1
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Darmasaputra GS, van Rijnberk LM, Galli M. Functional consequences of somatic polyploidy in development. Development 2024; 151:dev202392. [PMID: 38415794 PMCID: PMC10946441 DOI: 10.1242/dev.202392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Polyploid cells contain multiple genome copies and arise in many animal tissues as a regulated part of development. However, polyploid cells can also arise due to cell division failure, DNA damage or tissue damage. Although polyploidization is crucial for the integrity and function of many tissues, the cellular and tissue-wide consequences of polyploidy can be very diverse. Nonetheless, many polyploid cell types and tissues share a remarkable similarity in function, providing important information about the possible contribution of polyploidy to cell and tissue function. Here, we review studies on polyploid cells in development, underlining parallel functions between different polyploid cell types, as well as differences between developmentally-programmed and stress-induced polyploidy.
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Affiliation(s)
- Gabriella S. Darmasaputra
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT, Utrecht, the Netherlands
| | - Lotte M. van Rijnberk
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT, Utrecht, the Netherlands
| | - Matilde Galli
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT, Utrecht, the Netherlands
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2
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Mallart C, Netter S, Chalvet F, Claret S, Guichet A, Montagne J, Pret AM, Malartre M. JAK-STAT-dependent contact between follicle cells and the oocyte controls Drosophila anterior-posterior polarity and germline development. Nat Commun 2024; 15:1627. [PMID: 38388656 PMCID: PMC10883949 DOI: 10.1038/s41467-024-45963-z] [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: 05/26/2023] [Accepted: 02/08/2024] [Indexed: 02/24/2024] Open
Abstract
The number of embryonic primordial germ cells in Drosophila is determined by the quantity of germ plasm, whose assembly starts in the posterior region of the oocyte during oogenesis. Here, we report that extending JAK-STAT activity in the posterior somatic follicular epithelium leads to an excess of primordial germ cells in the future embryo. We show that JAK-STAT signaling is necessary for the differentiation of approximately 20 specialized follicle cells maintaining tight contact with the oocyte. These cells define, in the underlying posterior oocyte cortex, the anchoring of the germ cell determinant oskar mRNA. We reveal that the apical surface of these posterior anchoring cells extends long filopodia penetrating the oocyte. We identify two JAK-STAT targets in these cells that are each sufficient to extend the zone of contact with the oocyte, thereby leading to production of extra primordial germ cells. JAK-STAT signaling thus determines a fixed number of posterior anchoring cells required for anterior-posterior oocyte polarity and for the development of the future germline.
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Affiliation(s)
- Charlotte Mallart
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Sophie Netter
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université de Versailles-Saint-Quentin en Yvelines, Université Paris-Saclay, Gif- sur-Yvette, France
| | - Fabienne Chalvet
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Sandra Claret
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Antoine Guichet
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Jacques Montagne
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Anne-Marie Pret
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université de Versailles-Saint-Quentin en Yvelines, Université Paris-Saclay, Gif- sur-Yvette, France
| | - Marianne Malartre
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France.
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3
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Weng RY, Zhang L, Liu JL. Connecting Hippo Pathway and Cytoophidia in Drosophila Posterior Follicle Cells. Int J Mol Sci 2024; 25:1453. [PMID: 38338731 PMCID: PMC10855297 DOI: 10.3390/ijms25031453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/18/2024] [Accepted: 01/19/2024] [Indexed: 02/12/2024] Open
Abstract
CTP synthase (CTPS), the rate-limiting enzyme in the de novo synthesis of CTP, assembles into a filamentous structure termed the cytoophidium. The Hippo pathway regulates cell proliferation and apoptosis. The relationship of the nucleotide metabolism with the Hippo pathway is little known. Here, we study the impact of the Hippo pathway on the cytoophidium in Drosophila melanogaster posterior follicle cells (PFCs). We find that the inactivation of the Hippo pathway correlates with reduced cytoophidium length and number within PFCs. During the overexpression of CTPS, the presence of Hippo mutations also reduces the length of cytoophidia in PFCs. In addition, we observe that knocking down CTPS mitigates hpo (Hippo)-associated over-proliferation. In summary, our results suggest that there is a connection between the Hippo pathway and the nucleotide biosynthesis enzyme CTPS in PFCs.
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Affiliation(s)
- Rui-Yu Weng
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; (R.-Y.W.)
- State Key Laboratory of Cell Biology, Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Lei Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; (R.-Y.W.)
- State Key Laboratory of Cell Biology, Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
- Sheng Yushou Center of Cell Biology and Immunology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; (R.-Y.W.)
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4
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Lepesant JA, Roland-Gosselin F, Guillemet C, Bernard F, Guichet A. The Importance of the Position of the Nucleus in Drosophila Oocyte Development. Cells 2024; 13:201. [PMID: 38275826 PMCID: PMC10814754 DOI: 10.3390/cells13020201] [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: 11/22/2023] [Revised: 01/12/2024] [Accepted: 01/16/2024] [Indexed: 01/27/2024] Open
Abstract
Oogenesis is a developmental process leading to the formation of an oocyte, a haploid gamete, which upon fertilisation and sperm entry allows the male and the female pronuclei to fuse and give rise to a zygote. In addition to forming a haploid gamete, oogenesis builds up a store of proteins, mRNAs, and organelles in the oocyte needed for the development of the future embryo. In several species, such as Drosophila, the polarity axes determinants of the future embryo must be asymmetrically distributed prior to fertilisation. In the Drosophila oocyte, the correct positioning of the nucleus is essential for establishing the dorsoventral polarity axis of the future embryo and allowing the meiotic spindles to be positioned in close vicinity to the unique sperm entry point into the oocyte.
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Affiliation(s)
| | | | | | | | - Antoine Guichet
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France; (J.-A.L.); (F.R.-G.); (C.G.); (F.B.)
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5
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Berg C, Sieber M, Sun J. Finishing the egg. Genetics 2024; 226:iyad183. [PMID: 38000906 PMCID: PMC10763546 DOI: 10.1093/genetics/iyad183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 09/27/2023] [Indexed: 11/26/2023] Open
Abstract
Gamete development is a fundamental process that is highly conserved from early eukaryotes to mammals. As germ cells develop, they must coordinate a dynamic series of cellular processes that support growth, cell specification, patterning, the loading of maternal factors (RNAs, proteins, and nutrients), differentiation of structures to enable fertilization and ensure embryonic survival, and other processes that make a functional oocyte. To achieve these goals, germ cells integrate a complex milieu of environmental and developmental signals to produce fertilizable eggs. Over the past 50 years, Drosophila oogenesis has risen to the forefront as a system to interrogate the sophisticated mechanisms that drive oocyte development. Studies in Drosophila have defined mechanisms in germ cells that control meiosis, protect genome integrity, facilitate mRNA trafficking, and support the maternal loading of nutrients. Work in this system has provided key insights into the mechanisms that establish egg chamber polarity and patterning as well as the mechanisms that drive ovulation and egg activation. Using the power of Drosophila genetics, the field has begun to define the molecular mechanisms that coordinate environmental stresses and nutrient availability with oocyte development. Importantly, the majority of these reproductive mechanisms are highly conserved throughout evolution, and many play critical roles in the development of somatic tissues as well. In this chapter, we summarize the recent progress in several key areas that impact egg chamber development and ovulation. First, we discuss the mechanisms that drive nutrient storage and trafficking during oocyte maturation and vitellogenesis. Second, we examine the processes that regulate follicle cell patterning and how that patterning impacts the construction of the egg shell and the establishment of embryonic polarity. Finally, we examine regulatory factors that control ovulation, egg activation, and successful fertilization.
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Affiliation(s)
- Celeste Berg
- Department of Genome Sciences, University of Washington, Seattle, WA 98195-5065USA
| | - Matthew Sieber
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390USA
| | - Jianjun Sun
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT 06269USA
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Tian A, Wang X, Xu Y, Morejon V, Huang Y, Nwapuda C, Deng W. EGFR signaling controls directionality of epithelial multilayer formation upon loss of cell polarity. EMBO J 2023; 42:e113856. [PMID: 37953688 PMCID: PMC10711663 DOI: 10.15252/embj.2023113856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 10/18/2023] [Accepted: 10/20/2023] [Indexed: 11/14/2023] Open
Abstract
Apical-basal polarity is maintained by distinct protein complexes that reside in membrane junctions, and polarity loss in monolayered epithelial cells can lead to formation of multilayers, cell extrusion, and/or malignant overgrowth. Yet, how polarity loss cooperates with intrinsic signals to control directional invasion toward neighboring epithelial cells remains elusive. Using the Drosophila ovarian follicular epithelium as a model, we found that posterior follicle cells with loss of lethal giant larvae (lgl) or Discs large (Dlg) accumulate apically toward germline cells, whereas cells with loss of Bazooka (Baz) or atypical protein kinase C (aPKC) expand toward the basal side of wildtype neighbors. Further studies revealed that these distinct multilayering patterns in the follicular epithelium were determined by epidermal growth factor receptor (EGFR) signaling and its downstream target Pointed, a zinc-finger transcription factor. Additionally, we identified Rho kinase as a Pointed target that regulates formation of distinct multilayering patterns. These findings provide insight into how cell polarity genes and receptor tyrosine kinase signaling interact to govern epithelial cell organization and directional growth that contribute to epithelial tumor formation.
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Affiliation(s)
- Aiguo Tian
- Department of Biochemistry and Molecular BiologyTulane University School of Medicine, Louisiana Cancer Research CenterNew OrleansLAUSA
- Tulane Aging CenterTulane University School of MedicineNew OrleansLAUSA
| | - Xian‐Feng Wang
- Department of Biochemistry and Molecular BiologyTulane University School of Medicine, Louisiana Cancer Research CenterNew OrleansLAUSA
| | - Yuting Xu
- Department of Biochemistry and Molecular BiologyTulane University School of Medicine, Louisiana Cancer Research CenterNew OrleansLAUSA
| | - Virginia Morejon
- Department of Biochemistry and Molecular BiologyTulane University School of Medicine, Louisiana Cancer Research CenterNew OrleansLAUSA
| | - Yi‐Chun Huang
- Department of Biochemistry and Molecular BiologyTulane University School of Medicine, Louisiana Cancer Research CenterNew OrleansLAUSA
| | - Chidi Nwapuda
- Department of Biochemistry and Molecular BiologyTulane University School of Medicine, Louisiana Cancer Research CenterNew OrleansLAUSA
| | - Wu‐Min Deng
- Department of Biochemistry and Molecular BiologyTulane University School of Medicine, Louisiana Cancer Research CenterNew OrleansLAUSA
- Tulane Aging CenterTulane University School of MedicineNew OrleansLAUSA
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7
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Otis JP, Mowry KL. Hitting the mark: Localization of mRNA and biomolecular condensates in health and disease. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1807. [PMID: 37393916 PMCID: PMC10758526 DOI: 10.1002/wrna.1807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/29/2023] [Accepted: 06/06/2023] [Indexed: 07/04/2023]
Abstract
Subcellular mRNA localization is critical to a multitude of biological processes such as development of cellular polarity, embryogenesis, tissue differentiation, protein complex formation, cell migration, and rapid responses to environmental stimuli and synaptic depolarization. Our understanding of the mechanisms of mRNA localization must now be revised to include formation and trafficking of biomolecular condensates, as several biomolecular condensates that transport and localize mRNA have recently been discovered. Disruptions in mRNA localization can have catastrophic effects on developmental processes and biomolecular condensate biology and have been shown to contribute to diverse diseases. A fundamental understanding of mRNA localization is essential to understanding how aberrations in this biology contribute the etiology of numerous cancers though support of cancer cell migration and biomolecular condensate dysregulation, as well as many neurodegenerative diseases, through misregulation of mRNA localization and biomolecular condensate biology. This article is categorized under: RNA Export and Localization > RNA Localization RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.
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Affiliation(s)
- Jessica P. Otis
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States, 02912
| | - Kimberly L. Mowry
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States, 02912
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8
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Abstract
By the time a Drosophila egg is laid, both major body axes have already been defined and it contains all the nutrients needed to develop into a free-living larva in 24 h. By contrast, it takes almost a week to make an egg from a female germline stem cell, during the complex process of oogenesis. This review will discuss key symmetry-breaking steps in Drosophila oogenesis that lead to the polarisation of both body axes: the asymmetric divisions of the germline stem cells; the selection of the oocyte from the 16-cell germline cyst; the positioning of the oocyte at the posterior of the cyst; Gurken signalling from the oocyte to polarise the anterior-posterior axis of the somatic follicle cell epithelium around the developing germline cyst; the signalling back from the posterior follicle cells to polarise the anterior-posterior axis of the oocyte; and the migration of the oocyte nucleus that specifies the dorsal-ventral axis. Since each event creates the preconditions for the next, I will focus on the mechanisms that drive these symmetry-breaking steps, how they are linked and the outstanding questions that remain to be answered.
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9
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Roles for the RNA-Binding Protein Caper in Reproductive Output in Drosophila melanogaster. J Dev Biol 2022; 11:jdb11010002. [PMID: 36648904 PMCID: PMC9844462 DOI: 10.3390/jdb11010002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 12/15/2022] [Accepted: 12/20/2022] [Indexed: 12/28/2022] Open
Abstract
RNA binding proteins (RBPs) play a fundamental role in the post-transcriptional regulation of gene expression within the germline and nervous system. This is underscored by the prevalence of mutations within RBP-encoding genes being implicated in infertility and neurological disease. We previously described roles for the highly conserved RBP Caper in neurite morphogenesis in the Drosophila larval peripheral system and in locomotor behavior. However, caper function has not been investigated outside the nervous system, although it is widely expressed in many different tissue types during embryogenesis. Here, we describe novel roles for Caper in fertility and mating behavior. We find that Caper is expressed in ovarian follicles throughout oogenesis but is dispensable for proper patterning of the egg chamber. Additionally, reduced caper function, through either a genetic lesion or RNA interference-mediated knockdown of caper in the female germline, results in females laying significantly fewer eggs than their control counterparts. Moreover, this phenotype is exacerbated with age. caper dysfunction also results in partial embryonic and larval lethality. Given that caper is highly conserved across metazoa, these findings may also be relevant to vertebrates.
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10
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Milas A, de-Carvalho J, Telley IA. Follicle cell contact maintains main body axis polarity in the Drosophila melanogaster oocyte. J Cell Biol 2022; 222:213703. [PMID: 36409222 PMCID: PMC9682419 DOI: 10.1083/jcb.202209052] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/02/2022] [Accepted: 11/04/2022] [Indexed: 11/23/2022] Open
Abstract
In Drosophila melanogaster, the anterior-posterior body axis is maternally established and governed by differential localization of partitioning defective (Par) proteins within the oocyte. At mid-oogenesis, Par-1 accumulates at the oocyte posterior end, while Par-3/Bazooka is excluded there but maintains its localization along the remaining oocyte cortex. Past studies have proposed the need for somatic cells at the posterior end to initiate oocyte polarization by providing a trigger signal. To date, neither the molecular identity nor the nature of the signal is known. Here, we provide evidence that mechanical contact of posterior follicle cells (PFCs) with the oocyte cortex causes the posterior exclusion of Bazooka and maintains oocyte polarity. We show that Bazooka prematurely accumulates exclusively where posterior follicle cells have been mechanically detached or ablated. Furthermore, we provide evidence that PFC contact maintains Par-1 and oskar mRNA localization and microtubule cytoskeleton polarity in the oocyte. Our observations suggest that cell-cell contact mechanics modulates Par protein binding sites at the oocyte cortex.
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Affiliation(s)
- Ana Milas
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Rua da Quinta Grande, Portugal
| | - Jorge de-Carvalho
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Rua da Quinta Grande, Portugal
| | - Ivo A. Telley
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Rua da Quinta Grande, Portugal,Correspondence to Ivo A. Telley:
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11
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Yuen AC, Prasad AR, Fernandes VM, Amoyel M. A kinase translocation reporter reveals real-time dynamics of ERK activity in Drosophila. Biol Open 2022; 11:bio059364. [PMID: 35608229 PMCID: PMC9167624 DOI: 10.1242/bio.059364] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 04/28/2022] [Indexed: 12/12/2022] Open
Abstract
Extracellular signal-regulated kinase (ERK) lies downstream of a core signalling cascade that controls all aspects of development and adult homeostasis. Recent developments have led to new tools to image and manipulate the pathway. However, visualising ERK activity in vivo with high temporal resolution remains a challenge in Drosophila. We adapted a kinase translocation reporter (KTR) for use in Drosophila, which shuttles out of the nucleus when phosphorylated by ERK. We show that ERK-KTR faithfully reports endogenous ERK signalling activity in developing and adult tissues, and that it responds to genetic perturbations upstream of ERK. Using ERK-KTR in time-lapse imaging, we made two novel observations: firstly, sustained hyperactivation of ERK by expression of dominant-active epidermal growth factor receptor raised the overall level but did not alter the kinetics of ERK activity; secondly, the direction of migration of retinal basal glia correlated with their ERK activity levels, suggesting an explanation for the heterogeneity in ERK activity observed in fixed tissue. Our results show that KTR technology can be applied in Drosophila to monitor ERK activity in real-time and suggest that this modular tool can be further adapted to study other kinases. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
| | | | | | - Marc Amoyel
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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12
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Milas A, Telley IA. Polarity Events in the Drosophila melanogaster Oocyte. Front Cell Dev Biol 2022; 10:895876. [PMID: 35602591 PMCID: PMC9117655 DOI: 10.3389/fcell.2022.895876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
Cell polarity is a pre-requirement for many fundamental processes in animal cells, such as asymmetric cell division, axon specification, morphogenesis and epithelial tissue formation. For all these different processes, polarization is established by the same set of proteins, called partitioning defective (Par) proteins. During development in Drosophila melanogaster, decision making on the cellular and organism level is achieved with temporally controlled cell polarization events. The initial polarization of Par proteins occurs as early as in the germline cyst, when one of the 16 cells becomes the oocyte. Another marked event occurs when the anterior–posterior axis of the future organism is defined by Par redistribution in the oocyte, requiring external signaling from somatic cells. Here, we review the current literature on cell polarity events that constitute the oogenesis from the stem cell to the mature egg.
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Affiliation(s)
- Ana Milas
- *Correspondence: Ana Milas, ; Ivo A. Telley,
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13
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The great small organisms of developmental genetics: Caenorhabditis elegans and Drosophila melanogaster. Dev Biol 2022; 485:93-122. [PMID: 35247454 PMCID: PMC9092520 DOI: 10.1016/j.ydbio.2022.02.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/25/2022] [Accepted: 02/27/2022] [Indexed: 12/30/2022]
Abstract
Experimental embryologists working at the turn of the 19th century suggested fundamental mechanisms of development, such as localized cytoplasmic determinants and tissue induction. However, the molecular basis underlying these processes proved intractable for a long time, despite concerted efforts in many developmental systems to isolate factors with a biological role. That road block was overcome by combining developmental biology with genetics. This powerful approach used unbiased genome-wide screens to isolate mutants with developmental defects and to thereby identify genes encoding key determinants and regulatory pathways that govern development. Two small invertebrates were the pioneers: the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans. Their modes of development differ in many ways, but the two together led the way to unraveling the molecular mechanisms of many fundamental developmental processes. The discovery of the grand homologies between key players in development throughout the animal kingdom underscored the usefulness of studying these small invertebrate models for animal development and even human disease. We describe developmental genetics in Drosophila and C. elegans up to the rise of genomics at the beginning of the 21st Century. Finally, we discuss themes that emerge from the histories of such distinct organisms and prospects of this approach for the future.
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14
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Expression and Function of Toll Pathway Components in the Early Development of the Wasp Nasonia vitripennis. J Dev Biol 2022; 10:jdb10010007. [PMID: 35225961 PMCID: PMC8883978 DOI: 10.3390/jdb10010007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/20/2022] [Accepted: 01/22/2022] [Indexed: 11/22/2022] Open
Abstract
The Toll signaling pathway is the main source of embryonic DV polarity in the fly Drosophila melanogaster. This pathway appears to have been co-opted from an ancestral innate immunity system within the insects and has been deployed in different ways among insect taxa. Here we report the expression and function of homologs of the important components of the D. melanogaster Toll pathway in the wasp Nasonia vitripennis. We found homologs for all the components; many components had one or more additional paralogs in the wasp relative the fly. We also found significant deviations in expression patterns of N. vitripennis homologs. Finally, we provide some preliminary functional analyses of the N. vitripennis homologs, where we find a mixture of conservation and divergence of function.
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15
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Doerflinger H, Zimyanin V, St Johnston D. The Drosophila anterior-posterior axis is polarized by asymmetric myosin activation. Curr Biol 2022; 32:374-385.e4. [PMID: 34856125 PMCID: PMC8791603 DOI: 10.1016/j.cub.2021.11.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 10/11/2021] [Accepted: 11/10/2021] [Indexed: 11/29/2022]
Abstract
The Drosophila anterior-posterior axis is specified at mid-oogenesis when the Par-1 kinase is recruited to the posterior cortex of the oocyte, where it polarizes the microtubule cytoskeleton to define where the axis determinants, bicoid and oskar mRNAs, localize. This polarity is established in response to an unknown signal from the follicle cells, but how this occurs is unclear. Here we show that the myosin chaperone Unc-45 and non-muscle myosin II (MyoII) are required upstream of Par-1 in polarity establishment. Furthermore, the myosin regulatory light chain (MRLC) is di-phosphorylated at the oocyte posterior in response to the follicle cell signal, inducing longer pulses of myosin contractility at the posterior that may increase cortical tension. Overexpression of MRLC-T21A that cannot be di-phosphorylated or treatment with the myosin light-chain kinase inhibitor ML-7 abolishes Par-1 localization, indicating that the posterior of MRLC di-phosphorylation is essential for both polarity establishment and maintenance. Thus, asymmetric myosin activation polarizes the anterior-posterior axis by recruiting and maintaining Par-1 at the posterior cortex. This raises an intriguing parallel with anterior-posterior axis formation in C. elegans, where MyoII also acts upstream of the PAR proteins to establish polarity, but to localize the anterior PAR proteins rather than Par-1.
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Affiliation(s)
- Hélène Doerflinger
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Vitaly Zimyanin
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Daniel St Johnston
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.
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16
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Doherty CA, Amargant F, Shvartsman SY, Duncan FE, Gavis ER. Bidirectional communication in oogenesis: a dynamic conversation in mice and Drosophila. Trends Cell Biol 2021; 32:311-323. [PMID: 34922803 DOI: 10.1016/j.tcb.2021.11.005] [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: 08/10/2021] [Revised: 11/14/2021] [Accepted: 11/15/2021] [Indexed: 02/06/2023]
Abstract
In most animals, the oocyte is the largest cell by volume. The oocyte undergoes a period of large-scale growth during its development, prior to fertilization. At first glance, tissues that support the development of the oocyte in different organisms have diverse cellular characteristics that would seem to prohibit functional comparisons. However, these tissues often act with a common goal of establishing dynamic forms of two-way communication with the oocyte. We propose that this bidirectional communication between oocytes and support cells is a universal phenomenon that can be directly compared across species. Specifically, we highlight fruit fly and mouse oogenesis to demonstrate that similarities and differences in these systems should be used to inform and design future experiments in both models.
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Affiliation(s)
- Caroline A Doherty
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Farners Amargant
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Stanislav Y Shvartsman
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA; Center for Computational Biology, Flatiron Institute, New York, NY, USA.
| | - Francesca E Duncan
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
| | - Elizabeth R Gavis
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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17
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Chafino S, Martín D, Franch-Marro X. Activation of EGFR signaling by Tc-Vein and Tc-Spitz regulates the metamorphic transition in the red flour beetle Tribolium castaneum. Sci Rep 2021; 11:18807. [PMID: 34552169 PMCID: PMC8458297 DOI: 10.1038/s41598-021-98334-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 08/25/2021] [Indexed: 02/08/2023] Open
Abstract
Animal development relies on a sequence of specific stages that allow the formation of adult structures with a determined size. In general, juvenile stages are dedicated mainly to growth, whereas last stages are devoted predominantly to the maturation of adult structures. In holometabolous insects, metamorphosis marks the end of the growth period as the animals stops feeding and initiate the final differentiation of the tissues. This transition is controlled by the steroid hormone ecdysone produced in the prothoracic gland. In Drosophila melanogaster different signals have been shown to regulate the production of ecdysone, such as PTTH/Torso, TGFß and Egfr signaling. However, to which extent the roles of these signals are conserved remains unknown. Here, we study the role of Egfr signaling in post-embryonic development of the basal holometabolous beetle Tribolium castaneum. We show that Tc-Egfr and Tc-pointed are required to induced a proper larval-pupal transition through the control of the expression of ecdysone biosynthetic genes. Furthermore, we identified an additional Tc-Egfr ligand in the Tribolium genome, the neuregulin-like protein Tc-Vein (Tc-Vn), which contributes to induce larval-pupal transition together with Tc-Spitz (Tc-Spi). Interestingly, we found that in addition to the redundant role in the control of pupa formation, each ligand possesses different functions in organ morphogenesis. Whereas Tc-Spi acts as the main ligand in urogomphi and gin traps, Tc-Vn is required in wings and elytra. Altogether, our findings show that in Tribolium, post-embryonic Tc-Egfr signaling activation depends on the presence of two ligands and that its role in metamorphic transition is conserved in holometabolous insects.
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Affiliation(s)
- Sílvia Chafino
- grid.507636.10000 0004 0424 5398Institute of Evolutionary Biology (IBE, CSIC-Universitat Pompeu Fabra), Passeig de la Barceloneta 37, 08003 Barcelona, Catalonia Spain
| | - David Martín
- grid.507636.10000 0004 0424 5398Institute of Evolutionary Biology (IBE, CSIC-Universitat Pompeu Fabra), Passeig de la Barceloneta 37, 08003 Barcelona, Catalonia Spain
| | - Xavier Franch-Marro
- grid.507636.10000 0004 0424 5398Institute of Evolutionary Biology (IBE, CSIC-Universitat Pompeu Fabra), Passeig de la Barceloneta 37, 08003 Barcelona, Catalonia Spain
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18
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Slaidina M, Gupta S, Banisch TU, Lehmann R. A single-cell atlas reveals unanticipated cell type complexity in Drosophila ovaries. Genome Res 2021; 31:1938-1951. [PMID: 34389661 DOI: 10.1101/gr.274340.120] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 08/09/2021] [Indexed: 11/24/2022]
Abstract
Organ function relies on the spatial organization and functional coordination of numerous cell types. The Drosophila ovary is a widely used model system to study the cellular activities underlying organ function, including stem cell regulation, cell signaling and epithelial morphogenesis. However, the relative paucity of cell type-specific reagents hinders investigation of molecular functions at the appropriate cellular resolution. Here, we used single-cell RNA sequencing to characterize all cell types of the stem cell compartment and early follicles of the Drosophila ovary. We computed transcriptional signatures and identified specific markers for nine states of germ cell differentiation, and 23 somatic cell types and subtypes. We uncovered an unanticipated diversity of escort cells, the somatic cells that directly interact with differentiating germline cysts. Three escort cell subtypes reside in discrete anatomical positions, and express distinct sets of secreted and transmembrane proteins, suggesting that diverse micro-environments support the progressive differentiation of germ cells. Finally, we identified 17 follicle cell subtypes, and characterized their transcriptional profiles. Altogether, we provide a comprehensive resource of gene expression, cell type-specific markers, spatial coordinates and functional predictions for 34 ovarian cell types and subtypes.
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Affiliation(s)
| | - Selena Gupta
- Skirball Institute, NYU Grossman School of Medicine
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19
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Composite morphogenesis during embryo development. Semin Cell Dev Biol 2021; 120:119-132. [PMID: 34172395 DOI: 10.1016/j.semcdb.2021.06.007] [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: 03/24/2021] [Revised: 05/23/2021] [Accepted: 06/13/2021] [Indexed: 11/21/2022]
Abstract
Morphogenesis drives the formation of functional living shapes. Gene expression patterns and signaling pathways define the body plans of the animal and control the morphogenetic processes shaping the embryonic tissues. During embryogenesis, a tissue can undergo composite morphogenesis resulting from multiple concomitant shape changes. While previous studies have unraveled the mechanisms that drive simple morphogenetic processes, how a tissue can undergo multiple and simultaneous changes in shape is still not known and not much explored. In this chapter, we focus on the process of concomitant tissue folding and extension that is vital for the animal since it is key for embryo gastrulation and neurulation. Recent pioneering studies focus on this problem highlighting the roles of different spatially coordinated cell mechanisms or of the synergy between different patterns of gene expression to drive composite morphogenesis.
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20
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Rathore OS, Silva RD, Ascensão-Ferreira M, Matos R, Carvalho C, Marques B, Tiago MN, Prudêncio P, Andrade RP, Roignant JY, Barbosa-Morais NL, Martinho RG. NineTeen Complex-subunit Salsa is required for efficient splicing of a subset of introns and dorsal-ventral patterning. RNA (NEW YORK, N.Y.) 2020; 26:1935-1956. [PMID: 32963109 PMCID: PMC7668242 DOI: 10.1261/rna.077446.120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 09/07/2020] [Indexed: 06/11/2023]
Abstract
The NineTeen Complex (NTC), also known as pre-mRNA-processing factor 19 (Prp19) complex, regulates distinct spliceosome conformational changes necessary for splicing. During Drosophila midblastula transition, splicing is particularly sensitive to mutations in NTC-subunit Fandango, which suggests differential requirements of NTC during development. We show that NTC-subunit Salsa, the Drosophila ortholog of human RNA helicase Aquarius, is rate-limiting for splicing of a subset of small first introns during oogenesis, including the first intron of gurken Germline depletion of Salsa and splice site mutations within gurken first intron impair both adult female fertility and oocyte dorsal-ventral patterning, due to an abnormal expression of Gurken. Supporting causality, the fertility and dorsal-ventral patterning defects observed after Salsa depletion could be suppressed by the expression of a gurken construct without its first intron. Altogether, our results suggest that one of the key rate-limiting functions of Salsa during oogenesis is to ensure the correct expression and efficient splicing of the first intron of gurken mRNA. Retention of gurken first intron compromises the function of this gene most likely because it undermines the correct structure and function of the transcript 5'UTR.
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Affiliation(s)
- Om Singh Rathore
- Center for Biomedical Research (CBMR), Universidade do Algarve, Faro, 8005-139 Portugal
| | - Rui D Silva
- Center for Biomedical Research (CBMR), Universidade do Algarve, Faro, 8005-139 Portugal
| | - Mariana Ascensão-Ferreira
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Ricardo Matos
- Center for Biomedical Research (CBMR), Universidade do Algarve, Faro, 8005-139 Portugal
| | - Célia Carvalho
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Bruno Marques
- Center for Biomedical Research (CBMR), Universidade do Algarve, Faro, 8005-139 Portugal
| | - Margarida N Tiago
- Center for Biomedical Research (CBMR), Universidade do Algarve, Faro, 8005-139 Portugal
| | - Pedro Prudêncio
- Center for Biomedical Research (CBMR), Universidade do Algarve, Faro, 8005-139 Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Raquel P Andrade
- Center for Biomedical Research (CBMR), Universidade do Algarve, Faro, 8005-139 Portugal
- Department of Medicine and Biomedical Sciences and Algarve Biomedical Center, Universidade do Algarve, 8005-139 Faro, Portugal
| | - Jean-Yves Roignant
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
| | - Nuno L Barbosa-Morais
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Rui Gonçalo Martinho
- Center for Biomedical Research (CBMR), Universidade do Algarve, Faro, 8005-139 Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
- Department of Medical Sciences and Institute for Biomedicine (iBiMED), Universidade de Aveiro, 3810-193 Aveiro, Portugal
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21
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Revaitis NT, Niepielko MG, Marmion RA, Klein EA, Piccoli B, Yakoby N. Quantitative analyses of EGFR localization and trafficking dynamics in the follicular epithelium. Development 2020; 147:dev.183210. [PMID: 32680934 DOI: 10.1242/dev.183210] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 07/01/2020] [Indexed: 12/20/2022]
Abstract
To bridge the gap between qualitative and quantitative analyses of the epidermal growth factor receptor (EGFR) in tissues, we generated an sfGFP-tagged EGF receptor (EGFR-sfGFP) in Drosophila The homozygous fly appears similar to wild type with EGFR expression and activation patterns that are consistent with previous reports in the ovary, early embryo, and imaginal discs. Using ELISA, we quantified an average of 1100, 6200 and 2500 receptors per follicle cell (FC) at stages 8/9, 10 and ≥11 of oogenesis, respectively. Interestingly, the spatial localization of the EGFR to the apical side of the FCs at early stages depended on the TGFα-like ligand Gurken. At later stages, EGFR localized to basolateral positions of the FCs. Finally, we followed the endosomal localization of EGFR in the FCs. The EGFR colocalized with the late endosome, but no significant colocalization of the receptor was found with the early endosome. The EGFR-sfGFP fly is an exciting new resource for studying cellular localization and regulation of EGFR in tissues.
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Affiliation(s)
- Nicole T Revaitis
- Center for Computational and Integrative Biology, Rutgers, The State University of New Jersey, Camden, NJ 08103, USA
| | - Matthew G Niepielko
- New Jersey Center for Science, Technology & Mathematics, Kean University, Union, NJ 07083, USA
| | - Robert A Marmion
- Center for Computational and Integrative Biology, Rutgers, The State University of New Jersey, Camden, NJ 08103, USA
| | - Eric A Klein
- Center for Computational and Integrative Biology, Rutgers, The State University of New Jersey, Camden, NJ 08103, USA.,Department of Biology, Rutgers, The State University of New Jersey, Camden, NJ 08103, USA
| | - Benedetto Piccoli
- Center for Computational and Integrative Biology, Rutgers, The State University of New Jersey, Camden, NJ 08103, USA.,Department of Mathematical Sciences, Rutgers, The State University of New Jersey, Camden, NJ 08102, USA
| | - Nir Yakoby
- Center for Computational and Integrative Biology, Rutgers, The State University of New Jersey, Camden, NJ 08103, USA .,Department of Biology, Rutgers, The State University of New Jersey, Camden, NJ 08103, USA
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22
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Drechsler M, Lang LF, Al-Khatib L, Dirks H, Burger M, Schönlieb CB, Palacios IM. Optical flow analysis reveals that Kinesin-mediated advection impacts the orientation of microtubules in the Drosophila oocyte. Mol Biol Cell 2020; 31:1246-1258. [PMID: 32267197 PMCID: PMC7353148 DOI: 10.1091/mbc.e19-08-0440] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The orientation of microtubule (MT) networks is exploited by motors to deliver cargoes to specific intracellular destinations and is thus essential for cell polarity and function. Reconstituted in vitro systems have largely contributed to understanding the molecular framework regulating the behavior of MT filaments. In cells, however, MTs are exposed to various biomechanical forces that might impact on their orientation, but little is known about it. Oocytes, which display forceful cytoplasmic streaming, are excellent model systems to study the impact of motion forces on cytoskeletons in vivo. Here we implement variational optical flow analysis as a new approach to analyze the polarity of MTs in the Drosophila oocyte, a cell that displays distinct Kinesin-dependent streaming. After validating the method as robust for describing MT orientation from confocal movies, we find that increasing the speed of flows results in aberrant plus end growth direction. Furthermore, we find that in oocytes where Kinesin is unable to induce cytoplasmic streaming, the growth direction of MT plus ends is also altered. These findings lead us to propose that cytoplasmic streaming - and thus motion by advection – contributes to the correct orientation of MTs in vivo. Finally, we propose a possible mechanism for a specialized cytoplasmic actin network (the actin mesh) to act as a regulator of flow speeds to counteract the recruitment of Kinesin to MTs.
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Affiliation(s)
- Maik Drechsler
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.,Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom.,Department of Zoology and Developmental Biology, University of Osnabrück, 49076 Osnabrück, Germany
| | - Lukas F Lang
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, United Kingdom
| | - Layla Al-Khatib
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Hendrik Dirks
- Institute for Computational and Applied Mathematics, University of Münster, 48149 Münster, Germany
| | - Martin Burger
- Department of Mathematics, Friedrich-Alexander Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Carola-Bibiane Schönlieb
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, United Kingdom
| | - Isabel M Palacios
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.,Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, United Kingdom
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23
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Schotthöfer SK, Bohrmann J. Bioelectrical and cytoskeletal patterns correlate with altered axial polarity in the follicular epithelium of the Drosophila mutant gurken. BMC DEVELOPMENTAL BIOLOGY 2020; 20:5. [PMID: 32169045 PMCID: PMC7071586 DOI: 10.1186/s12861-020-00210-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 02/26/2020] [Indexed: 01/08/2023]
Abstract
Background Bioelectrical signals are known to be involved in the generation of cell and tissue polarity as well as in cytoskeletal dynamics. The epithelium of Drosophila ovarian follicles is a suitable model system for studying connections between electrochemical gradients, patterns of cytoskeletal elements and axial polarity. By interactions between soma and germline cells, the transforming growth factor-α homolog Gurken (Grk) establishes both the anteroposterior and the dorsoventral axis during oogenesis. Results In the follicular epithelium of the wild-type (wt) and the polarity mutant grk, we analysed stage-specific gradients of membrane potentials (Vmem) and intracellular pH (pHi) using the potentiometric dye DiBAC4(3) and the fluorescent pH-indicator 5-CFDA,AM, respectively. In addition, we compared the cytoskeletal organisation in the follicular epithelium of wt and grk using fluorescent phalloidin and an antibody against acetylated α-tubulin. Corresponding to impaired polarity in grk, the slope of the anteroposterior Vmem-gradient in stage S9 is significantly reduced compared to wt. Even more striking differences in Vmem- and pHi-patterns become obvious during stage S10B, when the respective dorsoventral gradients are established in wt but not in grk. Concurrent with bioelectrical differences, wt and grk exhibit differences concerning cytoskeletal patterns in the follicular epithelium. During all vitellogenic stages, basal microfilaments in grk are characterised by transversal alignment, while wt-typical condensations in centripetal follicle cells (S9) and in dorsal centripetal follicle cells (S10B) are absent. Moreover, in grk, longitudinal alignment of microtubules occurs throughout vitellogenesis in all follicle cells, whereas in wt, microtubules in mainbody and posterior follicle cells exhibit a more cell-autonomous organisation. Therefore, in contrast to wt, the follicular epithelium in grk is characterised by missing or shallower electrochemical gradients and by more coordinated transcellular cytoskeletal patterns. Conclusions Our results show that bioelectrical polarity and cytoskeletal polarity are closely linked to axial polarity in both wt and grk. When primary polarity signals are altered, both bioelectrical and cytoskeletal patterns in the follicular epithelium change. We propose that not only cell-specific levels of Vmem and pHi, or the polarities of transcellular electrochemical gradients, but also the slopes of these gradients are crucial for cytoskeletal modifications and, thus, for proper development of epithelial polarity.
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Affiliation(s)
- Susanne Katharina Schotthöfer
- RWTH Aachen University, Institut für Biologie II, Abt. Zoologie und Humanbiologie, Worringerweg 3, 52056, Aachen, Germany
| | - Johannes Bohrmann
- RWTH Aachen University, Institut für Biologie II, Abt. Zoologie und Humanbiologie, Worringerweg 3, 52056, Aachen, Germany.
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24
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Huizar F, Soundarrajan D, Paravitorghabeh R, Zartman J. Interplay between morphogen-directed positional information systems and physiological signaling. Dev Dyn 2020; 249:328-341. [PMID: 31794137 PMCID: PMC7328709 DOI: 10.1002/dvdy.140] [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: 08/23/2019] [Revised: 11/20/2019] [Accepted: 11/22/2019] [Indexed: 12/16/2022] Open
Abstract
The development of an organism from an undifferentiated single cell into a spatially complex structure requires spatial patterning of cell fates across tissues. Positional information, proposed by Lewis Wolpert in 1969, has led to the characterization of many components involved in regulating morphogen signaling activity. However, how morphogen gradients are established, maintained, and interpreted by cells still is not fully understood. Quantitative and systems-based approaches are increasingly needed to define general biological design rules that govern positional information systems in developing organisms. This short review highlights a selective set of studies that have investigated the roles of physiological signaling in modulating and mediating morphogen-based pattern formation. Similarities between neural transmission and morphogen-based pattern formation mechanisms suggest underlying shared principles of active cell-based communication. Within larger tissues, neural networks provide directed information, via physiological signaling, that supplements positional information through diffusion. Further, mounting evidence demonstrates that physiological signaling plays a role in ensuring robustness of morphogen-based signaling. We conclude by highlighting several outstanding questions regarding the role of physiological signaling in morphogen-based pattern formation. Elucidating how physiological signaling impacts positional information is critical for understanding the close coupling of developmental and cellular processes in the context of development, disease, and regeneration.
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Affiliation(s)
- Francisco Huizar
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, South Bend, Indiana
- Bioengineering Graduate Program, University of Notre Dame, South Bend, Indiana
| | - Dharsan Soundarrajan
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, South Bend, Indiana
| | - Ramezan Paravitorghabeh
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, South Bend, Indiana
| | - Jeremiah Zartman
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, South Bend, Indiana
- Bioengineering Graduate Program, University of Notre Dame, South Bend, Indiana
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25
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Hinnant TD, Merkle JA, Ables ET. Coordinating Proliferation, Polarity, and Cell Fate in the Drosophila Female Germline. Front Cell Dev Biol 2020; 8:19. [PMID: 32117961 PMCID: PMC7010594 DOI: 10.3389/fcell.2020.00019] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 01/10/2020] [Indexed: 01/05/2023] Open
Abstract
Gametes are highly specialized cell types produced by a complex differentiation process. Production of viable oocytes requires a series of precise and coordinated molecular events. Early in their development, germ cells are an interconnected group of mitotically dividing cells. Key regulatory events lead to the specification of mature oocytes and initiate a switch to the meiotic cell cycle program. Though the chromosomal events of meiosis have been extensively studied, it is unclear how other aspects of oocyte specification are temporally coordinated. The fruit fly, Drosophila melanogaster, has long been at the forefront as a model system for genetics and cell biology research. The adult Drosophila ovary continuously produces germ cells throughout the organism’s lifetime, and many of the cellular processes that occur to establish oocyte fate are conserved with mammalian gamete development. Here, we review recent discoveries from Drosophila that advance our understanding of how early germ cells balance mitotic exit with meiotic initiation. We discuss cell cycle control and establishment of cell polarity as major themes in oocyte specification. We also highlight a germline-specific organelle, the fusome, as integral to the coordination of cell division, cell polarity, and cell fate in ovarian germ cells. Finally, we discuss how the molecular controls of the cell cycle might be integrated with cell polarity and cell fate to maintain oocyte production.
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Affiliation(s)
- Taylor D Hinnant
- Department of Biology, East Carolina University, Greenville, NC, United States
| | - Julie A Merkle
- Department of Biology, University of Evansville, Evansville, IN, United States
| | - Elizabeth T Ables
- Department of Biology, East Carolina University, Greenville, NC, United States
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26
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Modulation of Cell-Cell Interactions in Drosophila Oocyte Development. Cells 2020; 9:cells9020274. [PMID: 31979180 PMCID: PMC7072342 DOI: 10.3390/cells9020274] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/17/2020] [Accepted: 01/21/2020] [Indexed: 02/07/2023] Open
Abstract
The Drosophila ovary offers a suitable model system to study the mechanisms that orchestrate diverse cellular processes. Oogenesis starts from asymmetric stem cell division, proper differentiation and the production of fully patterned oocytes equipped with all the maternal information required for embryogenesis. Spatial and temporal regulation of cell-cell interaction is particularly important to fulfill accurate biological outcomes at each step of oocyte development. Progress has been made in understanding diverse cell physiological regulation of signaling. Here we review the roles of specialized cellular machinery in cell-cell communication in different stages of oogenesis.
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27
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Schüpbach T. Genetic Screens to Analyze Pattern Formation of Egg and Embryo in Drosophila: A Personal History. Annu Rev Genet 2019; 53:1-18. [DOI: 10.1146/annurev-genet-112618-043708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In Drosophila development, the axes of the egg and future embryo are established during oogenesis. To learn about the underlying genetic and molecular pathways that lead to axis formation, I conducted a large-scale genetic screen at the beginning of my independent career. This led to the eventual understanding that both anterior-posterior and dorsal-ventral pattern information is transmitted from the oocyte to the surrounding follicle cells and in turn from the follicle cells back to the oocyte. How I came to conduct this screen and what further insights were gained by studying the mutants isolated in the screen are the topics of this autobiographical article.
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Affiliation(s)
- Trudi Schüpbach
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
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28
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Merkle JA, Wittes J, Schüpbach T. Signaling between somatic follicle cells and the germline patterns the egg and embryo of Drosophila. Curr Top Dev Biol 2019; 140:55-86. [PMID: 32591083 DOI: 10.1016/bs.ctdb.2019.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In Drosophila, specification of the embryonic body axes requires signaling between the germline and the somatic follicle cells. These signaling events are necessary to properly localize embryonic patterning determinants in the egg or eggshell during oogenesis. There are three maternal patterning systems that specify the anterior-posterior axis, and one that establishes the dorsal-ventral axis. We will first review oogenesis, focusing on the establishment of the oocyte and nurse cells and patterning of the follicle cells into different subpopulations. We then describe how two coordinated signaling events between the oocyte and follicle cells establish polarity of the oocyte and localize the anterior determinant bicoid, the posterior determinant oskar, and Gurken/epidermal growth factor (EGF), which breaks symmetry to initiate dorsal-ventral axis establishment. Next, we review how dorsal-ventral asymmetry of the follicle cells is transmitted to the embryo. This process also involves Gurken-EGF receptor (EGFR) signaling between the oocyte and follicle cells, leading to ventrally-restricted expression of the sulfotransferase Pipe. These events promote the ventral processing of Spaetzle, a ligand for Toll, which ultimately sets up the embryonic dorsal-ventral axis. We then describe the activation of the terminal patterning system by specialized polar follicle cells. Finally, we present open questions regarding soma-germline signaling during Drosophila oogenesis required for cell identity and embryonic axis formation.
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Affiliation(s)
- Julie A Merkle
- Department of Biology, University of Evansville, Evansville, IN, United States
| | - Julia Wittes
- Department of Biological Sciences, Columbia University, New York, NY, United States
| | - Trudi Schüpbach
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States.
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29
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Asymmetric Inheritance of Cell Fate Determinants: Focus on RNA. Noncoding RNA 2019; 5:ncrna5020038. [PMID: 31075989 PMCID: PMC6630313 DOI: 10.3390/ncrna5020038] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/30/2019] [Accepted: 05/06/2019] [Indexed: 12/20/2022] Open
Abstract
During the last decade, and mainly primed by major developments in high-throughput sequencing technologies, the catalogue of RNA molecules harbouring regulatory functions has increased at a steady pace. Current evidence indicates that hundreds of mammalian RNAs have regulatory roles at several levels, including transcription, translation/post-translation, chromatin structure, and nuclear architecture, thus suggesting that RNA molecules are indeed mighty controllers in the flow of biological information. Therefore, it is logical to suggest that there must exist a series of molecular systems that safeguard the faithful inheritance of RNA content throughout cell division and that those mechanisms must be tightly controlled to ensure the successful segregation of key molecules to the progeny. Interestingly, whilst a handful of integral components of mammalian cells seem to follow a general pattern of asymmetric inheritance throughout division, the fate of RNA molecules largely remains a mystery. Herein, we will discuss current concepts of asymmetric inheritance in a wide range of systems, including prions, proteins, and finally RNA molecules, to assess overall the biological impact of RNA inheritance in cellular plasticity and evolutionary fitness.
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Barr J, Charania S, Gilmutdinov R, Yakovlev K, Shidlovskii Y, Schedl P. The CPEB translational regulator, Orb, functions together with Par proteins to polarize the Drosophila oocyte. PLoS Genet 2019; 15:e1008012. [PMID: 30865627 PMCID: PMC6433291 DOI: 10.1371/journal.pgen.1008012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/25/2019] [Accepted: 02/12/2019] [Indexed: 01/05/2023] Open
Abstract
orb is a founding member of the CPEB family of translational regulators and is required at multiple steps during Drosophila oogenesis. Previous studies showed that orb is required during mid-oogenesis for the translation of the posterior/germline determinant oskar mRNA and the dorsal-ventral determinant gurken mRNA. Here, we report that orb also functions upstream of these axes determinants in the polarization of the microtubule network (MT). Prior to oskar and gurken translational activation, the oocyte MT network is repolarized. The MT organizing center at the oocyte posterior is disassembled, and a new MT network is established at the oocyte anterior. Repolarization depends upon cross-regulatory interactions between anterior (apical) and posterior (basal) Par proteins. We show that repolarization of the oocyte also requires orb and that orb is needed for the proper functioning of the Par proteins. orb interacts genetically with aPKC and cdc42 and in egg chambers compromised for orb activity, Par-1 and aPKC protein and aPKC mRNA are mislocalized. Moreover, like cdc42-, the defects in Par protein localization appear to be connected to abnormalities in the cortical actin cytoskeleton. These abnormalities also disrupt the localization of the spectraplakin Shot and the microtubule minus-end binding protein Patronin. These two proteins play a critical role in the repolarization of the MT network. The specification of polarity axes in the Drosophila egg and embryo depends on the proper organization of the microtubule (MT) and actin cytoskeleton during mid-oogenesis. During this period, the MT organizing center at the posterior of the oocyte is disassembled and a MT network is established at the anterior and anterior-lateral cortex of the oocyte. We show that the CPEB translation factor orb plays a critical role in the reorganization of the MT network. orb appears to function at several levels during MT reorganization. orb interacts genetically with genes encoding Par proteins, aPKC and cdc42, and disrupts the localization of Par-1 and aPKC within the oocyte. orb also plays an important role in organizing the cortical actin cytoskeleton. The defects in the actin cytoskeleton disrupt the cortical association of Shot and Patronin, which are responsible for nucleating the assembly of the anterior MT network.
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Affiliation(s)
- Justinn Barr
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Sofia Charania
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Rudolf Gilmutdinov
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Konstantin Yakovlev
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Yulii Shidlovskii
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Paul Schedl
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- * E-mail:
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Baskar R, Bakrhat A, Abdu U. GFP-Forked, a genetic reporter for studying Drosophila oocyte polarity. Biol Open 2019; 8:bio.039552. [PMID: 30598482 PMCID: PMC6361205 DOI: 10.1242/bio.039552] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The polarized organization of the Drosophila oocyte can be visualized by examining the asymmetric localization of mRNAs, which is supported by networks of polarized microtubules (MTs). In this study, we used the gene forked, the putative Drosophila homologue of espin, to develop a unique genetic reporter for asymmetric oocyte organization. We generated a null allele of the forked gene using the CRISPR-Cas9 system and found that forked is not required for determining the axes of the Drosophila embryo. However, ectopic expression of a truncated form of GFP-Forked generated a distinct network of asymmetric Forked, which first accumulated at the oocyte posterior and was then restricted to the anterolateral region of the oocyte cortex in mid-oogenesis. This localization pattern resembled that reported for the polarized MTs network. Indeed, pharmacological and genetic manipulation of the polarized organization of the oocyte showed that the filamentous Forked network diffused throughout the entire cortical surface of the oocyte, as would be expected upon perturbation of oocyte polarization. Finally, we demonstrated that Forked associated with Short-stop and Patronin foci, which assemble non-centrosomal MT-organizing centers. Our results thus show that clear visualization of asymmetric GFP-Forked network localization can be used as a novel tool for studying oocyte polarity. Summary: The novel asymmetric Forked network could be used as a genetic reporter for visualizing and studying oocyte polarity.
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Affiliation(s)
- Raju Baskar
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva 8410501, Israel
| | - Anna Bakrhat
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva 8410501, Israel
| | - Uri Abdu
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva 8410501, Israel
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A Gene Expression Screen in Drosophila melanogaster Identifies Novel JAK/STAT and EGFR Targets During Oogenesis. G3-GENES GENOMES GENETICS 2019; 9:47-60. [PMID: 30385460 PMCID: PMC6325903 DOI: 10.1534/g3.118.200786] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) and epidermal growth factor receptor (EGFR) signaling pathways are conserved regulators of tissue patterning, morphogenesis, and other cell biological processes. During Drosophila oogenesis, these pathways determine the fates of epithelial follicle cells (FCs). JAK/STAT and EGFR together specify a population of cells called the posterior follicle cells (PFCs), which signal to the oocyte to establish the embryonic axes. In this study, whole genome expression analysis was performed to identify genes activated by JAK/STAT and/or EGFR. We observed that 317 genes were transcriptionally upregulated in egg chambers with ectopic JAK/STAT and EGFR activity in the FCs. The list was enriched for genes encoding extracellular matrix (ECM) components and ECM-associated proteins. We tested 69 candidates for a role in axis establishment using RNAi knockdown in the FCs. We report that the signaling protein Semaphorin 1b becomes enriched in the PFCs in response to JAK/STAT and EGFR. We also identified ADAM metallopeptidase with thrombospondin type 1 motif A (AdamTS-A) as a novel target of JAK/STAT in the FCs that regulates egg chamber shape. AdamTS-A mRNA becomes enriched at the anterior and posterior poles of the egg chamber at stages 6 to 7 and is regulated by JAK/STAT. Altering AdamTS-A expression in the poles or middle of the egg chamber produces rounder egg chambers. We propose that AdamTS-A regulates egg shape by remodeling the basement membrane.
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Balaji R, Weichselberger V, Classen AK. Response of epithelial cell and tissue shape to external forces in vivo. Development 2019; 146:dev.171256. [DOI: 10.1242/dev.171256] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 07/29/2019] [Indexed: 12/25/2022]
Abstract
How actomyosin generates forces at epithelial adherens junctions has been extensively studied. However, less is known about how a balance between internal and external forces establishes epithelial cell, tissue and organ shape. We use the Drosophila egg chamber to investigate how contractility at adherens junction in the follicle epithelium is modulated to accommodate and resist forces arising from the growing germline. We find that between stages 6 and 9 adherens junction tension in the post-mitotic epithelium decreases, suggesting that the junctional network relaxes to accommodate germline growth. At that time, a prominent medial Myosin II network coupled to corrugating adherens junctions develops. Local enrichment of medial Myosin II in main body follicle cells resists germline-derived forces, thus constraining apical areas and consequently cuboidal cell shapes at stage 9. At the tissue and organ level, local reinforcement of medial-junctional architecture ensures the timely contact of main body cells with the expanding oocyte and imposes circumferential constraints on the germline guiding egg elongation. Our study provides insight into how adherens junction tension promotes cell and tissue shape transitions while integrating growth and shape of an internally enclosed structure in vivo.
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Affiliation(s)
- Ramya Balaji
- Albert-Ludwigs-University Freiburg, Center for Biological Systems Analysis, Habsburgerstr. 49, 79104 Freiburg, Germany
- Ludwig-Maximilians-University Munich, Faculty of Biology, Grosshaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
| | - Vanessa Weichselberger
- Albert-Ludwigs-University Freiburg, Center for Biological Systems Analysis, Habsburgerstr. 49, 79104 Freiburg, Germany
- Ludwig-Maximilians-University Munich, Faculty of Biology, Grosshaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University Freiburg, Germany
| | - Anne-Kathrin Classen
- Albert-Ludwigs-University Freiburg, Center for Biological Systems Analysis, Habsburgerstr. 49, 79104 Freiburg, Germany
- Ludwig-Maximilians-University Munich, Faculty of Biology, Grosshaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
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34
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Subcellular Specialization and Organelle Behavior in Germ Cells. Genetics 2018; 208:19-51. [PMID: 29301947 DOI: 10.1534/genetics.117.300184] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Accepted: 08/17/2017] [Indexed: 11/18/2022] Open
Abstract
Gametes, eggs and sperm, are the highly specialized cell types on which the development of new life solely depends. Although all cells share essential organelles, such as the ER (endoplasmic reticulum), Golgi, mitochondria, and centrosomes, germ cells display unique regulation and behavior of organelles during gametogenesis. These germ cell-specific functions of organelles serve critical roles in successful gamete production. In this chapter, I will review the behaviors and roles of organelles during germ cell differentiation.
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Tillery MML, Blake-Hedges C, Zheng Y, Buchwalter RA, Megraw TL. Centrosomal and Non-Centrosomal Microtubule-Organizing Centers (MTOCs) in Drosophila melanogaster. Cells 2018; 7:E121. [PMID: 30154378 PMCID: PMC6162459 DOI: 10.3390/cells7090121] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 08/19/2018] [Accepted: 08/20/2018] [Indexed: 12/14/2022] Open
Abstract
The centrosome is the best-understood microtubule-organizing center (MTOC) and is essential in particular cell types and at specific stages during Drosophila development. The centrosome is not required zygotically for mitosis or to achieve full animal development. Nevertheless, centrosomes are essential maternally during cleavage cycles in the early embryo, for male meiotic divisions, for efficient division of epithelial cells in the imaginal wing disc, and for cilium/flagellum assembly in sensory neurons and spermatozoa. Importantly, asymmetric and polarized division of stem cells is regulated by centrosomes and by the asymmetric regulation of their microtubule (MT) assembly activity. More recently, the components and functions of a variety of non-centrosomal microtubule-organizing centers (ncMTOCs) have begun to be elucidated. Throughout Drosophila development, a wide variety of unique ncMTOCs form in epithelial and non-epithelial cell types at an assortment of subcellular locations. Some of these cell types also utilize the centrosomal MTOC, while others rely exclusively on ncMTOCs. The impressive variety of ncMTOCs being discovered provides novel insight into the diverse functions of MTOCs in cells and tissues. This review highlights our current knowledge of the composition, assembly, and functional roles of centrosomal and non-centrosomal MTOCs in Drosophila.
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Affiliation(s)
- Marisa M L Tillery
- Department of Biomedical Sciences, Florida State University, 1115 West Call St., Tallahassee, FL 32306, USA.
| | - Caitlyn Blake-Hedges
- Department of Biomedical Sciences, Florida State University, 1115 West Call St., Tallahassee, FL 32306, USA.
| | - Yiming Zheng
- Department of Biomedical Sciences, Florida State University, 1115 West Call St., Tallahassee, FL 32306, USA.
| | - Rebecca A Buchwalter
- Department of Biomedical Sciences, Florida State University, 1115 West Call St., Tallahassee, FL 32306, USA.
| | - Timothy L Megraw
- Department of Biomedical Sciences, Florida State University, 1115 West Call St., Tallahassee, FL 32306, USA.
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36
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The role of the EGFR signaling pathway in stem cell differentiation during planarian regeneration and homeostasis. Semin Cell Dev Biol 2018; 87:45-57. [PMID: 29775660 DOI: 10.1016/j.semcdb.2018.05.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 05/07/2018] [Accepted: 05/14/2018] [Indexed: 12/25/2022]
Abstract
Cell signaling is essential for cells to adequately respond to their environment. One of the most evolutionarily conserved signaling pathways is that of the epidermal growth factor receptor (EGFR). Transmembrane receptors with intracellular tyrosine kinase activity are activated by the binding of their corresponding ligands. This in turn activates a wide variety of intracellular cascades and induces the up- or downregulation of target genes, leading to a specific cellular response. Freshwater planarians are an excellent model in which to study the role of cell signaling in the context of stem-cell based regeneration. Owing to the presence of a population of pluripotent stem cells called neoblasts, these animals can regenerate the entire organism from a tiny piece of the body. Here, we review the current state of knowledge of the planarian EGFR pathway. We describe the main components of the pathway and their functions in other animals, and focus in particular on receptors and ligands identified in the planarian Schmidtea mediterranea. Moreover, we summarize current data on the function of some of these components during planarian regeneration and homeostasis. We hypothesize that the EGFR pathway may act as a key regulator of the terminal differentiation of distinct populations of lineage-committed progenitors.
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37
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Kamath AD, Deehan MA, Frydman HM. Polar cell fate stimulates Wolbachia intracellular growth. Development 2018; 145:dev.158097. [PMID: 29467241 DOI: 10.1242/dev.158097] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 02/12/2018] [Indexed: 11/20/2022]
Abstract
Bacteria are crucial partners in the development and evolution of vertebrates and invertebrates. A large fraction of insects harbor Wolbachia, bacterial endosymbionts that manipulate host reproduction to favor their spreading. Because they are maternally inherited, Wolbachia are under selective pressure to reach the female germline and infect the offspring. However, Wolbachia infection is not limited to the germline. Somatic cell types, including stem cell niches, have higher Wolbachia loads compared with the surrounding tissue. Here, we show a novel Wolbachia tropism to polar cells (PCs), specialized somatic cells in the Drosophila ovary. During oogenesis, all stages of PC development are easily visualized, facilitating the investigation of the kinetics of Wolbachia intracellular growth. Wolbachia accumulation is triggered by particular events of PC morphogenesis, including differentiation from progenitors and between stages 8 and 9 of oogenesis. Moreover, induction of ectopic PC fate is sufficient to promote Wolbachia accumulation. We found that Wolbachia PC tropism is evolutionarily conserved across most Drosophila species, but not in Culex mosquitos. These findings highlight the coordination of endosymbiont tropism with host development and cell differentiation.
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Affiliation(s)
- Ajit D Kamath
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - Mark A Deehan
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - Horacio M Frydman
- Department of Biology, Boston University, Boston, MA 02215, USA .,National Emerging Infectious Disease Laboratory, Boston University, Boston, MA 02118, USA
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38
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Pleiotropic Functions of the Chromodomain-Containing Protein Hat-trick During Oogenesis in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2018; 8:1067-1077. [PMID: 29367451 PMCID: PMC5844294 DOI: 10.1534/g3.117.300526] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Chromatin-remodeling proteins have a profound role in the transcriptional regulation of gene expression during development. Here, we have shown that the chromodomain-containing protein Hat-trick is predominantly expressed within the oocyte nucleus, specifically within the heterochromatinized karyosome, and that a mild expression is observed in follicle cells. Colocalization of Hat-trick with Heterochromatin Protein 1 and synaptonemal complex component C(3)G along with the diffused karyosome after hat-trick downregulation shows the role of this protein in heterochromatin clustering and karyosome maintenance. Germline mosaic analysis reveals that hat-trick is required for maintaining the dorso-ventral patterning of eggs by regulating the expression of Gurken. The increased incidence of double-strand breaks (DSBs), delayed DSB repair, defects in karyosome formation, altered Vasa mobility, and, consequently, misexpression and altered localization of Gurken in hat-trick mutant egg chambers clearly suggest a putative involvement of Hat-trick in the early stages of oogenesis. In addition, based on phenotypic observations in hat-trick mutant egg chambers, we speculate a substantial role of hat-trick in cystoblast proliferation, oocyte determination, nurse cell endoreplication, germ cell positioning, cyst encapsulation, and nurse cell migration. Our results demonstrate that hat-trick has profound pleiotropic functions during oogenesis in Drosophila melanogaster.
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39
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KENGAKU M. Cytoskeletal control of nuclear migration in neurons and non-neuronal cells. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2018; 94:337-349. [PMID: 30416174 PMCID: PMC6275330 DOI: 10.2183/pjab.94.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/10/2018] [Indexed: 06/09/2023]
Abstract
Cell migration is a complex molecular event that requires translocation of a large, stiff nucleus, oftentimes through interstitial pores of submicron size in tissues. Remarkable progress in the past decade has uncovered an ever-increasing array of diverse nuclear dynamics and underlying cytoskeletal control in various cell models. In many cases, the microtubule motors dynein and kinesin directly interact with the nucleus via the LINC complex and steer directional nuclear movement, while actomyosin contractility and its global flow exert forces to deform and move the nucleus. In this review, I focus on the synergistic interplay of the cytoskeletal motors and spatiotemporal sites of force transmission in various nuclear migration models, with a special focus on neuronal migration in the vertebrate brain.
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Affiliation(s)
- Mineko KENGAKU
- Kyoto University Institute for Advanced Study, Institute for Integrated Cell-Material Sciences (KUIAS-iCeMS), Kyoto University, Japan
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40
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Comparative transcriptome analysis of ovary and testis reveals potential sex-related genes and pathways in spotted knifejaw Oplegnathus punctatus. Gene 2017; 637:203-210. [DOI: 10.1016/j.gene.2017.09.055] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 09/12/2017] [Accepted: 09/25/2017] [Indexed: 12/22/2022]
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41
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Bernard F, Lepesant JA, Guichet A. Nucleus positioning within Drosophila egg chamber. Semin Cell Dev Biol 2017; 82:25-33. [PMID: 29056490 DOI: 10.1016/j.semcdb.2017.10.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 10/09/2017] [Accepted: 10/12/2017] [Indexed: 12/12/2022]
Abstract
Both types of Drosophila egg chamber germ cells, i.e. oocyte and nurse cells, have to control their nucleus positions in order to produce a viable gamete. Interestingly, while actin microfilaments are crucial to position the nuclei in nurse cells, these are the microtubules that are important for oocyte nucleus to migrate and adopt the correct position. In this review, we discuss the mechanisms underlying these positioning processes in the two cell types with respect to the organization and dynamics of the actin and microtubule skeleton. In the nurse cells it is essential to keep firmly the nuclei in a central position to prevent them from obstructing the ring canals when the cytoplasmic content of the cells is dumped into the oocyte cells toward the end of oogenesis. This is achieved by the assembly of thick filopodia-like actin cables anchored to the plasma membrane, which grow inwardly and eventually encase tightly the nuclei in a cage-like structure. In the oocyte, the migration at an early stage of oogenesis of the nucleus from a posterior location to an anchorage site at an asymmetric anterior position, is an essential step in the setting up of the dorsoventral polarity axis of the future embryo. This process is controlled by an interplay between MT networks that just start to be untangled. Although both mechanisms have evolved to fulfill cell-type specific cell processes in the context of fly oogenesis, interesting parallels can be drawn with other nuclear positioning mechanisms in the mouse oocyte and the developing muscle respectively.
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Affiliation(s)
- Fred Bernard
- Institut Jacques Monod, CNRS UMR 7592, Université Paris-Diderot, Sorbonne Paris Cité, 75205, Paris Cedex, France.
| | - Jean-Antoine Lepesant
- Institut Jacques Monod, CNRS UMR 7592, Université Paris-Diderot, Sorbonne Paris Cité, 75205, Paris Cedex, France.
| | - Antoine Guichet
- Institut Jacques Monod, CNRS UMR 7592, Université Paris-Diderot, Sorbonne Paris Cité, 75205, Paris Cedex, France.
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42
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Elkouby YM, Mullins MC. Coordination of cellular differentiation, polarity, mitosis and meiosis - New findings from early vertebrate oogenesis. Dev Biol 2017; 430:275-287. [PMID: 28666956 DOI: 10.1016/j.ydbio.2017.06.029] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 06/23/2017] [Accepted: 06/26/2017] [Indexed: 12/21/2022]
Abstract
A mechanistic dissection of early oocyte differentiation in vertebrates is key to advancing our knowledge of germline development, reproductive biology, the regulation of meiosis, and all of their associated disorders. Recent advances in the field include breakthroughs in the identification of germline stem cells in Medaka, in the cellular architecture of the germline cyst in mice, in a mechanistic dissection of chromosomal pairing and bouquet formation in meiosis in mice, in tracing oocyte symmetry breaking to the chromosomal bouquet of meiosis in zebrafish, and in the biology of the Balbiani body, a universal oocyte granule. Many of the major events in early oogenesis are universally conserved, and some are co-opted for species-specific needs. The chromosomal events of meiosis are of tremendous consequence to gamete formation and have been extensively studied. New light is now being shed on other aspects of early oocyte differentiation, which were traditionally considered outside the scope of meiosis, and their coordination with meiotic events. The emerging theme is of meiosis as a common groundwork for coordinating multifaceted processes of oocyte differentiation. In an accompanying manuscript we describe methods that allowed for investigations in the zebrafish ovary to contribute to these breakthroughs. Here, we review these advances mostly from the zebrafish and mouse. We discuss oogenesis concepts across established model organisms, and construct an inclusive paradigm for early oocyte differentiation in vertebrates.
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Affiliation(s)
- Yaniv M Elkouby
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Mary C Mullins
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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43
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Distinct molecular cues ensure a robust microtubule-dependent nuclear positioning in the Drosophila oocyte. Nat Commun 2017; 8:15168. [PMID: 28447612 PMCID: PMC5414183 DOI: 10.1038/ncomms15168] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 03/02/2017] [Indexed: 11/08/2022] Open
Abstract
Controlling nucleus localization is crucial for a variety of cellular functions. In the Drosophila oocyte, nuclear asymmetric positioning is essential for the reorganization of the microtubule (MT) network that controls the polarized transport of axis determinants. A combination of quantitative three-dimensional live imaging and laser ablation-mediated force analysis reveal that nuclear positioning is ensured with an unexpected level of robustness. We show that the nucleus is pushed to the oocyte antero-dorsal cortex by MTs and that its migration can proceed through distinct tracks. Centrosome-associated MTs favour one migratory route. In addition, the MT-associated protein Mud/NuMA that is asymmetrically localized in an Asp-dependent manner at the nuclear envelope hemisphere where MT nucleation is higher promotes a separate route. Our results demonstrate that centrosomes do not provide an obligatory driving force for nuclear movement, but together with Mud, contribute to the mechanisms that ensure the robustness of asymmetric nuclear positioning. Asymmetric nuclear positioning in the fruit fly oocyte is essential for the correct localization of axis determinants. Here, the authors show that different microtubule-dependent mechanisms contribute to nuclear transport and ensure the robustness of nuclear positioning.
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44
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Duhart JC, Parsons TT, Raftery LA. The repertoire of epithelial morphogenesis on display: Progressive elaboration of Drosophila egg structure. Mech Dev 2017; 148:18-39. [PMID: 28433748 DOI: 10.1016/j.mod.2017.04.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 04/07/2017] [Accepted: 04/12/2017] [Indexed: 12/26/2022]
Abstract
Epithelial structures are foundational for tissue organization in all metazoans. Sheets of epithelial cells form lateral adhesive junctions and acquire apico-basal polarity perpendicular to the surface of the sheet. Genetic analyses in the insect model, Drosophila melanogaster, have greatly advanced our understanding of how epithelial organization is established, and how it is modulated during tissue morphogenesis. Major insights into collective cell migrations have come from analyses of morphogenetic movements within the adult follicular epithelium that cooperates with female germ cells to build a mature egg. Epithelial follicle cells progress through tightly choreographed phases of proliferation, patterning, reorganization and migrations, before they differentiate to form the elaborate structures of the eggshell. Distinct structural domains are organized by differential adhesion, within which lateral junctions are remodeled to further shape the organized epithelia. During collective cell migrations, adhesive interactions mediate supracellular organization of planar polarized macromolecules, and facilitate crawling over the basement membrane or traction against adjacent cell surfaces. Comparative studies with other insects are revealing the diversification of morphogenetic movements for elaboration of epithelial structures. This review surveys the repertoire of follicle cell morphogenesis, to highlight the coordination of epithelial plasticity with progressive differentiation of a secretory epithelium. Technological advances will keep this tissue at the leading edge for interrogating the precise spatiotemporal regulation of normal epithelial reorganization events, and provide a framework for understanding pathological tissue dysplasia.
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Affiliation(s)
- Juan Carlos Duhart
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154-4004, United States
| | - Travis T Parsons
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154-4004, United States
| | - Laurel A Raftery
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV 89154-4004, United States.
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45
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Bence M, Jankovics F, Lukácsovich T, Erdélyi M. Combining the auxin-inducible degradation system with CRISPR/Cas9-based genome editing for the conditional depletion of endogenous Drosophila melanogaster proteins. FEBS J 2017; 284:1056-1069. [PMID: 28207183 DOI: 10.1111/febs.14042] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 12/21/2016] [Accepted: 02/13/2017] [Indexed: 11/28/2022]
Abstract
Inducible protein degradation techniques have considerable advantages over classical genetic approaches, which generate loss-of-function phenotypes at the gene or mRNA level. The plant-derived auxin-inducible degradation system (AID) is a promising technique which enables the degradation of target proteins tagged with the AID motif in nonplant cells. Here, we present a detailed characterization of this method employed during the adult oogenesis of Drosophila. Furthermore, with the help of CRISPR/Cas9-based genome editing, we improve the utility of the AID system in the conditional elimination of endogenously expressed proteins. We demonstrate that the AID system induces efficient and reversible protein depletion of maternally provided proteins both in the ovary and the early embryo. Moreover, the AID system provides a fine spatiotemporal control of protein degradation and allows for the generation of different levels of protein knockdown in a well-regulated manner. These features of the AID system enable the unraveling of the discrete phenotypes of genes with highly complex functions. We utilized this system to generate a conditional loss-of-function allele which allows for the specific degradation of the Vasa protein without affecting its alternative splice variant (solo) and the vasa intronic gene (vig). With the help of this special allele, we demonstrate that dramatic decrease of Vasa protein in the vitellarium does not influence the completion of oogenesis as well as the establishment of proper anteroposterior and dorsoventral polarity in the developing oocyte. Our study suggests that both the localization and the translation of gurken mRNA in the vitellarium is independent from Vasa.
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Affiliation(s)
- Melinda Bence
- Institute of Genetics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Ferenc Jankovics
- Institute of Genetics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | | | - Miklós Erdélyi
- Institute of Genetics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
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46
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Abstract
Acquisition of oocyte polarity involves complex translocation and aggregation of intracellular organelles, RNAs, and proteins, along with strict posttranscriptional regulation. While much is still unknown regarding the formation of the animal-vegetal axis, an early marker of polarity, animal models have contributed to our understanding of these early processes controlling normal oogenesis and embryo development. In recent years, it has become clear that proteins with self-assembling properties are involved in assembling discrete subcellular compartments or domains underlying subcellular asymmetries in the early mitotic and meiotic cells of the female germline. These include asymmetries in duplication of the centrioles and formation of centrosomes and assembly of the organelle and RNA-rich Balbiani body, which plays a critical role in oocyte polarity. Notably, at specific stages of germline development, these transient structures in oocytes are temporally coincident and align with asymmetries in the position and arrangement of nuclear components, such as the nuclear pore and the chromosomal bouquet and the centrioles and cytoskeleton in the cytoplasm. Formation of these critical, transient structures and arrangements involves microtubule pathways, intrinsically disordered proteins (proteins with domains that tend to be fluid or lack a rigid ordered three-dimensional structure ranging from random coils, globular domains, to completely unstructured proteins), and translational repressors and activators. This review aims to examine recent literature and key players in oocyte polarity.
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Affiliation(s)
- Mara Clapp
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY, USA
| | - Florence L Marlow
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY, USA.
- Department of Neuroscience, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY, USA.
- Department of Cell, Developmental and Regenerative Medicine, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY, 10029-6574, USA.
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Dehghani M, Lasko P. Multiple Functions of the DEAD-Box Helicase Vasa in Drosophila Oogenesis. Results Probl Cell Differ 2017; 63:127-147. [PMID: 28779316 DOI: 10.1007/978-3-319-60855-6_6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The DEAD-box helicase Vasa (Vas) has been most extensively studied in the fruit fly, Drosophila melanogaster, and numerous roles for it in germline development have been discovered. Here, we summarize the present state of knowledge about processes during oogenesis that involve Vas, as well as functions of Vas as a maternal determinant of embryonic spatial patterning and germ cell specification. We review literature that implicates Vas in Piwi-interacting RNA (piRNA) biogenesis in germline cells and in regulating mitosis in germline stem cells (GSCs). We describe the functions of Vas in translational activation of two mRNAs, gurken (grk) and mei-P26, which encode proteins that are important regulators of developmental processes, as Grk specifies both the dorsal-ventral and the anterior-posterior axis of the embryo and Mei-P26 promotes GSC differentiation. The role of Vas in assembly of polar granules, ribonucleoprotein particles that accumulate in the posterior pole plasm of the oocyte and are essential for germ cell specification and posterior embryonic patterning, is also described.
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Affiliation(s)
- Mehrnoush Dehghani
- Department of Biology, McGill University, 3649 Promenade Sir William Osler, Montréal, Québec, Canada, H3G 0B1
| | - Paul Lasko
- Department of Biology, McGill University, 3649 Promenade Sir William Osler, Montréal, Québec, Canada, H3G 0B1.
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48
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Goldman CH, Gonsalvez GB. The Role of Microtubule Motors in mRNA Localization and Patterning Within the Drosophila Oocyte. Results Probl Cell Differ 2017; 63:149-168. [PMID: 28779317 DOI: 10.1007/978-3-319-60855-6_7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Messenger RNA (mRNA) localization is a powerful and prevalent mechanism of post-transcriptional gene regulation, enabling the cell to produce protein at the exact location at which it is needed. The phenomenon of mRNA localization has been observed in many types of cells in organisms ranging from yeast to man. Thus, the process appears to be widespread and highly conserved. Several model systems have been used to understand the mechanism by which mRNAs are localized. One such model, and the focus of this chapter, is the egg chamber of the female Drosophila melanogaster. The polarity of the developing Drosophila oocyte and resulting embryo relies on the specific localization of three critical mRNAs: gurken, bicoid, and oskar. If these mRNAs are not localized during oogenesis, the resulting progeny will not survive. The study of these mRNAs has served as a model for understanding the general mechanisms by which mRNAs are sorted. In this chapter, we will discuss how the localization of these mRNAs enables polarity establishment. We will also discuss the role of motor proteins in the localization pathway. Finally, we will consider potential mechanisms by which mRNAs can be anchored at their site of localization. It is likely that the lessons learned using the Drosophila oocyte model system will be applicable to mRNAs that are localized in other organisms as well.
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Affiliation(s)
- Chandler H Goldman
- Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, 1459 Laney Walker Blvd., CB2917, Augusta, GA, 30912, USA
| | - Graydon B Gonsalvez
- Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, 1459 Laney Walker Blvd., CB2917, Augusta, GA, 30912, USA.
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49
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Nieuwburg R, Nashchekin D, Jakobs M, Carter AP, Khuc Trong P, Goldstein RE, St Johnston D. Localised dynactin protects growing microtubules to deliver oskar mRNA to the posterior cortex of the Drosophila oocyte. eLife 2017; 6:e27237. [PMID: 29035202 PMCID: PMC5643094 DOI: 10.7554/elife.27237] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 09/19/2017] [Indexed: 11/13/2022] Open
Abstract
The localisation of oskar mRNA to the posterior of the Drosophila oocyte defines where the abdomen and germ cells form in the embryo. Kinesin 1 transports oskar mRNA to the oocyte posterior along a polarised microtubule cytoskeleton that grows from non-centrosomal microtubule organising centres (ncMTOCs) along the anterior/lateral cortex. Here, we show that the formation of this polarised microtubule network also requires the posterior regulation of microtubule growth. A missense mutation in the dynactin Arp1 subunit causes most oskar mRNA to localise in the posterior cytoplasm rather than cortically. oskar mRNA transport and anchoring are normal in this mutant, but the microtubules fail to reach the posterior pole. Thus, dynactin acts as an anti-catastrophe factor that extends microtubule growth posteriorly. Kinesin 1 transports dynactin to the oocyte posterior, creating a positive feedback loop that increases the length and persistence of the posterior microtubules that deliver oskar mRNA to the cortex.
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Affiliation(s)
- Ross Nieuwburg
- The Gurdon Institute and the Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Dmitry Nashchekin
- The Gurdon Institute and the Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Maximilian Jakobs
- The Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUnited Kingdom
| | - Andrew P Carter
- Division of Structural StudiesMedical Research Council, Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Philipp Khuc Trong
- Department of Applied Mathematics and Theoretical PhysicsUniversity of Cambridge, Centre for Mathematical SciencesCambridgeUnited Kingdom
| | - Raymond E Goldstein
- Department of Applied Mathematics and Theoretical PhysicsUniversity of Cambridge, Centre for Mathematical SciencesCambridgeUnited Kingdom
| | - Daniel St Johnston
- The Gurdon Institute and the Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
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50
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Abstract
PAR-1/MARK kinases are conserved serine/threonine kinases that are essential regulators of cell polarity. PAR-1/MARK kinases localize and function in opposition to the anterior PAR proteins to control the asymmetric distribution of factors in a wide variety polarized cells. In this review, we discuss the mechanisms that control the localization and activity of PAR-1/MARK kinases, including their antagonistic interactions with the anterior PAR proteins. We focus on the role PAR-1 plays in the asymmetric division of the Caenorhabditis elegans zygote, in the establishment of the anterior/posterior axis in the Drosophila oocyte and in the control of microtubule dynamics in mammalian neurons. In addition to conserved aspects of PAR-1 biology, we highlight the unique ways in which PAR-1 acts in these distinct cell types to orchestrate their polarization. Finally, we review the connections between disruptions in PAR-1/MARK function and Alzheimer's disease and cancer.
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Affiliation(s)
- Youjun Wu
- Dartmouth College, Hanover, NH, United States
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