1
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Kursel LE, Martinez JEA, Rog O. A suppressor screen in C. elegans identifies a multiprotein interaction that stabilizes the synaptonemal complex. Proc Natl Acad Sci U S A 2023; 120:e2314335120. [PMID: 38055743 PMCID: PMC10723054 DOI: 10.1073/pnas.2314335120] [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: 08/19/2023] [Accepted: 10/23/2023] [Indexed: 12/08/2023] Open
Abstract
Successful chromosome segregation into gametes depends on tightly regulated interactions between the parental chromosomes. During meiosis, chromosomes are aligned end-to-end by an interface called the synaptonemal complex, which also regulates exchanges between them. However, despite the functional and ultrastructural conservation of this essential interface, how protein-protein interactions within the synaptonemal complex regulate chromosomal interactions remains poorly understood. Here, we describe a genetic interaction in the C. elegans synaptonemal complex, comprised of short segments of three proteins, SYP-1, SYP-3, and SYP-4. We identified the interaction through a saturated suppressor screen of a mutant that destabilizes the synaptonemal complex. The specificity and tight distribution of suppressors suggest a charge-based interface that promotes interactions between synaptonemal complex subunits and, in turn, allows intimate interactions between chromosomes. Our work highlights the power of genetic studies to illuminate the mechanisms that underlie meiotic chromosome interactions.
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Affiliation(s)
- Lisa E. Kursel
- School of Biological Sciences and Center for Cell and Genome Sciences, The University of Utah, Salt Lake City, UT84112
| | - Jesus E. Aguayo Martinez
- School of Biological Sciences and Center for Cell and Genome Sciences, The University of Utah, Salt Lake City, UT84112
| | - Ofer Rog
- School of Biological Sciences and Center for Cell and Genome Sciences, The University of Utah, Salt Lake City, UT84112
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2
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Liu J, Murray JI. Mechanisms of lineage specification in Caenorhabditis elegans. Genetics 2023; 225:iyad174. [PMID: 37847877 DOI: 10.1093/genetics/iyad174] [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: 08/26/2023] [Accepted: 09/18/2023] [Indexed: 10/19/2023] Open
Abstract
The studies of cell fate and lineage specification are fundamental to our understanding of the development of multicellular organisms. Caenorhabditis elegans has been one of the premiere systems for studying cell fate specification mechanisms at single cell resolution, due to its transparent nature, the invariant cell lineage, and fixed number of somatic cells. We discuss the general themes and regulatory mechanisms that have emerged from these studies, with a focus on somatic lineages and cell fates. We next review the key factors and pathways that regulate the specification of discrete cells and lineages during embryogenesis and postembryonic development; we focus on transcription factors and include numerous lineage diagrams that depict the expression of key factors that specify embryonic founder cells and postembryonic blast cells, and the diverse somatic cell fates they generate. We end by discussing some future perspectives in cell and lineage specification.
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Affiliation(s)
- Jun Liu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - John Isaac Murray
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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3
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Kursel LE, Martinez JEA, Rog O. A suppressor screen in C. elegans identifies a multi-protein interaction interface that stabilizes the synaptonemal complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.21.554166. [PMID: 37662357 PMCID: PMC10473659 DOI: 10.1101/2023.08.21.554166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Successful chromosome segregation into gametes depends on tightly-regulated interactions between the parental chromosomes. During meiosis, chromosomes are aligned end-to-end by an interface called the synaptonemal complex, which also regulates exchanges between them. However, despite the functional and ultrastructural conservation of this essential interface, how protein-protein interactions within the synaptonemal complex regulate chromosomal interactions remains poorly understood. Here we describe a novel interaction interface in the C. elegans synaptonemal complex, comprised of short segments of three proteins, SYP-1, SYP-3 and SYP-4. We identified the interface through a saturated suppressor screen of a mutant that destabilizes the synaptonemal complex. The specificity and tight distribution of suppressors point to a charge-based interface that promotes interactions between synaptonemal complex subunits and, in turn, allows intimate interactions between chromosomes. Our work highlights the power of genetic studies to illuminate the mechanisms that underly meiotic chromosome interactions.
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Affiliation(s)
- Lisa E. Kursel
- School of Biological Sciences and Center for Cell and Genome Sciences, University of Utah, United States
| | - Jesus E. Aguayo Martinez
- School of Biological Sciences and Center for Cell and Genome Sciences, University of Utah, United States
| | - Ofer Rog
- School of Biological Sciences and Center for Cell and Genome Sciences, University of Utah, United States
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4
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Schmidt-Ott U, Yoon Y. Evolution and loss of ß-catenin and TCF-dependent axis specification in insects. CURRENT OPINION IN INSECT SCIENCE 2022; 50:100877. [PMID: 35104659 PMCID: PMC9133022 DOI: 10.1016/j.cois.2022.100877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 01/06/2022] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Mechanisms and evolution of primary axis specification in insects are discussed in the context of the roles of ß-catenin and TCF in polarizing metazoan embryos. Three hypotheses are presented. First, insects with sequential segmentation and posterior growth use cell-autonomous mechanisms for establishing embryo polarity via the nuclear ratio of ß-catenin and TCF. Second, TCF homologs establish competence for anterior specification. Third, the evolution of simultaneous segmentation mechanisms, also known as long-germ development, resulted in primary axis specification mechanisms that are independent of ß-catenin but reliant on TCF, a condition that preceded the frequent replacement of anterior determinants in long germ insects.
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Affiliation(s)
- Urs Schmidt-Ott
- University of Chicago, Dept. of Organismal Biology and Anatomy, 1027 East 57th Street, Chicago, IL 60637, USA.
| | - Yoseop Yoon
- University of California, Irvine, Dept. of Microbiology and Molecular Genetics, School of Medicine, 811 Health Sciences Rd., Med Sci B262, CA 92617, USA
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5
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McClay DR, Croce JC, Warner JF. Reprint of: Conditional specification of endomesoderm. Cells Dev 2021; 168:203731. [PMID: 34610899 DOI: 10.1016/j.cdev.2021.203731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/18/2021] [Accepted: 06/23/2021] [Indexed: 10/20/2022]
Abstract
Early in animal development many cells are conditionally specified based on observations that those cells can be directed toward alternate fates. The endomesoderm is so named because early specification produces cells that often have been observed to simultaneously express both early endoderm and mesoderm transcription factors. Experiments with these cells demonstrate that their progeny can directed entirely toward endoderm or mesoderm, whereas normally they establish both germ layers. This review examines the mechanisms that initiate the conditional endomesoderm state, its metastability, and the mechanisms that resolve that state into definitive endoderm and mesoderm.
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Affiliation(s)
- David R McClay
- Department of Biology, Duke University, Durham, NC, USA.
| | - Jenifer C Croce
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Institut de la Mer de Villefranche, Villefranche-sur-Mer, France.
| | - Jacob F Warner
- Department of Biology, University of North Carolina, Wilmington, NC, USA.
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6
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McClay DR, Croce JC, Warner JF. Conditional specification of endomesoderm. Cells Dev 2021; 167:203716. [PMID: 34245941 DOI: 10.1016/j.cdev.2021.203716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/18/2021] [Accepted: 06/23/2021] [Indexed: 10/20/2022]
Abstract
Early in animal development many cells are conditionally specified based on observations that those cells can be directed toward alternate fates. The endomesoderm is so named because early specification produces cells that often have been observed to simultaneously express both early endoderm and mesoderm transcription factors. Experiments with these cells demonstrate that their progeny can directed entirely toward endoderm or mesoderm, whereas normally they establish both germ layers. This review examines the mechanisms that initiate the conditional endomesoderm state, its metastability, and the mechanisms that resolve that state into definitive endoderm and mesoderm.
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Affiliation(s)
- David R McClay
- Department of Biology, Duke University, Durham, NC, USA.
| | - Jenifer C Croce
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Institut de la Mer de Villefranche, Villefranche-sur-Mer, France.
| | - Jacob F Warner
- Department of Biology, University of North Carolina, Wilmington, NC, USA.
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7
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Chevignon G, Foray V, Pérez-Jiménez MM, Libro S, Chung M, Foster JM, Landmann F. Dual RNAseq analyses at soma and germline levels reveal evolutionary innovations in the elephantiasis-agent Brugia malayi, and adaptation of its Wolbachia endosymbionts. PLoS Negl Trop Dis 2021; 15:e0008935. [PMID: 33406151 PMCID: PMC7787461 DOI: 10.1371/journal.pntd.0008935] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 10/31/2020] [Indexed: 12/23/2022] Open
Abstract
Brugia malayi is a human filarial nematode responsible for elephantiasis, a debilitating condition that is part of a broader spectrum of diseases called filariasis, including lymphatic filariasis and river blindness. Almost all filarial nematode species infecting humans live in mutualism with Wolbachia endosymbionts, present in somatic hypodermal tissues but also in the female germline which ensures their vertical transmission to the nematode progeny. These α-proteobacteria potentially provision their host with essential metabolites and protect the parasite against the vertebrate immune response. In the absence of Wolbachia wBm, B. malayi females become sterile, and the filarial nematode lifespan is greatly reduced. In order to better comprehend this symbiosis, we investigated the adaptation of wBm to the host nematode soma and germline, and we characterized these cellular environments to highlight their specificities. Dual RNAseq experiments were performed at the tissue-specific and ovarian developmental stage levels, reaching the resolution of the germline mitotic proliferation and meiotic differentiation stages. We found that most wBm genes, including putative effectors, are not differentially regulated between infected tissues. However, two wBm genes involved in stress responses are upregulated in the hypodermal chords compared to the germline, indicating that this somatic tissue represents a harsh environment to which wBm have adapted. A comparison of the B. malayi and C. elegans germline transcriptomes reveals a poor conservation of genes involved in the production of oocytes, with the filarial germline proliferative zone relying on a majority of genes absent from C. elegans. The first orthology map of the B. malayi genome presented here, together with tissue-specific expression enrichment analyses, indicate that the early steps of oogenesis are a developmental process involving genes specific to filarial nematodes, that likely result from evolutionary innovations supporting the filarial parasitic lifestyle.
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Affiliation(s)
- Germain Chevignon
- CRBM, University of Montpellier, CNRS, Montpellier, France
- Laboratoire de Génétique et Pathologie des Mollusques Marins, Ifremer, La Tremblade, France
| | - Vincent Foray
- CRBM, University of Montpellier, CNRS, Montpellier, France
- Institut de Recherche sur la Biologie de l’Insecte, UMR 7261, CNRS, Université de Tours, Tours, France
| | - Mercedes Maria Pérez-Jiménez
- CRBM, University of Montpellier, CNRS, Montpellier, France
- Centro Andaluz de Biología del Desarrollo (CABD)–Universidad Pablo de Olavide (UPO), Departamento de Biología Molecular e Ingeniería Bioquímica, UPO/CSIC/JA, Sevilla, Spain
| | - Silvia Libro
- Division of Protein Expression & Modification, New England Biolabs, Ipswich, Massachusetts, United States of America
| | - Matthew Chung
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Jeremy M. Foster
- Division of Protein Expression & Modification, New England Biolabs, Ipswich, Massachusetts, United States of America
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8
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Godard BG, Dumollard R, Munro E, Chenevert J, Hebras C, McDougall A, Heisenberg CP. Apical Relaxation during Mitotic Rounding Promotes Tension-Oriented Cell Division. Dev Cell 2020; 55:695-706.e4. [PMID: 33207225 DOI: 10.1016/j.devcel.2020.10.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 09/09/2020] [Accepted: 10/23/2020] [Indexed: 12/16/2022]
Abstract
Global tissue tension anisotropy has been shown to trigger stereotypical cell division orientation by elongating mitotic cells along the main tension axis. Yet, how tissue tension elongates mitotic cells despite those cells undergoing mitotic rounding (MR) by globally upregulating cortical actomyosin tension remains unclear. We addressed this question by taking advantage of ascidian embryos, consisting of a small number of interphasic and mitotic blastomeres and displaying an invariant division pattern. We found that blastomeres undergo MR by locally relaxing cortical tension at their apex, thereby allowing extrinsic pulling forces from neighboring interphasic blastomeres to polarize their shape and thus division orientation. Consistently, interfering with extrinsic forces by reducing the contractility of interphasic blastomeres or disrupting the establishment of asynchronous mitotic domains leads to aberrant mitotic cell division orientations. Thus, apical relaxation during MR constitutes a key mechanism by which tissue tension anisotropy controls stereotypical cell division orientation.
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Affiliation(s)
- Benoit G Godard
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France; Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Rémi Dumollard
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Edwin Munro
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Janet Chenevert
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Céline Hebras
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
| | - Alex McDougall
- Laboratoire de Biologie du Développement de Villefranche-sur-mer, Institut de la Mer de Villefranche-sur-mer, Sorbonne Université, CNRS, 06230 Villefranche-sur-mer, France
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9
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Vonica A, Bhat N, Phan K, Guo J, Iancu L, Weber JA, Karger A, Cain JW, Wang ECE, DeStefano GM, O'Donnell-Luria AH, Christiano AM, Riley B, Butler SJ, Luria V. Apcdd1 is a dual BMP/Wnt inhibitor in the developing nervous system and skin. Dev Biol 2020; 464:71-87. [PMID: 32320685 PMCID: PMC7307705 DOI: 10.1016/j.ydbio.2020.03.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 03/20/2020] [Accepted: 03/20/2020] [Indexed: 02/02/2023]
Abstract
Animal development and homeostasis depend on precise temporal and spatial intercellular signaling. Components shared between signaling pathways, generally thought to decrease specificity, paradoxically can also provide a solution to pathway coordination. Here we show that the Bone Morphogenetic Protein (BMP) and Wnt signaling pathways share Apcdd1 as a common inhibitor and that Apcdd1 is a taxon-restricted gene with novel domains and signaling functions. Previously, we showed that Apcdd1 inhibits Wnt signaling (Shimomura et al., 2010), here we find that Apcdd1 potently inhibits BMP signaling in body axis formation and neural differentiation in chicken, frog, zebrafish. Furthermore, we find that Apcdd1 has an evolutionarily novel protein domain. Our results from experiments and modeling suggest that Apcdd1 may coordinate the outputs of two signaling pathways that are central to animal development and human disease.
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Affiliation(s)
- Alin Vonica
- Departments of Genetics and Development, and Dermatology, Columbia University Medical Center, New York, NY, 10032, USA; Department of Biology, The Nazareth College, Rochester, NY, 14618, USA
| | - Neha Bhat
- Department of Biology, Texas A&M University, College Station, TX, 7783-3258, USA; Yale Cardiovascular Research Center, Yale School of Medicine, New Haven, CT, 06511, USA
| | - Keith Phan
- Department of Neurobiology, University of California, Los Angeles, CA, 90095-7239, USA
| | - Jinbai Guo
- Department of Biology, Texas A&M University, College Station, TX, 7783-3258, USA
| | - Lăcrimioara Iancu
- Institut für Algebra und Zahlentheorie, Universität Stuttgart, D-70569, Stuttgart, Germany; Institute of Mathematics, University of Aberdeen, Aberdeen, AB24 3UE, Scotland, UK
| | - Jessica A Weber
- Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Amir Karger
- IT-Research Computing, Harvard Medical School, Boston, MA, 02115, USA
| | - John W Cain
- Department of Mathematics, Harvard University, Cambridge, MA, 02138, USA
| | - Etienne C E Wang
- Departments of Genetics and Development, and Dermatology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Gina M DeStefano
- Departments of Genetics and Development, and Dermatology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Anne H O'Donnell-Luria
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA; Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Angela M Christiano
- Departments of Genetics and Development, and Dermatology, Columbia University Medical Center, New York, NY, 10032, USA.
| | - Bruce Riley
- Department of Biology, Texas A&M University, College Station, TX, 7783-3258, USA.
| | - Samantha J Butler
- Department of Neurobiology, University of California, Los Angeles, CA, 90095-7239, USA.
| | - Victor Luria
- Departments of Genetics and Development, and Dermatology, Columbia University Medical Center, New York, NY, 10032, USA; Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA.
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10
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Kroll JR, Tsiaxiras J, van Zon JS. Variability in β-catenin pulse dynamics in a stochastic cell fate decision in C. elegans. Dev Biol 2020; 461:110-123. [PMID: 32032579 PMCID: PMC7203549 DOI: 10.1016/j.ydbio.2020.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/31/2020] [Accepted: 02/02/2020] [Indexed: 11/30/2022]
Abstract
During development, cell fate decisions are often highly stochastic, but with the frequency of the different possible fates tightly controlled. To understand how signaling networks control the cell fate frequency of such random decisions, we studied the stochastic decision of the Caenorhabditis elegans P3.p cell to either fuse to the hypodermis or assume vulva precursor cell fate. Using time-lapse microscopy to measure the single-cell dynamics of two key inhibitors of cell fusion, the Hox gene LIN-39 and Wnt signaling through the β-catenin BAR-1, we uncovered significant variability in the dynamics of LIN-39 and BAR-1 levels. Most strikingly, we observed that BAR-1 accumulated in a single, 1–4 h pulse at the time of the P3.p cell fate decision, with strong variability both in pulse slope and time of pulse onset. We found that the time of BAR-1 pulse onset was delayed relative to the time of cell fusion in mutants with low cell fusion frequency, linking BAR-1 pulse timing to cell fate outcome. Overall, a model emerged where animal-to-animal variability in LIN-39 levels and BAR-1 pulse dynamics biases cell fate by modulating their absolute level at the time cell fusion is induced. Our results highlight that timing of cell signaling dynamics, rather than its average level or amplitude, could play an instructive role in determining cell fate. The fate of the C. elegans P3.p cell is stochastic. β-catenin (BAR-1) accumulated in P3.p at the time of the cell fate decision. There is variability in dynamics of Hox and β-catenin levels during the decision. BAR-1 accumulated with variable pulse slope and time of pulse onset. Pulse dynamics bias cell fate at the time of the cell fate decision.
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Affiliation(s)
- Jason R Kroll
- Department of Living Matter, AMOLF, 1098 XG, Amsterdam, the Netherlands
| | - Jasonas Tsiaxiras
- Department of Living Matter, AMOLF, 1098 XG, Amsterdam, the Netherlands
| | - Jeroen S van Zon
- Department of Living Matter, AMOLF, 1098 XG, Amsterdam, the Netherlands.
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11
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Axin Family of Scaffolding Proteins in Development: Lessons from C. elegans. J Dev Biol 2019; 7:jdb7040020. [PMID: 31618970 PMCID: PMC6956378 DOI: 10.3390/jdb7040020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/07/2019] [Accepted: 10/11/2019] [Indexed: 12/21/2022] Open
Abstract
Scaffold proteins serve important roles in cellular signaling by integrating inputs from multiple signaling molecules to regulate downstream effectors that, in turn, carry out specific biological functions. One such protein, Axin, represents a major evolutionarily conserved scaffold protein in metazoans that participates in the WNT pathway and other pathways to regulate diverse cellular processes. This review summarizes the vast amount of literature on the regulation and functions of the Axin family of genes in eukaryotes, with a specific focus on Caenorhabditis elegans development. By combining early studies with recent findings, the review is aimed to serve as an updated reference for the roles of Axin in C. elegans and other model systems.
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12
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Developmental Control of the Cell Cycle: Insights from Caenorhabditis elegans. Genetics 2019; 211:797-829. [PMID: 30846544 PMCID: PMC6404260 DOI: 10.1534/genetics.118.301643] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Accepted: 10/10/2018] [Indexed: 12/11/2022] Open
Abstract
During animal development, a single fertilized egg forms a complete organism with tens to trillions of cells that encompass a large variety of cell types. Cell cycle regulation is therefore at the center of development and needs to be carried out in close coordination with cell differentiation, migration, and death, as well as tissue formation, morphogenesis, and homeostasis. The timing and frequency of cell divisions are controlled by complex combinations of external and cell-intrinsic signals that vary throughout development. Insight into how such controls determine in vivo cell division patterns has come from studies in various genetic model systems. The nematode Caenorhabditis elegans has only about 1000 somatic cells and approximately twice as many germ cells in the adult hermaphrodite. Despite the relatively small number of cells, C. elegans has diverse tissues, including intestine, nerves, striated and smooth muscle, and skin. C. elegans is unique as a model organism for studies of the cell cycle because the somatic cell lineage is invariant. Somatic cells divide at set times during development to produce daughter cells that adopt reproducible developmental fates. Studies in C. elegans have allowed the identification of conserved cell cycle regulators and provided insights into how cell cycle regulation varies between tissues. In this review, we focus on the regulation of the cell cycle in the context of C. elegans development, with reference to other systems, with the goal of better understanding how cell cycle regulation is linked to animal development in general.
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13
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Memar N, Schiemann S, Hennig C, Findeis D, Conradt B, Schnabel R. Twenty million years of evolution: The embryogenesis of four Caenorhabditis species are indistinguishable despite extensive genome divergence. Dev Biol 2019; 447:182-199. [DOI: 10.1016/j.ydbio.2018.12.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 12/18/2018] [Accepted: 12/20/2018] [Indexed: 12/19/2022]
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14
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Combinatorial Contact Cues Specify Cell Division Orientation by Directing Cortical Myosin Flows. Dev Cell 2018; 46:257-270.e5. [PMID: 30032990 PMCID: PMC7695482 DOI: 10.1016/j.devcel.2018.06.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 04/13/2018] [Accepted: 06/22/2018] [Indexed: 12/31/2022]
Abstract
Cell division axes during development are specified in different orientations to establish multicellular assemblies, but the mechanisms that generate division axis diversity remain unclear. We show here that patterns of cell contact provide cues that diversify cell division orientation by modulating cortical non-muscle myosin flow. We reconstituted in vivo contact patterns using beads or isolated cells to show two findings. First, we identified three contact-dependent cues that pattern cell division orientation and myosin flow: physical contact, contact asymmetry, and a Wnt signal. Second, we experimentally demonstrated that myosin flow generates forces that trigger plasma membrane movements and propose that their anisotropy drives cell division orientation. Our data suggest that contact-dependent control of myosin specifies the division axes of Caenorhabditis elegans AB, ABa, EMS cells, and the mouse AB cell. The contact pattern-dependent generation of myosin flows, in concert with known microtubule/dynein pathways, may greatly expand division axis diversity during development.
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15
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Yamamoto K, Kimura A. An asymmetric attraction model for the diversity and robustness of cell arrangement in nematodes. Development 2017; 144:4437-4449. [PMID: 29183946 PMCID: PMC5769634 DOI: 10.1242/dev.154609] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 10/24/2017] [Indexed: 12/29/2022]
Abstract
During early embryogenesis in animals, cells are arranged into a species-specific pattern in a robust manner. Diverse cell arrangement patterns are observed, even among close relatives. In the present study, we evaluated the mechanisms by which the diversity and robustness of cell arrangements are achieved in developing embryos. We successfully reproduced various patterns of cell arrangements observed in various nematode species in Caenorhabditis elegans embryos by altering the eggshell shapes. The findings suggest that the observed diversity of cell arrangements can be explained by differences in the eggshell shape. Additionally, we found that the cell arrangement was robust against eggshell deformation. Computational modeling revealed that, in addition to repulsive forces, attractive forces are sufficient to achieve such robustness. The present model is also capable of simulating the effect of changing cell division orientation. Genetic perturbation experiments demonstrated that attractive forces derived from cell adhesion are necessary for the robustness. The proposed model accounts for both diversity and robustness of cell arrangements, and contributes to our understanding of how the diversity and robustness of cell arrangements are achieved in developing embryos. Summary: The cell arrangement pattern at the four-cell stage in nematode embryos is both diverse and robust. A numerical model that incorporates attractive, as well as repulsive, forces was constructed to explain this diversity and robustness.
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Affiliation(s)
- Kazunori Yamamoto
- Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima 411-8540, Japan.,Cell Architecture Laboratory, Structural Biology Center, National Institute of Genetics, Mishima 411-8540, Japan
| | - Akatsuki Kimura
- Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima 411-8540, Japan .,Cell Architecture Laboratory, Structural Biology Center, National Institute of Genetics, Mishima 411-8540, Japan
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16
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Robertson SM, Medina J, Oldenbroek M, Lin R. Reciprocal signaling by Wnt and Notch specifies a muscle precursor in the C. elegans embryo. Development 2017; 144:419-429. [PMID: 28049659 DOI: 10.1242/dev.145391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 12/12/2016] [Indexed: 11/20/2022]
Abstract
The MS blastomere produces one-third of the body wall muscles (BWMs) in the C. elegans embryo. MS-derived BWMs require two distinct cell-cell interactions, the first inhibitory and the second, two cell cycles later, required to overcome this inhibition. The inductive interaction is not required if the inhibitory signal is absent. Although the Notch receptor GLP-1 was implicated in both interactions, the molecular nature of the two signals was unknown. We now show that zygotically expressed MOM-2 (Wnt) is responsible for both interactions. Both the inhibitory and the activating interactions require precise spatiotemporal expression of zygotic MOM-2, which is dependent upon two distinct Notch signals. In a Notch mutant defective only in the inductive interaction, MS-derived BWMs can be restored by preventing zygotic MOM-2 expression, which removes the inhibitory signal. Our results suggest that the inhibitory interaction ensures the differential lineage specification of MS and its sister blastomere, whereas the inductive interaction promotes the expression of muscle-specifying genes by modulating TCF and β-catenin levels. These results highlight the complexity of cell fate specification by cell-cell interactions in a rapidly dividing embryo.
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Affiliation(s)
- Scott M Robertson
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jessica Medina
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Marieke Oldenbroek
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Rueyling Lin
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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17
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Lam AK, Phillips BT. Wnt Signaling Polarizes C. elegans Asymmetric Cell Divisions During Development. Results Probl Cell Differ 2017; 61:83-114. [PMID: 28409301 PMCID: PMC6057142 DOI: 10.1007/978-3-319-53150-2_4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Asymmetric cell division is a common mode of cell differentiation during the invariant lineage of the nematode, C. elegans. Beginning at the four-cell stage, and continuing throughout embryogenesis and larval development, mother cells are polarized by Wnt ligands, causing an asymmetric inheritance of key members of a Wnt/β-catenin signal transduction pathway termed the Wnt/β-catenin asymmetry pathway. The resulting daughter cells are distinct at birth with one daughter cell activating Wnt target gene expression via β-catenin activation of TCF, while the other daughter displays transcriptional repression of these target genes. Here, we seek to review the body of evidence underlying a unified model for Wnt-driven asymmetric cell division in C. elegans, identify global themes that occur during asymmetric cell division, as well as highlight tissue-specific variations. We also discuss outstanding questions that remain unanswered regarding this intriguing mode of asymmetric cell division.
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Affiliation(s)
- Arielle Koonyee Lam
- Interdisciplinary Graduate Program in Molecular and Cellular Biology, University of Iowa, Iowa City, IA, USA
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18
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Hale R, Strutt D. Conservation of Planar Polarity Pathway Function Across the Animal Kingdom. Annu Rev Genet 2015; 49:529-51. [DOI: 10.1146/annurev-genet-112414-055224] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Rosalind Hale
- Bateson Centre,
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom;
| | - David Strutt
- Bateson Centre,
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom;
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19
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Zacharias AL, Walton T, Preston E, Murray JI. Quantitative Differences in Nuclear β-catenin and TCF Pattern Embryonic Cells in C. elegans. PLoS Genet 2015; 11:e1005585. [PMID: 26488501 PMCID: PMC4619327 DOI: 10.1371/journal.pgen.1005585] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 09/16/2015] [Indexed: 12/22/2022] Open
Abstract
The Wnt signaling pathway plays a conserved role during animal development in transcriptional regulation of distinct targets in different developmental contexts but it remains unclear whether quantitative differences in the nuclear localization of effector proteins TCF and β-catenin contribute to context-specific regulation. We investigated this question in Caenorhabditis elegans embryos by quantifying nuclear localization of fluorescently tagged SYS-1/β-catenin and POP-1/TCF and expression of Wnt ligands at cellular resolution by time-lapse microscopy and automated lineage tracing. We identified reproducible, quantitative differences that generate a subset of Wnt-signaled cells with a significantly higher nuclear concentration of the TCF/β-catenin activating complex. Specifically, β-catenin and TCF are preferentially enriched in nuclei of daughter cells whose parents also had high nuclear levels of that protein, a pattern that could influence developmental gene expression. Consistent with this, we found that expression of synthetic reporters of POP-1-dependent activation is biased towards cells that had high nuclear SYS-1 in consecutive divisions. We identified new genes whose embryonic expression patterns depend on pop-1. Most of these require POP-1 for either transcriptional activation or repression, and targets requiring POP-1 for activation are more likely to be expressed in the cells with high nuclear SYS-1 in consecutive divisions than those requiring POP-1 for repression. Taken together, these results indicate that SYS-1 and POP-1 levels are influenced by the parent cell’s SYS-1/POP-1 levels and this may provide an additional mechanism by which POP-1 regulates distinct targets in different developmental contexts. The Wnt signaling pathway is active during the development of all multi-cellular animals and also improperly re-activated in many cancers. Here, we use time-lapse microscopy to quantify the nuclear localization of several proteins in response to Wnt signaling throughout early embryonic development in the nematode worm, C. elegans. We find that cells that received a Wnt signal in the previous division respond more strongly to a Wnt signal in the next division, in part by localizing more of the regulator β-catenin to the nucleus. This causes the relative enrichment of Wnt pathway proteins in the nuclei of repeatedly signaled cells, which we show likely impacts the activation of Wnt target genes. This represents a novel mechanism for the regulation of Wnt pathway targets in development and disease.
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Affiliation(s)
- Amanda L. Zacharias
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Travis Walton
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Elicia Preston
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - John Isaac Murray
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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20
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Dejima K, Kang S, Mitani S, Cosman PC, Chisholm AD. Syndecan defines precise spindle orientation by modulating Wnt signaling in C. elegans. Development 2014; 141:4354-65. [PMID: 25344071 DOI: 10.1242/dev.113266] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Wnt signals orient mitotic spindles in development, but it remains unclear how Wnt signaling is spatially controlled to achieve precise spindle orientation. Here, we show that C. elegans syndecan (SDN-1) is required for precise orientation of a mitotic spindle in response to a Wnt cue. We find that SDN-1 is the predominant heparan sulfate (HS) proteoglycan in the early C. elegans embryo, and that loss of HS biosynthesis or of the SDN-1 core protein results in misorientation of the spindle of the ABar blastomere. The ABar and EMS spindles both reorient in response to Wnt signals, but only ABar spindle reorientation is dependent on a new cell contact and on HS and SDN-1. SDN-1 transiently accumulates on the ABar surface as it contacts C, and is required for local concentration of Dishevelled (MIG-5) in the ABar cortex adjacent to C. These findings establish a new role for syndecan in Wnt-dependent spindle orientation.
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Affiliation(s)
- Katsufumi Dejima
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA Department of Physiology, Tokyo Women's Medical University, School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Sukryool Kang
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92037-0407, USA
| | - Shohei Mitani
- Department of Physiology, Tokyo Women's Medical University, School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Pamela C Cosman
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92037-0407, USA
| | - Andrew D Chisholm
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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21
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Oldenbroek M, Robertson SM, Guven-Ozkan T, Spike C, Greenstein D, Lin R. Regulation of maternal Wnt mRNA translation in C. elegans embryos. Development 2013; 140:4614-23. [PMID: 24131629 DOI: 10.1242/dev.096313] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The restricted spatiotemporal translation of maternal mRNAs, which is crucial for correct cell fate specification in early C. elegans embryos, is regulated primarily through the 3'UTR. Although genetic screens have identified many maternally expressed cell fate-controlling RNA-binding proteins (RBPs), their in vivo targets and the mechanism(s) by which they regulate these targets are less clear. These RBPs are translated in oocytes and localize to one or a few blastomeres in a spatially and temporally dynamic fashion unique for each protein and each blastomere. Here, we characterize the translational regulation of maternally supplied mom-2 mRNA, which encodes a Wnt ligand essential for two separate cell-cell interactions in early embryos. A GFP reporter that includes only the mom-2 3'UTR is translationally repressed properly in oocytes and early embryos, and then correctly translated only in the known Wnt signaling cells. We show that the spatiotemporal translation pattern of this reporter is regulated combinatorially by a set of nine maternally supplied RBPs. These nine proteins all directly bind the mom-2 3'UTR in vitro and function as positive or negative regulators of mom-2 translation in vivo. The net translational readout for the mom-2 3'UTR reporter is determined by competitive binding between positive- and negative-acting RBPs for the 3'UTR, along with the distinct spatiotemporal localization patterns of these regulators. We propose that the 3'UTR of maternal mRNAs contains a combinatorial code that determines the topography of associated RBPs, integrating positive and negative translational inputs.
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Affiliation(s)
- Marieke Oldenbroek
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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22
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Rasmussen JP, Feldman JL, Reddy SS, Priess JR. Cell interactions and patterned intercalations shape and link epithelial tubes in C. elegans. PLoS Genet 2013; 9:e1003772. [PMID: 24039608 PMCID: PMC3764189 DOI: 10.1371/journal.pgen.1003772] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 07/19/2013] [Indexed: 01/15/2023] Open
Abstract
Many animal organs are composed largely or entirely of polarized epithelial tubes, and the formation of complex organ systems, such as the digestive or vascular systems, requires that separate tubes link with a common polarity. The Caenorhabditis elegans digestive tract consists primarily of three interconnected tubes—the pharynx, valve, and intestine—and provides a simple model for understanding the cellular and molecular mechanisms used to form and connect epithelial tubes. Here, we use live imaging and 3D reconstructions of developing cells to examine tube formation. The three tubes develop from a pharynx/valve primordium and a separate intestine primordium. Cells in the pharynx/valve primordium polarize and become wedge-shaped, transforming the primordium into a cylindrical cyst centered on the future lumenal axis. For continuity of the digestive tract, valve cells must have the same, radial axis of apicobasal polarity as adjacent intestinal cells. We show that intestinal cells contribute to valve cell polarity by restricting the distribution of a polarizing cue, laminin. After developing apicobasal polarity, many pharyngeal and valve cells appear to explore their neighborhoods through lateral, actin-rich lamellipodia. For a subset of cells, these lamellipodia precede more extensive intercalations that create the valve. Formation of the valve tube begins when two valve cells become embedded at the left-right boundary of the intestinal primordium. Other valve cells organize symmetrically around these two cells, and wrap partially or completely around the orthogonal, lumenal axis, thus extruding a small valve tube from the larger cyst. We show that the transcription factors DIE-1 and EGL-43/EVI1 regulate cell intercalations and cell fates during valve formation, and that the Notch pathway is required to establish the proper boundary between the pharyngeal and valve tubes. Tubes composed of epithelial cells are universal building blocks of animal organs, and complex organs typically contain multiple interconnected tubes, such as in the digestive tract or vascular system. The nematode Caenorhabditis elegans provides a simple genetic system to study how tubes form and link. Understanding these events provides insight into basic biology, and can inform engineering strategies for building or repairing cellular tubes. A small tube called the valve connects the two major tubular organs of the nematode digestive tract, the pharynx and intestine. The pharynx and valve form from the same primordium, while the intestine forms from a separate primordium. Cells in each primordium polarize around a central axis, and valve formation involves connecting these axes. Using live imaging, we show that valve cells initially resemble other pharyngeal cells, but undergo additional and extensive intercalations around the lumenal axis, effectively squeezing a small tube from the larger primordium. Valve cells develop the same polarity axis as intestinal cells, and we show that this depends on interactions with the intestinal cells. We show that valve formation involves dynamic changes in the localization of adhesive proteins, and identify transcription factors that play a role in valve cell specification and intercalation.
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Affiliation(s)
- Jeffrey P. Rasmussen
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
- Molecular and Cellular Biology Program, University of Washington, Seattle, Washington, United States of America
| | - Jessica L. Feldman
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Sowmya Somashekar Reddy
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - James R. Priess
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
- Department of Biology, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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23
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Gómez-Orte E, Sáenz-Narciso B, Moreno S, Cabello J. Multiple functions of the noncanonical Wnt pathway. Trends Genet 2013; 29:545-53. [PMID: 23846023 DOI: 10.1016/j.tig.2013.06.003] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 05/29/2013] [Accepted: 06/07/2013] [Indexed: 01/11/2023]
Abstract
Thirty years after the identification of WNTs, understanding of their signal transduction pathways continues to expand. Here, we review recent advances in characterizing the Wnt-dependent signaling pathways in Caenorhabditis elegans linking polar signals to rearrangements of the cytoskeleton in different developmental processes, such as proper mitotic spindle orientation, cell migration, and engulfment of apoptotic corpses. In addition to the well-described transcriptional outputs of the canonical and noncanonical Wnt pathways, new branches regulating nontranscriptional outputs that control RAC (Ras related GTPase) activity are also discussed. These findings suggest that Wnt signaling is a master regulator not only of development, but also of cell polarization.
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Affiliation(s)
- Eva Gómez-Orte
- Center for Biomedical Research of La Rioja (CIBIR), C/Piqueras 98, 26006 Logroño, Spain
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24
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McGhee JD. TheCaenorhabditis elegansintestine. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2012; 2:347-67. [DOI: 10.1002/wdev.93] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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25
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Jackson BM, Eisenmann DM. β-catenin-dependent Wnt signaling in C. elegans: teaching an old dog a new trick. Cold Spring Harb Perspect Biol 2012; 4:a007948. [PMID: 22745286 PMCID: PMC3405868 DOI: 10.1101/cshperspect.a007948] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Wnt signaling is an evolutionarily ancient pathway used to regulate many events during metazoan development. Genetic results from Caenorhabditis elegans more than a dozen years ago suggested that Wnt signaling in this nematode worm might be different than in vertebrates and Drosophila: the worm had a small number of Wnts, too many β-catenins, and some Wnt pathway components functioned in an opposite manner than in other species. Work over the ensuing years has clarified that C. elegans does possess a canonical Wnt/β-catenin signaling pathway similar to that in other metazoans, but that the majority of Wnt signaling in this species may proceed via a variant Wnt/β-catenin signaling pathway that uses some new components (mitogen-activated protein kinase signaling enzymes), and in which some conserved pathway components (β-catenin, T-cell factor [TCF]) are used in new and interesting ways. This review summarizes our current understanding of the canonical and novel TCF/β-catenin-dependent signaling pathways in C. elegans.
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Affiliation(s)
- Belinda M Jackson
- Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA
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26
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Murray JI, Boyle TJ, Preston E, Vafeados D, Mericle B, Weisdepp P, Zhao Z, Bao Z, Boeck M, Waterston RH. Multidimensional regulation of gene expression in the C. elegans embryo. Genome Res 2012; 22:1282-94. [PMID: 22508763 PMCID: PMC3396369 DOI: 10.1101/gr.131920.111] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
How cells adopt different expression patterns is a fundamental question of developmental biology. We quantitatively measured reporter expression of 127 genes, primarily transcription factors, in every cell and with high temporal resolution in C. elegans embryos. Embryonic cells are highly distinct in their gene expression; expression of the 127 genes studied here can distinguish nearly all pairs of cells, even between cells of the same tissue type. We observed recurrent lineage-regulated expression patterns for many genes in diverse contexts. These patterns are regulated in part by the TCF-LEF transcription factor POP-1. Other genes' reporters exhibited patterns correlated with tissue, position, and left–right asymmetry. Sequential patterns both within tissues and series of sublineages suggest regulatory pathways. Expression patterns often differ between embryonic and larval stages for the same genes, emphasizing the importance of profiling expression in different stages. This work greatly expands the number of genes in each of these categories and provides the first large-scale, digitally based, cellular resolution compendium of gene expression dynamics in live animals. The resulting data sets will be a useful resource for future research.
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Affiliation(s)
- John Isaac Murray
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, USA
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27
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28
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Langenhan T, Russ AP. Latrophilin signalling in tissue polarity and morphogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 706:37-48. [PMID: 21618824 DOI: 10.1007/978-1-4419-7913-1_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Understanding the mechanisms that coordinate the polarity of cells and tissues during embryogenesis and morphogenesis is a fundamental problem in developmental biology. We have recently demonstrated that the putative neurotoxin receptor lat-1 defines a mechanism required for the alignment of cell division planes in the early embryo of the nematode C. elegans. Our analysis suggests that lat-1 is required for the propagation rather than the initial establishment of polarity signals. Similar to the role of the flamingo/CELSR protein family in the control of planar cell polarity, these results implicate an evolutionary conserved subfamily of adhesion-GPCRs in the control of tissue polarity and morphogenesis.
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Affiliation(s)
- Tobias Langenhan
- Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany.
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29
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Munro E, Bowerman B. Cellular symmetry breaking during Caenorhabditis elegans development. Cold Spring Harb Perspect Biol 2010; 1:a003400. [PMID: 20066102 DOI: 10.1101/cshperspect.a003400] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The nematode worm Caenorhabditis elegans has produced a wellspring of insights into mechanisms that govern cellular symmetry breaking during animal development. Here we focus on two highly conserved systems that underlie many of the key symmetry-breaking events that occur during embryonic and larval development in the worm. One involves the interplay between Par proteins, Rho GTPases, and the actomyosin cytoskeleton and mediates asymmetric cell divisions that establish the germline. The other uses elements of the Wnt signaling pathway and a highly reiterative mechanism that distinguishes anterior from posterior daughter cell fates. Much of what we know about these systems comes from intensive study of a few key events-Par/Rho/actomyosin-mediated polarization of the zygote in response to a sperm-derived cue and the Wnt-mediated induction of endoderm at the four-cell stage. However, a growing body of work is revealing how C. elegans exploits elements/variants of these systems to accomplish a diversity of symmetry-breaking tasks throughout embryonic and larval development.
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Affiliation(s)
- Edwin Munro
- Center for Cell Dynamics, Friday Harbor Labs, 620 University Rd, Friday Harbor WA 98250, USA.
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30
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Henry JQ, Perry KJ, Martindale MQ. -catenin and Early Development in the Gastropod, Crepidula fornicata. Integr Comp Biol 2010; 50:707-19. [DOI: 10.1093/icb/icq076] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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31
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Langenhan T, Prömel S, Mestek L, Esmaeili B, Waller-Evans H, Hennig C, Kohara Y, Avery L, Vakonakis I, Schnabel R, Russ AP. Latrophilin signaling links anterior-posterior tissue polarity and oriented cell divisions in the C. elegans embryo. Dev Cell 2009; 17:494-504. [PMID: 19853563 PMCID: PMC2819344 DOI: 10.1016/j.devcel.2009.08.008] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 07/16/2009] [Accepted: 08/24/2009] [Indexed: 11/27/2022]
Abstract
Understanding the mechanisms that coordinate the orientation of cell division planes during embryogenesis and morphogenesis is a fundamental problem in developmental biology. Here we show that the orphan receptor lat-1, a homolog of vertebrate latrophilins, plays an essential role in the establishment of tissue polarity in the C. elegans embryo. We provide evidence that lat-1 is required for the alignment of cell division planes to the anterior-posterior axis and acts in parallel to known polarity and morphogenesis signals. lat-1 is a member of the Adhesion-GPCR protein family and is structurally related to flamingo/CELSR, an essential component of the planar cell polarity pathway. We dissect the molecular requirements of lat-1 signaling and implicate lat-1 in an anterior-posterior tissue polarity pathway in the premorphogenesis stage of C. elegans development.
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Affiliation(s)
- Tobias Langenhan
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Simone Prömel
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Lamia Mestek
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Behrooz Esmaeili
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | | | - Christian Hennig
- Institut für Genetik, TU Braunschweig, 38106 Braunschweig, Germany
| | - Yuji Kohara
- Genome Biology Laboratory, National Institute of Genetics, Mishima 411-8560, Japan
| | - Leon Avery
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Ioannis Vakonakis
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Ralf Schnabel
- Institut für Genetik, TU Braunschweig, 38106 Braunschweig, Germany
| | - Andreas P. Russ
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
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32
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Phillips BT, Kimble J. A new look at TCF and beta-catenin through the lens of a divergent C. elegans Wnt pathway. Dev Cell 2009; 17:27-34. [PMID: 19619489 DOI: 10.1016/j.devcel.2009.07.002] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The canonical Wnt/beta-catenin pathway is extensively characterized, broadly conserved, and clinically important. In this review, we describe the C. elegans Wnt/beta-catenin asymmetry pathway and suggest that some of its unusual features may have important implications for the canonical Wnt/beta-catenin pathway.
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Affiliation(s)
- Bryan T Phillips
- Department of Biochemistry and Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, WI 53706-1544, USA.
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33
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Bertrand V, Hobert O. Linking asymmetric cell division to the terminal differentiation program of postmitotic neurons in C. elegans. Dev Cell 2009; 16:563-75. [PMID: 19386265 DOI: 10.1016/j.devcel.2009.02.011] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 01/09/2009] [Accepted: 02/13/2009] [Indexed: 01/02/2023]
Abstract
How asymmetric divisions are connected to the terminal differentiation program of neuronal subtypes is poorly understood. In C. elegans, two homeodomain transcription factors, TTX-3 (a LHX2/9 ortholog) and CEH-10 (a CHX10 ortholog), directly activate a large battery of terminal differentiation genes in the cholinergic interneuron AIY. We establish here a transcriptional cascade linking asymmetric division to this differentiation program. A transient lineage-specific input formed by the Zic factor REF-2 and the bHLH factor HLH-2 directly activates ttx-3 expression in the AIY mother. During the terminal division of the AIY mother, an asymmetric Wnt/beta-catenin pathway cooperates with TTX-3 to directly restrict ceh-10 expression to only one of the two daughter cells. TTX-3 and CEH-10 automaintain their expression, thereby locking in the differentiation state. Our study establishes how transient lineage and asymmetric division inputs are integrated and suggests that the Wnt/beta-catenin pathway is widely used to control the identity of neuronal lineages.
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Affiliation(s)
- Vincent Bertrand
- Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University Medical Center, New York, NY 10032, USA.
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34
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The N- or C-terminal domains of DSH-2 can activate the C. elegans Wnt/beta-catenin asymmetry pathway. Dev Biol 2009; 328:234-44. [PMID: 19298786 DOI: 10.1016/j.ydbio.2009.01.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 01/12/2009] [Accepted: 01/13/2009] [Indexed: 12/25/2022]
Abstract
Dishevelleds are modular proteins that lie at the crossroads of divergent Wnt signaling pathways. The DIX domain of dishevelleds modulates a beta-catenin destruction complex, and thereby mediates cell fate decisions through differential activation of Tcf transcription factors. The DEP domain of dishevelleds mediates planar polarity of cells within a sheet through regulation of actin modulators. In Caenorhabditis elegans asymmetric cell fate decisions are regulated by asymmetric localization of signaling components in a pathway termed the Wnt/beta-catenin asymmetry pathway. Which domain(s) of Disheveled regulate this pathway is unknown. We show that C. elegans embryos from dsh-2(or302) mutant mothers fail to successfully undergo morphogenesis, but transgenes containing either the DIX or the DEP domain of DSH-2 are sufficient to rescue the mutant phenotype. Embryos lacking zygotic function of SYS-1/beta-catenin, WRM-1/beta-catenin, or POP-1/Tcf show defects similar to dsh-2 mutants, including a loss of asymmetry in some cell fate decisions. Removal of two dishevelleds (dsh-2 and mig-5) leads to a global loss of POP-1 asymmetry, which can be rescued by addition of transgenes containing either the DIX or DEP domain of DSH-2. These results indicate that either the DIX or DEP domain of DSH-2 is capable of activating the Wnt/beta-catenin asymmetry pathway and regulating anterior-posterior fate decisions required for proper morphogenesis.
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Henry JQ, Perry KJ, Wever J, Seaver E, Martindale MQ. Beta-catenin is required for the establishment of vegetal embryonic fates in the nemertean, Cerebratulus lacteus. Dev Biol 2008; 317:368-79. [PMID: 18387602 DOI: 10.1016/j.ydbio.2008.02.042] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2007] [Revised: 02/20/2008] [Accepted: 02/21/2008] [Indexed: 11/15/2022]
Abstract
Downstream components of the canonical Wnt signaling pathway that result in the nuclear localization of beta-catenin are involved in diverse developmental processes including the formation of the mesendoderm, the regulation of axial properties and asymmetric cell divisions in a wide array of metazoans. The nemertean worm, Cerebratulus lacteus, represents a member of the understudied lophotrochozoan clade that exhibits a highly stereotyped spiral cleavage program in which ectodermal, endodermal, and mesodermal origins are known from intracellular fate mapping studies. Here, the embryonic distribution of beta-catenin protein was studied using injection of synthetic mRNA, encoding GFP-tagged beta-catenin, into fertilized eggs. During the early cleavage stages beta-catenin was destabilized/degraded in animal hemisphere blastomeres and became localized to the nuclei of the four vegetal-most cells at the 64-cell stage, which give rise to definitive larval and adult endoderm. Functional assays indicate that beta-catenin plays a key role in the development of the endoderm. Morpholino knockdown of endogenous beta-catenin, as confirmed by Western analysis, resulted in the failure to gastrulate, absence of the gut and an animalized phenotype in the resulting larvae, including the formation of ectopic (anterior) apical organ tissue with elongated apical tuft cilia and no indications of dorsoventral polarity. Similarly, over-expression of the cytoplasmic domain of cadherin or a beta-catenin-engrailed repressor fusion construct prevented endoderm formation and generated the same animalized phenotype. Injections of mRNA encoding either a stabilized, constitutively activated form of beta-catenin or a dominant negative form of GSK3-beta converted all or nearly all cells into endodermal fates expressing gut-specific esterase. Thus, beta-catenin appears to be both necessary and sufficient to promote endoderm formation in C. lacteus, consistent with its role in endoderm and endomesoderm formation in anthozoan cnidarians, ascidians, and echinoderms. Consistent with the results of other studies, beta-catenin may be viewed as playing a role in the development of posterior/vegetal larval fates (i.e., endoderm) in C. lacteus. However, unlike the case found in polychaete annelid and soil nematode embryos, there is no evidence for a role of beta-catenin in regulating cell fates and asymmetric cell divisions along the entire anterior-posterior axis.
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Affiliation(s)
- Jonathan Q Henry
- Department of Cell and Developmental Biology, University of Illinois, 601 S. Goodwin Ave., Urbana, IL 61801, USA.
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36
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Schneider SQ, Bowerman B. beta-Catenin asymmetries after all animal/vegetal- oriented cell divisions in Platynereis dumerilii embryos mediate binary cell-fate specification. Dev Cell 2007; 13:73-86. [PMID: 17609111 DOI: 10.1016/j.devcel.2007.05.002] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Revised: 04/30/2007] [Accepted: 05/02/2007] [Indexed: 10/23/2022]
Abstract
In response to Wnt signaling during animal development, beta-catenin accumulates in nuclei to mediate the transcriptional activation of target genes. Here, we show that a highly conserved beta-catenin in the annelid Platynereis dumerilii exhibits a reiterative, nearly universal embryonic pattern of nuclear accumulation remarkably similar to that observed in the nematode Caenorhabditis elegans. Platynereis exhibits beta-catenin sister-cell asymmetries after all cell divisions that occur along the animal/vegetal axis beginning early in embryogenesis, but not after two transverse divisions that establish bilateral symmetry in the trunk. Moreover, ectopic activation of nuclear beta-catenin accumulation in Platynereis causes animal-pole sister cells, which normally have low nuclear beta-catenin levels, to adopt the fate of their vegetal-pole sisters, which normally have high nuclear beta-catenin levels. The presence of reiterative and functionally important beta-catenin asymmetries in two distantly related animal phyla suggests an ancient metazoan origin of a beta-catenin-mediated binary cell-fate specification module.
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Bischoff M, Schnabel R. A posterior centre establishes and maintains polarity of the Caenorhabditis elegans embryo by a Wnt-dependent relay mechanism. PLoS Biol 2007; 4:e396. [PMID: 17121454 PMCID: PMC1637133 DOI: 10.1371/journal.pbio.0040396] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Accepted: 09/20/2006] [Indexed: 11/19/2022] Open
Abstract
Cellular polarity is a general feature of animal development. However, the mechanisms that establish and maintain polarity in a field of cells or even in the whole embryo remain elusive. Here we provide evidence that in the Caenorhabditis elegans embryo, the descendants of P1, the posterior blastomere of the 2-cell stage, constitute a polarising centre that orients the cell divisions of most of the embryo. This polarisation depends on a MOM-2/Wnt signal originating from the P1 descendants. Furthermore, we show that the MOM-2/Wnt signal is transduced from cell to cell by a relay mechanism. Our findings suggest how polarity is first established and then maintained in a field of cells. According to this model, the relay mechanism constantly orients the polarity of all cells towards the polarising centre, thus organising the whole embryo. This model may also apply to other systems such as Drosophila and vertebrates.
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Affiliation(s)
- Marcus Bischoff
- Technische Universität Braunschweig Carolo Wilhelmina, Institut für Genetik, Braunschweig, Germany
| | - Ralf Schnabel
- Technische Universität Braunschweig Carolo Wilhelmina, Institut für Genetik, Braunschweig, Germany
- * To whom correspondence should be addressed. E-mail:
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Wnt signaling in C. elegans: New insights into the regulation of POP‐1/ TCF‐mediated activation and repression. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s1574-3349(06)17003-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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39
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Abstract
The endomesoderm gene regulatory network (GRN) of C. elegans is a rich resource for studying the properties of cell-fate-specification pathways. This GRN contains both cell-autonomous and cell non-autonomous mechanisms, includes network motifs found in other GRNs, and ties maternal factors to terminal differentiation genes through a regulatory cascade. In most cases, upstream regulators and their direct downstream targets are known. With the availability of resources to study close and distant relatives of C. elegans, the molecular evolution of this network can now be examined. Within Caenorhabditis, components of the endomesoderm GRN are well conserved. A cursory examination of the preliminary genome sequences of two parasitic nematodes, Haemonchus contortus and Brugia malayi, suggests that evolution in this GRN is occurring most rapidly for the zygotic genes that specify blastomere identity.
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Affiliation(s)
- Morris F Maduro
- Department of Biology, University of California, Riverside, Riverside, CA 92521, USA.
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40
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Gleason JE, Szyleyko EA, Eisenmann DM. Multiple redundant Wnt signaling components function in two processes during C. elegans vulval development. Dev Biol 2006; 298:442-57. [PMID: 16930586 DOI: 10.1016/j.ydbio.2006.06.050] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 06/26/2006] [Accepted: 06/30/2006] [Indexed: 01/26/2023]
Abstract
In Caenorhabditis elegans, vulval precursor cell (VPC) fate is specified by the action of RTK/Ras, Notch and Wnt signaling pathways. While the identity of signals for the Ras and Notch pathways is known, the source and identity of the Wnt ligand acting on the VPCs are unknown. Single mutations in any of the five Wnt genes (lin-44, cwn-1, cwn-2, egl-20 and mom-2) do not cause strong defects in VPC fate specification, suggesting that functionally redundant Wnts are required. Surprisingly, we found that all five Wnts influence VPC fate. The strongest defects we observed were in the lin-44; cwn-1; egl-20 triple mutant. Anterior VPCs were more strongly affected by loss of Wnt function than posterior VPCs, and expression from WntColon, two colonsGFP transcriptional reporters showed that the Wnts most strongly affecting VPC fate were expressed predominantly in the posterior, suggesting that some of the redundant Wnt ligands act over a distance to affect the VPCs. In addition to ligand redundancy, we found that at least three Wnt receptors, lin-17, mom-5 and mig-1, function in the VPCs. We also examined ligand and receptor function in another Wnt-mediated vulval process, the orientation of the P7.p lineage. Here, too, we found that four of five Wnt receptors can influence P7.p orientation, suggesting that a surprising amount of functional redundancy exists in Wnt signaling during C. elegans vulval induction.
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Affiliation(s)
- Julie E Gleason
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
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Wu M, Herman MA. A novel noncanonical Wnt pathway is involved in the regulation of the asymmetric B cell division in C. elegans. Dev Biol 2006; 293:316-29. [PMID: 16631156 DOI: 10.1016/j.ydbio.2005.12.024] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Revised: 12/08/2005] [Accepted: 12/09/2005] [Indexed: 12/24/2022]
Abstract
The polarities of several cells that divide asymmetrically during Caenorhabditis elegans development are controlled by Wnt signaling. LIN-44/Wnt and LIN-17/Fz control the polarities of cells in the tail of developing C. elegans larvae, including the male-specific blast cell, B, that divides asymmetrically to generate a larger anterior daughter and a smaller posterior daughter. We determined that WRM-1 and the major canonical Wnt pathway components: BAR-1, SGG-1/GSK-3 and PRY-1/Axin were not involved in the control of B cell polarity. However, POP-1/Tcf is involved and is asymmetrically distributed to the B daughter nuclei, as it is in many cell divisions during C. elegans development. Aspects of the B cell division are reminiscent of the divisions controlled by the planar cell polarity (PCP) pathway that has been described in both Drosophila and vertebrate systems. We identified C. elegans homologs of Wnt/PCP signaling components and have determined that many of them appear to be involved in the regulation of B cell polarity. Specifically, MIG-5/Dsh, RHO-1/RhoA and LET-502/ROCK appear to play major roles, while other PCP components appear to play minor roles. We conclude that a noncanonical Wnt pathway, which is different from other Wnt pathways in C. elegans, regulates B cell polarity.
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Affiliation(s)
- Mingfu Wu
- Program in Molecular, Cellular and Developmental Biology, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
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42
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Bischoff M, Schnabel R. Global cell sorting is mediated by local cell-cell interactions in the C. elegans embryo. Dev Biol 2006; 294:432-44. [PMID: 16626685 DOI: 10.1016/j.ydbio.2006.03.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Revised: 02/23/2006] [Accepted: 03/07/2006] [Indexed: 11/29/2022]
Abstract
The Caenorhabditis elegans embryo achieves pattern formation by sorting cells into coherent regions before morphogenesis is initiated. The sorting of cells is coupled to their fate. Cells move extensively relative to each other to reach their correct position in the body plan. Analyzing the mechanism of cell sorting in in vitro culture experiments using 4D microscopy, we show that all AB-derived cells sort only according to their local neighbors, and that all cells are able to communicate with each other. The directions of cell movement do not depend on a cellular polarity but only on local cell-cell interactions; in experimental situations, this allows even the reversal of the polarity of whole regions of the embryo. The work defines a new mechanism of pattern formation we call "cell focusing".
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Affiliation(s)
- Marcus Bischoff
- Technische Universität Braunschweig Carolo Wilhelmina, Institut für Genetik, Spielmannstr. 7, D-38106 Braunschweig, Germany
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Hawkins NC, Ellis GC, Bowerman B, Garriga G. MOM-5 frizzled regulates the distribution of DSH-2 to control C. elegans asymmetric neuroblast divisions. Dev Biol 2005; 284:246-59. [PMID: 15990090 DOI: 10.1016/j.ydbio.2005.05.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2004] [Revised: 04/29/2005] [Accepted: 05/18/2005] [Indexed: 11/23/2022]
Abstract
Asymmetric cell divisions produce all 302 neurons of the C. elegans hermaphrodite. Here, we describe a role for a C. elegans Dishevelled homolog, DSH-2, in an asymmetric neuroblast division. In dsh-2 mutants, neurons normally descended from the anterior neuroblast daughter of the ABpl/rpppa blast cell were frequently duplicated, while non-neuronal cells produced by the posterior daughter cell were often missing. These observations indicate that in the absence of dsh-2 function, the posterior daughter cell was transformed into a second anterior-like cell. Loss of mom-5, a C. elegans frizzled homolog, produced a similar phenotype. We also show that the DSH-2 protein localized to the cell cortex in most cells of the embryo. In the absence of MOM-5/Fz, DSH-2 was localized to the cytoplasm, suggesting that MOM-5 regulates asymmetric cell division by controlling the localization of DSH-2. Although all neurons in C. elegans are produced by an invariant pattern of cell divisions, our results indicate that cell signaling may contribute to asymmetric neuroblast division during embryogenesis.
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Affiliation(s)
- Nancy C Hawkins
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3204, USA.
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44
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Kidd AR, Miskowski JA, Siegfried KR, Sawa H, Kimble J. A β-Catenin Identified by Functional Rather Than Sequence Criteria and Its Role in Wnt/MAPK Signaling. Cell 2005; 121:761-72. [PMID: 15935762 DOI: 10.1016/j.cell.2005.03.029] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Revised: 03/15/2005] [Accepted: 03/30/2005] [Indexed: 11/26/2022]
Abstract
Wnt/MAPK signaling is a common variant of Wnt signaling in C. elegans and has been implicated in vertebrates. The sys-1 gene works with Wnt/MAPK signaling to control cell fates during C. elegans development. We report that the SYS-1 amino acid sequence is novel but that SYS-1 functions as beta-catenin: SYS-1 rescues a bar-1/beta-catenin null mutant, binds the POP-1/TCF beta-catenin binding domain, and coactivates POP-1-dependent transcription. Moreover, we provide genetic and molecular evidence that SYS-1 levels are crucial to POP-1 activity. Our results suggest that Wnt/MAPK signaling promotes POP-1 export from the nucleus to accommodate the limiting availability of its SYS-1/beta-catenin transcriptional coactivator. Discovery of SYS-1/beta-catenin extends our definition of beta-catenins and brings together aspects of the canonical mechanism for Wnt signaling with the noncanonical Wnt/MAPK mechanism. We discuss the idea that a similar pathway may be employed broadly in animal development.
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Affiliation(s)
- Ambrose R Kidd
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Wisconsin 53706, USA
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45
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Park FD, Tenlen JR, Priess JR. C. elegans MOM-5/frizzled functions in MOM-2/Wnt-independent cell polarity and is localized asymmetrically prior to cell division. Curr Biol 2005; 14:2252-8. [PMID: 15620652 DOI: 10.1016/j.cub.2004.12.019] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2004] [Revised: 10/20/2004] [Accepted: 10/21/2004] [Indexed: 11/18/2022]
Abstract
C. elegans embryonic cells have a common anterior/posterior (a/p) polarity that is apparent in the localization of the transcription factor POP-1. The level of nuclear POP-1 remains high in the anterior daughters of dividing cells but is lowered in the posterior daughters. To generate POP-1 asymmetry, most early embryonic cells require contact with signaling cells that express the ligand MOM-2/Wnt; the point of cell contact specifies the daughter with low nuclear POP-1. In contrast, slightly older embryonic cells that have no apparent prior exposure to Wnt signaling can generate POP-1 asymmetry, provided these cells express MOM-5/Frizzled. We show here that MOM-5::GFP is enriched at the posterior pole of cells prior to division and that a similar asymmetry is observed in cultured cells with no apparent prior exposure to Wnt signaling. While depleting these latter cells of MOM-5/Frizzled causes both daughter cells to have high levels of POP-1, we show that both daughter cells have low levels of POP-1 in embryos with atypically high levels of MOM-5::GFP. These results suggest that MOM-5/Frizzled asymmetry leads to POP-1 asymmetry. In later embryogenesis, we find that MOM-5::GFP localizes to the leading edges of epidermal cells during ventral enclosure. These localization patterns suggest a parallel between MOM-5/Frizzled and the roles of Drosophila Frizzled in planar polarity and dorsal enclosure.
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Affiliation(s)
- Frederick D Park
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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46
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Deshpande R, Inoue T, Priess JR, Hill RJ. lin-17/Frizzled and lin-18 regulate POP-1/TCF-1 localization and cell type specification during C. elegans vulval development. Dev Biol 2005; 278:118-29. [PMID: 15649465 DOI: 10.1016/j.ydbio.2004.10.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2004] [Revised: 10/27/2004] [Accepted: 10/28/2004] [Indexed: 11/20/2022]
Abstract
The Caenorhabditis elegans vulva is comprised of highly similar anterior and posterior halves that are arranged in a mirror symmetric pattern. The cell lineages that form each half of the vulva are identical, except that they occur in opposite orientations with respect to the anterior/posterior axis. We show that most vulval cell divisions produce sister cells that have asymmetric levels of POP-1 and that the asymmetry has opposite orientations in the two halves of the vulva. We demonstrate that lin-17 (Frizzled type Wnt receptor) and lin-18 (Ryk) regulate the pattern of POP-1 localization and cell type specification in the posterior half of the vulva. In the absence of lin-17 and lin-18, posterior lineages are reversed and resemble anterior lineages. These experiments suggest that Wnt signaling pathways reorient cell lineages in the posterior half of the vulva from a default orientation displayed in the anterior half of the vulva.
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Affiliation(s)
- Rashmi Deshpande
- Department of Molecular Genetics, The Ohio State University, 963 Biological Science Building, 484 W. 12th Avenue, Columbus, OH 43210, USA
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47
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Walston T, Tuskey C, Edgar L, Hawkins N, Ellis G, Bowerman B, Wood W, Hardin J. Multiple Wnt Signaling Pathways Converge to Orient the Mitotic Spindle in Early C. elegans Embryos. Dev Cell 2004; 7:831-41. [PMID: 15572126 DOI: 10.1016/j.devcel.2004.10.008] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2004] [Revised: 09/24/2004] [Accepted: 10/05/2004] [Indexed: 10/26/2022]
Abstract
How cells integrate the input of multiple polarizing signals during division is poorly understood. We demonstrate that two distinct Caenorhabditis elegans Wnt pathways contribute to the polarization of the ABar blastomere by differentially regulating its duplicated centrosomes. Contact with the C blastomere orients the ABar spindle through a nontranscriptional Wnt spindle alignment pathway, while a Wnt/beta-catenin pathway controls the timing of ABar spindle rotation. The three C. elegans Dishevelled homologs contribute to these processes in different ways, suggesting that functional distinctions may exist among them. We also find that CKI (KIN-19) plays a role not only in the Wnt/beta-catenin pathway, but also in the Wnt spindle orientation pathway as well. Based on these findings, we establish a model for the coordination of cell-cell interactions and distinct Wnt signaling pathways that ensures the robust timing and orientation of spindle rotation during a developmentally regulated cell division event.
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Affiliation(s)
- Timothy Walston
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
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48
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Siegfried KR, Kidd AR, Chesney MA, Kimble J. The sys-1 and sys-3 genes cooperate with Wnt signaling to establish the proximal-distal axis of the Caenorhabditis elegans gonad. Genetics 2004; 166:171-86. [PMID: 15020416 PMCID: PMC1470708 DOI: 10.1534/genetics.166.1.171] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
To form the proximal-distal axis of the C. elegans gonad, two somatic gonadal precursor cells, Z1 and Z4, divide asymmetrically to generate one daughter with a proximal fate and one with a distal fate. Genes governing this process include the lin-17 frizzled receptor, wrm-1/beta-catenin, the pop-1/TCF transcription factor, lit-1/nemo-like kinase, and the sys-1 gene. Normally, all of these regulators promote the distal fate. Here we show that nuclear levels of a pop-1 GFP fusion protein are less abundant in the distal than in the proximal Z1/Z4 daughters. This POP-1 asymmetry is lost in mutants disrupting Wnt/MAPK regulation, but retained in sys-1 mutants. We find that sys-1 is haplo-insufficient for gonadogenesis defects and that sys-1 and pop-1 mutants display a strong genetic interaction in double heterozygotes. Therefore, sys-1 is a dose-sensitive locus and may function together with pop-1 to control Z1/Z4 asymmetry. To identify other regulatory genes in this process, we screened for mutants resembling sys-1. Four such genes were identified (gon-14, -15, -16, and sys-3) and shown to interact genetically with sys-1. However, only sys-3 promotes the distal fate at the expense of the proximal fate. We suggest that sys-3 is a new key gene in this pathway and that gon-14, gon-15, and gon-16 may cooperate with POP-1 and SYS-1 at multiple stages of gonad development.
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Affiliation(s)
- Kellee R Siegfried
- Laboratory of Genetics, University of Wisconsin, Madison, Wisconsin 53706-1544, USA
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