1
|
Fang HY, Forghani R, Clarke A, McQueen PG, Chandrasekaran A, O’Neill KM, Losert W, Papoian GA, Giniger E. Enabled primarily controls filopodial morphology, not actin organization, in the TSM1 growth cone in Drosophila. Mol Biol Cell 2023; 34:ar83. [PMID: 37223966 PMCID: PMC10398877 DOI: 10.1091/mbc.e23-01-0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 05/25/2023] Open
Abstract
Ena/VASP proteins are processive actin polymerases that are required throughout animal phylogeny for many morphogenetic processes, including axon growth and guidance. Here we use in vivo live imaging of morphology and actin distribution to determine the role of Ena in promoting the growth of the TSM1 axon of the Drosophila wing. Altering Ena activity causes stalling and misrouting of TSM1. Our data show that Ena has a substantial impact on filopodial morphology in this growth cone but exerts only modest effects on actin distribution. This is in contrast to the main regulator of Ena, Abl tyrosine kinase, which was shown previously to have profound effects on actin and only mild effects on TSM1 growth cone morphology. We interpret these data as suggesting that the primary role of Ena in this axon may be to link actin to the morphogenetic processes of the plasma membrane, rather than to regulate actin organization itself. These data also suggest that a key role of Ena, acting downstream of Abl, may be to maintain consistent organization and reliable evolution of growth cone structure, even as Abl activity varies in response to guidance cues in the environment.
Collapse
Affiliation(s)
- Hsiao Yu Fang
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Rameen Forghani
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Akanni Clarke
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Philip G. McQueen
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Aravind Chandrasekaran
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20752
| | - Kate M. O’Neill
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
- Institute for Physical Sciences and Department of Physics, University of Maryland, College Park, MD 20752
| | - Wolfgang Losert
- Institute for Physical Sciences and Department of Physics, University of Maryland, College Park, MD 20752
| | - Garegin A. Papoian
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20752
| | - Edward Giniger
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| |
Collapse
|
2
|
Zhao Y, Hua X, Bian Q, Wang D. Nanoplastic Exposure at Predicted Environmental Concentrations Induces Activation of Germline Ephrin Signal Associated with Toxicity Formation in the Caenorhabditis elegans Offspring. TOXICS 2022; 10:toxics10110699. [PMID: 36422907 PMCID: PMC9696181 DOI: 10.3390/toxics10110699] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 05/04/2023]
Abstract
In nematode Caenorhabditis elegans, exposure to polystyrene nanoparticles (PS-NPs) at predicted environmental concentrations can cause induction of transgenerational toxicity. However, the underlying mechanisms for toxicity formation of PS-NP in the offspring remain largely unknown. In this study, based on high-throughput sequencing, Ephrin ligand EFN-3 was identified as a target of KSR-1/2 (two kinase suppressors of Ras) in the germline during the control of transgenerational PS-NP toxicity. At parental generation (P0-G), exposure to 0.1-10 μg/L PS-NP caused the increase in expression of germline efn-3, and this increase in germline efn-3 expression could be further detected in the offspring, such as F1-G and F2-G. Germline RNAi of efn-3 caused a resistance to transgenerational PS-NP toxicity, suggesting that the activation of germline EFN-3 at P0-G mediated transgenerational PS-NP toxicity. In the offspring, Ephrin receptor VAB-1 was further activated by the increased EFN-3 caused by PS-NP exposure at P0-G, and RNAi of vab-1 also resulted in resistance to transgenerational PS-NP toxicity. VAB-1 acted in both the neurons and the germline to control toxicity of PS-NP in the offspring. In the neurons, VAB-1 regulated PS-NP toxicity by suppressing expressions of DBL-1, JNK-1, MPK-1, and GLB-10. In the germline, VAB-1 regulated PS-NP toxicity by increasing NDK-1 and LIN-23 expressions and decreasing EGL-1 expression. Therefore, germline Ephrin ligand EFN-3 and its receptor VAB-1 acted together to mediate the formation of transgenerational PS-NP toxicity. Our data highlight the important role of activation in germline Ephrin signals in mediating transgenerational toxicity of nanoplastics at predicted environmental concentrations in organisms.
Collapse
Affiliation(s)
- Yue Zhao
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
- Institute of Toxicology and Risk Assessment, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210009, China
| | - Xin Hua
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
| | - Qian Bian
- Institute of Toxicology and Risk Assessment, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing 210009, China
- Correspondence: (Q.B.); (D.W.)
| | - Dayong Wang
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
- Shenzhen Ruipuxun Academy for Stem Cell & Regenerative Medicine, Shenzhen 518122, China
- Correspondence: (Q.B.); (D.W.)
| |
Collapse
|
3
|
Santella A, Kolotuev I, Kizilyaprak C, Bao Z. Cross-modality synthesis of EM time series and live fluorescence imaging. eLife 2022; 11:77918. [PMID: 35666127 PMCID: PMC9213002 DOI: 10.7554/elife.77918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/05/2022] [Indexed: 11/13/2022] Open
Abstract
Analyses across imaging modalities allow the integration of complementary spatiotemporal information about brain development, structure, and function. However, systematic atlasing across modalities is limited by challenges to effective image alignment. We combine highly spatially resolved electron microscopy (EM) and highly temporally resolved time-lapse fluorescence microscopy (FM) to examine the emergence of a complex nervous system in Caenorhabditis elegans embryogenesis. We generate an EM time series at four classic developmental stages and create a landmark-based co-optimization algorithm for cross-modality image alignment, which handles developmental heterochrony among datasets to achieve accurate single-cell level alignment. Synthesis based on the EM series and time-lapse FM series carrying different cell-specific markers reveals critical dynamic behaviors across scales of identifiable individual cells in the emergence of the primary neuropil, the nerve ring, as well as a major sensory organ, the amphid. Our study paves the way for systematic cross-modality data synthesis in C. elegans and demonstrates a powerful approach that may be applied broadly.
Collapse
Affiliation(s)
- Anthony Santella
- Molecular Cytology Core, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Irina Kolotuev
- Electron Microscopy Facility, University of Lausanne, Lausanne, Switzerland
| | | | - Zhirong Bao
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
| |
Collapse
|
4
|
Rapti G. A perspective on C. elegans neurodevelopment: from early visionaries to a booming neuroscience research. J Neurogenet 2021; 34:259-272. [PMID: 33446023 DOI: 10.1080/01677063.2020.1837799] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The formation of the nervous system and its striking complexity is a remarkable feat of development. C. elegans served as a unique model to dissect the molecular events in neurodevelopment, from its early visionaries to the current booming neuroscience community. Soon after being introduced as a model, C. elegans was mapped at the level of genes, cells, and synapses, providing the first metazoan with a complete cell lineage, sequenced genome, and connectome. Here, I summarize mechanisms underlying C. elegans neurodevelopment, from the generation and diversification of neural components to their navigation and connectivity. I point out recent noteworthy findings in the fields of glia biology, sex dimorphism and plasticity in neurodevelopment, highlighting how current research connects back to the pioneering studies by Brenner, Sulston and colleagues. Multifaceted investigations in model organisms, connecting genes to cell function and behavior, expand our mechanistic understanding of neurodevelopment while allowing us to formulate emerging questions for future discoveries.
Collapse
Affiliation(s)
- Georgia Rapti
- European Molecular Biology Laboratory, Unit of Developmental Biology, Heidelberg, Germany
| |
Collapse
|
5
|
Basu A, Behera S, Bhardwaj S, Dey S, Ghosh-Roy A. Regulation of UNC-40/DCC and UNC-6/Netrin by DAF-16 promotes functional rewiring of the injured axon. Development 2021; 148:268990. [PMID: 34109380 DOI: 10.1242/dev.198044] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 05/04/2021] [Indexed: 01/02/2023]
Abstract
The adult nervous system has a limited capacity to regenerate after accidental damage. Post-injury functional restoration requires proper targeting of the injured axon to its postsynaptic cell. Although the initial response to axonal injury has been studied in great detail, it is rather unclear what controls the re-establishment of a functional connection. Using the posterior lateral microtubule neuron in Caenorhabditis elegans, we found that after axotomy, the regrowth from the proximal stump towards the ventral side and accumulation of presynaptic machinery along the ventral nerve cord correlated to the functional recovery. We found that the loss of insulin receptor DAF-2 promoted 'ventral targeting' in a DAF-16-dependent manner. We further showed that coordinated activities of DAF-16 in neuron and muscle promoted 'ventral targeting'. In response to axotomy, expression of the Netrin receptor UNC-40 was upregulated in the injured neuron in a DAF-16-dependent manner. In contrast, the DAF-2-DAF-16 axis contributed to the age-related decline in Netrin expression in muscle. Therefore, our study revealed an important role for insulin signaling in regulating the axon guidance molecules during the functional rewiring process.
Collapse
Affiliation(s)
- Atrayee Basu
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Sibaram Behera
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Smriti Bhardwaj
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Shirshendu Dey
- Fluorescence Microscopy Division, Bruker India Scientific PvT Ltd, International Trade Tower, Nehru Place, New Delhi 110019, India
| | - Anindya Ghosh-Roy
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| |
Collapse
|
6
|
Mori T, Kitani Y, Hatakeyama D, Machida K, Goto-Inoue N, Hayakawa S, Yamamoto N, Kashiwagi K, Kashiwagi A. Predation threats for a 24-h period activated the extension of axons in the brains of Xenopus tadpoles. Sci Rep 2020; 10:11737. [PMID: 32678123 PMCID: PMC7367293 DOI: 10.1038/s41598-020-67975-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 02/24/2020] [Indexed: 11/24/2022] Open
Abstract
The threat of predation is a driving force in the evolution of animals. We have previously reported that Xenopus laevis enhanced their tail muscles and increased their swimming speeds in the presence of Japanese larval salamander predators. Herein, we investigated the induced gene expression changes in the brains of tadpoles under the threat of predation using 3′-tag digital gene expression profiling. We found that many muscle genes were expressed after 24 h of exposure to predation. Ingenuity pathway analysis further showed that after 24 h of a predation threat, various signal transduction genes were stimulated, such as those affecting the actin cytoskeleton and CREB pathways, and that these might increase microtubule dynamics, axonogenesis, cognition, and memory. To verify the increase in microtubule dynamics, DiI was inserted through the tadpole nostrils. Extension of the axons was clearly observed from the nostril to the diencephalon and was significantly increased (P ≤ 0.0001) after 24 h of exposure to predation, compared with that of the control. The dynamic changes in the signal transductions appeared to bring about new connections in the neural networks, as suggested by the microtubule dynamics. These connections may result in improved memory and cognition abilities, and subsequently increase survivability.
Collapse
Affiliation(s)
- Tsukasa Mori
- Department of Marine Science and Resources, College of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa, 252-0880, Japan.
| | - Yoichiro Kitani
- Department of Marine Science and Resources, College of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa, 252-0880, Japan.,Institute of Nature and Environmental Technology, Kanazawa University, Kanazawa, Japan
| | - Den Hatakeyama
- Department of Marine Science and Resources, College of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa, 252-0880, Japan
| | - Kazumasa Machida
- Department of Marine Science and Resources, College of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa, 252-0880, Japan
| | - Naoko Goto-Inoue
- Department of Marine Science and Resources, College of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa, 252-0880, Japan
| | - Satoshi Hayakawa
- Department of Pathology and Microbiology, School of Medicine, Nihon University, Tokyo, Japan
| | - Naoyuki Yamamoto
- Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Keiko Kashiwagi
- Amphibian Research Center (Building M), Hiroshima University, Hiroshima, Japan
| | - Akihiko Kashiwagi
- Amphibian Research Center (Building M), Hiroshima University, Hiroshima, Japan
| |
Collapse
|
7
|
Chen MK, Du Y, Sun L, Hsu JL, Wang YH, Gao Y, Huang J, Hung MC. H 2O 2 induces nuclear transport of the receptor tyrosine kinase c-MET in breast cancer cells via a membrane-bound retrograde trafficking mechanism. J Biol Chem 2019; 294:8516-8528. [PMID: 30962283 DOI: 10.1074/jbc.ra118.005953] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 03/27/2019] [Indexed: 02/05/2023] Open
Abstract
Reactive oxygen species (ROS) are cellular by-products produced from metabolism and also anticancer agents, such as ionizing irradiation and chemotherapy drugs. The ROS H2O2 has high rates of production in cancer cells because of their rapid proliferation. ROS oxidize DNA, protein, and lipids, causing oxidative stress in cancer cells and making them vulnerable to other stresses. Therefore, cancer cell survival relies on maintaining ROS-induced stress at tolerable levels. Hepatocyte growth factor receptor (c-MET) is a receptor tyrosine kinase overexpressed in malignant cancer types, including breast cancer. Full-length c-MET triggers a signal transduction cascade from the plasma membrane that, through downstream signaling proteins, up-regulates cell proliferation and migration. Recently, c-MET was shown to interact and phosphorylate poly(ADP-ribose) polymerase 1 in the nucleus and to induce poly(ADP-ribose) polymerase inhibitor resistance. However, it remains unclear how c-MET moves from the cell membrane to the nucleus. Here, we demonstrate that H2O2 induces retrograde transport of membrane-associated full-length c-MET into the nucleus of human MCF10A and MCF12A or primary breast cancer cells. We further show that knocking down either coatomer protein complex subunit γ1 (COPG1) or Sec61 translocon β subunit (SEC61β) attenuates the accumulation of full-length nuclear c-MET. However, a c-MET kinase inhibitor did not block nuclear c-MET transport. Moreover, nuclear c-MET interacted with KU proteins in breast cancer cells, suggesting a role of full-length nuclear c-MET in ROS-induced DNA damage repair. We conclude that a membrane-bound retrograde vesicle transport mechanism facilitates membrane-to-nucleus transport of c-MET in breast cancer cells.
Collapse
Affiliation(s)
- Mei-Kuang Chen
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030; Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Yi Du
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Linlin Sun
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030; Tianjin Key Laboratory of Lung Cancer Metastasis and Tumor Microenvironment, Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Jennifer L Hsu
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Yu-Han Wang
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030; Graduate Institute of Biomedical Sciences, China Medical University, Taichung 402, Taiwan
| | - Yuan Gao
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030; Department of General Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Jiaxing Huang
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030; Department of Medical Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Mien-Chie Hung
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030; Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030; Graduate Institute of Biomedical Sciences, China Medical University, Taichung 402, Taiwan; Center of Molecular Medicine, China Medical University, Taichung 402, Taiwan.
| |
Collapse
|
8
|
Singhal A, Shaham S. Infrared laser-induced gene expression for tracking development and function of single C. elegans embryonic neurons. Nat Commun 2017; 8:14100. [PMID: 28098184 PMCID: PMC5253673 DOI: 10.1038/ncomms14100] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/28/2016] [Indexed: 11/09/2022] Open
Abstract
Visualizing neural-circuit assembly in vivo requires tracking growth of optically resolvable neurites. The Caenorhabditis elegans embryonic nervous system, comprising 222 neurons and 56 glia, is attractive for comprehensive studies of development; however, embryonic reporters are broadly expressed, making single-neurite tracking/manipulation challenging. We present a method, using an infrared laser, for reproducible heat-dependent gene expression in small sublineages (one to four cells) without radiation damage. We go beyond proof-of-principle, and use our system to label and track single neurons during early nervous-system assembly. We uncover a retrograde extension mechanism for axon growth, and reveal the aetiology of axon-guidance defects in sax-3/Robo and vab-1/EphR mutants. We also perform cell-specific rescues, determining DAF-6/patched-related site of action during sensory-organ development. Simultaneous ablation and labelling of cells using our system reveals roles for glia in dendrite extension. Our method can be applied to other optically/IR-transparent organisms, and opens the door to high-resolution systematic analyses of C. elegans morphogenesis.
Collapse
Affiliation(s)
- Anupriya Singhal
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA
| | - Shai Shaham
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA
| |
Collapse
|
9
|
Walck-Shannon E, Lucas B, Chin-Sang I, Reiner D, Kumfer K, Cochran H, Bothfeld W, Hardin J. CDC-42 Orients Cell Migration during Epithelial Intercalation in the Caenorhabditis elegans Epidermis. PLoS Genet 2016; 12:e1006415. [PMID: 27861585 PMCID: PMC5127194 DOI: 10.1371/journal.pgen.1006415] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 10/10/2016] [Indexed: 12/22/2022] Open
Abstract
Cell intercalation is a highly directed cell rearrangement that is essential for animal morphogenesis. As such, intercalation requires orchestration of cell polarity across the plane of the tissue. CDC-42 is a Rho family GTPase with key functions in cell polarity, yet its role during epithelial intercalation has not been established because its roles early in embryogenesis have historically made it difficult to study. To circumvent these early requirements, in this paper we use tissue-specific and conditional loss-of-function approaches to identify a role for CDC-42 during intercalation of the Caenorhabditis elegans dorsal embryonic epidermis. CDC-42 activity is enriched in the medial tips of intercalating cells, which extend as cells migrate past one another. Moreover, CDC-42 is involved in both the efficient formation and orientation of cell tips during cell rearrangement. Using conditional loss-of-function we also show that the PAR complex functions in tip formation and orientation. Additionally, we find that the sole C. elegans Eph receptor, VAB-1, functions during this process in an Ephrin-independent manner. Using epistasis analysis, we find that vab-1 lies in the same genetic pathway as cdc-42 and is responsible for polarizing CDC-42 activity to the medial tip. Together, these data establish a previously uncharacterized role for polarized CDC-42, in conjunction with PAR-6, PAR-3 and an Eph receptor, during epithelial intercalation. As embryos develop, tissues must change shape to establish an animal’s form. One key form-shaping movement, cell intercalation, often occurs when a tissue elongates in a preferred direction. How cells in epithelial sheets can intercalate while maintaining tissue integrity is not well understood. Here we use the dorsal epidermis in embryos of the nematode worm, C. elegans, to study cell intercalation. As cells begin to intercalate, they form highly polarized tips that lead their migration. While some mechanisms that polarize intercalating cells have been established in other systems, our work identifies a new role for CDC-42—a highly conserved, highly regulated protein that controls the actin cytoskeleton. We previously established that a related protein, Rac, is involved in tip extension during dorsal intercalation. CDC-42 also contributes to this process in addition to helping orient the extending tip. CDC-42 appears to work in conjunction with two other known cell polarity proteins, PAR-3 and PAR-6, and the cell surface receptor, VAB-1. Our work identifies a novel pathway involving proteins conserved from worms to humans that regulates a ubiquitous process during animal development.
Collapse
Affiliation(s)
- Elise Walck-Shannon
- Department of Zoology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Bethany Lucas
- Program in Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Ian Chin-Sang
- Department of Biology, Queen's University, Kingston, Ontario, Canada
| | - David Reiner
- Center for Translational Cancer Research, Institute of Biosciences and Technology and Department of Medical Physiology, Texas A&M Health Science Center, Houston, Texas, United States of America
| | - Kraig Kumfer
- Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Hunter Cochran
- Department of Zoology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - William Bothfeld
- Department of Zoology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jeff Hardin
- Department of Zoology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Program in Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
| |
Collapse
|
10
|
Chisholm AD, Hutter H, Jin Y, Wadsworth WG. The Genetics of Axon Guidance and Axon Regeneration in Caenorhabditis elegans. Genetics 2016; 204:849-882. [PMID: 28114100 PMCID: PMC5105865 DOI: 10.1534/genetics.115.186262] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 09/06/2016] [Indexed: 11/18/2022] Open
Abstract
The correct wiring of neuronal circuits depends on outgrowth and guidance of neuronal processes during development. In the past two decades, great progress has been made in understanding the molecular basis of axon outgrowth and guidance. Genetic analysis in Caenorhabditis elegans has played a key role in elucidating conserved pathways regulating axon guidance, including Netrin signaling, the slit Slit/Robo pathway, Wnt signaling, and others. Axon guidance factors were first identified by screens for mutations affecting animal behavior, and by direct visual screens for axon guidance defects. Genetic analysis of these pathways has revealed the complex and combinatorial nature of guidance cues, and has delineated how cues guide growth cones via receptor activity and cytoskeletal rearrangement. Several axon guidance pathways also affect directed migrations of non-neuronal cells in C. elegans, with implications for normal and pathological cell migrations in situations such as tumor metastasis. The small number of neurons and highly stereotyped axonal architecture of the C. elegans nervous system allow analysis of axon guidance at the level of single identified axons, and permit in vivo tests of prevailing models of axon guidance. C. elegans axons also have a robust capacity to undergo regenerative regrowth after precise laser injury (axotomy). Although such axon regrowth shares some similarities with developmental axon outgrowth, screens for regrowth mutants have revealed regeneration-specific pathways and factors that were not identified in developmental screens. Several areas remain poorly understood, including how major axon tracts are formed in the embryo, and the function of axon regeneration in the natural environment.
Collapse
Affiliation(s)
| | - Harald Hutter
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, and
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093
- Department of Pathology and Laboratory Medicine, Howard Hughes Medical Institute, Chevy Chase, Maryland, and
| | - William G Wadsworth
- Department of Pathology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| |
Collapse
|
11
|
Dong B, Moseley-Alldredge M, Schwieterman AA, Donelson CJ, McMurry JL, Hudson ML, Chen L. EFN-4 functions in LAD-2-mediated axon guidance in Caenorhabditis elegans. Development 2016; 143:1182-91. [PMID: 26903502 DOI: 10.1242/dev.128934] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 02/12/2016] [Indexed: 11/20/2022]
Abstract
During development of the nervous system, growing axons rely on guidance molecules to direct axon pathfinding. A well-characterized family of guidance molecules are the membrane-associated ephrins, which together with their cognate Eph receptors, direct axon navigation in a contact-mediated fashion. InC. elegans, the ephrin-Eph signaling system is conserved and is best characterized for their roles in neuroblast migration during early embryogenesis. This study demonstrates a role for the C. elegans ephrin EFN-4 in axon guidance. We provide both genetic and biochemical evidence that is consistent with the C. elegans divergent L1 cell adhesion molecule LAD-2 acting as a non-canonical ephrin receptor to EFN-4 to promote axon guidance. We also show that EFN-4 probably functions as a diffusible factor because EFN-4 engineered to be soluble can promote LAD-2-mediated axon guidance. This study thus reveals a potential additional mechanism for ephrins in regulating axon guidance and expands the repertoire of receptors by which ephrins can signal.
Collapse
Affiliation(s)
- Bingyun Dong
- Department of Genetics, Cell Biology & Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Melinda Moseley-Alldredge
- Department of Genetics, Cell Biology & Development, University of Minnesota, Minneapolis, MN 55455, USA Developmental Biology Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Alicia A Schwieterman
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA 30144, USA
| | - Cory J Donelson
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA 30144, USA
| | - Jonathan L McMurry
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA 30144, USA
| | - Martin L Hudson
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA 30144, USA
| | - Lihsia Chen
- Department of Genetics, Cell Biology & Development, University of Minnesota, Minneapolis, MN 55455, USA Developmental Biology Center, University of Minnesota, Minneapolis, MN 55455, USA
| |
Collapse
|
12
|
The Caenorhabditis elegans Ephrin EFN-4 Functions Non-cell Autonomously with Heparan Sulfate Proteoglycans to Promote Axon Outgrowth and Branching. Genetics 2015; 202:639-60. [PMID: 26645816 DOI: 10.1534/genetics.115.185298] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 12/02/2015] [Indexed: 01/21/2023] Open
Abstract
The Eph receptors and their cognate ephrin ligands play key roles in many aspects of nervous system development. These interactions typically occur within an individual tissue type, serving either to guide axons to their terminal targets or to define boundaries between the rhombomeres of the hindbrain. We have identified a novel role for the Caenorhabditis elegans ephrin EFN-4 in promoting primary neurite outgrowth in AIY interneurons and D-class motor neurons. Rescue experiments reveal that EFN-4 functions non-cell autonomously in the epidermis to promote primary neurite outgrowth. We also find that EFN-4 plays a role in promoting ectopic axon branching in a C. elegans model of X-linked Kallmann syndrome. In this context, EFN-4 functions non-cell autonomously in the body-wall muscle and in parallel with HS modification genes and HSPG core proteins. This is the first report of an epidermal ephrin providing a developmental cue to the nervous system.
Collapse
|
13
|
Abstract
Neuronal wiring during development requires that the growth cones of axons and dendrites are correctly guided to their appropriate targets. As in other animals, axon growth cones in Caenorhabditis elegans integrate information in their extracellular environment via interactions among transiently expressed cell surface receptors, their ligands, and the extracellular matrix (ECM). Components of the ECM undergo a wide variety of post-translational modifications that may affect efficacy of binding to neuronal guidance molecules. The most common modification of the ECM is prolyl 4-hydroxylation. However, little is known of its importance in the control of axon guidance. In a screen of prolyl 4-hydroxylase (P4H) mutants, we found that genetic removal of a specific P4H subunit, DPY-18, causes dramatic defects in C. elegans neuroanatomy. In dpy-18 mutant animals, the axons of specific ventral nerve cord neurons do not respect the ventral midline boundary and cross over to the contralateral axon fascicle. We found that these defects are independent of the known role of dpy-18 in regulating body size and that dpy-18 acts from multiple tissues to regulate axon guidance. Finally, we found that the neuronal defects in dpy-18 mutant animals are dependent on the expression of muscle-derived basement membrane collagens and motor neuron-derived ephrin ligands. Loss of dpy-18 causes dysregulated ephrin expression and this is at least partially responsible for the neurodevelopmental defects observed. Together, our data suggest that DPY-18 regulates ephrin expression to direct axon guidance, a role for P4Hs that may be conserved in higher organisms.
Collapse
|