complex association with mRNA cargos. Microtubule-based transport mediates the sorting and dispersal of many cellular components and pathogens. However, the mechanisms by which motor complexes are recruited to and regulated on different cargos remain poorly understood. Here we describe a large-scale biochemical screen for novel factors associated with RNA localization signals mediating minus end–directed mRNA transport during Drosophila development. We identified the protein Lissencephaly-1 (Lis1) and found that minus-end travel distances of localizing transcripts are dramatically reduced in lis1 mutant embryos. Surprisingly, given its well-documented role in regulating dynein mechanochemistry, we uncovered an important requirement for Lis1 in promoting the recruitment of dynein and its accessory complex dynactin to RNA localization complexes. Furthermore, we provide evidence that Lis1 levels regulate the overall association of dynein with dynactin. Our data therefore reveal a critical role for Lis1 within the mRNA localization machinery and suggest a model in which Lis1 facilitates motor complex association with cargos by promoting the interaction of dynein with dynactin.
Collapse
Affiliation(s)
- Carly I Dix
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, England, UK
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Noatynska A, Gotta M, Meraldi P. Mitotic spindle (DIS)orientation and DISease: cause or consequence? ACTA ACUST UNITED AC 2013; 199:1025-35. [PMID: 23266953 PMCID: PMC3529530 DOI: 10.1083/jcb.201209015] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Correct alignment of the mitotic spindle during cell division is crucial for cell fate determination, tissue organization, and development. Mutations causing brain diseases and cancer in humans and mice have been associated with spindle orientation defects. These defects are thought to lead to an imbalance between symmetric and asymmetric divisions, causing reduced or excessive cell proliferation. However, most of these disease-linked genes encode proteins that carry out multiple cellular functions. Here, we discuss whether spindle orientation defects are the direct cause for these diseases, or just a correlative side effect.
Collapse
Affiliation(s)
- Anna Noatynska
- Department of Physiology and Metabolism, University of Geneva, 1211 Geneva, Switzerland
| | | | | |
Collapse
|
17
|
Deubiquitylation machinery is required for embryonic polarity in Caenorhabditis elegans. PLoS Genet 2012; 8:e1003092. [PMID: 23209443 PMCID: PMC3510043 DOI: 10.1371/journal.pgen.1003092] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 10/01/2012] [Indexed: 11/19/2022] Open
Abstract
The Caenorhabditis elegans one-cell embryo polarizes in response to a cue from the paternally donated centrosome and asymmetrically segregates cell fate determinants that direct the developmental program of the worm. We have found that genes encoding putative deubiquitylating enzymes (DUBs) are required for polarization of one-cell embryos. Maternal loss of the proteins MATH-33 and USP-47 leads to variable inability to correctly establish and maintain asymmetry as defined by posterior and anterior polarity proteins PAR-2 and PAR-3. The first observable defect is variable positioning of the centrosome with respect to the cell cortex and the male pronucleus. The severity of the polarity defects correlates with distance of the centrosome from the cortex. Furthermore, polarity defects can be bypassed by mutations that bring the centrosome in close proximity to the cortex. In addition we find that polarity and centrosome positioning defects can be suppressed by compromising protein turnover. We propose that the DUB activity of MATH-33 and USP-47 stabilizes one or more proteins required for association of the centrosome with the cortex. Because these DUBs are homologous to two members of a group of DUBs that act in fission yeast polarity, we tested additional members of that family and found that another C. elegans DUB gene, usp-46, also contributes to polarity. Our finding that deubiquitylating enzymes required for polarity in Schizosaccharomyces pombe are also required in C. elegans raises the possibility that these DUBs act through an evolutionarily conserved mechanism to control cell polarity. In eukaryotes, modification of proteins by the covalent ligation of a protein called ubiquitin is an important regulatory mechanism. In this study we found that deubiquitylation enzymes, which are known to cleave ubiquitin off of target proteins, are required for asymmetry in one-cell embryos of the nematode C. elegans. In one-cell embryos the establishment of asymmetry depends on a signal from the centrosome, a microtubule-organizing center. This signal breaks homogeneity in the contractile cytoskeleton located at the cortex of the embryo. We have identified three deubiquitylation enzymes that are necessary for the centrosome to properly localize adjacent to the cortex to perform its symmetry-breaking role. Furthermore, a homologous group of enzymes in fission yeast also regulates cell polarity. Our results suggest that a novel mechanism of centrosome localization regulated by ubiquitylation exists in C. elegans; this mechanism is masked by genetic redundancy and may be an evolutionarily conserved mechanism for cell asymmetry.
Collapse
|
18
|
Dunsch AK, Hammond D, Lloyd J, Schermelleh L, Gruneberg U, Barr FA. Dynein light chain 1 and a spindle-associated adaptor promote dynein asymmetry and spindle orientation. ACTA ACUST UNITED AC 2012; 198:1039-54. [PMID: 22965910 PMCID: PMC3444778 DOI: 10.1083/jcb.201202112] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The asymmetric cortical localization of dynein during spindle orientation requires dynein light chain 1 and a spindle-microtubule–associated adaptor formed by CHIA and HMMR. The cytoplasmic dynein motor generates pulling forces to center and orient the mitotic spindle within the cell. During this positioning process, dynein oscillates from one pole of the cell cortex to the other but only accumulates at the pole farthest from the spindle. Here, we show that dynein light chain 1 (DYNLL1) is required for this asymmetric cortical localization of dynein and has a specific function defining spindle orientation. DYNLL1 interacted with a spindle-microtubule–associated adaptor formed by CHICA and HMMR via TQT motifs in CHICA. In cells depleted of CHICA or HMMR, the mitotic spindle failed to orient correctly in relation to the growth surface. Furthermore, CHICA TQT motif mutants localized to the mitotic spindle but failed to recruit DYNLL1 to spindle microtubules and did not correct the spindle orientation or dynein localization defects. These findings support a model where DYNLL1 and CHICA-HMMR form part of the regulatory system feeding back spindle position to dynein at the cell cortex.
Collapse
Affiliation(s)
- Anja K Dunsch
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, England, UK
| | | | | | | | | | | |
Collapse
|
19
|
Sitaram P, Anderson MA, Jodoin JN, Lee E, Lee LA. Regulation of dynein localization and centrosome positioning by Lis-1 and asunder during Drosophila spermatogenesis. Development 2012; 139:2945-54. [PMID: 22764052 DOI: 10.1242/dev.077511] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Dynein, a microtubule motor complex, plays crucial roles in cell-cycle progression in many systems. The LIS1 accessory protein directly binds dynein, although its precise role in regulating dynein remains unclear. Mutation of human LIS1 causes lissencephaly, a developmental brain disorder. To gain insight into the in vivo functions of LIS1, we characterized a male-sterile allele of the Drosophila homolog of human LIS1. We found that centrosomes do not properly detach from the cell cortex at the onset of meiosis in most Lis-1 spermatocytes; centrosomes that do break cortical associations fail to attach to the nucleus. In Lis-1 spermatids, we observed loss of attachments between the nucleus, basal body and mitochondria. The localization pattern of LIS-1 protein throughout Drosophila spermatogenesis mirrors that of dynein. We show that dynein recruitment to the nuclear surface and spindle poles is severely reduced in Lis-1 male germ cells. We propose that Lis-1 spermatogenesis phenotypes are due to loss of dynein regulation, as we observed similar phenotypes in flies null for Tctex-1, a dynein light chain. We have previously identified asunder (asun) as another regulator of dynein localization and centrosome positioning during Drosophila spermatogenesis. We now report that Lis-1 is a strong dominant enhancer of asun and that localization of LIS-1 in male germ cells is ASUN dependent. We found that Drosophila LIS-1 and ASUN colocalize and coimmunoprecipitate from transfected cells, suggesting that they function within a common complex. We present a model in which Lis-1 and asun cooperate to regulate dynein localization and centrosome positioning during Drosophila spermatogenesis.
Collapse
Affiliation(s)
- Poojitha Sitaram
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, U-4225 Medical Research Building III, 465 21st Avenue South, Nashville, TN 37232-8240, USA
| | | | | | | | | |
Collapse
|
20
|
Egan MJ, Tan K, Reck-Peterson SL. Lis1 is an initiation factor for dynein-driven organelle transport. ACTA ACUST UNITED AC 2012; 197:971-82. [PMID: 22711696 PMCID: PMC3384415 DOI: 10.1083/jcb.201112101] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The dynein-associated protein Lis1 may be a ubiquitous determinant of dynein-dependent transport required primarily at the stage of motility initiation. The molecular motor cytoplasmic dynein is responsible for most minus-end–directed, microtubule-based transport in eukaryotic cells. It is especially important in neurons, where defects in microtubule-based motility have been linked to neurological diseases. For example, lissencephaly is caused by mutations in the dynein-associated protein Lis1. In this paper, using the long, highly polarized hyphae of the filamentous fungus Aspergillus nidulans, we show that three morphologically and functionally distinct dynein cargos showed transport defects in the genetic absence of Lis1/nudF, raising the possibility that Lis1 is ubiquitously used for dynein-based transport. Surprisingly, both dynein and its cargo moved at normal speeds in the absence of Lis1 but with reduced frequency. Moreover, Lis1, unlike dynein and dynactin, was absent from moving dynein cargos, further suggesting that Lis1 is not required for dynein-based cargo motility once it has commenced. Based on these observations, we propose that Lis1 has a general role in initiating dynein-driven motility.
Collapse
Affiliation(s)
- Martin J Egan
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | | | | |
Collapse
|
21
|
Cowles MW, Hubert A, Zayas RM. A Lissencephaly-1 homologue is essential for mitotic progression in the planarian Schmidtea mediterranea. Dev Dyn 2012; 241:901-10. [PMID: 22411224 DOI: 10.1002/dvdy.23775] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2012] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Planarians are renowned for their capacity to replace lost tissues from adult pluripotent stem cells (neoblasts). Here we report that Lissencephaly-1 (lis1), which has roles in cellular processes such as mitotic spindle apparatus orientation and in signal regulation required for stem cell self-renewal, is required for stem cell maintenance in the planarian Schmidtea mediterranea. RESULTS In planarians, lis1 is expressed in differentiated tissues and stem cells. lis1 RNAi leads to head regression, ventral curling, and death by lysis. By labeling the neoblasts and proliferating cells, we found lis1 knockdown animals show a dramatic increase in the number of mitotic cells, followed by depletion of the stem cell pool. Analysis of the mitotic spindles in dividing neoblasts revealed that defective spindle positioning is correlated with cells arrested at metaphase. In addition, we show that inhibiting a planarian homologue of nudE, predicted to encode a LIS-1 interacting protein, also leads to cell cycle progression defects. CONCLUSIONS Our results provide evidence for a conserved role of LIS1 and NUDE in regulating the function of the mitotic spindle apparatus in a representative Lophotrochozoan and that planarians will be useful organisms in which to investigate LIS1 regulation of signaling events underlying stem cell self-renewal.
Collapse
Affiliation(s)
- Martis W Cowles
- Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | | | | |
Collapse
|
22
|
Hayashi H, Kimura K, Kimura A. Localized accumulation of tubulin during semi-open mitosis in the Caenorhabditis elegans embryo. Mol Biol Cell 2012; 23:1688-99. [PMID: 22398724 PMCID: PMC3338436 DOI: 10.1091/mbc.e11-09-0815] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The assembly of microtubules inside the cell is controlled both spatially and temporally. During mitosis, microtubule assembly must be activated locally at the nascent spindle region for mitotic spindle assembly to occur efficiently. In this paper, we report that mitotic spindle components, such as free tubulin subunits, accumulated in the nascent spindle region, independent of spindle formation in the Caenorhabditis elegans embryo. This accumulation coincided with nuclear envelope permeabilization, suggesting that permeabilization might trigger the accumulation. When permeabilization was induced earlier by knockdown of lamin, tubulin also accumulated earlier. The boundaries of the region of accumulation coincided with the remnant nuclear envelope, which remains after nuclear envelope breakdown in cells that undergo semi-open mitosis, such as those of C. elegans. Ran, a small GTPase protein, was required for tubulin accumulation. Fluorescence recovery after photobleaching analysis revealed that the accumulation was accompanied by an increase in the immobile fraction of free tubulin inside the remnant nuclear envelope. We propose that this newly identified mechanism of accumulation of free tubulin-and probably of other molecules-at the nascent spindle region contributes to efficient assembly of the mitotic spindle in the C. elegans embryo.
Collapse
Affiliation(s)
- Hanako Hayashi
- Department of Genetics (Sokendai-Mishima), School of Life Science, Graduate University for Advanced Studies (Sokendai), Yata 1111, Mishima, Shizuoka 411-8540, Japan
| | | | | |
Collapse
|
23
|
Manneville JB, Etienne-Manneville S. Positioning centrosomes and spindle poles: looking at the periphery to find the centre. Biol Cell 2012; 98:557-65. [PMID: 16907664 DOI: 10.1042/bc20060017] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Centrosome positioning is tightly controlled throughout the cell cycle and probably shares common regulatory mechanisms with spindle-pole positioning. In this article, we detail the possible mechanisms controlling centrosome and spindle positioning in various organisms both in interphase and mitotic cells, and discuss recent findings showing how microtubule plus-end-associated proteins interact with the cell cortex. We suggest that microtubule plus-end complexes simultaneously regulate microtubule dynamics and microtubule anchoring at the cell periphery to allow proper centrosome and spindle-pole positioning.
Collapse
|
24
|
Kyvelidou C, Tserevelakis GJ, Filippidis G, Ranella A, Kleovoulou A, Fotakis C, Athanassakis I. Following the course of pre-implantation embryo patterning by non-linear microscopy. J Struct Biol 2011; 176:379-86. [DOI: 10.1016/j.jsb.2011.09.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 09/11/2011] [Accepted: 09/19/2011] [Indexed: 02/04/2023]
|
25
|
Gusnowski EM, Srayko M. Visualization of dynein-dependent microtubule gliding at the cell cortex: implications for spindle positioning. ACTA ACUST UNITED AC 2011; 194:377-86. [PMID: 21825072 PMCID: PMC3153651 DOI: 10.1083/jcb.201103128] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Distinct dynein–microtubule interactions are used for asymmetric spindle-positioning tasks in the C. elegans embryo. Dynein motors move along the microtubule (MT) lattice in a processive “walking” manner. In the one-cell Caenorhabditis elegans embryo, dynein is required for spindle-pulling forces during mitosis. Posteriorly directed spindle-pulling forces are higher than anteriorly directed forces, and this imbalance results in posterior spindle displacement during anaphase and an asymmetric division. To address how dynein could be asymmetrically activated to achieve posterior spindle displacement, we developed an assay to measure dynein’s activity on individual MTs at the embryo cortex. Our study reveals that cortical dynein motors maintain a basal level of activity that propels MTs along the cortex, even under experimental conditions that drastically reduce anaphase spindle forces. This suggests that dynein-based MT gliding is not sufficient for anaphase spindle-pulling force. Instead, we find that this form of dynein activity is most prominent during spindle centering in early prophase. We propose a model whereby different dynein–MT interactions are used for specific spindle-positioning tasks in the one-cell embryo.
Collapse
Affiliation(s)
- Eva M Gusnowski
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
| | | |
Collapse
|
26
|
Tserevelakis GJ, Filippidis G, Megalou EV, Fotakis C, Tavernarakis N. Cell tracking in live Caenorhabditis elegans embryos via third harmonic generation imaging microscopy measurements. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:046019. [PMID: 21529088 DOI: 10.1117/1.3569615] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
In this study, we demonstrate the potential of employing third harmonic generation (THG) imaging microscopy measurements for cell tracking studies in live Caenorhabditis elegans (C. elegans) embryos. A 1028-nm femtosecond laser was used for the excitation of unstained C. elegans samples. Different C. elegans embryonic stages (from two-cell to threefold) were imaged. Live biological specimens were irradiated for prolonged periods of time (up to 7 h), testifying to the nondestructive nature of this nonlinear imaging technique. Thus, THG image contrast modality is a powerful diagnostic tool for probing in vivo cell division during early embryogenesis.
Collapse
Affiliation(s)
- George J Tserevelakis
- Foundation of Research and Technology-Hellas, Institute of Electronic Structure and Laser, PO Box 1385, Heraklion, Crete 71110, Greece
| | | | | | | | | |
Collapse
|
27
|
Valinluck M, Ahlgren S, Sawada M, Locken K, Banuett F. Role of the nuclear migration protein Lis1 in cell morphogenesis in Ustilago maydis. Mycologia 2010; 102:493-512. [PMID: 20524583 DOI: 10.3852/09-193] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Ustilago maydis is a basidiomycete fungus that exhibits a yeast-like and a filamentous form. Growth of the fungus in the host leads to additional morphological transitions. The different morphologies are characterized by distinct nuclear movements. Dynein and alpha-tubulin are required for nuclear movements and for cell morphogenesis of the yeast-like form. Lis1 is a microtubule plus-end tracking protein (+TIPs) conserved in eukaryotes and required for nuclear migration and spindle positioning. Defects in nuclear migration result in altered cell fate and aberrant development in metazoans, slow growth in fungi and disease in humans (e.g. lissencephaly). Here we investigate the role of the human LIS1 homolog in U. maydis and demonstrate that it is essential for cell viability, not previously seen in other fungi. With a conditional null mutation we show that lis1 is necessary for nuclear migration in the yeast-like cell and during the dimorphic transition. Studies of asynchronous exponentially growing cells and time-lapse microscopy uncovered novel functions of lis1: It is necessary for cell morphogenesis, positioning of the septum and cell wall integrity. lis1-depleted cells exhibit altered axes of growth and loss of cell polarity leading to grossly aberrant cells with clusters of nuclei and morphologically altered buds devoid of nuclei. Altered septum positioning and cell wall deposition contribute to the aberrant morphology. lis1-depleted cells lyse, indicative of altered cell wall properties or composition. We also demonstrate, with indirect immunofluorescence to visualize tubulin, that lis1 is necessary for the normal organization of the microtubule cytoskeleton: lis1-depleted cells contain more and longer microtubules that can form coils perpendicular to the long axis of the cell. We propose that lis1 controls microtubule dynamics and thus the regulated delivery of vesicles to growth sites and other cell domains that govern nuclear movements.
Collapse
Affiliation(s)
- Michael Valinluck
- Department of Biological Sciences, California State University, 1250 Bellflower Boulevard, Long Beach, California 90840 USA
| | | | | | | | | |
Collapse
|
28
|
Tserevelakis G, Filippidis G, Krmpot A, Vlachos M, Fotakis C, Tavernarakis N. Imaging Caenorhabditis elegans embryogenesis by third-harmonic generation microscopy. Micron 2010; 41:444-7. [DOI: 10.1016/j.micron.2010.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 02/09/2010] [Accepted: 02/10/2010] [Indexed: 10/19/2022]
|
29
|
Fortin SM, Marshall SL, Jaeger EC, Greene PE, Brady LK, Isaac RE, Schrandt JC, Brooks DR, Lyczak R. The PAM-1 aminopeptidase regulates centrosome positioning to ensure anterior-posterior axis specification in one-cell C. elegans embryos. Dev Biol 2010; 344:992-1000. [PMID: 20599902 DOI: 10.1016/j.ydbio.2010.06.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 06/09/2010] [Accepted: 06/11/2010] [Indexed: 01/08/2023]
Abstract
In the one-cell Caenorhabditis elegans embryo, the anterior-posterior (A-P) axis is established when the sperm donated centrosome contacts the posterior cortex. While this contact appears to be essential for axis polarization, little is known about the mechanisms governing centrosome positioning during this process. pam-1 encodes a puromycin sensitive aminopeptidase that regulates centrosome positioning in the early embryo. Previously we showed that pam-1 mutants fail to polarize the A-P axis. Here we show that PAM-1 can be found in mature sperm and in cytoplasm throughout early embryogenesis where it concentrates around mitotic centrosomes and chromosomes. We provide further evidence that PAM-1 acts early in the polarization process by showing that PAR-1 and PAR-6 do not localize appropriately in pam-1 mutants. Additionally, we tested the hypothesis that PAM-1's role in polarity establishment is to ensure centrosome contact with the posterior cortex. We inactivated the microtubule motor dynein, DHC-1, in pam-1 mutants, in an attempt to prevent centrosome movement from the cortex and restore anterior-posterior polarity. When this was done, the aberrant centrosome movements of pam-1 mutants were not observed and anterior-posterior polarity was properly established, with proper localization of cortical and cytoplasmic determinants. We conclude that PAM-1's role in axis polarization is to prevent premature movement of the centrosome from the posterior cortex, ensuring proper axis establishment in the embryo.
Collapse
|
30
|
Gil-Krzewska AJ, Farber E, Buttner EA, Hunter CP. Regulators of the actin cytoskeleton mediate lethality in a Caenorhabditis elegans dhc-1 mutant. Mol Biol Cell 2010; 21:2707-20. [PMID: 20554764 PMCID: PMC2912356 DOI: 10.1091/mbc.e09-07-0593] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Both LIS-1 and the dynein heavy-chain DHC-1 are required for integrity of the actin cytoskeleton in Caenorhabditis elegans. An RNAi screen revealed that knockdown of other actin regulators, including actin-capping protein genes and prefoldin subunit genes, suppresses dhc-1(or195ts)–induced lethality. Functional analysis of cytoplasmic dynein in Caenorhabditis elegans has revealed a wide range of cellular functions for this minus-end–directed motor protein. Dynein transports a variety of cargos to diverse cellular locations, and thus cargo selection and destination are likely regulated by accessory proteins. The microtubule-associated proteins LIS-1 and dynein interact, but the nature of this interaction remains poorly understood. Here we show that both LIS-1 and the dynein heavy-chain DHC-1 are required for integrity of the actin cytoskeleton in C. elegans. Although both dhc-1(or195ts) and lis-1 loss-of-function disrupt the actin cytoskeleton and produce embryonic lethality, a double mutant suppresses these defects. A targeted RNA interference screen revealed that knockdown of other actin regulators, including actin-capping protein genes and prefoldin subunit genes, suppresses dhc-1(or195ts)–induced lethality. We propose that release or relocation of the mutant dynein complex mediates this suppression of dhc-1(or195ts)--induced phenotypes. These results reveal an unexpected direct or indirect interaction between the actin cytoskeleton and dynein activity.
Collapse
|
31
|
Lam C, Vergnolle MAS, Thorpe L, Woodman PG, Allan VJ. Functional interplay between LIS1, NDE1 and NDEL1 in dynein-dependent organelle positioning. J Cell Sci 2010; 123:202-12. [PMID: 20048338 DOI: 10.1242/jcs.059337] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
LIS1, NDE1 and NDEL1 modulate cytoplasmic dynein function in several cellular contexts. However, evidence that they regulate dynein-dependent organelle positioning is limited. Here, we show that depletion of NDE1 or NDEL1 alone profoundly affected the organisation of the Golgi complex but did not cause it to disperse, and slightly affected the position of endocytic compartments. However, striking dispersal of organelles was observed when both NDE1 and NDEL1 were depleted. A substantial portion of NDE1 and NDEL1 is membrane associated, and depletion of these proteins led to complete loss of dynein from membranes. Knockdown of LIS1 also caused the Golgi complex to fragment and disperse throughout the cell, and caused endocytic compartments to relocalise to the periphery. Depletion of LIS1, which is primarily cytosolic, led to partial loss of membrane-associated dynein, without affecting NDE1 and NDEL1. These data suggest that NDE1 and NDEL1 act upstream of LIS1 in dynein recruitment, and/or activation, on the membrane. Consistent with this hypothesis, expression of exogenous NDE1 or NDEL1 rescued the effects of LIS1 depletion on Golgi organisation, whereas LIS1 was only partially effective at rescuing the loss of NDE1 and NDEL1.
Collapse
Affiliation(s)
- Connie Lam
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, UK
| | | | | | | | | |
Collapse
|
32
|
Fridolfsson HN, Ly N, Meyerzon M, Starr DA. UNC-83 coordinates kinesin-1 and dynein activities at the nuclear envelope during nuclear migration. Dev Biol 2010; 338:237-50. [PMID: 20005871 PMCID: PMC2826220 DOI: 10.1016/j.ydbio.2009.12.004] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 12/04/2009] [Accepted: 12/04/2009] [Indexed: 11/19/2022]
Abstract
Nuclei migrate during many events, including fertilization, establishment of polarity, differentiation, and cell division. The Caenorhabditis elegans KASH protein UNC-83 localizes to the outer nuclear membrane where it recruits kinesin-1 to provide the major motor activity required for nuclear migration in embryonic hyp7 cells. Here we show that UNC-83 also recruits two dynein-regulating complexes to the cytoplasmic face of the nucleus that play a regulatory role. One consists of the NudE homolog NUD-2 and the NudF/Lis1/Pac1 homolog LIS-1, and the other includes dynein light chain DLC-1, the BicaudalD homolog BICD-1, and the Egalitarian homologue EGAL-1. Genetic disruption of any member of these two complexes caused nuclear migration defects that were enhanced in some double mutant animals, suggesting that BICD-1 and EGAL-1 function in parallel to NUD-2. Dynein heavy chain mutant animals also had a nuclear migration defect, suggesting these complexes function through dynein. Deletion analysis indicated that independent domains of UNC-83 interact with kinesin and dynein. These data suggest a model where UNC-83 acts as the cargo-specific adaptor between the outer nuclear membrane and the microtubule motors kinesin-1 and dynein. Kinesin-1 functions as the major force generator during nuclear migration, while dynein is involved in regulation of bidirectional transport of the nucleus.
Collapse
Affiliation(s)
- Heidi N. Fridolfsson
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Nina Ly
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Marina Meyerzon
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Daniel A. Starr
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| |
Collapse
|
33
|
Gouveia SM, Akhmanova A. Cell and Molecular Biology of Microtubule Plus End Tracking Proteins. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 285:1-74. [DOI: 10.1016/b978-0-12-381047-2.00001-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
|
34
|
Abstract
Eukaryotic cells use cytoskeletal motor proteins to transport many different intracellular cargos. Numerous kinesins and myosins have evolved to cope with the various transport needs that have arisen during eukaryotic evolution. Surprisingly, a single cytoplasmic dynein (a minus end-directed microtubule motor) carries out similarly diverse transport activities as the many different types of kinesin. How is dynein coupled to its wide range of cargos and how is it spatially and temporally regulated? The answer could lie in the several multifunctional adaptors, including dynactin, lissencephaly 1, nuclear distribution protein E (NUDE) and NUDE-like, Bicaudal D, Rod-ZW10-Zwilch and Spindly, that regulate dynein function and localization.
Collapse
|
35
|
Abstract
Development of a multicellular organism from a fertilized egg depends on a precise balance between symmetric cell divisions to expand the pool of similar cells, and asymmetric cell divisions to create cell-type diversity. Spindle orientation can influence the generation of symmetric or asymmetric cell fates depending on how it is coupled to cell-intrinsic polarity cues, or how it is positioned relative to cell-extrinsic cues such as niche-derived signals. In this review, we describe the mechanism of spindle orientation in budding yeast, Drosophila melanogaster, Caenorhabditis elegans and mammalian neural progenitors, with the goal of highlighting conserved mechanisms and indicating open questions for the future.
Collapse
|
36
|
Meyerzon M, Gao Z, Liu J, Wu JC, Malone CJ, Starr DA. Centrosome attachment to the C. elegans male pronucleus is dependent on the surface area of the nuclear envelope. Dev Biol 2009; 327:433-46. [PMID: 19162001 PMCID: PMC2668512 DOI: 10.1016/j.ydbio.2008.12.030] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Revised: 12/13/2008] [Accepted: 12/19/2008] [Indexed: 01/11/2023]
Abstract
A close association must be maintained between the male pronucleus and the centrosomes during pronuclear migration. In C. elegans, simultaneous depletion of inner nuclear membrane LEM proteins EMR-1 and LEM-2, depletion of the nuclear lamina proteins LMN-1 or BAF-1, or the depletion of nuclear import components leads to embryonic lethality with small pronuclei. Here, a novel centrosome detachment phenotype in C. elegans zygotes is described. Zygotes with defects in the nuclear envelope had small pronuclei with a single centrosome detached from the male pronucleus. ZYG-12, SUN-1, and LIS-1, which function at the nuclear envelope with dynein to attach centrosomes, were observed at normal concentrations on the nuclear envelope of pronuclei with detached centrosomes. Analysis of time-lapse images showed that as mutant pronuclei grew in surface area, they captured detached centrosomes. Larger tetraploid or smaller histone::mCherry pronuclei suppressed or enhanced the centrosome detachment phenotype respectively. In embryos fertilized with anucleated sperm, only one centrosome was captured by small female pronuclei, suggesting the mechanism of capture is dependent on the surface area of the outer nuclear membrane available to interact with aster microtubules. We propose that the limiting factor for centrosome attachment to the surface of abnormally small pronuclei is dynein.
Collapse
Affiliation(s)
- Marina Meyerzon
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Zhizhen Gao
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA 16802
| | - Jin Liu
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Jui-Ching Wu
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Christian J. Malone
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA 16802
| | - Daniel A. Starr
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| |
Collapse
|
37
|
Gassmann R, Essex A, Hu JS, Maddox PS, Motegi F, Sugimoto A, O'Rourke SM, Bowerman B, McLeod I, Yates JR, Oegema K, Cheeseman IM, Desai A. A new mechanism controlling kinetochore-microtubule interactions revealed by comparison of two dynein-targeting components: SPDL-1 and the Rod/Zwilch/Zw10 complex. Genes Dev 2008; 22:2385-99. [PMID: 18765790 DOI: 10.1101/gad.1687508] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Chromosome segregation requires stable bipolar attachments of spindle microtubules to kinetochores. The dynein/dynactin motor complex localizes transiently to kinetochores and is implicated in chromosome segregation, but its role remains poorly understood. Here, we use the Caenorhabditis elegans embryo to investigate the function of kinetochore dynein by analyzing the Rod/Zwilch/Zw10 (RZZ) complex and the associated coiled-coil protein SPDL-1. Both components are essential for Mad2 targeting to kinetochores and spindle checkpoint activation. RZZ complex inhibition, which abolishes both SPDL-1 and dynein/dynactin targeting to kinetochores, slows but does not prevent the formation of load-bearing kinetochore-microtubule attachments and reduces the fidelity of chromosome segregation. Surprisingly, inhibition of SPDL-1, which abolishes dynein/dynactin targeting to kinetochores without perturbing RZZ complex localization, prevents the formation of load-bearing attachments during most of prometaphase and results in extensive chromosome missegregation. Coinhibition of SPDL-1 along with the RZZ complex reduces the phenotypic severity to that observed following RZZ complex inhibition alone. We propose that the RZZ complex can inhibit the formation of load-bearing attachments and that this activity of the RZZ complex is normally controlled by dynein/dynactin localized via SPDL-1. This mechanism could coordinate the hand-off from initial weak dynein-mediated lateral attachments, which help orient kinetochores and enhance their ability to capture microtubules, to strong end-coupled attachments that drive chromosome segregation.
Collapse
Affiliation(s)
- Reto Gassmann
- Ludwig Institute for Cancer Research/Dept of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Hebbar S, Mesngon MT, Guillotte AM, Desai B, Ayala R, Smith DS. Lis1 and Ndel1 influence the timing of nuclear envelope breakdown in neural stem cells. ACTA ACUST UNITED AC 2008; 182:1063-71. [PMID: 18809722 PMCID: PMC2542469 DOI: 10.1083/jcb.200803071] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Lis1 and Ndel1 are essential for animal development. They interact directly with one another and with cytoplasmic dynein. The developing brain is especially sensitive to reduced Lis1 or Ndel1 levels, as both proteins influence spindle orientation, neural cell fate decisions, and neuronal migration. We report here that Lis1 and Ndel1 reduction in a mitotic cell line impairs prophase nuclear envelope (NE) invagination (PNEI). This dynein-dependent process facilitates NE breakdown (NEBD) and occurs before the establishment of the bipolar spindle. Ndel1 phosphorylation is important for this function, regulating binding to both Lis1 and dynein. Prophase cells in the ventricular zone (VZ) of embryonic day 13.5 Lis1+/− mouse brains show reduced PNEI, and the ratio of prophase to prometaphase cells is increased, suggesting an NEBD delay. Moreover, prophase cells in the VZ contain elevated levels of Ndel1 phosphorylated at a key cdk5 site. Our data suggest that a delay in NEBD in the VZ could contribute to developmental defects associated with Lis1–Ndel1 disruption.
Collapse
Affiliation(s)
- Sachin Hebbar
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | | | | | | | | | | |
Collapse
|
39
|
Green RA, Audhya A, Pozniakovsky A, Dammermann A, Pemble H, Monen J, Portier N, Hyman A, Desai A, Oegema K. Expression and imaging of fluorescent proteins in the C. elegans gonad and early embryo. Methods Cell Biol 2008; 85:179-218. [PMID: 18155464 DOI: 10.1016/s0091-679x(08)85009-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Caenorhabditis elegans gonad and early embryo have recently emerged as an attractive metazoan model system for studying cell and developmental biology. The success of this system is attributable to the stereotypical architecture and reproducible cell divisions of the gonad/early embryo, coupled with penetrant RNAi-mediated protein depletion. These features have facilitated the development of visual assays with high spatiotemporal resolution to monitor specific subcellular processes. Assay development has relied heavily on the emergence of methods to circumvent germline silencing to allow the expression of transgenes encoding fluorescent fusion proteins. In this chapter, we discuss methods for the expression and imaging of fluorescent proteins in the C. elegans germline, including the design of transgenes for optimal expression, the generation of transgenic worm lines by ballistic bombardment, the construction of multimarker lines by mating, and methods for live imaging of the gonad and early embryo.
Collapse
Affiliation(s)
- Rebecca A Green
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Coupling of cortical dynein and G alpha proteins mediates spindle positioning in Caenorhabditis elegans. Nat Cell Biol 2007; 9:1294-302. [PMID: 17922003 DOI: 10.1038/ncb1649] [Citation(s) in RCA: 195] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Accepted: 09/25/2007] [Indexed: 12/25/2022]
Abstract
Despite being essential for spatial cell division control, the mechanisms governing spindle positioning remain incompletely understood. In the Caenorhabditis elegans one-cell stage embryo, the spindle becomes asymmetrically positioned during anaphase through the action of as-yet unidentified cortical force generators that pull on astral microtubules and that depend on two G alpha proteins and associated proteins. We performed spindle-severing experiments following temporally restricted gene inactivation and drug exposure, and established that microtubule dynamics and dynein are both required for generating efficient pulling forces. We found that the G alpha-associated proteins GPR-1/2 and LIN-5 interact in vivo with LIS-1, a component of the dynein complex. Moreover, we discovered that the LIN-5, GPR-1/2 and the G alpha proteins promote the presence of the dynein complex at the cell cortex. Our findings suggest a mechanism by which the G alpha proteins enable GPR-1/2 and LIN-5 recruitment to the cortex, thus ensuring the presence of cortical dynein. Together with microtubule dynamics, this allows pulling forces to be exerted and proper cell division to be achieved.
Collapse
|
41
|
Yamaguchi N, Koizumi H, Aoki J, Natori Y, Nishikawa K, Natori Y, Takanezawa Y, Arai H. Type I platelet-activating factor acetylhydrolase catalytic subunits over-expression induces pleiomorphic nuclei and centrosome amplification. Genes Cells 2007; 12:1153-61. [PMID: 17903175 DOI: 10.1111/j.1365-2443.2007.01126.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
LIS1, a causative gene product for type I lissencephaly, binds to and regulates the dynein motor and the centrosome. LIS1 also forms a complex with the catalytic subunits alpha1 and alpha2 of type I platelet-activating factor acetylhydrolase [PAF-AH (I)]. However, the cellular function of the catalytic subunits remains unknown. In this study, we showed that over-expression of the catalytic subunits, especially alpha2, in cultured cells induced dramatic phenotypical changes including nuclear shape change, centrosomal amplification and microtubule disorganization. We examined if these effects were due to the catalytic activity and/or binding of alpha2 to LIS1. Substitution of a single amino acid Glu39 of murine alpha1 and alpha2 by Asp (alpha2-E39D) did not affect catalytic activity but completely abolished LIS1 binding. Over-expression of either alpha2-E39D or the catalytically inactive alpha2-S48C revealed that alpha2-E39D, but not alpha2-S48C, lost its ability to induce above-mentioned phenotypic changes. Biochemical analyses showed that LIS1 present in the precipitate fraction of murine brain homogenates could be translocated to the soluble fraction by alpha2, but not by alpha2-E39D. These results suggest that over-expression of the PAF-AH (I) catalytic subunits induces centrosomal amplification and microtubule disorganization by disturbing intracellular localization of LIS1.
Collapse
Affiliation(s)
- Noritaka Yamaguchi
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | | | | | | | | | | | | | | |
Collapse
|
42
|
Griffis ER, Stuurman N, Vale RD. Spindly, a novel protein essential for silencing the spindle assembly checkpoint, recruits dynein to the kinetochore. ACTA ACUST UNITED AC 2007; 177:1005-15. [PMID: 17576797 PMCID: PMC2064361 DOI: 10.1083/jcb.200702062] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The eukaryotic spindle assembly checkpoint (SAC) monitors microtubule attachment to kinetochores and prevents anaphase onset until all kinetochores are aligned on the metaphase plate. In higher eukaryotes, cytoplasmic dynein is involved in silencing the SAC by removing the checkpoint proteins Mad2 and the Rod–Zw10–Zwilch complex (RZZ) from aligned kinetochores (Howell, B.J., B.F. McEwen, J.C. Canman, D.B. Hoffman, E.M. Farrar, C.L. Rieder, and E.D. Salmon. 2001. J. Cell Biol. 155:1159–1172; Wojcik, E., R. Basto, M. Serr, F. Scaerou, R. Karess, and T. Hays. 2001. Nat. Cell Biol. 3:1001–1007). Using a high throughput RNA interference screen in Drosophila melanogaster S2 cells, we have identified a new protein (Spindly) that accumulates on unattached kinetochores and is required for silencing the SAC. After the depletion of Spindly, dynein cannot target to kinetochores, and, as a result, cells arrest in metaphase with high levels of kinetochore-bound Mad2 and RZZ. We also identified a human homologue of Spindly that serves a similar function. However, dynein's nonkinetochore functions are unaffected by Spindly depletion. Our findings indicate that Spindly is a novel regulator of mitotic dynein, functioning specifically to target dynein to kinetochores.
Collapse
Affiliation(s)
- Eric R Griffis
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94158, USA
| | | | | |
Collapse
|
43
|
Zhang J, Megraw TL. Proper recruitment of gamma-tubulin and D-TACC/Msps to embryonic Drosophila centrosomes requires Centrosomin Motif 1. Mol Biol Cell 2007; 18:4037-49. [PMID: 17671162 PMCID: PMC1995719 DOI: 10.1091/mbc.e07-05-0474] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Centrosomes are microtubule-organizing centers and play a dominant role in assembly of the microtubule spindle apparatus at mitosis. Although the individual binding steps in centrosome maturation are largely unknown, Centrosomin (Cnn) is an essential mitotic centrosome component required for assembly of all other known pericentriolar matrix (PCM) proteins to achieve microtubule-organizing activity at mitosis in Drosophila. We have identified a conserved motif (Motif 1) near the amino terminus of Cnn that is essential for its function in vivo. Cnn Motif 1 is necessary for proper recruitment of gamma-tubulin, D-TACC (the homolog of vertebrate transforming acidic coiled-coil proteins [TACC]), and Minispindles (Msps) to embryonic centrosomes but is not required for assembly of other centrosome components including Aurora A kinase and CP60. Centrosome separation and centrosomal satellite formation are severely disrupted in Cnn Motif 1 mutant embryos. However, actin organization into pseudocleavage furrows, though aberrant, remains partially intact. These data show that Motif 1 is necessary for some but not all of the activities conferred on centrosome function by intact Cnn.
Collapse
Affiliation(s)
- Jiuli Zhang
- Department of Pharmacology and The Cecil and Ida Green Center for Reproductive Biology Sciences, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9051
| | - Timothy L. Megraw
- Department of Pharmacology and The Cecil and Ida Green Center for Reproductive Biology Sciences, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9051
| |
Collapse
|
44
|
Hachet V, Canard C, Gönczy P. Centrosomes promote timely mitotic entry in C. elegans embryos. Dev Cell 2007; 12:531-41. [PMID: 17419992 DOI: 10.1016/j.devcel.2007.02.015] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Revised: 02/16/2007] [Accepted: 02/20/2007] [Indexed: 02/05/2023]
Abstract
Several mitotic regulators, including Cyclin B1/Cdk1, are present at centrosomes prior to mitosis onset, but it is unclear whether centrosomes promote mitotic entry in vivo. Here we developed a sensitive assay in C. elegans embryos for the temporal analysis of mitotic entry, in which the male and female pronuclei undergo asynchronous entry into mitosis when separated from one another. Using this assay, we found that centrosome integrity is necessary for timing mitotic entry. Centrosomes do not function in this instance through their ability to nucleate microtubules. Instead, centrosomes serve to focus the Aurora A kinase AIR-1, which is essential for timely mitotic entry. Furthermore, analysis of embryos in which centrosomes and pronuclei are detached from one another demonstrates that centrosomes are sufficient to promote mitosis onset. Together, our findings support a model in which centrosomes serve as integrative centers for mitotic regulators and thus trigger mitotic entry in a timely fashion.
Collapse
Affiliation(s)
- Virginie Hachet
- Swiss Institute for Experimental Cancer Research (ISREC), and School of Life Sciences, Swiss Federal Institute of Technology (EPFL), CH-1066 Lausanne, Switzerland
| | | | | |
Collapse
|
45
|
Abstract
PURPOSE OF REVIEW Animal models provide a means to investigate fundamental mechanisms of abnormal electrical discharge (i.e., seizures). Understanding the pathogenesis of epilepsy and therapy development have greatly benefited from these models. Here we review recent mouse mutants featuring spontaneous seizures and simpler organisms. RECENT FINDINGS New genetically engineered mice provide additional insights to cellular mechanisms underlying seizure generation (BK calcium-activated potassium channels and interneuron-expressed sodium channels), genetic interactions that exacerbate seizure phenotype (Scn2a, Kcnq2 and background) and neurodevelopmental influences (Dlx transcription factors). Mutants for neuronal nicotinic acetylcholine receptors, Glut-1 deficiency and aquaporin channels highlight additional seizure phenotypes in mice. Additional models in Caenorhabditis elegans (Lis-1) and Danio rerio (pentylenetetrazole) highlight a reductionist approach. Taking further advantage of 'simple' organisms, antiepileptic drugs and genetic modifiers of seizure activity are being uncovered in Drosophila. SUMMARY Studies of epilepsy in mutant mice provide a framework for understanding critical features of the brain that regulate excitability. These, and as yet undiscovered, mouse mutants will continue to serve as the foundation for basic epilepsy research. Interestingly, an even greater potential for analyzing epileptic phenotypes may lie in the more widespread use of genetically tractable organisms such as worms, flies and zebrafish.
Collapse
Affiliation(s)
- Scott C Baraban
- Epilepsy Research Laboratory, Department of Neurological Surgery, University of California, San Francisco, CA 94143, USA.
| |
Collapse
|
46
|
Buttner EA, Gil-Krzewska AJ, Rajpurohit AK, Hunter CP. Progression from mitotic catastrophe to germ cell death in Caenorhabditis elegans lis-1 mutants requires the spindle checkpoint. Dev Biol 2007; 305:397-410. [PMID: 17376425 PMCID: PMC2000799 DOI: 10.1016/j.ydbio.2007.02.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Revised: 12/23/2006] [Accepted: 02/16/2007] [Indexed: 01/31/2023]
Abstract
Deletion of the lissencephaly disease gene LIS-1 in humans causes an extreme disorganization of the brain associated with significant reduction in cortical neurons. Here we show that deletion or RNA interference (RNAi) of Caenorhabditis elegans lis-1 results in a reduction in germline nuclei and causes a variety of cellular, developmental, and neurological defects throughout development. Our analysis of the germline defects suggests that the reduction in nuclei number stems from dysfunctional mitotic spindles resulting in cell cycle arrest and eventually programmed cell death (apoptosis). Deletion of the spindle checkpoint gene mdf-1 blocks lis-1(lf)-induced cell cycle arrest and germline apoptosis, placing the spindle checkpoint pathway upstream of the programmed cell death pathway. These results suggest that apoptosis may contribute to the cell-sparse pathology of lissencephaly.
Collapse
Affiliation(s)
- Edgar A Buttner
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138-2020, USA.
| | | | | | | |
Collapse
|
47
|
Locke CJ, Williams SN, Schwarz EM, Caldwell GA, Caldwell KA. Genetic interactions among cortical malformation genes that influence susceptibility to convulsions in C. elegans. Brain Res 2006; 1120:23-34. [PMID: 16996038 DOI: 10.1016/j.brainres.2006.08.067] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2006] [Revised: 08/17/2006] [Accepted: 08/20/2006] [Indexed: 11/30/2022]
Abstract
Epilepsy is estimated to affect 1-2% of the world population, yet remains poorly understood at a molecular level. We have previously established the roundworm Caenorhabditis elegans as a model for investigating genetic susceptibilities to seizure-like convulsions in vivo. Here we investigate the behavioral consequences of decreasing the activity of nematode gene homologs within the LIS1 pathway that are associated with a human cortical malformation termed lissencephaly. Bioinformatic analysis revealed the nud-2 gene, encoding the worm homolog of mammalian effectors of LIS1, termed NDE1 and NDEL1. Phenotypic analysis of animals targeted by RNA interference (RNAi) was performed using a pentylenetetrazole (PTZ) exposure paradigm to induce convulsions. Worms depleted for LIS1 pathway components (NUD-1, NUD-2, DHC-1, CDK-5, and CDKA-1) exhibited significant convulsions following PTZ and RNAi treatment. Strains harboring fluorescent markers for GABAergic neuronal architecture and synaptic vesicle trafficking were employed to discern putative mechanisms accounting for observed convulsion behaviors. We found that depletion of LIS1 pathway components resulted in defective GABA synaptic vesicle trafficking. We also utilized combinations of specific genetic backgrounds to create a sensitized state for convulsion susceptibility and discovered that convulsion effects were significantly enhanced when LIS-1 and other pathway components were compromised within the same animals. Thus, interactions among gene products with LIS-1 may mediate intrinsic thresholds of neuronal synchrony.
Collapse
Affiliation(s)
- Cody J Locke
- Department of Biological Sciences, The University of Alabama, Box 870344, Tuscaloosa, AL 35487-0344, USA
| | | | | | | | | |
Collapse
|
48
|
Labbé JC, Roy R. New developmental insights from high-throughput biological analysis in Caenorhabditis elegans. Clin Genet 2006; 69:306-14. [PMID: 16630163 DOI: 10.1111/j.1399-0004.2006.00587.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The use of Caenorhabditis elegans as a model system for understanding animal development and human disease has long been recognized as an efficient tool of discovery. Recent developments, particularly in our understanding of RNA-mediated interference and its ability to modify gene activity, have facilitated the use of C. elegans in determining gene function via high-throughput analysis. These new strategies have provided a framework that allows investigators to analyse gene function globally at the genomic level and will likely become a prototypic model for biological analysis in the post-genome era.
Collapse
Affiliation(s)
- J-C Labbé
- Institut de recherche en immunologie et en cancérologie, Universite de Montreal, Montreal, Quebec, Canada.
| | | |
Collapse
|
49
|
Abstract
The manuscript by Tsai et al. (935–945) is a tour de force analysis of a controversial issue in developmental neurobiology, namely the molecular basis of the devastating human brain malformation, type I lissencephaly (Lis1) (Jellinger, K., and A. Rett. 1976. Neuropadiatrie. 7:66–91). For several decades, defects in neuronal migration have been assumed to underlie all defects in cortical histogenesis. In the paper by Tsai et al., the authors use a variety of elegant approaches, including the first real-time imaging of cortical neurons with reduced levels of LIS1, to demonstrate that LIS1 and dynactin act as regulators of dynein during cortical histogenesis. A loss of LIS1 results in both a failure to exit the cortical germinal zone and abnormal neuronal process formation. Thus, the primary action of the mutation is to disrupt the production of neurons in the developing brain as well as their migration.
Collapse
Affiliation(s)
- Mary E Hatten
- Laboratory of Developmental Neurobiology, The Rockefeller University, New York, NY 10021, USA.
| |
Collapse
|
50
|
Siller KH, Serr M, Steward R, Hays TS, Doe CQ. Live imaging of Drosophila brain neuroblasts reveals a role for Lis1/dynactin in spindle assembly and mitotic checkpoint control. Mol Biol Cell 2005; 16:5127-40. [PMID: 16107559 PMCID: PMC1266413 DOI: 10.1091/mbc.e05-04-0338] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Revised: 07/08/2005] [Accepted: 08/10/2005] [Indexed: 01/28/2023] Open
Abstract
Lis1 is required for nuclear migration in fungi, cell cycle progression in mammals, and the formation of a folded cerebral cortex in humans. Lis1 binds dynactin and the dynein motor complex, but the role of Lis1 in many dynein/dynactin-dependent processes is not clearly understood. Here we generate and/or characterize mutants for Drosophila Lis1 and a dynactin subunit, Glued, to investigate the role of Lis1/dynactin in mitotic checkpoint function. In addition, we develop an improved time-lapse video microscopy technique that allows live imaging of GFP-Lis1, GFP-Rod checkpoint protein, green fluorescent protein (GFP)-labeled chromosomes, or GFP-labeled mitotic spindle dynamics in neuroblasts within whole larval brain explants. Our mutant analyses show that Lis1/dynactin have at least two independent functions during mitosis: first promoting centrosome separation and bipolar spindle assembly during prophase/prometaphase, and subsequently generating interkinetochore tension and transporting checkpoint proteins off kinetochores during metaphase, thus promoting timely anaphase onset. Furthermore, we show that Lis1/dynactin/dynein physically associate and colocalize on centrosomes, spindle MTs, and kinetochores, and that regulation of Lis1/dynactin kinetochore localization in Drosophila differs from both Caenorhabditis elegans and mammals. We conclude that Lis1/dynactin act together to regulate multiple, independent functions in mitotic cells, including spindle formation and cell cycle checkpoint release.
Collapse
|