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Nyberg KG, Navales FG, Keles E, Nguyen JQ, Hertz LM, Carthew RW. Robust and heritable knockdown of gene expression using a self-cleaving ribozyme in Drosophila. Genetics 2024; 227:iyae067. [PMID: 38701221 PMCID: PMC11304983 DOI: 10.1093/genetics/iyae067] [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: 01/19/2024] [Revised: 04/11/2024] [Accepted: 04/20/2024] [Indexed: 05/05/2024] Open
Abstract
The current toolkit for genetic manipulation in the model animal Drosophila melanogaster is extensive and versatile but not without its limitations. Here, we report a powerful and heritable method to knockdown gene expression in D. melanogaster using the self-cleaving N79 hammerhead ribozyme, a modification of a naturally occurring ribozyme found in the parasite Schistosoma mansoni. A 111-bp ribozyme cassette, consisting of the N79 ribozyme surrounded by insulating spacer sequences, was inserted into 4 independent long noncoding RNA genes as well as the male-specific splice variant of doublesex using scarless CRISPR/Cas9-mediated genome editing. Ribozyme-induced RNA cleavage resulted in robust destruction of 3' fragments typically exceeding 90%. Single molecule RNA fluorescence in situ hybridization results suggest that cleavage and destruction can even occur for nascent transcribing RNAs. Knockdown was highly specific to the targeted RNA, with no adverse effects observed in neighboring genes or the other splice variants. To control for potential effects produced by the simple insertion of 111 nucleotides into genes, we tested multiple catalytically inactive ribozyme variants and found that a variant with scrambled N79 sequence best recapitulated natural RNA levels. Thus, self-cleaving ribozymes offer a novel approach for powerful gene knockdown in Drosophila, with potential applications for the study of noncoding RNAs, nuclear-localized RNAs, and specific splice variants of protein-coding genes.
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Affiliation(s)
- Kevin G Nyberg
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Fritz Gerald Navales
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Eren Keles
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Joseph Q Nguyen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Laura M Hertz
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Richard W Carthew
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
- NSF-Simons National Institute for Theory and Mathematics in Biology, Evanston, IL 60208, USA
- NSF-Simons Center for Quantitative Biology, Evanston, IL 60208, USA
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2
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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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3
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Hopkins BR, Barmina O, Kopp A. A single-cell atlas of the sexually dimorphic Drosophila foreleg and its sensory organs during development. PLoS Biol 2023; 21:e3002148. [PMID: 37379332 DOI: 10.1371/journal.pbio.3002148] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 05/03/2023] [Indexed: 06/30/2023] Open
Abstract
To respond to the world around them, animals rely on the input of a network of sensory organs distributed throughout the body. Distinct classes of sensory organs are specialized for the detection of specific stimuli such as strain, pressure, or taste. The features that underlie this specialization relate both to the neurons that innervate sensory organs and the accessory cells they comprise. To understand the genetic basis of this diversity of cell types, both within and between sensory organs, we performed single-cell RNA sequencing on the first tarsal segment of the male Drosophila melanogaster foreleg during pupal development. This tissue displays a wide variety of functionally and structurally distinct sensory organs, including campaniform sensilla, mechanosensory bristles, and chemosensory taste bristles, as well as the sex comb, a recently evolved male-specific structure. In this study, we characterize the cellular landscape in which the sensory organs reside, identify a novel cell type that contributes to the construction of the neural lamella, and resolve the transcriptomic differences among support cells within and between sensory organs. We identify the genes that distinguish between mechanosensory and chemosensory neurons, resolve a combinatorial transcription factor code that defines 4 distinct classes of gustatory neurons and several types of mechanosensory neurons, and match the expression of sensory receptor genes to specific neuron classes. Collectively, our work identifies core genetic features of a variety of sensory organs and provides a rich, annotated resource for studying their development and function.
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Affiliation(s)
- Ben R Hopkins
- Department of Evolution and Ecology, University of California, Davis, California, United States of America
| | - Olga Barmina
- Department of Evolution and Ecology, University of California, Davis, California, United States of America
| | - Artyom Kopp
- Department of Evolution and Ecology, University of California, Davis, California, United States of America
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4
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Logan G, Chou WC, McCartney BM. A Diaphanous and Enabled-dependent asymmetric actin cable array repositions nuclei during Drosophila oogenesis. Development 2022; 149:275657. [DOI: 10.1242/dev.197442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 05/24/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Cells reposition their nuclei for diverse specialized functions through a wide variety of cytoskeletal mechanisms. During Drosophila oogenesis, 15 nurse cells connected by ring canals to each other and the oocyte contract, ‘dumping’ their cytoplasm into the oocyte. Prior to dumping, actin cables initiate from the nurse cell cortex and elongate toward their nuclei, pushing them away from ring canals to prevent obstruction. How the cable arrays reposition nuclei is unknown. We found that these arrays are asymmetric, with regional differences in actin cable growth rate dependent on the differential localization of the actin assembly factors Enabled and Diaphanous. Enabled mislocalization produces a uniform growth rate. In oocyte-contacting nurse cells with asymmetric cable arrays, nuclei move away from ring canals. With uniform arrays, these nuclei move toward the adjacent ring canal instead. This correlated with ring canal nuclear blockage and incomplete dumping. Our data suggest that nuclear repositioning relies on the regulated cortical localization of Diaphanous and Enabled to produce actin cable arrays with asymmetric growth that push nuclei away from ring canals, enabling successful oogenesis.
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Affiliation(s)
- Gregory Logan
- Carnegie Mellon University Department of Biological Sciences , , 4400 Fifth Avenue, Pittsburgh, PA 15213 , USA
| | - Wei-Chien Chou
- Carnegie Mellon University Department of Biological Sciences , , 4400 Fifth Avenue, Pittsburgh, PA 15213 , USA
| | - Brooke M. McCartney
- Carnegie Mellon University Department of Biological Sciences , , 4400 Fifth Avenue, Pittsburgh, PA 15213 , USA
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5
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Pravder HD, Grabowska D, Roychoudhury K, Zhang B, Frank D, Zakrzewski P, Lenartowska M, Miller KG. PFTAIRE Kinase L63 Interactor 1A (Pif1A Protein) Is Required for Actin Cone Movement during Spermatid Individualization in Drosophila melanogaster. Int J Mol Sci 2022; 23:ijms23063011. [PMID: 35328431 PMCID: PMC8950383 DOI: 10.3390/ijms23063011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/02/2022] [Accepted: 03/08/2022] [Indexed: 01/25/2023] Open
Abstract
A useful model for determining the mechanisms by which actin and actin binding proteins control cellular architecture is the Drosophila melanogaster process of spermatogenesis. During the final step of spermatogenesis, 64 syncytial spermatids individualized as stable actin cones move synchronously down the axonemes and remodel the membranes. To identify new genes involved in spermatid individualization, we screened a collection of Drosophila male-sterile mutants and found that, in the line Z3-5009, actin cones formed near to the spermatid nuclei but failed to move, resulting in failed spermatid individualization. However, we show by phalloidin actin staining, electron microscopy and immunocytochemical localization of several actin binding proteins that the early cones had normal structure. We sequenced the genome of the Z3-5009 line and identified mutations in the PFTAIRE kinase L63 interactor 1A (Pif1A) gene. Quantitative real-time PCR showed that Pif1A transcript abundance was decreased in the mutant, and a transgene expressing Pif1A fused to green fluorescent protein (GFP) was able to fully rescue spermatid individualization and male fertility. Pif1A-GFP localized to the front of actin cones before initiation of movement. We propose that Pif1A plays a pivotal role in directing actin cone movement.
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Affiliation(s)
- Harrison D. Pravder
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA; (H.D.P.); (D.G.); (K.R.); (B.Z.); (K.G.M.)
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Dorota Grabowska
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA; (H.D.P.); (D.G.); (K.R.); (B.Z.); (K.G.M.)
- Department of Radiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Kaushik Roychoudhury
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA; (H.D.P.); (D.G.); (K.R.); (B.Z.); (K.G.M.)
| | - Betty Zhang
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA; (H.D.P.); (D.G.); (K.R.); (B.Z.); (K.G.M.)
| | - Deborah Frank
- Department of Obstetrics and Gynecology, Center for Reproductive Health Sciences, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA;
| | - Przemysław Zakrzewski
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Torun, 87-100 Torun, Poland;
- School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Marta Lenartowska
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Torun, 87-100 Torun, Poland;
- Correspondence:
| | - Kathryn G. Miller
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA; (H.D.P.); (D.G.); (K.R.); (B.Z.); (K.G.M.)
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6
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Hurbain I, Macé AS, Romao M, Prince E, Sengmanivong L, Ruel L, Basto R, Thérond PP, Raposo G, D'Angelo G. Microvilli-derived extracellular vesicles carry Hedgehog morphogenic signals for Drosophila wing imaginal disc development. Curr Biol 2021; 32:361-373.e6. [PMID: 34890558 DOI: 10.1016/j.cub.2021.11.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 08/12/2021] [Accepted: 11/10/2021] [Indexed: 12/20/2022]
Abstract
Morphogens are secreted molecules that regulate and coordinate major developmental processes, such as cell differentiation and tissue morphogenesis. Depending on the mechanisms of secretion and the nature of their carriers, morphogens act at short and long range. We investigated the paradigmatic long-range activity of Hedgehog (Hh), a well-known morphogen, and its contribution to the growth and patterning of the Drosophila wing imaginal disc. Extracellular vesicles (EVs) contribute to Hh long-range activity; however, the nature, the site, and the mechanisms underlying the biogenesis of these vesicular carriers remain unknown. Here, through the analysis of mutants and a series of Drosophila RNAi-depleted wing imaginal discs using fluorescence and live-imaging electron microscopy, including tomography and 3D reconstruction, we demonstrate that microvilli of the wing imaginal disc epithelium are the site of generation of small EVs that transport Hh across the tissue. Further, we show that the Prominin-like (PromL) protein is critical for microvilli integrity. Together with actin cytoskeleton and membrane phospholipids, PromL maintains microvilli architecture that is essential to promote its secretory function. Importantly, the distribution of Hh to microvilli and its release via these EVs contribute to the proper morphogenesis of the wing imaginal disc. Our results demonstrate that microvilli-derived EVs are carriers for Hh long-range signaling in vivo. By establishing that members of the Prominin protein family are key determinants of microvilli formation and integrity, our findings support the view that microvilli-derived EVs conveying Hh may provide a means for exchanging signaling cues of high significance in tissue development and cancer.
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Affiliation(s)
- Ilse Hurbain
- Institut Curie, PSL Research University, CNRS, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France; Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), 26, rue d'Ulm, 75248 Paris Cedex 05, France
| | - Anne-Sophie Macé
- Institut Curie, PSL Research University, CNRS, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France; Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), 26, rue d'Ulm, 75248 Paris Cedex 05, France
| | - Maryse Romao
- Institut Curie, PSL Research University, CNRS, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France; Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), 26, rue d'Ulm, 75248 Paris Cedex 05, France
| | - Elodie Prince
- Université Côte d'Azur, UMR7277 CNRS, Inserm U1091, Institute of Biology Valrose (iBV), Parc Valrose, 06108 Nice Cedex 2, France
| | - Lucie Sengmanivong
- Institut Curie, PSL Research University, CNRS, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France; Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), 26, rue d'Ulm, 75248 Paris Cedex 05, France
| | - Laurent Ruel
- Université Côte d'Azur, UMR7277 CNRS, Inserm U1091, Institute of Biology Valrose (iBV), Parc Valrose, 06108 Nice Cedex 2, France
| | - Renata Basto
- Institut Curie, PSL Research University, CNRS, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Pascal P Thérond
- Université Côte d'Azur, UMR7277 CNRS, Inserm U1091, Institute of Biology Valrose (iBV), Parc Valrose, 06108 Nice Cedex 2, France
| | - Graça Raposo
- Institut Curie, PSL Research University, CNRS, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France; Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), 26, rue d'Ulm, 75248 Paris Cedex 05, France
| | - Gisela D'Angelo
- Institut Curie, PSL Research University, CNRS, UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France; Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), 26, rue d'Ulm, 75248 Paris Cedex 05, France.
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7
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Lebo DPV, Chirn A, Taylor JD, Levan A, Doerre Torres V, Agreda E, Serizier SB, Lord AK, Jenkins VK, McCall K. An RNAi screen of the kinome in epithelial follicle cells of the Drosophila melanogaster ovary reveals genes required for proper germline death and clearance. G3-GENES GENOMES GENETICS 2021; 11:6080751. [PMID: 33693600 PMCID: PMC8022946 DOI: 10.1093/g3journal/jkaa066] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 12/09/2020] [Indexed: 02/07/2023]
Abstract
Programmed cell death and cell corpse clearance are an essential part of organismal health and development. Cell corpses are often cleared away by professional phagocytes such as macrophages. However, in certain tissues, neighboring cells known as nonprofessional phagocytes can also carry out clearance functions. Here, we use the Drosophila melanogaster ovary to identify novel genes required for clearance by nonprofessional phagocytes. In the Drosophila ovary, germline cells can die at multiple time points. As death proceeds, the epithelial follicle cells act as phagocytes to facilitate the clearance of these cells. We performed an unbiased kinase screen to identify novel proteins and pathways involved in cell clearance during two death events. Of 224 genes examined, 18 demonstrated severe phenotypes during developmental death and clearance while 12 demonstrated severe phenotypes during starvation-induced cell death and clearance, representing a number of pathways not previously implicated in phagocytosis. Interestingly, it was found that several genes not only affected the clearance process in the phagocytes, but also non-autonomously affected the process by which germline cells died. This kinase screen has revealed new avenues for further exploration and investigation.
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Affiliation(s)
- Diane P V Lebo
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - Alice Chirn
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - Jeffrey D Taylor
- Department of Biology, Boston University, Boston, MA 02215, USA.,Program in Biochemistry and Molecular Biology, Boston University, Boston, MA 02215, USA
| | - Andre Levan
- Department of Biology, Boston University, Boston, MA 02215, USA.,Program in Biochemistry and Molecular Biology, Boston University, Boston, MA 02215, USA
| | | | - Emily Agreda
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - Sandy B Serizier
- Department of Biology, Boston University, Boston, MA 02215, USA.,Program in Molecular Biology, Cell Biology, and Biochemistry, Boston University, Boston, MA 02215, USA
| | - Allison K Lord
- Department of Biology, Boston University, Boston, MA 02215, USA
| | | | - Kimberly McCall
- Department of Biology, Boston University, Boston, MA 02215, USA
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8
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Krishnan RK, Baskar R, Anna B, Elia N, Boermel M, Bausch AR, Abdu U. Recapitulating Actin Module Organization in the Drosophila Oocyte Reveals New Roles for Bristle-Actin-Modulating Proteins. Int J Mol Sci 2021; 22:ijms22084006. [PMID: 33924532 PMCID: PMC8070096 DOI: 10.3390/ijms22084006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 04/05/2021] [Accepted: 04/06/2021] [Indexed: 11/16/2022] Open
Abstract
The generation of F-actin bundles is controlled by the action of actin-binding proteins. In Drosophila bristle development, two major actin-bundling proteins—Forked and Fascin—were identified, but still the molecular mechanism by which these actin-bundling proteins and other proteins generate bristle actin bundles is unknown. In this study, we developed a technique that allows recapitulation of bristle actin module organization using the Drosophila ovary by a combination of confocal microscopy, super-resolution structured illumination microscopy, and correlative light and electron microscope analysis. Since Forked generated a distinct ectopic network of actin bundles in the oocyte, the additive effect of two other actin-associated proteins, namely, Fascin and Javelin (Jv), was studied. We found that co-expression of Fascin and Forked demonstrated that the number of actin filaments within the actin bundles dramatically increased, and in their geometric organization, they resembled bristle-like actin bundles. On the other hand, co-expression of Jv with Forked increased the length and density of the actin bundles. When all three proteins co-expressed, the actin bundles were longer and denser, and contained a high number of actin filaments in the bundle. Thus, our results demonstrate that the Drosophila oocyte could serve as a test tube for actin bundle analysis.
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Affiliation(s)
- Ramesh Kumar Krishnan
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel; (R.K.K.); (R.B.); (B.A.); (N.E.)
| | - Raju Baskar
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel; (R.K.K.); (R.B.); (B.A.); (N.E.)
| | - Bakhrat Anna
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel; (R.K.K.); (R.B.); (B.A.); (N.E.)
| | - Natalie Elia
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel; (R.K.K.); (R.B.); (B.A.); (N.E.)
- National Institute for Biotechnology in the Negev (NIBN), Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Mandy Boermel
- Electron Microscopy Core Facility, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany;
| | - Andreas R. Bausch
- Lehrstuhl für Zellbiophysik E27, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany;
- Center for Protein Assemblies (CPA), Ernst-Otto-Fischer Str. 8, 85747 Garching, Germany
| | - Uri Abdu
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel; (R.K.K.); (R.B.); (B.A.); (N.E.)
- Correspondence:
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9
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Sallee JL, Crawford JM, Singh V, Kiehart DP. Mutations in Drosophila crinkled/Myosin VIIA disrupt denticle morphogenesis. Dev Biol 2021; 470:121-135. [PMID: 33248112 PMCID: PMC7855556 DOI: 10.1016/j.ydbio.2020.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 11/17/2020] [Accepted: 11/19/2020] [Indexed: 10/22/2022]
Abstract
Actin filament crosslinking, bundling and molecular motor proteins are necessary for the assembly of epithelial projections such as microvilli, stereocilia, hairs, and bristles. Mutations in such proteins cause defects in the shape, structure, and function of these actin - based protrusions. One protein necessary for stereocilia formation, Myosin VIIA, is an actin - based motor protein conserved throughout phylogeny. In Drosophila melanogaster, severe mutations in the MyoVIIA homolog crinkled (ck) are "semi - lethal" with only a very small percentage of flies surviving to adulthood. Such survivors show morphological defects related to actin bundling in hairs and bristles. To better understand ck/MyoVIIA's function in bundled - actin structures, we used dominant female sterile approaches to analyze the loss of maternal and zygotic (M/Z) ck/MyoVIIA in the morphogenesis of denticles, small actin - based projections on the ventral epidermis of Drosophila embryos. M/Z ck mutants displayed severe defects in denticle morphology - actin filaments initiated in the correct location, but failed to elongate and bundle to form normal projections. Using deletion mutant constructs, we demonstrated that both of the C - terminal MyTH4 and FERM domains are necessary for proper denticle formation. Furthermore, we show that ck/MyoVIIA interacts genetically with dusky - like (dyl), a member of the ZPD family of proteins that links the extracellular matrix to the plasma membrane, and when mutated also disrupts normal denticle formation. Loss of either protein alone does not alter the localization of the other; however, loss of the two proteins together dramatically enhances the defects in denticle shape observed when either protein alone was absent. Our data indicate that ck/MyoVIIA plays a key role in the formation and/or organization of actin filament bundles, which drive proper shape of cellular projections.
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Affiliation(s)
- Jennifer L Sallee
- Department of Biology, Duke University, Durham, NC, 27708, USA; Department of Biology, North Central College, Naperville, IL, 60540, USA.
| | | | - Vinay Singh
- Department of Biology, Duke University, Durham, NC, 27708, USA
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10
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Gerdes JA, Mannix KM, Hudson AM, Cooley L. HtsRC-Mediated Accumulation of F-Actin Regulates Ring Canal Size During Drosophila melanogaster Oogenesis. Genetics 2020; 216:717-734. [PMID: 32883702 PMCID: PMC7648574 DOI: 10.1534/genetics.120.303629] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 08/30/2020] [Indexed: 12/21/2022] Open
Abstract
Ring canals in the female germline of Drosophila melanogaster are supported by a robust filamentous actin (F-actin) cytoskeleton, setting them apart from ring canals in other species and tissues. Previous work has identified components required for the expansion of the ring canal actin cytoskeleton, but has not identified the proteins responsible for F-actin recruitment or accumulation. Using a combination of CRISPR-Cas9 mediated mutagenesis and UAS-Gal4 overexpression, we show that HtsRC-a component specific to female germline ring canals-is both necessary and sufficient to drive F-actin accumulation. Absence of HtsRC in the germline resulted in ring canals lacking inner rim F-actin, while overexpression of HtsRC led to larger ring canals. HtsRC functions in combination with Filamin to recruit F-actin to ectopic actin structures in somatic follicle cells. Finally, we present findings that indicate that HtsRC expression and robust female germline ring canal expansion are important for high fecundity in fruit flies but dispensable for their fertility-a result that is consistent with our understanding of HtsRC as a newly evolved gene specific to female germline ring canals.
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Affiliation(s)
- Julianne A Gerdes
- Department of Genetics, Yale University School of Medicine, New Haven, 06520 Connecticut
| | - Katelynn M Mannix
- Department of Genetics, Yale University School of Medicine, New Haven, 06520 Connecticut
| | - Andrew M Hudson
- Department of Genetics, Yale University School of Medicine, New Haven, 06520 Connecticut
| | - Lynn Cooley
- Department of Genetics, Yale University School of Medicine, New Haven, 06520 Connecticut
- Department of Cell Biology, Yale University School of Medicine, New Haven, 06520 Connecticut
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511 Connecticut
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11
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Pharmaco-Genetic Screen To Uncover Actin Regulators Targeted by Prostaglandins During Drosophila Oogenesis. G3-GENES GENOMES GENETICS 2019; 9:3555-3565. [PMID: 31506320 PMCID: PMC6829128 DOI: 10.1534/g3.119.400704] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Prostaglandins (PGs) are lipid signaling molecules with numerous physiologic functions, including pain/inflammation, fertility, and cancer. PGs are produced downstream of cyclooxygenase (COX) enzymes, the targets of non-steroidal anti-inflammatory drugs (NSAIDs). In numerous systems, PGs regulate actin cytoskeletal remodeling, however, their mechanisms of action remain largely unknown. To address this deficiency, we undertook a pharmaco-genetic interaction screen during late-stage Drosophila oogenesis. Drosophila oogenesis is as an established model for studying both actin dynamics and PGs. Indeed, during Stage 10B, cage-like arrays of actin bundles surround each nurse cell nucleus, and during Stage 11, the cortical actin contracts, squeezing the cytoplasmic contents into the oocyte. Both of these cytoskeletal properties are required for follicle development and fertility, and are regulated by PGs. Here we describe a pharmaco-genetic interaction screen that takes advantage of the fact that Stage 10B follicles will mature in culture and COX inhibitors, such as aspirin, block this in vitro follicle maturation. In the screen, aspirin was used at a concentration that blocks 50% of the wild-type follicles from maturing in culture. By combining this aspirin treatment with heterozygosity for mutations in actin regulators, we quantitatively identified enhancers and suppressors of COX inhibition. Here we present the screen results and initial follow-up studies on three strong enhancers – Enabled, Capping protein, and non-muscle Myosin II Regulatory Light Chain. Overall, these studies provide new insight into how PGs regulate both actin bundle formation and cellular contraction, properties that are not only essential for development, but are misregulated in disease.
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Differentially and Co-expressed Genes in Embryo, Germ-Line and Somatic Tissues of Tribolium castaneum. G3-GENES GENOMES GENETICS 2019; 9:2363-2373. [PMID: 31113821 PMCID: PMC6643895 DOI: 10.1534/g3.119.400340] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Transcriptomic studies of Tribolium castaneum have led to significant advances in our understanding of co-regulation and differential expression of genes in development. However, previously used microarray approaches have covered only a subset of known genes. The aim of this study was to investigate gene expression patterns of beetle embryo, germ-line and somatic tissues. We identified 12,302 expressed genes and determined differentially expressed up and down-regulated genes among all samples. For example, 1624 and 3639 genes were differentially increased in expression greater than or equal to twofold change (FDR < 0.01) in testis vs. ovary (virgin female) and ovary vs. embryo (0-5 hr), respectively. Of these, many developmental, somatic and germ-line differentially expressed genes were identified. Furthermore, many maternally deposited transcripts were identified, whose expression either decreased rapidly or persisted during embryogenesis. Genes with the largest change in expression were predominantly decreased during early embryogenesis as compared to ovary or were increased in testis compared to embryo. We also identify zygotic genes induced after fertilization. The genome wide variation in transcript regulation in maternal and zygotic genes could provide additional information on how the anterior posterior axis formation is established in Tribolium embryos as compared to Drosophila Together, our data will facilitate studies of comparative developmental biology as well as help identify candidate genes for identifying cis-elements to drive transgenic constructs.
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13
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Zhang R, Qu X, Zhang M, Jiang Y, Dai A, Zhao W, Cao D, Lan Y, Yu R, Wang H, Huang S. The Balance between Actin-Bundling Factors Controls Actin Architecture in Pollen Tubes. iScience 2019; 16:162-176. [PMID: 31181400 PMCID: PMC6556835 DOI: 10.1016/j.isci.2019.05.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 04/29/2019] [Accepted: 05/21/2019] [Indexed: 11/19/2022] Open
Abstract
How actin-bundling factors cooperatively regulate shank-localized actin bundles remains largely unexplored. Here we demonstrate that FIM5 and PLIM2a/PLIM2b decorate shank-localized actin bundles and that loss of function of PLIM2a and/or PLIM2b suppresses phenotypes associated with fim5 mutants. Specifically, knockout of PLIM2a and/or PLIM2b partially suppresses the disorganized actin bundle and intracellular trafficking phenotype in fim5 pollen tubes. PLIM2a/PLIM2b generates thick but loosely packed actin bundles, whereas FIM5 generates thin but tight actin bundles that tend to be cross-linked into networks in vitro. Furthermore, PLIM2a/PLIM2b and FIM5 compete for binding to actin filaments in vitro, and PLIM2a/PLIM2b decorate disorganized actin bundles in fim5 pollen tubes. These data together suggest that the disorganized actin bundles in fim5 mutants are at least partially due to gain of function of PLIM2a/PLIM2b. Our data suggest that the balance between FIM5 and PLIM2a/PLIM2b is crucial for the normal bundling and organization of shank-localized actin bundles in pollen tubes. The transcription of PLIM2a and PLIM2b is upregulated in fim5 pollen tubes Downregulation of PLIM2a and/or PLIM2b suppresses the defects in fim5 pollen tubes Both FIM5 and PLIM2a/PLIM2b decorate shank-localized actin filaments FIM5 can inhibit the binding of PLIM2a and PLIM2b to actin filaments
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Affiliation(s)
- Ruihui Zhang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaolu Qu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Meng Zhang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yuxiang Jiang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Anbang Dai
- Ministry of Education Key Laboratory of Protein Sciences, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wanying Zhao
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Dai Cao
- School of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Yaxian Lan
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Rong Yu
- School of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Hongwei Wang
- Ministry of Education Key Laboratory of Protein Sciences, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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Zhang S, Wang C, Xie M, Liu J, Kong Z, Su H. Actin Bundles in The Pollen Tube. Int J Mol Sci 2018; 19:ijms19123710. [PMID: 30469514 PMCID: PMC6321563 DOI: 10.3390/ijms19123710] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/18/2018] [Accepted: 11/19/2018] [Indexed: 12/31/2022] Open
Abstract
The angiosperm pollen tube delivers two sperm cells into the embryo sac through a unique growth strategy, named tip growth, to accomplish fertilization. A great deal of experiments have demonstrated that actin bundles play a pivotal role in pollen tube tip growth. There are two distinct actin bundle populations in pollen tubes: the long, rather thick actin bundles in the shank and the short, highly dynamic bundles near the apex. With the development of imaging techniques over the last decade, great breakthroughs have been made in understanding the function of actin bundles in pollen tubes, especially short subapical actin bundles. Here, we tried to draw an overall picture of the architecture, functions and underlying regulation mechanism of actin bundles in plant pollen tubes.
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Affiliation(s)
- Shujuan Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Chunbo Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Min Xie
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Jinyu Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Zhe Kong
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Hui Su
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
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15
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Immuno-Gold Labeling of Drosophila Follicles for Transmission Electron Microscopy. Methods Mol Biol 2016. [PMID: 27557575 DOI: 10.1007/978-1-4939-3795-0_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Detecting the localization of cellular components using gold nanoparticles has come to offer tremendous advantages in cell biology, allowing for the high resolution imaging of the cellular organization at the subcellular level. This is further aided by the breakthroughs in the cryopreparation of samples, which focus at the retention of antigenicity in efforts to mirror the native state of the tissues and cells as closely as possible. Herein, we describe the methodology for immuno-gold labeling of Drosophila follicles, following preparation of the samples using the Tokuyasu method for ultracryosectioning.
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16
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Lazzaretti D, Veith K, Kramer K, Basquin C, Urlaub H, Irion U, Bono F. The bicoid mRNA localization factor Exuperantia is an RNA-binding pseudonuclease. Nat Struct Mol Biol 2016; 23:705-13. [PMID: 27376588 DOI: 10.1038/nsmb.3254] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 06/09/2016] [Indexed: 12/20/2022]
Abstract
Anterior patterning in Drosophila is mediated by the localization of bicoid (bcd) mRNA at the anterior pole of the oocyte. Exuperantia (Exu) is a putative exonuclease (EXO) associated with bcd and required for its localization. We present the crystal structure of Exu, which reveals a dimeric assembly with each monomer consisting of a 3'-5' EXO-like domain and a sterile alpha motif (SAM)-like domain. The catalytic site is degenerate and inactive. Instead, the EXO-like domain mediates dimerization and RNA binding. We show that Exu binds RNA directly in vitro, that the SAM-like domain is required for RNA binding activity and that Exu binds a structured element present in the bcd 3' untranslated region with high affinity. Through structure-guided mutagenesis, we show that Exu dimerization is essential for bcd localization. Our data demonstrate that Exu is a noncanonical RNA-binding protein with EXO-SAM-like domain architecture that interacts with its target RNA as a homodimer.
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Affiliation(s)
| | - Katharina Veith
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Katharina Kramer
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics, Institute for Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Claire Basquin
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics, Institute for Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Uwe Irion
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Fulvia Bono
- Max Planck Institute for Developmental Biology, Tübingen, Germany
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17
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18
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Newton ILG, Savytskyy O, Sheehan KB. Wolbachia utilize host actin for efficient maternal transmission in Drosophila melanogaster. PLoS Pathog 2015; 11:e1004798. [PMID: 25906062 PMCID: PMC4408098 DOI: 10.1371/journal.ppat.1004798] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 03/11/2015] [Indexed: 11/23/2022] Open
Abstract
Wolbachia pipientis is a ubiquitous, maternally transmitted bacterium that infects the germline of insect hosts. Estimates are that Wolbachia infect nearly 40% of insect species on the planet, making it the most prevalent infection on Earth. The bacterium, infamous for the reproductive phenotypes it induces in arthropod hosts, has risen to recent prominence due to its use in vector control. Wolbachia infection prevents the colonization of vectors by RNA viruses, including Drosophila C virus and important human pathogens such as Dengue and Chikungunya. Here we present data indicating that Wolbachia utilize the host actin cytoskeleton during oogenesis for persistence within and transmission between Drosophila melanogaster generations. We show that phenotypically wild type flies heterozygous for cytoskeletal mutations in Drosophila profilin (chic(221/+) and chic(1320/+)) or villin (qua(6-396/+)) either clear a Wolbachia infection, or result in significantly reduced infection levels. This reduction of Wolbachia is supported by PCR evidence, Western blot results and cytological examination. This phenotype is unlikely to be the result of maternal loading defects, defects in oocyte polarization, or germline stem cell proliferation, as the flies are phenotypically wild type in egg size, shape, and number. Importantly, however, heterozygous mutant flies exhibit decreased total G-actin in the ovary, compared to control flies and chic(221) heterozygous mutants exhibit decreased expression of profilin. Additionally, RNAi knockdown of profilin during development decreases Wolbachia titers. We analyze evidence in support of alternative theories to explain this Wolbachia phenotype and conclude that our results support the hypothesis that Wolbachia utilize the actin skeleton for efficient transmission and maintenance within Drosophila.
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Affiliation(s)
- Irene L. G. Newton
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Oleksandr Savytskyy
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Kathy B. Sheehan
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
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19
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Groen CM, Jayo A, Parsons M, Tootle TL. Prostaglandins regulate nuclear localization of Fascin and its function in nucleolar architecture. Mol Biol Cell 2015; 26:1901-17. [PMID: 25808493 PMCID: PMC4436834 DOI: 10.1091/mbc.e14-09-1384] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 03/18/2015] [Indexed: 01/14/2023] Open
Abstract
Fascin, a conserved actin-bundling protein, is not only cytoplasmic but also localizes to the nucleus and nuclear periphery in both Drosophila and mammalian cell contexts. In Drosophila, prostaglandin signaling regulates this localization. In addition, Fascin plays a critical role in nucleolar architecture in both Drosophila and mammalian cells. Fascin, a highly conserved actin-bundling protein, localizes and functions at new cellular sites in both Drosophila and multiple mammalian cell types. During Drosophila follicle development, in addition to being cytoplasmic, Fascin is in the nuclei of the germline-derived nurse cells during stages 10B–12 (S10B–12) and at the nuclear periphery during stage 13 (S13). This localization is specific to Fascin, as other actin-binding proteins, Villin and Profilin, do not exhibit the same subcellular distribution. In addition, localization of fascin1 to the nucleus and nuclear periphery is observed in multiple mammalian cell types. Thus the regulation and function of Fascin at these new cellular locations is likely to be highly conserved. In Drosophila, loss of prostaglandin signaling causes a global reduction in nuclear Fascin and a failure to relocalize to the nuclear periphery. Alterations in nuclear Fascin levels result in defects in nucleolar morphology in both Drosophila follicles and cultured mammalian cells, suggesting that nuclear Fascin plays an important role in nucleolar architecture. Given the numerous roles of Fascin in development and disease, including cancer, our novel finding that Fascin has functions within the nucleus sheds new light on the potential roles of Fascin in these contexts.
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Affiliation(s)
- Christopher M Groen
- Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Asier Jayo
- Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, United Kingdom
| | - Maddy Parsons
- Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, United Kingdom
| | - Tina L Tootle
- Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242
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20
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Borgatta M, Hernandez C, Decosterd LA, Chèvre N, Waridel P. Shotgun Ecotoxicoproteomics of Daphnia pulex: Biochemical Effects of the Anticancer Drug Tamoxifen. J Proteome Res 2014; 14:279-91. [DOI: 10.1021/pr500916m] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Myriam Borgatta
- Institute
of Earth Surface Dynamics, Géopolis, University of Lausanne, 1015 Lausanne, Switzerland
| | - Céline Hernandez
- Protein
Analysis Facility, Center for Integrative Genomics, Génopode, University of Lausanne, 1015 Lausanne, Switzerland
| | - Laurent Arthur Decosterd
- Division
of Clinical Pharmacology and Toxicology, Centre Hospitalier Universitaire Vaudois (CHUV), 1011 Lausanne, Switzerland
| | - Nathalie Chèvre
- Institute
of Earth Surface Dynamics, Géopolis, University of Lausanne, 1015 Lausanne, Switzerland
| | - Patrice Waridel
- Protein
Analysis Facility, Center for Integrative Genomics, Génopode, University of Lausanne, 1015 Lausanne, Switzerland
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21
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Spracklen AJ, Fagan TN, Lovander KE, Tootle TL. The pros and cons of common actin labeling tools for visualizing actin dynamics during Drosophila oogenesis. Dev Biol 2014; 393:209-226. [PMID: 24995797 DOI: 10.1016/j.ydbio.2014.06.022] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 04/04/2014] [Accepted: 06/17/2014] [Indexed: 10/25/2022]
Abstract
Dynamic remodeling of the actin cytoskeleton is required for both development and tissue homeostasis. While fixed image analysis has provided significant insight into such events, a complete understanding of cytoskeletal dynamics requires live imaging. Numerous tools for the live imaging of actin have been generated by fusing the actin-binding domain from an actin-interacting protein to a fluorescent protein. Here we comparatively assess the utility of three such tools--Utrophin, Lifeact, and F-tractin--for characterizing the actin remodeling events occurring within the germline-derived nurse cells during Drosophila mid-oogenesis or follicle development. Specifically, we used the UAS/GAL4 system to express these tools at different levels and in different cells, and analyzed these tools for effects on fertility, alterations in the actin cytoskeleton, and ability to label filamentous actin (F-actin) structures by both fixed and live imaging. While both Utrophin and Lifeact robustly label F-actin structures within the Drosophila germline, when strongly expressed they cause sterility and severe actin defects including cortical actin breakdown resulting in multi-nucleate nurse cells, early F-actin filament and aggregate formation during stage 9 (S9), and disorganized parallel actin filament bundles during stage 10B (S10B). However, by using a weaker germline GAL4 driver in combination with a higher temperature, Utrophin can label F-actin with minimal defects. Additionally, strong Utrophin expression within the germline causes F-actin formation in the nurse cell nuclei and germinal vesicle during mid-oogenesis. Similarly, Lifeact expression results in nuclear F-actin only within the germinal vesicle. F-tractin expresses at a lower level than the other two labeling tools, but labels cytoplasmic F-actin structures well without causing sterility or striking actin defects. Together these studies reveal how critical it is to evaluate the utility of each actin labeling tool within the tissue and cell type of interest in order to identify the tool that represents the best compromise between acceptable labeling and minimal disruption of the phenomenon being observed. In this case, we find that F-tractin, and perhaps Utrophin, when Utrophin expression levels are optimized to label efficiently without causing actin defects, can be used to study F-actin dynamics within the Drosophila nurse cells.
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Affiliation(s)
- Andrew J Spracklen
- Anatomy and Cell Biology Department, Carver College of Medicine, University of Iowa, 51 Newton Rd, Iowa City, IA 52242, USA
| | - Tiffany N Fagan
- Anatomy and Cell Biology Department, Carver College of Medicine, University of Iowa, 51 Newton Rd, Iowa City, IA 52242, USA
| | - Kaylee E Lovander
- Anatomy and Cell Biology Department, Carver College of Medicine, University of Iowa, 51 Newton Rd, Iowa City, IA 52242, USA
| | - Tina L Tootle
- Anatomy and Cell Biology Department, Carver College of Medicine, University of Iowa, 51 Newton Rd, Iowa City, IA 52242, USA.
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22
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Ogienko AA, Karagodin DA, Lashina VV, Baiborodin SI, Omelina ES, Baricheva EM. Capping protein beta is required for actin cytoskeleton organisation and cell migration during Drosophila oogenesis. Cell Biol Int 2014; 37:149-59. [PMID: 23339103 DOI: 10.1002/cbin.10025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Accepted: 11/24/2012] [Indexed: 11/08/2022]
Abstract
Capping protein (CP) is a well-characterised actin-binding protein important for regulation of actin filament (AF) assembly. CP caps the barbed end of AFs, inhibiting the addition and loss of actin monomers. In Drosophila melanogaster, the gene encoding CP β-subunit is named capping protein beta (cpb; see Hopmann et al. [1996] J Cell Biol 133: 1293-305). The cpb level is reduced in the Drosophila bristle actin cytoskeleton and becomes disorganised with abnormal morphology. A reduced level of the CP protein in ovary results in disruption of oocyte determination, and disturbance of nurse cell (NC) cortical integrity and dumping. We describe novel defects appearing in cpb mutants during oogenesis, in which cpb plays an important role in border and centripetal follicle cell migration, ring canal development and cytoplasmic AF formation. The number of long cytoplasmic AFs was dramatically reduced in cpb hypomorphs and abnormal actin aggregates was seen on the inner side of NC membranes. A hypothesis to explain the formation of abnormal short-cut cytoplasmic AFs and actin aggregates in the cpb mutant NCs was proffered, along with a discussion of the reasons for 'dumpless' phenotype formation in the mutants.
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Affiliation(s)
- Anna A Ogienko
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, pr. Lavrentieva 10, Novosibirsk 630090, Russia.
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23
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Sánchez-Herrero E. Hox targets and cellular functions. SCIENTIFICA 2013; 2013:738257. [PMID: 24490109 PMCID: PMC3892749 DOI: 10.1155/2013/738257] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 11/20/2013] [Indexed: 06/03/2023]
Abstract
Hox genes are a group of genes that specify structures along the anteroposterior axis in bilaterians. Although in many cases they do so by modifying a homologous structure with a different (or no) Hox input, there are also examples of Hox genes constructing new organs with no homology in other regions of the body. Hox genes determine structures though the regulation of targets implementing cellular functions and by coordinating cell behavior. The genetic organization to construct or modify a certain organ involves both a genetic cascade through intermediate transcription factors and a direct regulation of targets carrying out cellular functions. In this review I discuss new data from genome-wide techniques, as well as previous genetic and developmental information, to describe some examples of Hox regulation of different cell functions. I also discuss the organization of genetic cascades leading to the development of new organs, mainly using Drosophila melanogaster as the model to analyze Hox function.
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Affiliation(s)
- Ernesto Sánchez-Herrero
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Nicolás Cabrera 1, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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24
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Huelsmann S, Ylänne J, Brown NH. Filopodia-like actin cables position nuclei in association with perinuclear actin in Drosophila nurse cells. Dev Cell 2013; 26:604-15. [PMID: 24091012 PMCID: PMC3791400 DOI: 10.1016/j.devcel.2013.08.014] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 06/18/2013] [Accepted: 08/17/2013] [Indexed: 11/21/2022]
Abstract
Controlling the position of the nucleus is vital for a number of cellular processes from yeast to humans. In Drosophila nurse cells, nuclear positioning is crucial during dumping, when nurse cells contract and expel their contents into the oocyte. We provide evidence that in nurse cells, continuous filopodia-like actin cables, growing from the plasma membrane and extending to the nucleus, achieve nuclear positioning. These actin cables move nuclei away from ring canals. When nurse cells contract, actin cables associate laterally with the nuclei, in some cases inducing nuclear turning so that actin cables become partially wound around the nuclei. Our data suggest that a perinuclear actin meshwork connects actin cables to nuclei via actin-crosslinking proteins such as the filamin Cheerio. We provide a revised model for how actin structures position nuclei in nurse cells, employing evolutionary conserved machinery. Actin cables in Drosophila nurse cells are unsegmented filopodia-like structures E-cadherin is required for the orientation of actin cables toward the nucleus Nuclear positioning is achieved by continuous elongation of actin cables Actin cables associate with perinuclear actin-containing crosslinkers like filamin
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Affiliation(s)
- Sven Huelsmann
- Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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25
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Spracklen AJ, Kelpsch DJ, Chen X, Spracklen CN, Tootle TL. Prostaglandins temporally regulate cytoplasmic actin bundle formation during Drosophila oogenesis. Mol Biol Cell 2013; 25:397-411. [PMID: 24284900 PMCID: PMC3907279 DOI: 10.1091/mbc.e13-07-0366] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Tight regulation of actin remodeling is essential for development, and misregulation results in disease. Cytoskeletal dynamics are regulated by prostaglandins (PGs)—lipid signals. PGs temporally regulate actin remodeling during Drosophila oogenesis, at least in part, by modulating the activity of the actin elongation factor Enabled. Prostaglandins (PGs)—lipid signals produced downstream of cyclooxygenase (COX) enzymes—regulate actin dynamics in cell culture and platelets, but their roles during development are largely unknown. Here we define a new role for Pxt, the Drosophila COX-like enzyme, in regulating the actin cytoskeleton—temporal restriction of actin remodeling during oogenesis. PGs are required for actin filament bundle formation during stage 10B (S10B). In addition, loss of Pxt results in extensive early actin remodeling, including actin filaments and aggregates, within the posterior nurse cells of S9 follicles; wild-type follicles exhibit similar structures at a low frequency. Hu li tai shao (Hts-RC) and Villin (Quail), an actin bundler, localize to all early actin structures, whereas Enabled (Ena), an actin elongation factor, preferentially localizes to those in pxt mutants. Reduced Ena levels strongly suppress early actin remodeling in pxt mutants. Furthermore, loss of Pxt results in reduced Ena localization to the sites of bundle formation during S10B. Together these data lead to a model in which PGs temporally regulate actin remodeling during Drosophila oogenesis by controlling Ena localization/activity, such that in S9, PG signaling inhibits, whereas at S10B, it promotes Ena-dependent actin remodeling.
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Affiliation(s)
- Andrew J Spracklen
- Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242 Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242
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26
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Abstract
Abstract Chitin is the second most abundant polysaccharide on earth. It is produced at the apical side of epidermal, tracheal, fore-, and hindgut epithelial cells in insects as a central component of the protective and supporting extracellular cuticle. Chitin is also an important constituent of the midgut peritrophic matrix that encases the food supporting its digestion and protects the epithelium against invasion by possibly ingested pathogens. The enzyme producing chitin is a glycosyltransferase that resides in the apical plasma membrane forming a pore to extrude the chains of chitin into the extracellular space. The apical plasma membrane is not only a platform for chitin synthases but, probably through its shape and equipment with distinct factors, also plays an important role in orienting and organizing chitin fibers. Here, I review findings on the cellular and molecular constitution of the apical plasma membrane of chitin-producing epithelia mainly focusing on work done in the fruit fly Drosophila melanogaster.
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Affiliation(s)
- Bernard Moussian
- Animal Genetics, Interfaculty Institute for Cell Biology, University of Tübingen, 72076 Tübingen, Germany.
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Senchenko VN, Kisseljova NP, Ivanova TA, Dmitriev AA, Krasnov GS, Kudryavtseva AV, Panasenko GV, Tsitrin EB, Lerman MI, Kisseljov FL, Kashuba VI, Zabarovsky ER. Novel tumor suppressor candidates on chromosome 3 revealed by NotI-microarrays in cervical cancer. Epigenetics 2013; 8:409-20. [PMID: 23478628 DOI: 10.4161/epi.24233] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Genetic and epigenetic alterations in cervical carcinomas were investigated using NotI-microarrays containing 180 cloned sequences flanking all NotI-sites associated with genes on chromosome 3. In total, 48 paired normal/tumor DNA samples, specifically enriched in NotI-sites, were hybridized to NotI-microarrays. Thirty genes, including tumor suppressors or candidates (for example, VHL, RBSP3/CTDSPL, ITGA9, LRRC3B, ALDH1L1, EPHB1) and genes previously unknown as cancer-associated (ABHD5, C3orf77, PRL32, LOC285375, FGD5 and others), showed methylation/deletion in 21-44% of tumors. The genes were more frequently altered in squamous cell carcinomas (SCC) than in adenocarcinomas (ADC, p<0.01). A set of seven potential markers (LRRN1, PRICKLE2, VHL, BHLHE40, RBSP3, CGGBP1 and SOX14) is promising for discrimination of ADC and SCC. Alterations of more than 20 genes simultaneously were revealed in 23% of SCC. Bisulfite sequencing analysis confirmed methylation as a frequent event in SCC. High down-regulation frequency was shown for RBSP3, ITGA9, VILL, APRG1/C3orf35 and RASSF1 (isoform A) genes (3p21.3 locus) in SCC. Both frequency and extent of RASSF1A and RBSP3 mRNA level decrease were more pronounced in tumors with lymph node metastases compared with non-metastatic ones (p ≤ 0.05). We confirmed by bisulfite sequencing that RASSF1 promoter methylation was a rare event in SCC and, for the first time, demonstrated RASSF1A down-regulation at both the mRNA and protein levels without promoter methylation in tumors of this histological type. Thus, our data revealed novel tumor suppressor candidates located on chromosome 3 and a frequent loss of epigenetic stability of 3p21.3 locus in combination with down-regulation of genes in cervical cancer.
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Affiliation(s)
- Vera N Senchenko
- Engelhardt Institute of Molecular Biology; Russian Academy of Sciences; Moscow, Russia
| | - Natalia P Kisseljova
- N.N. Blokhin Russian Cancer Research Center; Russian Academy of Medical Sciences; Moscow, Russia
| | - Tatyana A Ivanova
- N.N. Blokhin Russian Cancer Research Center; Russian Academy of Medical Sciences; Moscow, Russia; Karolinska Institute; Department of Microbiology, Tumour and Cell Biology; Stockholm, Sweden
| | - Alexey A Dmitriev
- Engelhardt Institute of Molecular Biology; Russian Academy of Sciences; Moscow, Russia
| | - George S Krasnov
- Engelhardt Institute of Molecular Biology; Russian Academy of Sciences; Moscow, Russia; I.I.Mechnikov Scientific Research Institute of Vaccines and Sera; Russian Academy of Medical Sciences; Moscow, Russia
| | - Anna V Kudryavtseva
- Engelhardt Institute of Molecular Biology; Russian Academy of Sciences; Moscow, Russia
| | - Grigory V Panasenko
- Institute of Molecular Biology and Genetics; Ukrainian Academy of Sciences; Kiev, Ukraine
| | - Evgeny B Tsitrin
- Koltzov Institute of Developmental Biology; Russian Academy of Sciences; Moscow, Russia
| | | | - Fyodor L Kisseljov
- N.N. Blokhin Russian Cancer Research Center; Russian Academy of Medical Sciences; Moscow, Russia
| | - Vladimir I Kashuba
- Institute of Molecular Biology and Genetics; Ukrainian Academy of Sciences; Kiev, Ukraine
| | - Eugene R Zabarovsky
- Karolinska Institute; Department of Microbiology, Tumour and Cell Biology; Stockholm, Sweden
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28
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Groen CM, Spracklen AJ, Fagan TN, Tootle TL. Drosophila Fascin is a novel downstream target of prostaglandin signaling during actin remodeling. Mol Biol Cell 2012; 23:4567-78. [PMID: 23051736 PMCID: PMC3510018 DOI: 10.1091/mbc.e12-05-0417] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Prostaglandins (PGs) regulate the actin cytoskeleton. However, their mechanisms of action are unknown. Use of Drosophila oogenesis—specifically nurse cell dumping—as a model shows that PGs regulate the actin bundler Fascin to control parallel actin filament bundle formation and cortical actin integrity. Although prostaglandins (PGs)—lipid signals produced downstream of cyclooxygenase (COX) enzymes—regulate actin cytoskeletal dynamics, their mechanisms of action are unknown. We previously established Drosophila oogenesis, in particular nurse cell dumping, as a new model to determine how PGs regulate actin remodeling. PGs, and thus the Drosophila COX-like enzyme Pxt, are required for both the parallel actin filament bundle formation and the cortical actin strengthening required for dumping. Here we provide the first link between Fascin (Drosophila Singed, Sn), an actin-bundling protein, and PGs. Loss of either pxt or fascin results in similar actin defects. Fascin interacts, both pharmacologically and genetically, with PGs, as reduced Fascin levels enhance the effects of COX inhibition and synergize with reduced Pxt levels to cause both parallel bundle and cortical actin defects. Conversely, overexpression of Fascin in the germline suppresses the effects of COX inhibition and genetic loss of Pxt. These data lead to the conclusion that PGs regulate Fascin to control actin remodeling. This novel interaction has implications beyond Drosophila, as both PGs and Fascin-1, in mammalian systems, contribute to cancer cell migration and invasion.
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Affiliation(s)
- Christopher M Groen
- Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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29
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Bao C, Wang J, Zhang R, Zhang B, Zhang H, Zhou Y, Huang S. Arabidopsis VILLIN2 and VILLIN3 act redundantly in sclerenchyma development via bundling of actin filaments. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 71:962-75. [PMID: 22563899 DOI: 10.1111/j.1365-313x.2012.05044.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The organization of the actin cytoskeleton has been implicated in sclerenchyma development. However, the molecular mechanisms linking the actin cytoskeleton to this process remain poorly understood. In particular, there have been no studies showing that direct genetic manipulation of the actin cytoskeleton affects sclerenchyma development. Villins belong to the villin/gelsolin/fragmin superfamily and are versatile actin-modifying proteins. Several recent studies have implicated villins in tip growth of single cells, but how villins act in multicellular plant development remains largely unknown. Here, we found that two closely related villin isovariants from Arabidopsis, VLN2 and VLN3, act redundantly in sclerenchyma development. Detailed analysis of cross-sections from inflorescence stems of vln2 vln3 double mutant plants revealed a reduction in stem size and in the number of vascular bundles; however, no defects in synthesis of the secondary cell wall were detected. Surprisingly, the vln2 vln3 double mutation did not affect cell elongation of inter-fascicular fibers. Biochemical analyses showed that recombinant VLN2 was able to cap, sever and bundle actin filaments, similar to VLN3. Consistent with these biochemical activities, loss of function of VLN2 and VLN3 resulted in a decrease in the amount of F-actin and actin bundles in plant cells. Collectively, our findings demonstrate that VLN2 and VLN3 act redundantly in sclerenchyma development via bundling of actin filaments.
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Affiliation(s)
- Chanchan Bao
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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30
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Zanet J, Jayo A, Plaza S, Millard T, Parsons M, Stramer B. Fascin promotes filopodia formation independent of its role in actin bundling. ACTA ACUST UNITED AC 2012; 197:477-86. [PMID: 22564415 PMCID: PMC3352952 DOI: 10.1083/jcb.201110135] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Mutation of a critical residue of fascin eliminates the protein’s actin-bundling activity but maintains its positive role in filopodia formation Fascin is an evolutionarily conserved actin-binding protein that plays a key role in forming filopodia. It is widely thought that this function involves fascin directly bundling actin filaments, which is controlled by an N-terminal regulatory serine residue. In this paper, by studying cellular processes in Drosophila melanogaster that require fascin activity, we identify a regulatory residue within the C-terminal region of the protein (S289). Unexpectedly, although mutation (S289A) of this residue disrupted the actin-bundling capacity of fascin, fascin S289A fully rescued filopodia formation in fascin mutant flies. Live imaging of migrating macrophages in vivo revealed that this mutation restricted the localization of fascin to the distal ends of filopodia. The corresponding mutation of human fascin (S274) similarly affected its interaction with actin and altered filopodia dynamics within carcinoma cells. These data reveal an evolutionarily conserved role for this regulatory region and unveil a function for fascin, uncoupled from actin bundling, at the distal end of filopodia.
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Affiliation(s)
- Jennifer Zanet
- Randall Division of Cell and Molecular Biophysics, King's College London, SE1 1UL London, England, UK
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31
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Khurana S, George SP. The role of actin bundling proteins in the assembly of filopodia in epithelial cells. Cell Adh Migr 2011; 5:409-20. [PMID: 21975550 PMCID: PMC3218608 DOI: 10.4161/cam.5.5.17644] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 08/05/2011] [Indexed: 01/22/2023] Open
Abstract
The goal of this review is to highlight how emerging new models of filopodia assembly, which include tissue specific actin-bundling proteins, could provide more comprehensive representations of filopodia assembly that would describe more adequately and effectively the complexity and plasticity of epithelial cells. This review also describes how the true diversity of actin bundling proteins must be considered to predict the far-reaching significance and versatile functions of filopodia in epithelial cells.
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Affiliation(s)
- Seema Khurana
- Department of Biology and Biochemistry, University of Houston, Houston, TX, USA.
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32
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Graham AM, Munday MD, Kaftanoglu O, Page RE, Amdam GV, Rueppell O. Support for the reproductive ground plan hypothesis of social evolution and major QTL for ovary traits of Africanized worker honey bees (Apis mellifera L.). BMC Evol Biol 2011; 11:95. [PMID: 21489230 PMCID: PMC3100260 DOI: 10.1186/1471-2148-11-95] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 04/13/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The reproductive ground plan hypothesis of social evolution suggests that reproductive controls of a solitary ancestor have been co-opted during social evolution, facilitating the division of labor among social insect workers. Despite substantial empirical support, the generality of this hypothesis is not universally accepted. Thus, we investigated the prediction of particular genes with pleiotropic effects on ovarian traits and social behavior in worker honey bees as a stringent test of the reproductive ground plan hypothesis. We complemented these tests with a comprehensive genome scan for additional quantitative trait loci (QTL) to gain a better understanding of the genetic architecture of the ovary size of honey bee workers, a morphological trait that is significant for understanding social insect caste evolution and general insect biology. RESULTS Back-crossing hybrid European x Africanized honey bee queens to the Africanized parent colony generated two study populations with extraordinarily large worker ovaries. Despite the transgressive ovary phenotypes, several previously mapped QTL for social foraging behavior demonstrated ovary size effects, confirming the prediction of pleiotropic genetic effects on reproductive traits and social behavior. One major QTL for ovary size was detected in each backcross, along with several smaller effects and two QTL for ovary asymmetry. One of the main ovary size QTL coincided with a major QTL for ovary activation, explaining 3/4 of the phenotypic variance, although no simple positive correlation between ovary size and activation was observed. CONCLUSIONS Our results provide strong support for the reproductive ground plan hypothesis of evolution in study populations that are independent of the genetic stocks that originally led to the formulation of this hypothesis. As predicted, worker ovary size is genetically linked to multiple correlated traits of the complex division of labor in worker honey bees, known as the pollen hoarding syndrome. The genetic architecture of worker ovary size presumably consists of a combination of trait-specific loci and general regulators that affect the whole behavioral syndrome and may even play a role in caste determination. Several promising candidate genes in the QTL intervals await further study to clarify their potential role in social insect evolution and the regulation of insect fertility in general.
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Affiliation(s)
- Allie M Graham
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27403, USA
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33
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Ogienko AA, Karagodin DA, Pavlova NV, Fedorova SA, Voloshina MV, Baricheva EM. Molecular and genetic description of a new hypomorphic mutation of Trithorax-like gene and analysis of its effect on Drosophila melanogaster oogenesis. Russ J Dev Biol 2011. [DOI: 10.1134/s1062360408020070] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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34
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Zhang H, Qu X, Bao C, Khurana P, Wang Q, Xie Y, Zheng Y, Chen N, Blanchoin L, Staiger CJ, Huang S. Arabidopsis VILLIN5, an actin filament bundling and severing protein, is necessary for normal pollen tube growth. THE PLANT CELL 2010; 22:2749-67. [PMID: 20807879 PMCID: PMC2947167 DOI: 10.1105/tpc.110.076257] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
A dynamic actin cytoskeleton is essential for pollen germination and tube growth. However, the molecular mechanisms underlying the organization and turnover of the actin cytoskeleton in pollen remain poorly understood. Villin plays a key role in the formation of higher-order structures from actin filaments and in the regulation of actin dynamics in eukaryotic cells. It belongs to the villin/gelsolin/fragmin superfamily of actin binding proteins and is composed of six gelsolin-homology domains at its core and a villin headpiece domain at its C terminus. Recently, several villin family members from plants have been shown to sever, cap, and bundle actin filaments in vitro. Here, we characterized a villin isovariant, Arabidopsis thaliana VILLIN5 (VLN5), that is highly and preferentially expressed in pollen. VLN5 loss-of-function retarded pollen tube growth and sensitized actin filaments in pollen grains and tubes to latrunculin B. In vitro biochemical analyses revealed that VLN5 is a typical member of the villin family and retains a full suite of activities, including barbed-end capping, filament bundling, and calcium-dependent severing. The severing activity was confirmed with time-lapse evanescent wave microscopy of individual actin filaments in vitro. We propose that VLN5 is a major regulator of actin filament stability and turnover that functions in concert with oscillatory calcium gradients in pollen and therefore plays an integral role in pollen germination and tube growth.
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Affiliation(s)
- Hua Zhang
- Center for Signal Transduction and Metabolomics, Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate School of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaolu Qu
- Center for Signal Transduction and Metabolomics, Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate School of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chanchan Bao
- Center for Signal Transduction and Metabolomics, Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate School of Chinese Academy of Sciences, Beijing, 100049, China
| | - Parul Khurana
- Department of Biological Sciences and Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907-2064
| | - Qiannan Wang
- Center for Signal Transduction and Metabolomics, Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate School of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yurong Xie
- Center for Signal Transduction and Metabolomics, Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yiyan Zheng
- Center for Signal Transduction and Metabolomics, Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate School of Chinese Academy of Sciences, Beijing, 100049, China
| | - Naizhi Chen
- Center for Signal Transduction and Metabolomics, Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Laurent Blanchoin
- Institut de Recherches en Technologie et Sciences pour le Vivant, Laboratoire de Physiologie Cellulaire Végétale, Commissariat à l’Energie Atomique/Centre National de la Recherche Scientifique/Université Joseph Fourier, F38054 Grenoble, France
| | - Christopher J. Staiger
- Department of Biological Sciences and Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907-2064
| | - Shanjin Huang
- Center for Signal Transduction and Metabolomics, Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Address correspondence to
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35
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Khurana P, Henty JL, Huang S, Staiger AM, Blanchoin L, Staiger CJ. Arabidopsis VILLIN1 and VILLIN3 have overlapping and distinct activities in actin bundle formation and turnover. THE PLANT CELL 2010; 22:2727-48. [PMID: 20807878 PMCID: PMC2947172 DOI: 10.1105/tpc.110.076240] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 07/29/2010] [Accepted: 08/17/2010] [Indexed: 05/20/2023]
Abstract
Actin filament bundles are higher-order cytoskeletal structures that are crucial for the maintenance of cellular architecture and cell expansion. They are generated from individual actin filaments by the actions of bundling proteins like fimbrins, LIMs, and villins. However, the molecular mechanisms of dynamic bundle formation and turnover are largely unknown. Villins belong to the villin/gelsolin/fragmin superfamily and comprise at least five isovariants in Arabidopsis thaliana. Different combinations of villin isovariants are coexpressed in various tissues and cells. It is not clear whether these isovariants function together and act redundantly or whether they have unique activities. VILLIN1 (VLN1) is a simple filament-bundling protein and is Ca(2+) insensitive. Based on phylogenetic analyses and conservation of Ca(2+) binding sites, we predict that VLN3 is a Ca(2+)-regulated villin capable of severing actin filaments and contributing to bundle turnover. The bundling activity of both isovariants was observed directly with time-lapse imaging and total internal reflection fluorescence (TIRF) microscopy in vitro, and the mechanism mimics the "catch and zipper" action observed in vivo. Using time-lapse TIRF microscopy, we observed and quantified the severing of individual actin filaments by VLN3 at physiological calcium concentrations. Moreover, VLN3 can sever actin filament bundles in the presence of VLN1 when calcium is elevated to micromolar levels. Collectively, these results demonstrate that two villin isovariants have overlapping and distinct activities.
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Affiliation(s)
- Parul Khurana
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-2064
| | - Jessica L. Henty
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-2064
| | - Shanjin Huang
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-2064
| | - Andrew M. Staiger
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-2064
| | - Laurent Blanchoin
- Institut de Recherches en Technologie et Sciences pour le Vivant, Commissariat à l'Energie Atomique/Centre National de la Recherche Scientifique/Institut National de la Recherche Agronomique/Université Joseph Fourier, Commissariat à l’Energie Atomique Grenoble, F38054 Grenoble, France
| | - Christopher J. Staiger
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-2064
- The Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907
- Address correspondence to
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Staiger CJ, Poulter NS, Henty JL, Franklin-Tong VE, Blanchoin L. Regulation of actin dynamics by actin-binding proteins in pollen. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:1969-86. [PMID: 20159884 DOI: 10.1093/jxb/erq012] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A dynamic network of polymers, the actin cytoskeleton, co-ordinates numerous fundamental cellular processes. In pollen tubes, organelle movements and cytoplasmic streaming, organization of the tip zone, vesicle trafficking, and tip growth have all been linked to actin-based function. Further, during the self-incompatibility response of Papaver rhoeas, destruction of the cytoskeleton is a primary target implicated in the rapid cessation of pollen tube growth and alterations in actin dynamics are associated with the initiation of programmed cell death. Surprisingly, these diverse cellular processes are accomplished with only a small amount of filamentous actin and a huge pool of polymerizable monomers. These observations hint at incredibly fast and complex actin dynamics in pollen. To understand the molecular mechanisms regulating actin dynamics in plant cells, the abundant actin monomer-binding proteins, a major filament nucleator, a family of bundling and severing proteins, and a modulator of growth at the barbed-end of actin filaments have been characterized biochemically. The activities of these proteins are generally consistent with textbook models for actin turnover. For example, the three monomer-binding proteins, profilin, ADF, and CAP, are thought to function synergistically to enhance turnover and the exchange of subunits between monomer and polymer pools. How individual actin filaments behave in living cells, however, remains largely unexplored. Actin dynamics were examined using variable angle epifluorescence microscopy (VAEM) in expanding hypocotyl epidermal cells. Our observations of single filament behaviour are not consistent with filament turnover by treadmilling, but rather represent a novel property called stochastic dynamics. A new model for the dynamic control of actin filament turnover in plant cells is presented.
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Affiliation(s)
- Christopher J Staiger
- Department of Biological Sciences and Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907-2064, USA.
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37
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Zhai Z, Fuchs AL, Lohmann I. Cellular analysis of newly identified Hox downstream genes in Drosophila. Eur J Cell Biol 2009; 89:273-8. [PMID: 20018403 DOI: 10.1016/j.ejcb.2009.11.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Hox genes code for conserved homeodomain transcription factors, which act as regional regulators for the specification of segmental identities along the anterior-posterior axis in all animals studied. They execute their function mainly through the activation or repression of their downstream genes. We have recently identified a large number of genes to be directly or indirectly targeted by Hox proteins through gene expression profiling in the model organism Drosophila. However, the cell-specific regulation of these downstream genes and the functional significance of the regulation are largely unknown. We have validated and functionally studied many of the newly identified downstream genes of the Hox proteins Deformed (Dfd) and Abdominal-B (Abd-B), and provide evidence that Hox proteins regulate a diverse group of downstream genes, from transcription factors to realisators with major and minor roles during morphogenesis.
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Affiliation(s)
- Zongzhao Zhai
- BIOQUANT Center, Cluster of Excellence - CellNetworks, Heidelberg, University of Heidelberg, Im Neuenheimer Feld 267, D-69120 Heidelberg, Germany
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38
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Gates J, Nowotarski SH, Yin H, Mahaffey JP, Bridges T, Herrera C, Homem CCF, Janody F, Montell DJ, Peifer M. Enabled and Capping protein play important roles in shaping cell behavior during Drosophila oogenesis. Dev Biol 2009; 333:90-107. [PMID: 19576200 DOI: 10.1016/j.ydbio.2009.06.030] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 06/20/2009] [Accepted: 06/22/2009] [Indexed: 12/29/2022]
Abstract
During development, cells craft an impressive array of actin-based structures, mediating events as diverse as cytokinesis, apical constriction, and cell migration. One challenge is to determine how cells regulate actin assembly and disassembly to carry out these cell behaviors. During Drosophila oogenesis diverse cell behaviors are seen in the soma and germline. We used oogenesis to explore developmental roles of two important actin regulators: Enabled/VASP proteins and Capping protein. We found that Enabled plays an important role in cortical integrity of nurse cells, formation of robust bundled actin filaments in late nurse cells that facilitate nurse cell dumping, and migration of somatic border cells. During nurse cell dumping, Enabled localizes to barbed ends of the nurse cell actin filaments, suggesting its mechanism of action. We further pursued this mechanism using mutant Enabled proteins, each affecting one of its protein domains. These data suggest critical roles for the EVH2 domain and its tetramerization subdomain, while the EVH1 domain appears less critical. Enabled appears to be negatively regulated during oogenesis by Abelson kinase. We also explored the function of Capping protein. This revealed important roles in oocyte determination, nurse cell cortical integrity and nurse cell dumping, and support the idea that Capping protein and Enabled act antagonistically during dumping. Together these data reveal places that these actin regulators shape oogenesis.
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Affiliation(s)
- Julie Gates
- Lineberger Comprehensive Cancer Center and Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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39
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Bicaudal C and trailer hitch have similar roles in gurken mRNA localization and cytoskeletal organization. Dev Biol 2009; 328:434-44. [PMID: 19217894 DOI: 10.1016/j.ydbio.2009.02.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 01/13/2009] [Accepted: 02/03/2009] [Indexed: 01/16/2023]
Abstract
Bicaudal C and trailer hitch are both required for dorsoventral patterning of the Drosophila oocyte. Each mutant produces ventralized eggs, a phenotype typically associated with failure of the oocyte to provide a dorsalization signal--the Gurken protein--to the follicle cells. Bicaudal C and trailer hitch are both implicated in post-transcriptional gene regulation. Bicaudal C acts in recruiting a deadenylase to specific mRNAs, leading to translational repression. The role of trailer hitch is less well defined, but mutants have defects in protein secretion, and show aberrant distribution of an endoplasmic reticulum exit site marker whose mRNA is associated with Trailer hitch protein. We show that Bicaudal C and trailer hitch interact genetically. Mutants of these two genes have shared defects in localization of gurken and other anteriorly-localized mRNAs, as well as altered microtubule organization which may underlie the mRNA localization defects. Bicaudal C and trailer hitch mutants also share a syndrome of actin-related abnormalities, including the formation of ectopic actin cages near the anterior of the oocyte. The cages sequester Gurken protein, blocking its secretion and thus interfering with signaling of the follicle cells to specify dorsal fate.
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40
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Bosveld F, Rana A, Lemstra W, Kampinga HH, Sibon OCM. Drosophila phosphopantothenoylcysteine synthetase is required for tissue morphogenesis during oogenesis. BMC Res Notes 2008; 1:75. [PMID: 18759961 PMCID: PMC2542404 DOI: 10.1186/1756-0500-1-75] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Accepted: 08/29/2008] [Indexed: 12/04/2022] Open
Abstract
Background Coenzyme A (CoA) is an essential metabolite, synthesized from vitamin B5 by the subsequent action of five enzymes: PANK, PPCS, PPCDC, PPAT and DPCK. Mutations in Drosophila dPPCS disrupt female fecundity and in this study we analyzed the female sterile phenotype of dPPCS mutants in detail. Results We demonstrate that dPPCS is required for various processes that occur during oogenesis including chorion patterning. Our analysis demonstrates that a mutation in dPPCS disrupts the organization of the somatic and germ line cells, affects F-actin organization and results in abnormal PtdIns(4,5)P2 localization. Improper cell organization coincides with aberrant localization of the membrane molecules Gurken (Grk) and Notch, whose activities are required for specification of the follicle cells that pattern the eggshell. Mutations in dPPCS also induce alterations in scutellar patterning and cause wing vein abnormalities. Interestingly, mutations in dPANK and dPPAT-DPCK result in similar patterning defects. Conclusion Together, our results demonstrate that de novo CoA biosynthesis is required for proper tissue morphogenesis.
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Affiliation(s)
- Floris Bosveld
- Department of Cell Biology, Section of Radiation & Stress Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
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41
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Dynamic length regulation of sensory stereocilia. Semin Cell Dev Biol 2008; 19:502-10. [PMID: 18692583 DOI: 10.1016/j.semcdb.2008.07.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Accepted: 07/15/2008] [Indexed: 01/02/2023]
Abstract
Stereocilia, the mechanosensory organelles of hair cells, are a distinctive class of actin-based cellular protrusions with an unparalleled ability to regulate their lengths over time. Studies on actin turnover in stereocilia, as well as the identification of several deafness-related proteins essential for proper stereocilia structure and function, provide new insights into the mechanisms and molecules involved in stereocilia length regulation and long-term maintenance. Comparisons of ongoing investigations on stereocilia with studies on other actin protrusions offer new opportunities to further understand common principles for length regulation, the diversity of its mechanisms, and how the specific needs of each cell are met.
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42
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Noguchi T, Lenartowska M, Rogat AD, Frank DJ, Miller KG. Proper cellular reorganization during Drosophila spermatid individualization depends on actin structures composed of two domains, bundles and meshwork, that are differentially regulated and have different functions. Mol Biol Cell 2008; 19:2363-72. [PMID: 18353976 DOI: 10.1091/mbc.e07-08-0840] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
During spermatid individualization in Drosophila, actin structures (cones) mediate cellular remodeling that separates the syncytial spermatids into individual cells. These actin cones are composed of two structural domains, a front meshwork and a rear region of parallel bundles. We show here that the two domains form separately in time, are regulated by different sets of actin-associated proteins, can be formed independently, and have different roles. Newly forming cones were composed only of bundles, whereas the meshwork formed later, coincident with the onset of cone movement. Polarized distributions of myosin VI, Arp2/3 complex, and the actin-bundling proteins, singed (fascin) and quail (villin), occurred when movement initiated. When the Arp2/3 complex was absent, meshwork formation was compromised, but surprisingly, the cones still moved. Despite the fact that the cones moved, membrane reorganization and cytoplasmic exclusion were abnormal and individualization failed. In contrast, when profilin, a regulator of actin assembly, was absent, bundle formation was greatly reduced. The meshwork still formed, but no movement occurred. Analysis of this actin structure's formation and participation in cellular reorganization provides insight into how the mechanisms used in cell motility are modified to mediate motile processes within specialized cells.
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Affiliation(s)
- Tatsuhiko Noguchi
- Laboratory for Morphogenetic Signaling, Center for Developmental Biology, RIKEN Kobe, Kobe 650-0047, Japan
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43
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Ogienko AA, Fedorova SA, Baricheva EM. Basic aspects of ovarian development in Drosophila melanogaster. RUSS J GENET+ 2007. [DOI: 10.1134/s1022795407100055] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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44
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Hegan PS, Mermall V, Tilney LG, Mooseker MS. Roles for Drosophila melanogaster myosin IB in maintenance of enterocyte brush-border structure and resistance to the bacterial pathogen Pseudomonas entomophila. Mol Biol Cell 2007; 18:4625-36. [PMID: 17855510 PMCID: PMC2043548 DOI: 10.1091/mbc.e07-02-0191] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Drosophila myosin IB (Myo1B) is one of two class I myosins in the Drosophila genome. In the larval and adult midgut enterocyte, Myo1B is present within the microvillus (MV) of the apical brush border (BB) where it forms lateral tethers between the MV membrane and underlying actin filament core. Expression of green fluorescent protein-Myo1B tail domain in the larval gut showed that the tail domain is sufficient for localization of Myo1B to the BB. A Myo1B deletion mutation exhibited normal larval gut physiology with respect to food uptake, clearance, and pH regulation. However, there is a threefold increase in terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive enterocyte nuclei in the Myo1B mutant. Ultrastructural analysis of mutant midgut revealed many perturbations in the BB, including membrane tethering defects, MV vesiculation, and membrane shedding. The apical localization of both singed (fascin) and Dmoesin is impaired. BBs isolated from mutant and control midgut revealed that the loss of Myo1B causes the BB membrane and underlying cytoskeleton to become destabilized. Myo1B mutant larvae also exhibit enhanced sensitivity to oral infection by the bacterial pathogen Pseudomonas entomophila, and severe cytoskeletal defects are observed in the BB of proximal midgut epithelial cells soon after infection. Resistance to P. entomophila infection is restored in Myo1B mutant larvae expressing a Myo1B transgene. These results indicate that Myo1B may play a role in the local midgut response pathway of the Imd innate immune response to Gram-negative bacterial infection.
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Affiliation(s)
- Peter S Hegan
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA.
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45
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Neuman-Silberberg FS. Drosophila female sterile mutation spoonbill interferes with multiple pathways in oogenesis. Genesis 2007; 45:369-81. [PMID: 17492752 DOI: 10.1002/dvg.20303] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
spoonbill is a Drosophila female-sterile mutation, which displays a range of eggshell and egg chamber patterning defects. Previous analysis has shown that the mutation interfered with the function of two major signaling pathways, GRK/EGFR and DPP. In this report, the nature of spoonbill was further investigated to examine whether it was associated with additional pathways in oogenesis. Clonal analysis, presented here, demonstrated that most of the aberrant phenotypes associated with spoonbill were dependent on a mutant germline. Nevertheless, SPOONBILL may function also in the soma to ensure proper polarization and migration of the border-cell-cluster. Further, genetic interaction studies implicated spoonbill in additional unrelated pathways such as the one(s) involved in actin polymerization/depolymerization. Based on the previous data and the results presented here, it is anticipated that spoonbill may encode a multifunctional protein that perhaps coordinately regulated the activity of multiple signaling pathways during oogenesis.
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Affiliation(s)
- F Shira Neuman-Silberberg
- Department of Virology and Developmental Genetics, Faculty of Health Sciences and Cancer Research Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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46
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Riparbelli MG, Gigliotti S, Callaini G. The Drosophila nucleoporin gene nup154 is required for correct microfilament dynamics and cell death during oogenesis. ACTA ACUST UNITED AC 2007; 64:590-604. [PMID: 17410542 DOI: 10.1002/cm.20206] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The Drosophila nucleoporin gene nup154 is required in both male and female germline for successful gametogenesis. Mutant flies lack differentiated sperm and lay abnormal eggs. We demonstrated that the egg phenotype was associated with specific alterations of the actin cytoskeleton at different stages of oogenesis. Actually, mutant egg chambers displayed an abnormal organization of both subcortical microfilaments and cytoplasmic actin bundles, that led to defective nurse cell dumping. TUNEL analysis also showed that the dumpless phenotype was associated with delayed apoptosis. The nup154 gene product was localized by conventional immunofluorescence microscopy to the nuclear envelope in a distinct punctuate pattern, characteristic of nuclear pore complex components. TEM analysis revealed that the protein was mainly distributed along filamentous structures that extended radially on the nuclear side of the pore, suggesting that Nup154 could be an integral component of the basket filaments associated with the nuclear pore complexes. We propose that Nup154 is necessary for correct nuclear pore complex functions and that the proper regulation of the actin cytoskeleton dynamics strongly relies upon nuclear pore integrity.
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47
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Smirnov SL, Isern NG, Jiang ZG, Hoyt DW, McKnight CJ. The isolated sixth gelsolin repeat and headpiece domain of villin bundle F-actin in the presence of calcium and are linked by a 40-residue unstructured sequence. Biochemistry 2007; 46:7488-96. [PMID: 17547371 PMCID: PMC2674016 DOI: 10.1021/bi700110v] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Villin is an F-actin regulating, modular protein with a gelsolin-like core and a distinct C-terminal "headpiece" domain. Localized in the microvilli of the absorptive epithelium, villin can bundle F-actin and, at higher calcium concentrations, is capable of a gelsolin-like F-actin severing. The headpiece domain can, in isolation, bind F-actin and is crucial for F-actin bundling by villin. While the three-dimensional structure of the isolated headpiece is known, its conformation in the context of attachment to the villin core remains unexplored. Furthermore, the dynamics of the linkage of the headpiece to the core has not been determined. To address these issues, we employ a 208-residue modular fragment of villin, D6-HP, which consists of the sixth gelsolin-like domain of villin (D6) and the headpiece (HP). We demonstrate that this protein fragment requires calcium for structural stability and, surprisingly, is capable of Ca2+-dependent F-actin bundling, suggesting that D6 contains a cryptic F-actin binding site. NMR resonance assignments and 15N relaxation measurements of D6-HP in 5 mM Ca2+ demonstrate that D6-HP consists of two independent structural domains (D6 and HP) connected by an unfolded 40-residue linker sequence. The headpiece domain in D6-HP retains its structure and interacts with D6 only through the linker sequence without engaging in other interactions. Chemical shift values indicate essentially the same secondary structure elements for D6 in D6-HP as in the highly homologous gelsolin domain 6. Thus, the headpiece domain of villin is structurally and functionally independent of the core domain.
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Affiliation(s)
- Serge L Smirnov
- Department of Physiology and Biophysics, Boston University School of Medicine, 715 Albany Street, Boston, Massachusetts 02118, USA
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48
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Peyre JB, Seabrooke S, Randlett O, Kisiel M, Aigaki T, Stewart BA. Interaction of cytoskeleton genes with NSF2-induced neuromuscular junction overgrowth. Genesis 2007; 44:595-600. [PMID: 17139674 DOI: 10.1002/dvg.20254] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
N-Ethylmaleimide sensitive factor (NSF) is an ATPase whose activity is important for intracellular trafficking. Previous genetic analysis of Drosophila NSF2 revealed a potential link between NSF and the actin cytoskeleton. The present study was therefore undertaken to specifically examine genetic interactions between the cytoskeleton and NSF. First, we tested for loss-of-function interaction and, indeed, we found that the combination of flies heterozygous for Act5C and NSF2 alleles led to reduced viability. Second, we expanded our gain-of-function approach to include cytoskeletal genes that were not included in our previous screen. Thirteen of 30 genes tested were found to suppress neuromuscular junction (NMJ) overgrowth. Altogether, these data support the idea that diverse NSF2 developmental and physiological phenotypes are related to disruption of the cytoskeleton and the large number of genes which can partially restore NMJ overgrowth and suggests that NSF may function near the top of the actin regulatory pathway.
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49
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Martin DN, Balgley B, Dutta S, Chen J, Rudnick P, Cranford J, Kantartzis S, DeVoe DL, Lee C, Baehrecke EH. Proteomic analysis of steroid-triggered autophagic programmed cell death during Drosophila development. Cell Death Differ 2007; 14:916-23. [PMID: 17256009 DOI: 10.1038/sj.cdd.4402098] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Two morphological forms of programmed cell death, apoptosis and autophagic cell death, remove unneeded or damaged cells during animal development. Although the mechanisms that regulate apoptosis are well studied, little is known about autophagic cell death. A shotgun proteome analysis of purified dying larval salivary glands in Drosophila was used to identify proteins that are expressed during autophagic programmed cell death. A total of 5661 proteins were identified from stages before and after the onset of cell death. Analyses of these data enabled us to identify proteins from a number of interesting categories including regulators of transcription, the apoptosis, autophagy, lysosomal, and ubiquitin proteasome degradation pathways, and proteins involved in growth control. Several of the identified proteins, including the serine/threonine kinase warts (Wts), were not detected using whole-genome DNA microarrays, providing support for the importance of such high-throughput proteomic technology. Wts regulates cell-cycle arrest and apoptosis, and significantly, mutations in wts prevent destruction of salivary glands.
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Affiliation(s)
- D N Martin
- Center for Biosystems Research, University of Maryland Biotechnology Institute, College Park, MD 20742-4450, USA
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50
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Verdier V, Johndrow JE, Betson M, Chen GC, Hughes DA, Parkhurst SM, Settleman J. Drosophila Rho-kinase (DRok) is required for tissue morphogenesis in diverse compartments of the egg chamber during oogenesis. Dev Biol 2006; 297:417-32. [PMID: 16887114 PMCID: PMC2504748 DOI: 10.1016/j.ydbio.2006.05.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Revised: 05/11/2006] [Accepted: 05/15/2006] [Indexed: 11/16/2022]
Abstract
The Rho-kinases are widely utilized downstream targets of the activated Rho GTPase that have been directly implicated in many aspects of Rho-dependent effects on F-actin assembly, acto-myosin contractility, and microtubule stability, and consequently play an essential role in regulating cell shape, migration, polarity, and division. We have determined that the single closely related Drosophila Rho-kinase ortholog, DRok, is required for several aspects of oogenesis, including maintaining the integrity of the oocyte cortex, actin-mediated tethering of nurse cell nuclei, "dumping" of nurse cell contents into the oocyte, establishment of oocyte polarity, and the trafficking of oocyte yolk granules. These defects are associated with abnormalities in DRok-dependent actin dynamics and appear to be mediated by multiple downstream effectors of activated DRok that have previously been implicated in oogenesis. DRok regulates at least one of these targets, the membrane cytoskeletal cross-linker DMoesin, via a direct phosphorylation that is required to promote localization of DMoesin to the oocyte cortex. The collective oogenesis defects associated with DRok deficiency reveal its essential role in multiple aspects of proper oocyte formation and suggest that DRok defines a novel class of oogenesis determinants that function as key regulators of several distinct actin-dependent processes required for proper tissue morphogenesis.
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Affiliation(s)
- Valerie Verdier
- Massachusetts General Hospital Cancer Center and Harvard Medical School, 149 13 Street, Charlestown, MA 02129, USA
| | - James E. Johndrow
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, A1-162, PO Box 19024, Seattle, WA 98109-1024, USA
| | | | - Guang-Chao Chen
- Massachusetts General Hospital Cancer Center and Harvard Medical School, 149 13 Street, Charlestown, MA 02129, USA
| | - David A. Hughes
- The Faculty of Life Sciences, The University of Manchester, Sackville Street, Manchester, United Kingdom
| | - Susan M. Parkhurst
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, A1-162, PO Box 19024, Seattle, WA 98109-1024, USA
| | - Jeffrey Settleman
- Massachusetts General Hospital Cancer Center and Harvard Medical School, 149 13 Street, Charlestown, MA 02129, USA
- Corresponding author, Telephone 617-724-9556, Fax: 617-726-7808,
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