1
|
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.
Collapse
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
| |
Collapse
|
2
|
Nuanpirom J, Suksri P, Yodsawat P, Sangket U, Sathapondecha P. Transcriptome profiling of gonad-stimulating factors in thoracic ganglia and a potential role of Indian hedgehog gene in vitellogenesis of banana shrimp Fenneropenaeus merguiensis. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2023; 47:101114. [PMID: 37542866 DOI: 10.1016/j.cbd.2023.101114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/25/2023] [Accepted: 07/25/2023] [Indexed: 08/07/2023]
Abstract
Shrimp reproduction is controlled by several factors. Central nervous tissues, especially thoracic ganglia and brain, are known sources of gonad stimulating factors (GSFs) in crustaceans, but the GSFs in shrimp have not yet been clarified. Hence, we aimed to characterize and study putative GSFs from thoracic ganglia of adult female Fenneropenaeus merguiensis. An analysis of thoracic ganglia transcriptome revealed 3224 putative GSFs of a total 77,681 unigenes. Only 376 putative GSFs were differentially expressed during ovarian developmental stages. Eight candidate GSFs were validated for their expression patterns in thoracic ganglia, including the Indian hedgehog gene. F. merguiensis Indian hedgehog (FmIHH) was then investigated for its role in vitellogenesis. The obtained full-length cDNA of FmIHH was similar to other crustacean IHHs rather than Sonic and Desert HHs. The FmIHH was dominantly expressed in thoracic ganglia, and its expression was significantly increased in the vitellogenic stages before being downregulated at the mature stage of ovarian development. Injection of the recombinant FmIHH (His-TF-IHH) protein stimulated vitellogenin expression in ovaries on day 3 and 7, and also increased the gonadosomatic index. In addition, crustacean hyperglycemic hormone expression and total sugar were significantly decreased in eyestalks and hemolymph, respectively, after injection of His-TF-IHH, while lactic acid was increased. Both total sugar and lactic acid were unchanged in ovaries of His-TF-IHH injected shrimp. These results suggested that FmIHH plays a crucial role in vitellogenesis and regulate sugar uptake during ovarian development.
Collapse
Affiliation(s)
- Jiratchaya Nuanpirom
- Center for Genomics and Bioinformatics Research, Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Phassorn Suksri
- Center for Genomics and Bioinformatics Research, Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Prasert Yodsawat
- Center for Genomics and Bioinformatics Research, Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Unitsa Sangket
- Center for Genomics and Bioinformatics Research, Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Ponsit Sathapondecha
- Center for Genomics and Bioinformatics Research, Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
| |
Collapse
|
3
|
Cai Y, Lv W, Jiang Y, Li Q, Su P, Pang Y. Molecular evolution of the BRINP and ASTN genes and expression profles in response to pathogens and spinal cord injury repair in lamprey (Lethenteron reissneri). FISH & SHELLFISH IMMUNOLOGY 2022; 131:274-282. [PMID: 36228880 DOI: 10.1016/j.fsi.2022.09.076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/26/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Bone morphogenic protein/retinoic acid inducible neural-specific proteins (BRINPs) and astrotactins (ASTNs) are two members of membrane attack complex/perforin-like (MACPF) superfamily proteins that present high expression in the growing and mature vertebrate neurons. Lamprey has a unique evolutionary status as a representative of the oldest jawless vertebrates, making it an ideal animal model for understanding vertebrate evolution. The evolutionary origins of BRINPs and ASTNs genes in vertebrates, however, have not been shown in lampreys. Here, BRINP and ASTN genes were found in lamprey genomes and the evolutionary relationships of them were investigated by phylogenetic analysis. Protein domains, motifs, genetic structure, and crystal structure analysis revealed that the features of BRINP and ASTN appear to be conserved in vertebrates. Genomic synteny analysis indicated that lamprey BRINP and ASTN neighbor genes differed dramatically from jawed vertebrate. Real-time quantitative results illustrated that the BRINP and ASTN genes family might take part in immune defence and spinal cord injury repair. This study not only enriches a better understanding of the evolution of the BRINP and ASTN genes but also offers a foundation for exploring their roles in the development of the vertebrate central nervous system (CNS).
Collapse
Affiliation(s)
- Yang Cai
- College of Life Sciences, Liaoning Normal University, Dalian, 116081, China; Lamprey Research Center, Liaoning Normal University, Dalian, 116081, China; Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, 116034, China
| | - Wanrong Lv
- College of Life Sciences, Liaoning Normal University, Dalian, 116081, China; Lamprey Research Center, Liaoning Normal University, Dalian, 116081, China; Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, 116034, China
| | - Ying Jiang
- College of Life Sciences, Liaoning Normal University, Dalian, 116081, China; Lamprey Research Center, Liaoning Normal University, Dalian, 116081, China; Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, 116034, China
| | - Qingwei Li
- College of Life Sciences, Liaoning Normal University, Dalian, 116081, China; Lamprey Research Center, Liaoning Normal University, Dalian, 116081, China; Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, 116034, China.
| | - Peng Su
- College of Life Sciences, Liaoning Normal University, Dalian, 116081, China; Lamprey Research Center, Liaoning Normal University, Dalian, 116081, China; Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, 116034, China.
| | - Yue Pang
- College of Life Sciences, Liaoning Normal University, Dalian, 116081, China; Lamprey Research Center, Liaoning Normal University, Dalian, 116081, China; Collaborative Innovation Center of Seafood Deep Processing, Dalian Polytechnic University, Dalian, 116034, China.
| |
Collapse
|
4
|
Karunaraj P, Tidswell O, Duncan EJ, Lovegrove MR, Jefferies G, Johnson TK, Beck CW, Dearden PK. Noggin proteins are multifunctional extracellular regulators of cell signalling. Genetics 2022; 221:6561546. [PMID: 35357435 PMCID: PMC9071555 DOI: 10.1093/genetics/iyac049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 03/25/2022] [Indexed: 11/14/2022] Open
Abstract
Noggin is an extracellular cysteine knot protein that plays a crucial role in vertebrate dorsoventral patterning. Noggin binds and inhibits the activity of bone morphogenetic proteins via a conserved N-terminal clip domain. Noncanonical orthologs of Noggin that lack a clip domain (“Noggin-like” proteins) are encoded in many arthropod genomes and are thought to have evolved into receptor tyrosine kinase ligands that promote Torso/receptor tyrosine kinase signaling rather than inhibiting bone morphogenic protein signaling. Here, we examined the molecular function of noggin/noggin-like genes (ApNL1 and ApNL2) from the arthropod pea aphid using the dorso-ventral patterning of Xenopus and the terminal patterning system of Drosophila to identify whether these proteins function as bone morphogenic protein or receptor tyrosine kinase signaling regulators. Our findings reveal that ApNL1 from the pea aphid can regulate both bone morphogenic protein and receptor tyrosine kinase signaling pathways, and unexpectedly, that the clip domain is not essential for its antagonism of bone morphogenic protein signaling. Our findings indicate that ancestral noggin/noggin-like genes were multifunctional regulators of signaling that have specialized to regulate multiple cell signaling pathways during the evolution of animals.
Collapse
Affiliation(s)
- Prashath Karunaraj
- Laboratory for Development and Regeneration, Department of Zoology, University of Otago, Dunedin 9016, Aotearoa-New Zealand.,Genomics Aotearoa and Department of Biochemistry, University of Otago, Dunedin 9016, Aotearoa-New Zealand
| | - Olivia Tidswell
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany
| | - Elizabeth J Duncan
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | | | - Grace Jefferies
- School of Biological Sciences, Monash University, Melbourne VIC 3800, Australia
| | - Travis K Johnson
- School of Biological Sciences, Monash University, Melbourne VIC 3800, Australia
| | - Caroline W Beck
- Laboratory for Development and Regeneration, Department of Zoology, University of Otago, Dunedin 9016, Aotearoa-New Zealand
| | - Peter K Dearden
- Genomics Aotearoa and Department of Biochemistry, University of Otago, Dunedin 9016, Aotearoa-New Zealand
| |
Collapse
|
5
|
The great small organisms of developmental genetics: Caenorhabditis elegans and Drosophila melanogaster. Dev Biol 2022; 485:93-122. [PMID: 35247454 PMCID: PMC9092520 DOI: 10.1016/j.ydbio.2022.02.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/25/2022] [Accepted: 02/27/2022] [Indexed: 12/30/2022]
Abstract
Experimental embryologists working at the turn of the 19th century suggested fundamental mechanisms of development, such as localized cytoplasmic determinants and tissue induction. However, the molecular basis underlying these processes proved intractable for a long time, despite concerted efforts in many developmental systems to isolate factors with a biological role. That road block was overcome by combining developmental biology with genetics. This powerful approach used unbiased genome-wide screens to isolate mutants with developmental defects and to thereby identify genes encoding key determinants and regulatory pathways that govern development. Two small invertebrates were the pioneers: the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans. Their modes of development differ in many ways, but the two together led the way to unraveling the molecular mechanisms of many fundamental developmental processes. The discovery of the grand homologies between key players in development throughout the animal kingdom underscored the usefulness of studying these small invertebrate models for animal development and even human disease. We describe developmental genetics in Drosophila and C. elegans up to the rise of genomics at the beginning of the 21st Century. Finally, we discuss themes that emerge from the histories of such distinct organisms and prospects of this approach for the future.
Collapse
|
6
|
Nüsslein-Volhard C. The Toll gene in Drosophila pattern formation. Trends Genet 2021; 38:231-245. [PMID: 34649739 DOI: 10.1016/j.tig.2021.09.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 12/13/2022]
Abstract
Toll-like receptors (TLRs) play a crucial role in innate immunity in animals. Their discovery was rewarded a Nobel Prize to Jules Hoffmann and Bruce Beutler in 2011. The name Toll stems from a Drosophila mutant that was isolated in 1980 by Eric Wieschaus and myself as a byproduct of our screen for segmentation genes in Drosophila for which we received the Nobel Prize in 1995. It was named Toll due to its amazing dominant phenotype displayed in embryos from Toll/+ females. The analysis of Toll by Kathryn Anderson in my laboratory in Tübingen and subsequently in her own laboratory in Berkeley singled out Toll as a central component of the complex pathway regulating dorsoventral polarity and pattern of the Drosophila embryo. The Drosophila Toll story provides a striking example for the value of curiosity-driven research in providing fundamental insights that later gain strong impact on applied medical research.
Collapse
Affiliation(s)
- Christiane Nüsslein-Volhard
- Max-Planck-Institute for Developmental Biology, Tübingen, BW 72076, Germany; Dedicated to the memory of Kathryn Anderson (1952-2020).
| |
Collapse
|
7
|
Insulin-Like Signalling Influences the Coordination of Larval Hemocyte Number with Body Size in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2020; 10:2213-2220. [PMID: 32341056 PMCID: PMC7341137 DOI: 10.1534/g3.120.401313] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Blood cells, known as hemocytes in invertebrates, play important and conserved roles in immunity, wound healing and tissue remodelling. The control of hemocyte number is therefore critical to ensure these functions are not compromised, and studies using Drosophila melanogaster are proving useful for understanding how this occurs. Recently, the embryonic patterning gene, torso-like (tsl), was identified as being required both for normal hemocyte development and for providing immunity against certain pathogens. Here, we report that Tsl is required specifically during the larval phase of hematopoiesis, and that tsl mutant larvae likely have reduced hemocyte numbers due to a reduced larval growth rate and compromised insulin signaling. Consistent with this, we find that impairing insulin-mediated growth, either by nutrient deprivation or genetically, results in fewer hemocytes. This is likely the result of impaired insulin-like signaling in the hemocytes themselves, since modulation of Insulin-like Receptor (InR) activity specifically in hemocytes causes concomitant changes to their population size in developing larvae. Taken together, our work reveals the strong relationship that exists between body size and hemocyte number, and suggests that insulin-like signaling contributes to, but is not solely responsible for, keeping these tightly aligned during larval development.
Collapse
|
8
|
Merkle JA, Wittes J, Schüpbach T. Signaling between somatic follicle cells and the germline patterns the egg and embryo of Drosophila. Curr Top Dev Biol 2019; 140:55-86. [PMID: 32591083 DOI: 10.1016/bs.ctdb.2019.10.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In Drosophila, specification of the embryonic body axes requires signaling between the germline and the somatic follicle cells. These signaling events are necessary to properly localize embryonic patterning determinants in the egg or eggshell during oogenesis. There are three maternal patterning systems that specify the anterior-posterior axis, and one that establishes the dorsal-ventral axis. We will first review oogenesis, focusing on the establishment of the oocyte and nurse cells and patterning of the follicle cells into different subpopulations. We then describe how two coordinated signaling events between the oocyte and follicle cells establish polarity of the oocyte and localize the anterior determinant bicoid, the posterior determinant oskar, and Gurken/epidermal growth factor (EGF), which breaks symmetry to initiate dorsal-ventral axis establishment. Next, we review how dorsal-ventral asymmetry of the follicle cells is transmitted to the embryo. This process also involves Gurken-EGF receptor (EGFR) signaling between the oocyte and follicle cells, leading to ventrally-restricted expression of the sulfotransferase Pipe. These events promote the ventral processing of Spaetzle, a ligand for Toll, which ultimately sets up the embryonic dorsal-ventral axis. We then describe the activation of the terminal patterning system by specialized polar follicle cells. Finally, we present open questions regarding soma-germline signaling during Drosophila oogenesis required for cell identity and embryonic axis formation.
Collapse
Affiliation(s)
- Julie A Merkle
- Department of Biology, University of Evansville, Evansville, IN, United States
| | - Julia Wittes
- Department of Biological Sciences, Columbia University, New York, NY, United States
| | - Trudi Schüpbach
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States.
| |
Collapse
|
9
|
Stevens LM, Zhang Y, Volnov Y, Chen G, Stein DS. Isolation of secreted proteins from Drosophila ovaries and embryos through in vivo BirA-mediated biotinylation. PLoS One 2019; 14:e0219878. [PMID: 31658274 PMCID: PMC6816556 DOI: 10.1371/journal.pone.0219878] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 10/15/2019] [Indexed: 02/07/2023] Open
Abstract
The extraordinarily strong non-covalent interaction between biotin and avidin (kD = 10-14-10-16) has permitted this interaction to be used in a wide variety of experimental contexts. The Biotin Acceptor Peptide (BAP), a 15 amino acid motif that can be biotinylated by the E. coli BirA protein, has been fused to proteins-of-interest, making them substrates for in vivo biotinylation. Here we report on the construction and characterization of a modified BirA bearing signals for secretion and endoplasmic reticulum (ER) retention, for use in experimental contexts requiring biotinylation of secreted proteins. When expressed in the Drosophila female germline or ovarian follicle cells under Gal4-mediated transcriptional control, the modified BirA protein could be detected and shown to be enzymatically active in ovaries and progeny embryos. Surprisingly, however, it was not efficiently retained in the ER, and instead appeared to be secreted. To determine whether this secreted protein, now designated secBirA, could biotinylate secreted proteins, we generated BAP-tagged versions of two secreted Drosophila proteins, Torsolike (Tsl) and Gastrulation Defective (GD), which are normally expressed maternally and participate in embryonic pattern formation. Both Tsl-BAP and GD-BAP were shown to exhibit normal patterning activity. Co-expression of Tsl-BAP together with secBirA in ovarian follicle cells resulted in its biotinylation, which permitted its isolation from both ovaries and progeny embryos using Avidin-coupled affinity matrix. In contrast, co-expression with secBirA in the female germline did not result in detectable biotinylation of GD-BAP, possibly because the C-terminal location of the BAP tag made it inaccessible to BirA in vivo. Our results indicate that secBirA directs biotinylation of proteins bound for secretion in vivo, providing access to powerful experimental approaches for secreted proteins-of-interest. However, efficient biotinylation of target proteins may vary depending upon the location of the BAP tag or other structural features of the protein.
Collapse
Affiliation(s)
- Leslie M. Stevens
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
- Section of Molecular Cell and Developmental Biology, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
| | - Yuan Zhang
- Section of Molecular Cell and Developmental Biology, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
| | - Yuri Volnov
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
| | - Geng Chen
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
- Section of Molecular Cell and Developmental Biology, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
| | - David S. Stein
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
- Section of Molecular Cell and Developmental Biology, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
| |
Collapse
|
10
|
Taylor SE, Tuffery J, Bakopoulos D, Lequeux S, Warr CG, Johnson TK, Dearden PK. The torso-like gene functions to maintain the structure of the vitelline membrane in Nasonia vitripennis, implying its co-option into Drosophila axis formation. Biol Open 2019; 8:bio.046284. [PMID: 31488408 PMCID: PMC6777369 DOI: 10.1242/bio.046284] [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] [Indexed: 12/05/2022] Open
Abstract
Axis specification is a fundamental developmental process. Despite this, the mechanisms by which it is controlled across insect taxa are strikingly different. An excellent example of this is terminal patterning, which in Diptera such as Drosophila melanogaster occurs via the localized activation of the receptor tyrosine kinase Torso. In Hymenoptera, however, the same process appears to be achieved via localized mRNA. How these mechanisms evolved and what they evolved from remains largely unexplored. Here, we show that torso-like, known for its role in Drosophila terminal patterning, is instead required for the integrity of the vitelline membrane in the hymenopteran wasp Nasonia vitripennis. We find that other genes known to be involved in Drosophila terminal patterning, such as torso and Ptth, also do not function in Nasonia embryonic development. These findings extended to orthologues of Drosophila vitelline membrane proteins known to play a role in localizing Torso-like in Drosophila; in Nasonia these are instead required for dorso–ventral patterning, gastrulation and potentially terminal patterning. Our data underscore the importance of the vitelline membrane in insect development, and implies phenotypes caused by knockdown of torso-like must be interpreted in light of its function in the vitelline membrane. In addition, our data imply that the signalling components of the Drosophila terminal patterning systems were co-opted from roles in regulating moulting, and co-option into terminal patterning involved the evolution of a novel interaction with the vitelline membrane protein Torso-like. This article has an associated First Person interview with the first author of the paper. Summary: In the parasitic wasp Nasonia, Tsl, a key component of the process that defines the termini of the embryo of Drosophila, has a function in the structure of the vitelline membrane.
Collapse
Affiliation(s)
- Shannon E Taylor
- Genomics Aotearoa and Biochemistry Department, University of Otago, P.O. Box 56, Dunedin, Aotearoa-New Zealand
| | - Jack Tuffery
- Genomics Aotearoa and Biochemistry Department, University of Otago, P.O. Box 56, Dunedin, Aotearoa-New Zealand
| | - Daniel Bakopoulos
- School of Biological Sciences, Monash University, 18 Innovation Walk, Clayton VIC 3800, Australia
| | - Sharon Lequeux
- Otago Micro- and Nano- scale Imaging, University of Otago, PO Box 913, Dunedin, New Zealand, Aotearoa-New Zealand
| | - Coral G Warr
- School of Medicine, University of Tasmania, 17 Liverpool St Hobart, TAS 7000, Australia
| | - Travis K Johnson
- School of Biological Sciences, Monash University, 18 Innovation Walk, Clayton VIC 3800, Australia
| | - Peter K Dearden
- Genomics Aotearoa and Biochemistry Department, University of Otago, P.O. Box 56, Dunedin, Aotearoa-New Zealand
| |
Collapse
|
11
|
Control of growth factor signalling by MACPF proteins. Biochem Soc Trans 2019; 47:801-810. [PMID: 31209154 DOI: 10.1042/bst20180179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/17/2019] [Accepted: 05/28/2019] [Indexed: 11/17/2022]
Abstract
Members of the membrane attack complex/perforin-like (MACPF) protein superfamily have long captured interest because of their unique ability to assemble into large oligomeric pores on the surfaces of cells. The best characterised of these act in vertebrate immunity where they function to deliver pro-apoptotic factors or induce the cytolysis and death of targeted cells. Less appreciated, however, is that rather than causing cell death, MACPF proteins have also evolved to control cellular signalling pathways and influence developmental programmes such as pattern formation and neurogenesis. Torso-like (Tsl) from the fruit fly Drosophila, for example, functions to localise the activity of a growth factor for patterning its embryonic termini. It remains unclear whether these developmental proteins employ an attenuated form of the classical MACPF lytic pore, or if they have evolved to function via alternative mechanisms of action. In this minireview, we examine the evidence that links pore-forming MACPF proteins to the control of growth factor and cytokine signalling. We will then attempt to reconcile how the MACPF domain may have been repurposed during evolution for developmental events rather than cell killing.
Collapse
|
12
|
Mineo A, Furriols M, Casanova J. The trigger (and the restriction) of Torso RTK activation. Open Biol 2018; 8:180180. [PMID: 30977718 PMCID: PMC6303783 DOI: 10.1098/rsob.180180] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 11/08/2018] [Indexed: 01/09/2023] Open
Abstract
The Torso pathway is an ideal model of receptor tyrosine kinase systems, in particular when addressing questions such as how receptor activity is turned on and, equally important, how it is restricted, how different outcomes can be generated from a single signal, and the extent to which gene regulation by signalling pathways relies on the relief of transcriptional repression. In this regard, we considered it pertinent to single out the fundamental notions learned from the Torso pathway beyond the specificities of this system (Furriols and Casanova 2003 EMBO J. 22, 1947-1952. ( doi:10.1093/emboj/cdg224 )). Since then, the Torso system has gained relevance and its implications beyond its original involvement in morphogenesis and into many disciplines such as oncogenesis, hormone control and neurobiology are now acknowledged. Thus, we believe that it is timely to highlight additional notions supported by new findings and to draw attention to future prospects. Given the late development of research in the field, we wish to devote this review to the events leading to the activation of the Torso receptor, the main focus of our most recent work.
Collapse
Affiliation(s)
- Alessandro Mineo
- Institut de Biologia Molecular de Barcelona (CSIC), C/Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain
- Institut de Recerca Biomèdica de Barcelona, (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), C/Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain
| | - Marc Furriols
- Institut de Biologia Molecular de Barcelona (CSIC), C/Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain
- Institut de Recerca Biomèdica de Barcelona, (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), C/Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain
| | - Jordi Casanova
- Institut de Biologia Molecular de Barcelona (CSIC), C/Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain
- Institut de Recerca Biomèdica de Barcelona, (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), C/Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain
| |
Collapse
|
13
|
Holes in the Plasma Membrane Mimic Torso-Like Perforin in Torso Tyrosine Kinase Receptor Activation in the Drosophila Embryo. Genetics 2018; 210:257-262. [PMID: 30049783 DOI: 10.1534/genetics.118.301397] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 07/24/2018] [Indexed: 11/18/2022] Open
Abstract
Receptor tyrosine kinase (RTK) pathways play central roles in development, and, when abnormally activated, they can lead to pathological conditions, including oncogenesis. Thus, RTK activation, mediated by ligand binding, is under tight control, a critical step being the conversion of an inactive precursor into the active form of the ligand. A variety of mechanisms have been shown to be involved in this conversion; however, little attention has been paid to how mechanical phenomena may impinge on this process. Here we address this issue by studying Torso, an RTK activated at both poles of the Drosophila embryo at the blastoderm stage. Torso activation is induced by a cleaved form of Trunk, a growth factor-like protein, but it also requires the accumulation of the Torso-like (Tsl) protein at both ends of the blastoderm. Tsl is the only known protein in Drosophila bearing a membrane attack complex/perforin (MACPF) domain-a motif present in proteins involved in pore formation at cell membranes. However, while different hypotheses have been put forward to account for the function of Tsl in Torso receptor activation, little is known about its molecular role and whether it indeed contributes to membrane pore formation. Here, we show that mechanically induced holes in the Drosophila embryo can substitute for Tsl function. These results suggest that Tsl is required for an exchange between the interior of the Drosophila embryo and its surrounding milieu and that mechanically induced cell injuries may contribute to abnormal RTK activation.
Collapse
|
14
|
Genome-Wide Screen for New Components of the Drosophila melanogaster Torso Receptor Tyrosine Kinase Pathway. G3-GENES GENOMES GENETICS 2018; 8:761-769. [PMID: 29363515 PMCID: PMC5844297 DOI: 10.1534/g3.117.300491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Patterning of the Drosophila embryonic termini by the Torso (Tor) receptor pathway has long served as a valuable paradigm for understanding how receptor tyrosine kinase signaling is controlled. However, the mechanisms that underpin the control of Tor signaling remain to be fully understood. In particular, it is unclear how the Perforin-like protein Torso-like (Tsl) localizes Tor activity to the embryonic termini. To shed light on this, together with other aspects of Tor pathway function, we conducted a genome-wide screen to identify new pathway components that operate downstream of Tsl. Using a set of molecularly defined chromosomal deficiencies, we screened for suppressors of ligand-dependent Tor signaling induced by unrestricted Tsl expression. This approach yielded 59 genomic suppressor regions, 11 of which we mapped to the causative gene, and a further 29 that were mapped to <15 genes. Of the identified genes, six represent previously unknown regulators of embryonic Tor signaling. These include twins (tws), which encodes an integral subunit of the protein phosphatase 2A complex, and α-tubulin at 84B (αTub84B), a major constituent of the microtubule network, suggesting that these may play an important part in terminal patterning. Together, these data comprise a valuable resource for the discovery of new Tor pathway components. Many of these may also be required for other roles of Tor in development, such as in the larval prothoracic gland where Tor signaling controls the initiation of metamorphosis.
Collapse
|
15
|
Torso-Like Is a Component of the Hemolymph and Regulates the Insulin Signaling Pathway in Drosophila. Genetics 2018; 208:1523-1533. [PMID: 29440191 DOI: 10.1534/genetics.117.300601] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 02/12/2018] [Indexed: 01/01/2023] Open
Abstract
In Drosophila, key developmental transitions are governed by the steroid hormone ecdysone. A number of neuropeptide-activated signaling pathways control ecdysone production in response to environmental signals, including the insulin signaling pathway, which regulates ecdysone production in response to nutrition. Here, we find that the Membrane Attack Complex/Perforin-like protein Torso-like, best characterized for its role in activating the Torso receptor tyrosine kinase in early embryo patterning, also regulates the insulin signaling pathway in Drosophila We previously reported that the small body size and developmental delay phenotypes of torso-like null mutants resemble those observed when insulin signaling is reduced. Here we report that, in addition to growth defects, torso-like mutants also display metabolic and nutritional plasticity phenotypes characteristic of mutants with impaired insulin signaling. We further find that in the absence of torso-like, the expression of insulin-like peptides is increased, as is their accumulation in insulin-producing cells. Finally, we show that Torso-like is a component of the hemolymph and that it is required in the prothoracic gland to control developmental timing and body size. Taken together, our data suggest that the secretion of Torso-like from the prothoracic gland influences the activity of insulin signaling throughout the body in Drosophila.
Collapse
|
16
|
Johnson TK, Henstridge MA, Warr CG. MACPF/CDC proteins in development: Insights from Drosophila torso-like. Semin Cell Dev Biol 2017; 72:163-170. [DOI: 10.1016/j.semcdb.2017.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 05/01/2017] [Accepted: 05/11/2017] [Indexed: 01/08/2023]
|
17
|
Pae J, Cinalli RM, Marzio A, Pagano M, Lehmann R. GCL and CUL3 Control the Switch between Cell Lineages by Mediating Localized Degradation of an RTK. Dev Cell 2017; 42:130-142.e7. [PMID: 28743001 DOI: 10.1016/j.devcel.2017.06.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 05/15/2017] [Accepted: 06/27/2017] [Indexed: 11/29/2022]
Abstract
The separation of germline from somatic lineages is fundamental to reproduction and species preservation. Here, we show that Drosophila Germ cell-less (GCL) is a critical component in this process by acting as a switch that turns off a somatic lineage pathway. GCL, a conserved BTB (Broad-complex, Tramtrack, and Bric-a-brac) protein, is a substrate-specific adaptor for Cullin3-RING ubiquitin ligase complex (CRL3GCL). We show that CRL3GCL promotes PGC fate by mediating degradation of Torso, a receptor tyrosine kinase (RTK) and major determinant of somatic cell fate. This mode of RTK degradation does not depend upon receptor activation but is prompted by release of GCL from the nuclear envelope during mitosis. The cell-cycle-dependent change in GCL localization provides spatiotemporal specificity for RTK degradation and sequesters CRL3GCL to prevent it from participating in excessive activities. This precisely orchestrated mechanism of CRL3GCL function and regulation defines cell fate at the single-cell level.
Collapse
Affiliation(s)
- Juhee Pae
- HHMI and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | - Ryan M Cinalli
- HHMI and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | - Antonio Marzio
- HHMI, Department of Biochemistry and Molecular Pharmacology and Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016, USA
| | - Michele Pagano
- HHMI, Department of Biochemistry and Molecular Pharmacology and Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016, USA
| | - Ruth Lehmann
- HHMI and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA.
| |
Collapse
|
18
|
Maternal Torso-Like Coordinates Tissue Folding During Drosophila Gastrulation. Genetics 2017; 206:1459-1468. [PMID: 28495958 DOI: 10.1534/genetics.117.200576] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 05/04/2017] [Indexed: 11/18/2022] Open
Abstract
The rapid and orderly folding of epithelial tissue during developmental processes such as gastrulation requires the precise coordination of changes in cell shape. Here, we report that the perforin-like protein Torso-like (Tsl), the key extracellular determinant for Drosophila embryonic terminal patterning, also functions to control epithelial morphogenesis. We find that tsl null mutants display a ventral cuticular hole phenotype that is independent of the loss of terminal structures, and arises as a consequence of mesoderm invagination defects. We show that the holes are caused by uncoordinated constriction of ventral cell apices, resulting in the formation of an incomplete ventral furrow. Consistent with these data, we find that loss of tsl is sensitive to gene dosage of RhoGEF2, a critical mediator of Rho1-dependent ventral cell shape changes during furrow formation, suggesting that Tsl may act in this pathway. In addition, loss of tsl strongly suppressed the effects of ectopic expression of Folded Gastrulation (Fog), a secreted protein that promotes apical constriction. Taken together, our data suggest that Tsl controls Rho1-mediated apical constriction via Fog. Therefore, we propose that Tsl regulates extracellular Fog activity to synchronize cell shape changes and coordinate ventral morphogenesis in Drosophila Identifying the Tsl-mediated event that is common to both terminal patterning and morphogenesis will be valuable for our understanding of the extracellular control of developmental signaling by perforin-like proteins.
Collapse
|
19
|
Amarnath S, Stevens LM, Stein DS. Reconstitution of Torso signaling in cultured cells suggests a role for both Trunk and Torso-like in receptor activation. Development 2017; 144:677-686. [PMID: 28087630 DOI: 10.1242/dev.146076] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 12/30/2016] [Indexed: 12/15/2022]
Abstract
Formation of the Drosophila embryonic termini is controlled by the localized activation of the receptor tyrosine kinase Torso. Both Torso and Torso's presumed ligand, Trunk, are expressed uniformly in the early embryo. Polar activation of Torso requires Torso-like, which is expressed by follicle cells adjacent to the ends of the developing oocyte. We find that Torso expressed at high levels in cultured Drosophila cells is activated by individual application of Trunk, Torso-like or another known Torso ligand, Prothoracicotropic Hormone. In addition to assays of downstream signaling activity, Torso dimerization was detected using bimolecular fluorescence complementation. Trunk and Torso-like were active when co-transfected with Torso and when presented to Torso-expressing cells in conditioned medium. Trunk and Torso-like were also taken up from conditioned medium specifically by cells expressing Torso. At low levels of Torso, similar to those present in the embryo, Trunk and Torso-like alone were ineffective but acted synergistically to stimulate Torso signaling. Our results suggest that Torso interacts with both Trunk and Torso-like, which cooperate to mediate dimerization and activation of Torso at the ends of the Drosophila embryo.
Collapse
Affiliation(s)
- Smita Amarnath
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Patterson Labs 532, 2401 Speedway, Austin, TX 78712, USA
| | - Leslie M Stevens
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Patterson Labs 532, 2401 Speedway, Austin, TX 78712, USA
| | - David S Stein
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Patterson Labs 532, 2401 Speedway, Austin, TX 78712, USA
| |
Collapse
|
20
|
Development of the Cellular Immune System of Drosophila Requires the Membrane Attack Complex/Perforin-Like Protein Torso-Like. Genetics 2016; 204:675-681. [PMID: 27535927 DOI: 10.1534/genetics.115.185462] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 08/08/2016] [Indexed: 01/12/2023] Open
Abstract
Pore-forming members of the membrane attack complex/perforin-like (MACPF) protein superfamily perform well-characterized roles as mammalian immune effectors. For example, complement component 9 and perforin function to directly form pores in the membrane of Gram-negative pathogens or virally infected/transformed cells, respectively. In contrast, the only known MACPF protein in Drosophila melanogaster, Torso-like, plays crucial roles during development in embryo patterning and larval growth. Here, we report that in addition to these functions, Torso-like plays an important role in Drosophila immunity. However, in contrast to a hypothesized effector function in, for example, elimination of Gram-negative pathogens, we find that torso-like null mutants instead show increased susceptibility to certain Gram-positive pathogens such as Staphylococcus aureus and Enterococcus faecalis We further show that this deficit is due to a severely reduced number of circulating immune cells and, as a consequence, an impaired ability to phagocytose bacterial particles. Together these data suggest that Torso-like plays an important role in controlling the development of the Drosophila cellular immune system.
Collapse
|
21
|
Johnson TK, Henstridge MA, Herr A, Moore KA, Whisstock JC, Warr CG. Torso-like mediates extracellular accumulation of Furin-cleaved Trunk to pattern the Drosophila embryo termini. Nat Commun 2015; 6:8759. [PMID: 26508274 PMCID: PMC4640135 DOI: 10.1038/ncomms9759] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 09/28/2015] [Indexed: 01/21/2023] Open
Abstract
Patterning of the Drosophila embryonic termini is achieved by localized activation of the Torso receptor by the growth factor Trunk. Governing this event is the perforin-like protein Torso-like, which is localized to the extracellular space at the embryo poles and has long been proposed to control localized proteolytic activation of Trunk. However, a protease involved in terminal patterning remains to be identified, and the role of Torso-like remains unknown. Here we find that Trunk is cleaved intracellularly by Furin proteases. We further show that Trunk is secreted, and that levels of extracellular Trunk are greatly reduced in torso-like null mutants. On the basis of these and previous findings, we suggest that Torso-like functions to mediate secretion of Trunk, thus providing the mechanism for spatially restricted activation of Torso. Our data represent an alternative mechanism for the spatial control of receptor signalling, and define a different role for perforin-like proteins in eukaryotes. Activation of the growth factor Trunk patterns the Drosophila embryonic termini but how this is regulated is unclear. Here, Johnson et al. report that Trunk is cleaved intracellularly by Furin proteases, and its extracellular accumulation is then mediated by the perforin-like protein Torso-like.
Collapse
Affiliation(s)
- Travis K Johnson
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Michelle A Henstridge
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Anabel Herr
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Karyn A Moore
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - James C Whisstock
- Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Coral G Warr
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| |
Collapse
|
22
|
Conformational changes during pore formation by the perforin-related protein pleurotolysin. PLoS Biol 2015; 13:e1002049. [PMID: 25654333 PMCID: PMC4318580 DOI: 10.1371/journal.pbio.1002049] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 12/10/2014] [Indexed: 12/17/2022] Open
Abstract
Membrane attack complex/perforin-like (MACPF) proteins comprise the largest superfamily of pore-forming proteins, playing crucial roles in immunity and pathogenesis. Soluble monomers assemble into large transmembrane pores via conformational transitions that remain to be structurally and mechanistically characterised. Here we present an 11 Å resolution cryo-electron microscopy (cryo-EM) structure of the two-part, fungal toxin Pleurotolysin (Ply), together with crystal structures of both components (the lipid binding PlyA protein and the pore-forming MACPF component PlyB). These data reveal a 13-fold pore 80 Å in diameter and 100 Å in height, with each subunit comprised of a PlyB molecule atop a membrane bound dimer of PlyA. The resolution of the EM map, together with biophysical and computational experiments, allowed confident assignment of subdomains in a MACPF pore assembly. The major conformational changes in PlyB are a ∼70° opening of the bent and distorted central β-sheet of the MACPF domain, accompanied by extrusion and refolding of two α-helical regions into transmembrane β-hairpins (TMH1 and TMH2). We determined the structures of three different disulphide bond-trapped prepore intermediates. Analysis of these data by molecular modelling and flexible fitting allows us to generate a potential trajectory of β-sheet unbending. The results suggest that MACPF conformational change is triggered through disruption of the interface between a conserved helix-turn-helix motif and the top of TMH2. Following their release we propose that the transmembrane regions assemble into β-hairpins via top down zippering of backbone hydrogen bonds to form the membrane-inserted β-barrel. The intermediate structures of the MACPF domain during refolding into the β-barrel pore establish a structural paradigm for the transition from soluble monomer to pore, which may be conserved across the whole superfamily. The TMH2 region is critical for the release of both TMH clusters, suggesting why this region is targeted by endogenous inhibitors of MACPF function. Animals, plants, fungi, and bacteria all use pore-forming proteins of the membrane attack complex-perforin (MACPF) family as lethal, cell-killing weapons. These proteins are able to insert into the plasma membranes of target cells, creating large pores that short circuit the natural separation between the intracellular and extracellular milieu, with catastrophic results. However, the pore-forming proteins must undergo a substantial transformation from soluble precursors to a large barrel-shaped transmembrane complex as they punch their way into cells. Using a combination of X-ray crystallography and cryo electron microscopy, we have visualized, for the first time, the mechanism of action of one of these pore-forming proteins—pleurotolysin, a MACPF protein from the edible oyster mushroom. This enabled us to propose a model of the pleurotolysin pore by fitting the crystallographic structures of the pore proteins into a three-dimensional map of the pore obtained by cryo electron microscopy. We then designed a set of double mutants that allowed us to chemically trap intermediate states along the trajectory of the pore formation process, and to determine their structures too. By combining these data we proposed a detailed molecular mechanism for pore formation. The pleurotolysin first assembles into rings of 13 subunits, each of which then opens up by about 70° during pore formation. This process is accompanied by refolding and extrusion of two compact regions from each subunit into long hairpins that then zipper together to form an 80-Å wide barrel-shaped channel through the membrane. A combination of structural methods reveals the complex process by which the perforin-like fungal toxin Pleurotolysin rearranges its structure to form a pore that punches a hole in target cell membranes.
Collapse
|
23
|
Duncan EJ, Johnson TK, Whisstock JC, Warr CG, Dearden PK. Capturing embryonic development from metamorphosis: how did the terminal patterning signalling pathway of Drosophila evolve? CURRENT OPINION IN INSECT SCIENCE 2014; 1:45-51. [PMID: 32846729 DOI: 10.1016/j.cois.2014.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 04/29/2014] [Accepted: 04/29/2014] [Indexed: 06/11/2023]
Abstract
The Torso receptor tyrosine kinase has two crucial roles in Drosophila melanogaster development. One is in the control of insect moulting, which is regulated by the neuropeptide hormone PTTH (prothoracicotropic hormone). PTTH activates ERK signalling via Torso in the prothoracic gland to stimulate ecdysone secretion. Torso also has a role in control of one of the earliest events in embryogenesis in Drosophila; patterning of the embryonic termini. Here Torso is activated by a different, but related, peptide called Trunk. During terminal patterning another protein, Torso-like, has a key role in mediating activation of Torso by Trunk. Torso-like is also expressed in the prothoracic gland and null-mutants have defective developmental timing in Drosophila. This function, however, has been recently shown to be independent of Torso and PTTH. We refer to these proteins, Trunk, PTTH, Torso and Torso-like, as the Torso-activation module. Outside Drosophila we see that the genes encoding the Torso-activation module have a complex phylogenetic history, with different origins and multiple losses of components of this signalling pathway during arthropod evolution. This, together with expression and functional data in a range of insects, leads us to propose that the terminal patterning pathway in Drosophila and Tribolium arose through co-option of PTTH/Trunk and Torso, which has a role in developmental timing, into a new context, and that Torso-like was recruited specifically in the ovary to modulate the specificity of this pathway.
Collapse
Affiliation(s)
- Elizabeth J Duncan
- Genetics Otago, University of Otago, P.O. Box 56, Dunedin, Aotearoa, New Zealand; Gravida; The National Centre for Growth and Development, University of Otago, P.O. Box 56, Dunedin, Aotearoa, New Zealand
| | - Travis K Johnson
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - James C Whisstock
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia; Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, VIC 3800, Australia
| | - Coral G Warr
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Peter K Dearden
- Genetics Otago, University of Otago, P.O. Box 56, Dunedin, Aotearoa, New Zealand; Gravida; The National Centre for Growth and Development, University of Otago, P.O. Box 56, Dunedin, Aotearoa, New Zealand.
| |
Collapse
|
24
|
Trunk cleavage is essential for Drosophila terminal patterning and can occur independently of Torso-like. Nat Commun 2014; 5:3419. [DOI: 10.1038/ncomms4419] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 02/10/2014] [Indexed: 02/07/2023] Open
|
25
|
Senior MJ, Wallace MI. Fluorescence imaging of MACPF/CDC proteins: new techniques and their application. Subcell Biochem 2014; 80:293-319. [PMID: 24798018 DOI: 10.1007/978-94-017-8881-6_15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Structural and biochemical investigations have helped illuminate many of the important details of MACPF/CDC pore formation. However, conventional techniques are limited in their ability to tackle many of the remaining key questions, and new biophysical techniques might provide the means to improve our understanding. Here we attempt to identify the properties of MACPF/CDC proteins that warrant further study, and explore how new developments in fluorescence imaging are able to probe these properties.
Collapse
Affiliation(s)
- Michael J Senior
- Department of Chemistry, Oxford University, 12 Mansfield Rd, Oxford, OX1 3TA, UK
| | | |
Collapse
|
26
|
Abstract
The complement system is an intricate network of serum proteins that mediates humoral innate immunity through an amplification cascade that ultimately leads to recruitment of inflammatory cells or opsonisation or killing of pathogens. One effector arm of this network is the terminal pathway of complement, which leads to the formation of the membrane attack complex (MAC) composed of complement components C5b, C6, C7, C8 and C9. Upon formation of C5 convertases via the classical or alternative pathways of complement activation, C5b is generated from C5 by proteolytic cleavage, nucleating a series of association and polymerisation reactions of the MAC-constituting complement components that culminate in pore formation of pathogenic membranes. Recent structures of MAC components and homologous proteins significantly increased our understanding of oligomerisation, membrane association and integration, shedding light onto the molecular mechanism of this important branch of the innate immune system.
Collapse
|
27
|
Abstract
Membrane Attack Complex/Perforin (MACPF) and Cholesterol-Dependent Cytolysins (CDC) form the MACPF/CDC superfamily of important effector proteins widespread in nature. MACPFs and CDCs were discovered separately with no sequence similarity at that stage being apparent between the two protein families such that they were not, until recently, considered evolutionary related. The breakthrough showing they are came with recent structural work that also shed light on the molecular mechanism of action of various MACPF proteins. Similarity in structural properties and conserved functional features indicate that both protein families have the same evolutionary origin. We will describe the distribution of MACPF/CDC proteins in nature and discuss briefly their similarity and functional role in different biological processes.
Collapse
Affiliation(s)
- Gregor Anderluh
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia,
| | | | | | | |
Collapse
|
28
|
Torso-like functions independently of Torso to regulate Drosophila growth and developmental timing. Proc Natl Acad Sci U S A 2013; 110:14688-92. [PMID: 23959885 DOI: 10.1073/pnas.1309780110] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Activation of the Drosophila receptor tyrosine kinase Torso (Tor) only at the termini of the embryo is achieved by the localized expression of the maternal gene Torso-like (Tsl). Tor has a second function in the prothoracic gland as the receptor for prothoracicotropic hormone (PTTH) that initiates metamorphosis. Consistent with the function of Tor in this tissue, Tsl also localizes to the prothoracic gland and influences developmental timing. Despite these commonalities, in our studies of Tsl we unexpectedly found that tsl and tor have opposing effects on body size; tsl null mutants are smaller than normal, rather than larger as would be expected if the PTTH/Tor pathway was disrupted. We further found that whereas both genes regulate developmental timing, tsl does so independently of tor. Although tsl null mutants exhibit a similar length delay in time to pupariation to tor mutants, in tsl:tor double mutants this delay is strikingly enhanced. Thus, loss of tsl is additive rather than epistatic to loss of tor. We also find that phenotypes generated by ectopic PTTH expression are independent of tsl. Finally, we show that a modified form of tsl that can rescue developmental timing cannot rescue terminal patterning, indicating that Tsl can function via distinct mechanisms in different contexts. We conclude that Tsl is not just a specialized cue for Torso signaling but also acts independently of PTTH/Tor in the control of body size and the timing of developmental progression. These data highlight surprisingly diverse developmental functions for this sole Drosophila member of the perforin-like superfamily.
Collapse
|
29
|
Gilbert RJC, Mikelj M, Dalla Serra M, Froelich CJ, Anderluh G. Effects of MACPF/CDC proteins on lipid membranes. Cell Mol Life Sci 2013; 70:2083-98. [PMID: 22983385 PMCID: PMC11114033 DOI: 10.1007/s00018-012-1153-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/29/2012] [Accepted: 08/30/2012] [Indexed: 12/15/2022]
Abstract
Recent work on the MACPF/CDC superfamily of pore-forming proteins has focused on the structural analysis of monomers and pore-forming oligomeric complexes. We set the family of proteins in context and highlight aspects of their function which the direct and exclusive equation of oligomers with pores fails to explain. Starting with a description of the distribution of MACPF/CDC proteins across the domains of life, we proceed to show how their evolutionary relationships can be understood on the basis of their structural homology and re-evaluate models for pore formation by perforin, in particular. We furthermore highlight data showing the role of incomplete oligomeric rings (arcs) in pore formation and how this can explain small pores generated by oligomers of proteins belonging to the family. We set this in the context of cell biological and biophysical data on the proteins' function and discuss how this helps in the development of an understanding of how they act in processes such as apicomplexan parasites gliding through cells and exiting from cells.
Collapse
Affiliation(s)
- Robert J. C. Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN UK
| | - Miha Mikelj
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Mauro Dalla Serra
- National Research Council, Institute of Biophysics and Bruno Kessler Foundation, via alla Cascata 56/C, 38123 Trento, Italy
| | - Christopher J. Froelich
- Department of Medicine, NorthShore University HealthSystem Research Institute, Evanston, IL 60201 USA
| | - Gregor Anderluh
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
- National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| |
Collapse
|
30
|
Abstract
Tyrosine phosphorylation plays a significant role in a wide range of cellular processes. The Drosophila genome encodes more than 20 receptor tyrosine kinases and extensive studies in the past 20 years have illustrated their diverse roles and complex signaling mechanisms. Although some receptor tyrosine kinases have highly specific functions, others strikingly are used in rather ubiquitous manners. Receptor tyrosine kinases regulate a broad expanse of processes, ranging from cell survival and proliferation to differentiation and patterning. Remarkably, different receptor tyrosine kinases share many of the same effectors and their hierarchical organization is retained in disparate biological contexts. In this comprehensive review, we summarize what is known regarding each receptor tyrosine kinase during Drosophila development. Astonishingly, very little is known for approximately half of all Drosophila receptor tyrosine kinases.
Collapse
Affiliation(s)
- Richelle Sopko
- Department of Genetics, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | | |
Collapse
|
31
|
Bickel RD, Cleveland HC, Barkas J, Jeschke CC, Raz AA, Stern DL, Davis GK. The pea aphid uses a version of the terminal system during oviparous, but not viviparous, development. EvoDevo 2013; 4:10. [PMID: 23552511 PMCID: PMC3639227 DOI: 10.1186/2041-9139-4-10] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 02/18/2013] [Indexed: 01/03/2023] Open
Abstract
Background In most species of aphid, female nymphs develop into either sexual or asexual adults depending on the length of the photoperiod to which their mothers were exposed. The progeny of these sexual and asexual females, in turn, develop in dramatically different ways. The fertilized oocytes of sexual females begin embryogenesis after being deposited on leaves (oviparous development) while the oocytes of asexual females complete embryogenesis within the mother (viviparous development). Compared with oviparous development, viviparous development involves a smaller transient oocyte surrounded by fewer somatic epithelial cells and a smaller early embryo that comprises fewer cells. To investigate whether patterning mechanisms differ between the earliest stages of the oviparous and viviparous modes of pea aphid development, we examined the expression of pea aphid orthologs of genes known to specify embryonic termini in other insects. Results Here we show that pea aphid oviparous ovaries express torso-like in somatic posterior follicle cells and activate ERK MAP kinase at the posterior of the oocyte. In addition to suggesting that some posterior features of the terminal system are evolutionarily conserved, our detection of activated ERK in the oocyte, rather than in the embryo, suggests that pea aphids may transduce the terminal signal using a mechanism distinct from the one used in Drosophila. In contrast with oviparous development, the pea aphid version of the terminal system does not appear to be used during viviparous development, since we did not detect expression of torso-like in the somatic epithelial cells that surround either the oocyte or the blastoderm embryo and we did not observe restricted activated ERK in the oocyte. Conclusions We suggest that while oviparous oocytes and embryos may specify posterior fate through an aphid terminal system, viviparous oocytes and embryos employ a different mechanism, perhaps one that does not rely on an interaction between the oocyte and surrounding somatic cells. Together, these observations provide a striking example of a difference in the fundamental events of early development that is both environmentally induced and encoded by the same genome.
Collapse
Affiliation(s)
- Ryan D Bickel
- Department of Biology, Bryn Mawr College, Bryn Mawr, PA 19010, USA.
| | | | | | | | | | | | | |
Collapse
|
32
|
Li M, Wen S, Guo X, Bai B, Gong Z, Liu X, Wang Y, Zhou Y, Chen X, Liu L, Chen R. The novel long non-coding RNA CRG regulates Drosophila locomotor behavior. Nucleic Acids Res 2012; 40:11714-27. [PMID: 23074190 PMCID: PMC3526303 DOI: 10.1093/nar/gks943] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Long non-coding RNAs (lncRNAs) that have no protein-coding capacity make up a large proportion of the transcriptome of various species. Many lncRNAs are expressed within the animal central nervous system in spatial- and temporal-specific patterns, indicating that lncRNAs play important roles in cellular processes, neural development, and even in cognitive and behavioral processes. However, relatively little is known about their in vivo functions and underlying molecular mechanisms in the nervous system. Here, we report a neural-specific Drosophila lncRNA, CASK regulatory gene (CRG), which participates in locomotor activity and climbing ability by positively regulating its neighboring gene CASK (Ca(2+)/calmodulin-dependent protein kinase). CRG deficiency led to reduced locomotor activity and a defective climbing ability-phenotypes that are often seen in CASK mutant. CRG mutant also showed reduced CASK expression level while CASK over-expression could rescue the CRG mutant phenotypes in reciprocal. At the molecular level, CRG was required for the recruitment of RNA polymerase II to the CASK promoter regions, which in turn enhanced CASK expression. Our work has revealed new functional roles of lncRNAs and has provided insights to explore the pathogenesis of neurological diseases associated with movement disorders.
Collapse
Affiliation(s)
- Meixia Li
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
El-Sherif E, Lynch JA, Brown SJ. Comparisons of the embryonic development of Drosophila, Nasonia, and Tribolium. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2012; 1:16-39. [PMID: 23801665 PMCID: PMC5323069 DOI: 10.1002/wdev.3] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Studying the embryogenesis of diverse insect species is crucial to understanding insect evolution. Here, we review current advances in understanding the development of two emerging model organisms: the wasp Nasonia vitripennis and the beetle Tribolium castaneum in comparison with the well-studied fruit fly Drosophila melanogaster. Although Nasonia represents the most basally branching order of holometabolous insects, it employs a derived long germband mode of embryogenesis, more like that of Drosophila, whereas Tribolium undergoes an intermediate germband mode of embryogenesis, which is more similar to the ancestral mechanism. Comparing the embryonic development and genetic regulation of early patterning events in these three insects has given invaluable insights into insect evolution. The similar mode of embryogenesis of Drosophila and Nasonia is reflected in their reliance on maternal morphogenetic gradients. However, they employ different genes as maternal factors, reflecting the evolutionary distance separating them. Tribolium, on the other hand, relies heavily on self-regulatory mechanisms other than maternal cues, reflecting its sequential nature of segmentation and the need for reiterated patterning.
Collapse
Affiliation(s)
- Ezzat El-Sherif
- Program of Genetics, Kansas State University, Manhattan, Kansas
| | - Jeremy A Lynch
- Institute for Developmental Biology, University of Cologne, Cologne, Germany
| | - Susan J Brown
- Division of Biology, Kansas State University, Manhattan, Kansas
| |
Collapse
|
34
|
Rosado CJ, Kondos S, Bull TE, Kuiper MJ, Law RHP, Buckle AM, Voskoboinik I, Bird PI, Trapani JA, Whisstock JC, Dunstone MA. The MACPF/CDC family of pore-forming toxins. Cell Microbiol 2008; 10:1765-74. [PMID: 18564372 PMCID: PMC2654483 DOI: 10.1111/j.1462-5822.2008.01191.x] [Citation(s) in RCA: 211] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pore-forming toxins (PFTs) are commonly associated with bacterial pathogenesis. In eukaryotes, however, PFTs operate in the immune system or are deployed for attacking prey (e.g. venoms). This review focuses upon two families of globular protein PFTs: the cholesterol-dependent cytolysins (CDCs) and the membrane attack complex/perforin superfamily (MACPF). CDCs are produced by Gram-positive bacteria and lyse or permeabilize host cells or intracellular organelles during infection. In eukaryotes, MACPF proteins have both lytic and non-lytic roles and function in immunity, invasion and development. The structure and molecular mechanism of several CDCs are relatively well characterized. Pore formation involves oligomerization and assembly of soluble monomers into a ring-shaped pre-pore which undergoes conformational change to insert into membranes, forming a large amphipathic transmembrane β-barrel. In contrast, the structure and mechanism of MACPF proteins has remained obscure. Recent crystallographic studies now reveal that although MACPF and CDCs are extremely divergent at the sequence level, they share a common fold. Together with biochemical studies, these structural data suggest that lytic MACPF proteins use a CDC-like mechanism of membrane disruption, and will help understand the roles these proteins play in immunity and development.
Collapse
Affiliation(s)
- Carlos J Rosado
- Department of Biochemistry, Monash University, Clayton, Victoria 3800, Australia
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Cinnamon E, Helman A, Ben-Haroush Schyr R, Orian A, Jiménez G, Paroush Z. Multiple RTK pathways downregulate Groucho-mediated repression in Drosophila embryogenesis. Development 2008; 135:829-37. [PMID: 18216172 DOI: 10.1242/dev.015206] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
RTK pathways establish cell fates in a wide range of developmental processes. However, how the pathway effector MAPK coordinately regulates the expression of multiple target genes is not fully understood. We have previously shown that the EGFR RTK pathway causes phosphorylation and downregulation of Groucho, a global co-repressor that is widely used by many developmentally important repressors for silencing their various targets. Here, we use specific antibodies that reveal the dynamics of Groucho phosphorylation by MAPK, and show that Groucho is phosphorylated in response to several RTK pathways during Drosophila embryogenesis. Focusing on the regulation of terminal patterning by the Torso RTK pathway, we demonstrate that attenuation of Groucho's repressor function via phosphorylation is essential for the transcriptional output of the pathway and for terminal cell specification. Importantly, Groucho is phosphorylated by an efficient mechanism that does not alter its subcellular localisation or decrease its stability; rather, modified Groucho endures long after MAPK activation has terminated. We propose that phosphorylation of Groucho provides a widespread, long-term mechanism by which RTK signals control target gene expression.
Collapse
Affiliation(s)
- Einat Cinnamon
- Department of Biochemistry, Faculty of Medicine, The Hebrew University, Jerusalem, Israel
| | | | | | | | | | | |
Collapse
|
36
|
Lynch JA, Olesnicky EC, Desplan C. Regulation and function of tailless in the long germ wasp Nasonia vitripennis. Dev Genes Evol 2006; 216:493-8. [PMID: 16670873 DOI: 10.1007/s00427-006-0076-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2006] [Accepted: 04/04/2006] [Indexed: 10/24/2022]
Abstract
In the long germ insect Drosophila, the gene tailless acts to pattern the terminal regions of the embryo. Loss of function of this gene results in the deletion of the anterior and posterior terminal structures and the eighth abdominal segment. Drosophila tailless is activated by the maternal terminal system through Torso signaling at both poles of the embryo, with additional activation by Bicoid at the anterior. Here, we describe the expression and function of tailless in a long germ Hymenoptera, the wasp Nasonia vitripennis. Despite the morphological similarities in the mode of development of these two insects, we find major differences in the regulation and function of tailless between Nasonia and Drosophila. In contrast to the fly, Nasonia tll appears to rely on otd for its activation at both poles. In addition, the anterior domain of Nasonia tll appears to have little or no segmental patterning function, while the posterior tll domain has a much more extensive patterning role than its Drosophila counterpart.
Collapse
Affiliation(s)
- Jeremy A Lynch
- Center for Developmental genetics, Department of Biology, New York University, 1009 Silver Center, 100 Washington Square East, New York, NY 10003, USA
| | | | | |
Collapse
|
37
|
Singh N, Zhu W, Hanes SD. Sap18 is required for the maternal gene bicoid to direct anterior patterning in Drosophila melanogaster. Dev Biol 2005; 278:242-54. [PMID: 15649476 DOI: 10.1016/j.ydbio.2004.11.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2004] [Revised: 11/05/2004] [Accepted: 11/09/2004] [Indexed: 10/26/2022]
Abstract
Development of the insect head is a complex process that in Drosophila requires the anterior determinant, Bicoid. Bicoid is present in an anterior-to-posterior concentration gradient, and binds DNA and stimulates transcription of head-specific genes. Many of these genes, including the gap-gene hunchback, are initially activated in a broad domain across the head primordium, but later retract so that their expression is cleared from the anterior-most segmented regions. Here, we show that retraction requires a Bicoid-interacting protein, Sap18, which is part of the Sin3/Rpd3 histone deacetylase complex. In sensitized-mutant backgrounds (e.g., bcdE1/+, removal of maternal sap18 results in embryos that are missing labrally derived parts of the cephalopharyngeal skeleton. These sap18 mutant embryos fail to repress hb expression, and show reduced anterior cap expression of the labral determinant cap 'n' collar. These phenotypes are enhanced by lowering the dose of rpd3, which encodes the catalytic subunit of the deacetylase complex. The results suggest a model where, in labral regions of the head, Bicoid is converted from an activator into a repressor by recruitment of a co-repressor to Bicoid-dependent promoters. Bicoid's activity, therefore, depends not only on its concentration gradient, but also on its interactions with modifier proteins within spatially restricted domains.
Collapse
Affiliation(s)
- Navjot Singh
- Molecular Genetics Program, Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, NY 12208, USA
| | | | | |
Collapse
|
38
|
Li WX. Functions and mechanisms of receptor tyrosine kinase Torso signaling: lessons from Drosophila embryonic terminal development. Dev Dyn 2005; 232:656-72. [PMID: 15704136 PMCID: PMC3092428 DOI: 10.1002/dvdy.20295] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The Torso receptor tyrosine kinase (RTK) is required for cell fate specification in the terminal regions (head and tail) of the early Drosophila embryo. Torso contains a split tyrosine kinase domain and belongs to the type III subgroup of the RTK superfamily that also includes the platelet-derived growth factor receptors, stem cell or steel factor receptor c-Kit proto-oncoprotein, colony-stimulating factor-1 receptor, and vascular endothelial growth factor receptor. The Torso pathway has been a model system for studying RTK signal transduction. Genetic and biochemical studies of Torso signaling have provided valuable insights into the biological functions and mechanisms of RTK signaling during early Drosophila embryogenesis.
Collapse
Affiliation(s)
- Willis X Li
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York 14642, USA.
| |
Collapse
|
39
|
Tanaka ED, Hartfelder K. The initial stages of oogenesis and their relation to differential fertility in the honey bee (Apis mellifera) castes. ARTHROPOD STRUCTURE & DEVELOPMENT 2004; 33:431-442. [PMID: 18089049 DOI: 10.1016/j.asd.2004.06.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2003] [Revised: 06/01/2004] [Accepted: 06/23/2004] [Indexed: 05/25/2023]
Abstract
Neither the overall differences in ovariole number nor the caste-specifically modulated expression of vitellogenin can fully explain the striking caste differences in honey bee reproduction, in particular the mechanisms that block oogenesis in virgin queens and in workers kept in the presence of a queen. For this reason we investigated the initial stages of oogenesis in queens in relation to mating status and in workers exposed to different social conditions. A striking feature in ovarioles of both castes was a considerably elongated terminal filament which consisted not only of normal terminal filament cells but also contained apparently undifferentiated cells that were tentatively considered as stem cells. BrdU incorporation was detected in the upper germarium, as well as in the terminal filament. Cytoskeleton analysis by TRITC-phalloidin labeling for F-actin, and immunofluorescence detection for beta-tubulin did not reveal structural differences in the early oogenesis steps between queens and queenless workers. In contrast, queenright workers showed signs of a disorganized microtubule and microfilament system that could explain the histological evidence for progressive cell death observed in the germaria. In addition to cytoplasmic tubulin we also detected marked intranuclear foci indicating the presence of nuclear beta(II)-tubulin.
Collapse
Affiliation(s)
- Erica D Tanaka
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Brazil
| | | |
Collapse
|
40
|
Li J, Xia F, Li WX. Coactivation of STAT and Ras Is Required for Germ Cell Proliferation and Invasive Migration in Drosophila. Dev Cell 2003; 5:787-98. [PMID: 14602078 PMCID: PMC3092433 DOI: 10.1016/s1534-5807(03)00328-9] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Primordial germ cells (PGCs) undergo proliferation, invasion, guided migration, and aggregation to form the gonad. Here we show that in Drosophila, the receptor tyrosine kinase Torso activates both STAT and Ras during the early phase of PGC development, and coactivation of STAT and Ras is required for PGC proliferation and invasive migration. Embryos mutant for stat92E or Ras1 have fewer PGCs, and these cells migrate slowly, errantly, and fail to coalesce. Conversely, overactivation of these molecules causes supernumerary PGCs, their premature transit through the gut epithelium, and ectopic colonization. A requirement for RTK in Drosophila PGC development is analogous to the mouse, in which the RTK c-kit is required, suggesting a conserved molecular mechanism governing PGC behavior in flies and mammals.
Collapse
|
41
|
Abstract
Recent data indicate that Torsolike, a spatial cue for patterning terminal structures of a Drosophila embryo, is stably anchored in the fruitfly eggshell; an as yet unidentified factor is required for the high activity of Torsolike at the embryo termini.
Collapse
Affiliation(s)
- Ellen K LeMosy
- Department of Cellular Biology and Anatomy, Medical College of Georgia, 1459 Laney Walker Boulevard, CB2915, Augusta, GE 30901, USA.
| |
Collapse
|
42
|
Affiliation(s)
- Marc Furriols
- Institut de Biologia Molecular de Barcelona (CSIC), C/ Jordi Girona 18-26, E-08034 Barcelona, Spain
| | | |
Collapse
|
43
|
Chen YJ, Chiang CS, Weng LC, Lengyel JA, Liaw GJ. Tramtrack69 is required for the early repression of tailless expression. Mech Dev 2002; 116:75-83. [PMID: 12128207 DOI: 10.1016/s0925-4773(02)00143-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
During embryogenesis, the activated Torso receptor tyrosine kinase (TOR RTK) pathway activates tailless (tll) expression by a relief-of-repression mechanism. Various lines of evidence have suggested that multiple factors are required for this repression. We show that Tramtrack69 (TTK69) binds to two sites within tll cis-regulatory DNA, TC2 and TC5, and that TTK69 is phosphorylated by mitogen activated protein kinase. In embryos lacking maternal ttk69 activity, the expression of both endogenous tll and lacZ driven by the tll minimal regulatory region (tll-MRR) are expanded. Further, in wild-type embryos, the tll-MRR mutated in TC5 drives uniform lacZ expression before late stage 4. We conclude that TTK69 is required for early (before the end of stage 4) repression of tll transcription.
Collapse
Affiliation(s)
- Yueh-Jung Chen
- Institute of Genetics, National Yang-Ming University, Shih-Pai, Taipei 112, Taiwan, ROC
| | | | | | | | | |
Collapse
|
44
|
Affiliation(s)
- D St Johnston
- Wellcome/CRC Institute and The Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK
| |
Collapse
|
45
|
Stein D, Stevens LM. The Torso Ligand, Unmasked? Sci Signal 2001. [DOI: 10.1126/scisignal.982001pe2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
46
|
Stein D, Stevens LM. The torso ligand, unmasked? SCIENCE'S STKE : SIGNAL TRANSDUCTION KNOWLEDGE ENVIRONMENT 2001; 2001:pe2. [PMID: 11752676 DOI: 10.1126/stke.2001.98.pe2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
When a transmembrane receptor protein tyrosine kinase (RTK) is expressed throughout the plasma membrane, yet only a specific handful of them must be activated, what's a ligand to do? During the development of the anterior and posterior termini of the Drosophila embryo, uniformly secreted ligand precursors are activated by proteolysis near the location of the receptors that must be activated. Stein and Stevens discuss the recent publication by Casali and Casanova that describes the mechanism of activation of the Drosophila RTK called Torso. In addition, Casali and Casanova may have identified a physiologically relevant ligand for Torso called Trunk. Proteolytic cleavage of the Trunk precursor can activate Torso-dependent signaling, but the existence of cleaved Trunk has not yet been demonstrated in vivo for Drosophila. Stein and Stevens discuss the ramifications of such a highly regulated process of ligand activation, and also prefer alternative scenarios for Torso activation.
Collapse
Affiliation(s)
- D Stein
- Section of Molecular Cell and Developmental Biology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.
| | | |
Collapse
|
47
|
Abstract
The invasiveness of cancer cells resembles the normal behavior of cells that migrate into surrounding tissues during development. For example, the border cells in the Drosophila ovary undergo a partial epithelial to mesenchymal transition and invade the neighboring cluster of germline cells, migrating to the oocyte border. Once there, they provide patterning information to the oocyte and produce an eggshell specialization known as the micropyle. Border cell migration has been subjected to extensive genetic analyses using a variety of screening approaches. Recent findings demonstrate that conversion of the border cells from a stationary group of epithelial cells to invasive cells requires integration of the activities of at least two transcriptional regulatory pathways. One such pathway requires the slbo gene, which encodes Drosophila C/EBP, a basic region/leucine zipper transcriptional activator that is required for elevated expression of a number of downstream targets, including DE-cadherin and focal adhesion kinase (FAK). An independent pathway requires the activity of the ecdysone receptor and a recently identified co-activator for the ecdysone receptor known as Taiman (abbreviated TAI, pronounced ti-maan', meaning too slow). Ecdysone is produced in the Drosophila ovary in response to adequate nutrition and is required for progression of oogenesis through stage 9, when border cell migration occurs. Border cells mutant for tai accumulate abnormally high levels of adhesion complexes at their surfaces, which may account for their inability to migrate. Thus border cell migration requires a differentiation program mediated by the C/EBP pathway, which is required for elevated expression of a number of proteins required for motility. In addition, migration requires a hormonal signal that relays information regarding nutritional status and appears to be required for regulation of the proper localization of some of the C/EBP targets. These findings suggest that steroid hormones can regulate cell motility relatively directly, independent of the effects on proliferation. This may contribute to the metastatic effects of steroid hormones on certain cancers and the inhibition of metastasis by steroid hormone antagonists such as tamoxifen.
Collapse
Affiliation(s)
- D J Montell
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, 725 North Wolfe Street, 21205-2185, Baltimore, MD, USA.
| |
Collapse
|
48
|
Casali A, Casanova J. The spatial control of Torso RTK activation: a C-terminal fragment of the Trunk protein acts as a signal for Torso receptor in the Drosophila embryo. Development 2001; 128:1709-15. [PMID: 11290307 DOI: 10.1242/dev.128.9.1709] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Regulated activation of receptor tyrosine kinases depends on both the presence of the receptors at the cell surface and on the availability of their ligands. In Drosophila, the torso tyrosine kinase receptor is distributed along the surface of the embryo but it is only activated at the poles by a diffusible extracellular ligand generated at each pole that is trapped by the receptor, thereby impeding further diffusion. Although it is known that this signal depends on the activity of several genes, such as torso-like and trunk, it is still unclear how is generated. The identification of the signal responsible for the torso receptor activation is an essential step towards understanding the mechanism that regulates the local restriction of torso signalling. Here we report that a fragment containing the carboxy-terminal 108 amino acids of the trunk protein retains trunk activity and is sufficient to activate torso signalling. We also show that this fragment bypasses the requirements for the other genes involved in the activation of the torso receptor. These results suggest that a cleaved form of the trunk protein acts as a signal for the torso receptor. We therefore propose that the restricted activation of the torso receptor is defined by the spatial control of the proteolytic processing of the trunk protein.
Collapse
Affiliation(s)
- A Casali
- Institut de Biologia Molecular de Barcelona, CSIC, C/ Jordi Girona 18-26, Spain
| | | |
Collapse
|
49
|
Schaeffer V, Killian D, Desplan C, Wimmer EA. High bicoid levels render the terminal system dispensable for Drosophila head development. Development 2000; 127:3993-9. [PMID: 10952897 DOI: 10.1242/dev.127.18.3993] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In Drosophila, the gradient of the Bicoid (Bcd) morphogen organizes the anteroposterior axis while the ends of the embryo are patterned by the maternal terminal system. At the posterior pole, expression of terminal gap genes is mediated by the local activation of the Torso receptor tyrosine kinase (Tor). At the anterior, terminal gap genes are also activated by the Tor pathway but Bcd contributes to their activation. Here we present evidence that Tor and Bcd act independently on common target genes in an additive manner. Furthermore, we show that the terminal maternal system is not required for proper head development, since high levels of Bcd activity can functionally rescue the lack of terminal system activity at the anterior pole. This observation is consistent with a recent evolution of an anterior morphogenetic center consisting of Bcd and anterior Tor function.
Collapse
Affiliation(s)
- V Schaeffer
- Department of Biology, New York University, New York NY 10003 USA
| | | | | | | |
Collapse
|
50
|
Dearden P, Grbic M, Falciani F, Akam M. Maternal expression and early zygotic regulation of the Hox3/zen gene in the grasshopper Schistocerca gregaria. Evol Dev 2000; 2:261-70. [PMID: 11252555 DOI: 10.1046/j.1525-142x.2000.00065.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In insects, a key step in the early patterning of the egg is to distinguish the primordium of the embryo proper from those regions that will form extra-embryonic membranes. In Drosophila, where these processes are well understood, the structure of the extra-embryonic membranes is highly derived. The distinct amnion and serosa typical of lower insects is replaced by a single, fused, and much reduced membrane, the amnioserosa, which never secretes an embryonic cuticle. We have used the Zen gene as a marker to study the formation of the extra-embryonic membranes, and other aspects of early embryonic patterning, in the grasshopper Schistocerca gregaria (African Plague Locust). Zen genes are derived from Hox genes, but in Drosophila they appear to have lost any role in patterning the A/P axis of the embryo; instead, they are involved in D/V patterning and the specification of the extra-embryonic membranes. We show that the Schistocerca zen gene is expressed during embryogenesis in three distinct phases. The first of these is during cleavage, when Sgzen is transiently expressed in all energids that reach the cell surface. The second phase of expression initiates in a ring of "necklace cells" that surround the forming embryo, and demarcate the boundary between the amnion and serosa. This leads to expression throughout the serosa. The final phase of expression is in the amnion, after this has separated from the serosa. This complex pattern implies that the role of Sgzen in Schistocerca is not limited solely to the specification of cell identity in the extra-embryonic membranes. We also report that the Schistocerca zen gene is expressed maternally, unlike its Drosophila and Tribolium counterparts. A distinct maternal transcript, and maternal Zen protein, accumulate in the developing oocyte from early post-meiotic stages. They remain uniformly distributed in the oocyte cytoplasm until late vitellogenic stages, when the protein and RNA become somewhat concentrated at the egg cortex and in the posterior polar cap of the oocyte, probably by passive exclusion from the yolk. The cytoplasmic localization of Sgzen protein in the oocyte, and at some stages during embryogenesis, implies that nuclear exclusion of this transcription factor is specifically controlled.
Collapse
Affiliation(s)
- P Dearden
- University Museum of Zoology, Department of Zoology, Cambridge, UK.
| | | | | | | |
Collapse
|