1
|
Scanlan JL, Robin C, Mirth CK. Rethinking the ecdysteroid source during Drosophila pupal-adult development. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2023; 152:103891. [PMID: 36481381 DOI: 10.1016/j.ibmb.2022.103891] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/30/2022] [Accepted: 12/04/2022] [Indexed: 06/17/2023]
Abstract
Ecdysteroids, typified by 20-hydroxyecdysone (20E), are essential hormones for the development, reproduction and physiology of insects and other arthropods. For over half a century, the vinegar fly Drosophila melanogaster (Ephydroidea: Diptera) has been used as a model of ecdysteroid biology. Many aspects of the biosynthesis and regulation of ecdysteroids in this species are understood at the molecular level, particularly with respect to their secretion from the prothoracic gland (PG) cells of the ring gland, widely considered the dominant biosynthetic tissue during development. Discrete pulses of 20E orchestrate transitions during the D. melanogaster life cycle, the sources of which are generally well understood, apart from the large 20E pulse at the onset of pharate adult development, which has received little recent attention. As the source of this pharate adult pulse (PAP) is a curious blind spot in Drosophila endocrinology, we evaluate published biochemical and genetic data as they pertain to three hypotheses for the source of PAP 20E: the PG; an alternative biosynthetic tissue; or the recycling of stored 20E. Based on multiple lines of evidence, we contend the PAP cannot be derived from biosynthesis, with other data consistent with D. melanogaster able to recycle ecdysteroids before and during metamorphosis. Published data also suggest the PAP is conserved across Diptera, with evidence for pupal-adult ecdysteroid recycling occurring in other cyclorrhaphan flies. Further experimental work is required to test the ecdysteroid recycling hypothesis, which would establish fundamental knowledge of the function, regulation, and evolution of metamorphic hormones in dipterans and other insects.
Collapse
Affiliation(s)
- Jack L Scanlan
- School of BioSciences, The University of Melbourne, Parkville Campus, Melbourne, Victoria, 3010, Australia.
| | - Charles Robin
- School of BioSciences, The University of Melbourne, Parkville Campus, Melbourne, Victoria, 3010, Australia
| | - Christen K Mirth
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| |
Collapse
|
2
|
Banisch TU, Slaidina M, Gupta S, Ho M, Gilboa L, Lehmann R. A transitory signaling center controls timing of primordial germ cell differentiation. Dev Cell 2021; 56:1742-1755.e4. [PMID: 34081907 PMCID: PMC8330407 DOI: 10.1016/j.devcel.2021.05.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 03/07/2021] [Accepted: 05/10/2021] [Indexed: 12/16/2022]
Abstract
Organogenesis requires exquisite spatiotemporal coordination of cell morphogenesis, migration, proliferation, and differentiation of multiple cell types. For gonads, this involves complex interactions between somatic and germline tissues. During Drosophila ovary morphogenesis, primordial germ cells (PGCs) either are sequestered in stem cell niches and are maintained in an undifferentiated germline stem cell state or transition directly toward differentiation. Here, we identify a mechanism that links hormonal triggers of somatic tissue morphogenesis with PGC differentiation. An early ecdysone pulse initiates somatic swarm cell (SwC) migration, positioning these cells close to PGCs. A second hormone peak activates Torso-like signal in SwCs, which stimulates the Torso receptor tyrosine kinase (RTK) signaling pathway in PGCs promoting their differentiation by de-repression of the differentiation gene, bag of marbles. Thus, systemic temporal cues generate a transitory signaling center that coordinates ovarian morphogenesis with stem cell self-renewal and differentiation programs, highlighting a more general role for such centers in reproductive and developmental biology.
Collapse
Affiliation(s)
- Torsten U Banisch
- Department of Cell Biology, Howard Hughes Medical Institute, Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY 10016, USA.
| | - Maija Slaidina
- Department of Cell Biology, Howard Hughes Medical Institute, Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY 10016, USA
| | - Selena Gupta
- Department of Cell Biology, Howard Hughes Medical Institute, Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY 10016, USA
| | - Megan Ho
- Department of Cell Biology, Howard Hughes Medical Institute, Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY 10016, USA
| | - Lilach Gilboa
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ruth Lehmann
- Department of Cell Biology, Howard Hughes Medical Institute, Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY 10016, USA.
| |
Collapse
|
3
|
Erkelenz S, Stanković D, Mundorf J, Bresser T, Claudius AK, Boehm V, Gehring NH, Uhlirova M. Ecd promotes U5 snRNP maturation and Prp8 stability. Nucleic Acids Res 2021; 49:1688-1707. [PMID: 33444449 PMCID: PMC7897482 DOI: 10.1093/nar/gkaa1274] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 12/07/2020] [Accepted: 12/21/2020] [Indexed: 12/13/2022] Open
Abstract
Pre-mRNA splicing catalyzed by the spliceosome represents a critical step in the regulation of gene expression contributing to transcriptome and proteome diversity. The spliceosome consists of five small nuclear ribonucleoprotein particles (snRNPs), the biogenesis of which remains only partially understood. Here we define the evolutionarily conserved protein Ecdysoneless (Ecd) as a critical regulator of U5 snRNP assembly and Prp8 stability. Combining Drosophila genetics with proteomic approaches, we demonstrate the Ecd requirement for the maintenance of adult healthspan and lifespan and identify the Sm ring protein SmD3 as a novel interaction partner of Ecd. We show that the predominant task of Ecd is to deliver Prp8 to the emerging U5 snRNPs in the cytoplasm. Ecd deficiency, on the other hand, leads to reduced Prp8 protein levels and compromised U5 snRNP biogenesis, causing loss of splicing fidelity and transcriptome integrity. Based on our findings, we propose that Ecd chaperones Prp8 to the forming U5 snRNP allowing completion of the cytoplasmic part of the U5 snRNP biogenesis pathway necessary to meet the cellular demand for functional spliceosomes.
Collapse
Affiliation(s)
- Steffen Erkelenz
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne 50931, Germany
| | - Dimitrije Stanković
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne 50931, Germany
| | - Juliane Mundorf
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
| | - Tina Bresser
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
| | - Ann-Katrin Claudius
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
| | - Volker Boehm
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne 50931, Germany.,Institute for Genetics, University of Cologne, Cologne 50674, Germany
| | - Niels H Gehring
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne 50931, Germany.,Institute for Genetics, University of Cologne, Cologne 50674, Germany
| | - Mirka Uhlirova
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne 50931, Germany
| |
Collapse
|
4
|
Ray M, Lakhotia SC. Activated Ras/JNK driven Dilp8 in imaginal discs adversely affects organismal homeostasis during early pupal stage in Drosophila, a new checkpoint for development. Dev Dyn 2019; 248:1211-1231. [PMID: 31415125 DOI: 10.1002/dvdy.102] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/23/2019] [Accepted: 08/08/2019] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Dilp8-mediated inhibition of ecdysone synthesis and pupation in holometabolous insects maintains developmental homeostasis through stringent control of timing and strength of molting signals. We examined reasons for normal pupation but early pupal death observed in certain cases. RESULTS Overexpression of activated Ras in developing eye/wing discs inhibited Ptth expression in brain via upregulated JNK signaling mediated Dilp8 secretion from imaginal discs, which inhibited ecdysone synthesis in prothoracic gland after pupariation, leading to death of ~25- to 30-hour-old pupae. Inhibition of elevated Ras signaling completely rescued early pupal death while post-pupation administration of ecdysone to organisms with elevated Ras signaling in eye discs partially rescued their early pupal death. Unlike the earlier known Dilp8 action in delaying pupation, hyperactivated Ras mediated elevation of pJNK signaling in imaginal discs caused Dilp8 secretion after pupariation. Ectopic expression of certain other transgene causing pupal lethality similarly enhanced pJNK and early pupal Dilp8 levels. Suboptimal ecdysone levels after 8 hours of pupation prevented the early pupal metamorphic changes and caused organismal death. CONCLUSIONS Our results reveal early pupal stage as a novel Dilp8 mediated post-pupariation checkpoint and provide further evidence for interorgan signaling during development, wherein a peripheral tissue influences the CNS driven endocrine function.
Collapse
Affiliation(s)
- Mukulika Ray
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Subhash C Lakhotia
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| |
Collapse
|
5
|
Verma P, Tapadia MG. Early gene Broad complex plays a key role in regulating the immune response triggered by ecdysone in the Malpighian tubules of Drosophila melanogaster. Mol Immunol 2015; 66:325-39. [DOI: 10.1016/j.molimm.2015.03.249] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 03/24/2015] [Accepted: 03/27/2015] [Indexed: 11/28/2022]
|
6
|
Zhang C, Robinson BS, Xu W, Yang L, Yao B, Zhao H, Byun PK, Jin P, Veraksa A, Moberg KH. The ecdysone receptor coactivator Taiman links Yorkie to transcriptional control of germline stem cell factors in somatic tissue. Dev Cell 2015; 34:168-80. [PMID: 26143992 DOI: 10.1016/j.devcel.2015.05.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Revised: 04/25/2015] [Accepted: 05/14/2015] [Indexed: 12/16/2022]
Abstract
The Hippo pathway is a conserved signaling cascade that modulates tissue growth. Although its core elements are well defined, factors modulating Hippo transcriptional outputs remain elusive. Here we show that components of the steroid-responsive ecdysone (Ec) pathway modulate Hippo transcriptional effects in imaginal disc cells. The Ec receptor coactivator Taiman (Tai) interacts with the Hippo transcriptional coactivator Yorkie (Yki) and promotes expression of canonical Yki-responsive genes. Tai enhances Yki-driven growth, while Tai loss, or a form of Tai unable to bind Yki, suppresses Yki-driven tissue growth. This growth suppression is not correlated with impaired induction of canonical Hippo-responsive genes but with suppression of a distinct pro-growth program of Yki-induced/Tai-dependent genes, including the germline stem cell factors nanos and piwi. These data reveal Hippo/Ec pathway crosstalk in the form a Yki-Tai complex that collaboratively induces germline genes as part of a transcriptional program that is normally repressed in developing somatic epithelia.
Collapse
Affiliation(s)
- Can Zhang
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Brian S Robinson
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Pathology & Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Wenjian Xu
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Liu Yang
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Bing Yao
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Heya Zhao
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Phil K Byun
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; Graduate Program in Genetics and Molecular Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Peng Jin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Alexey Veraksa
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Kenneth H Moberg
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| |
Collapse
|
7
|
Unexpected role of the steroid-deficiency protein ecdysoneless in pre-mRNA splicing. PLoS Genet 2014; 10:e1004287. [PMID: 24722212 PMCID: PMC3983036 DOI: 10.1371/journal.pgen.1004287] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 02/20/2014] [Indexed: 11/19/2022] Open
Abstract
The steroid hormone ecdysone coordinates insect growth and development, directing the major postembryonic transition of forms, metamorphosis. The steroid-deficient ecdysoneless1 (ecd1) strain of Drosophila melanogaster has long served to assess the impact of ecdysone on gene regulation, morphogenesis, or reproduction. However, ecd also exerts cell-autonomous effects independently of the hormone, and mammalian Ecd homologs have been implicated in cell cycle regulation and cancer. Why the Drosophila ecd1 mutants lack ecdysone has not been resolved. Here, we show that in Drosophila cells, Ecd directly interacts with core components of the U5 snRNP spliceosomal complex, including the conserved Prp8 protein. In accord with a function in pre-mRNA splicing, Ecd and Prp8 are cell-autonomously required for survival of proliferating cells within the larval imaginal discs. In the steroidogenic prothoracic gland, loss of Ecd or Prp8 prevents splicing of a large intron from CYP307A2/spookier (spok) pre-mRNA, thus eliminating this essential ecdysone-biosynthetic enzyme and blocking the entry to metamorphosis. Human Ecd (hEcd) can substitute for its missing fly ortholog. When expressed in the Ecd-deficient prothoracic gland, hEcd re-establishes spok pre-mRNA splicing and protein expression, restoring ecdysone synthesis and normal development. Our work identifies Ecd as a novel pre-mRNA splicing factor whose function has been conserved in its human counterpart. Whether the role of mammalian Ecd in cancer involves pre-mRNA splicing remains to be discovered.
Collapse
|
8
|
Suh HW, Yun S, Song H, Jung H, Park YJ, Kim TD, Yoon SR, Choi I. TXNIP interacts with hEcd to increase p53 stability and activity. Biochem Biophys Res Commun 2013; 438:264-9. [PMID: 23880345 DOI: 10.1016/j.bbrc.2013.07.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 07/10/2013] [Indexed: 10/26/2022]
Abstract
The p53 protein plays a central role in cell cycle arrest and apoptosis in response to diverse stress stimuli. Human ecdysoneless (hEcd) is known for its role in stabilizing the p53 protein level and increasing p53-mediated transcription. Here, we report that thioredoxin interacting protein (TXNIP), a member of the tumor suppressor family, interacts with hEcd and decreases MDM2-mediated p53 ubiquitination, leading to p53 stabilization and an increase in p53 activity. The ectopic overexpression of both TXNIP and Ecd increased actinomycin D-mediated cell death in MCF-7 cells, whereas knockdown of TXNIP and Ecd decreased cell death. These results show that TXNIP is a new regulator of the Ecd-MDM2-p53 loop.
Collapse
Affiliation(s)
- Hyun-Woo Suh
- Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Yuseong-gu, Daejeon 305-806, Republic of Korea
| | | | | | | | | | | | | | | |
Collapse
|
9
|
Dey P, Rachagani S, Chakraborty S, Singh PK, Zhao X, Gurumurthy CB, Anderson JM, Lele S, Hollingsworth MA, Band V, Batra SK. Overexpression of ecdysoneless in pancreatic cancer and its role in oncogenesis by regulating glycolysis. Clin Cancer Res 2012; 18:6188-98. [PMID: 22977192 DOI: 10.1158/1078-0432.ccr-12-1789] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To study the expression and function of a novel cell-cycle regulatory protein, human ecdysoneless (Ecd), during pancreatic cancer pathogenesis. EXPERIMENTAL DESIGN Immunohistochemical expression profiling of Ecd was done in nonneoplastic normal pancreatic tissues and pancreatic ductal adenocarcinoma lesions (from tissue microarray and Rapid Autopsy program) as well as precancerous PanIN lesions and metastatic organs. To analyze the biological significance of Ecd in pancreatic cancer progression, Ecd was stably knocked down in pancreatic cancer cell line followed by in vitro and in vivo functional assays. RESULTS Normal pancreatic ducts showed very weak to no Ecd expression compared to significant positive expression in pancreatic cancer tissues (mean ± SE composite score: 0.3 ± 0.2 and 3.8 ± 0.2 respectively, P < 0.0001) as well as in PanIN precursor lesions with a progressive increase in Ecd expression with increasing dysplasia (PanIN-1-PanIN-3). Analysis of matched primary tumors and metastases from patients with pancreatic cancer revealed that Ecd is highly expressed in both primary pancreatic tumor and in distant metastatic sites. Furthermore, knockdown of Ecd suppressed cell proliferation in vitro and tumorigenicity of pancreatic cancer cells in mice orthotopic tumors. Microarray study revealed that Ecd regulates expression of glucose transporter GLUT4 in pancreatic cancer cells and was subsequently shown to modulate glucose uptake, lactate production, and ATP generation by pancreatic cancer cells. Finally, knockdown of Ecd also reduced level of pAkt, key signaling molecule known to regulate aerobic glycolysis in cancer cells. CONCLUSION Ecd is a novel tumor-promoting factor that is differentially expressed in pancreatic cancer and potentially regulates glucose metabolism within cancer cells.
Collapse
Affiliation(s)
- Parama Dey
- Department of Biochemistry and Molecular Biology, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Huang X, Warren JT, Gilbert LI. New players in the regulation of ecdysone biosynthesis. J Genet Genomics 2009; 35:1-10. [PMID: 18222403 DOI: 10.1016/s1673-8527(08)60001-6] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 11/24/2007] [Accepted: 11/24/2007] [Indexed: 02/04/2023]
Abstract
Insect ecdysone steroid hormone regulates major developmental transitions, such as molting and metamorphosis. The production of ecdysone correlates well with the timing of these transitions. Finding out how the ecdysone biosynthesis is regulated is crucial to fully understand these sophisticated developmental switches. Here we summarized recent findings in the regulation of ecdysone biosynthesis from the aspects of cell signaling, key biosynthetic enzymes and substrate cholesterol trafficking.
Collapse
Affiliation(s)
- Xun Huang
- Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
| | | | | |
Collapse
|
11
|
Cranna N, Quinn L. Impact of steroid hormone signals on Drosophila cell cycle during development. Cell Div 2009; 4:3. [PMID: 19154610 PMCID: PMC2647916 DOI: 10.1186/1747-1028-4-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Accepted: 01/20/2009] [Indexed: 11/30/2022] Open
Abstract
Metamorphosis of Drosophila involves proliferation, differentiation and death of larval tissues in order to form the adult fly. The major steroid hormone implicated in the larval-pupal transition and adult tissue modelling is ecdysone. Previous reviews have draw together studies connecting ecdysone signaling to the processes of apoptosis and differentiation. Here we discuss those reports connecting the ecdysone pulse to developmentally regulated cell cycle progression.
Collapse
Affiliation(s)
- Nicola Cranna
- Department of Anatomy and Cell Biology, University of Melbourne, Parkville 3010, Melbourne, Australia.
| | | |
Collapse
|
12
|
Gilbert LI. Drosophila is an inclusive model for human diseases, growth and development. Mol Cell Endocrinol 2008; 293:25-31. [PMID: 18374475 DOI: 10.1016/j.mce.2008.02.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Accepted: 02/11/2008] [Indexed: 01/01/2023]
Abstract
Cytogenetic studies over the last century have led to the complete mapping of the Drosophila polytene chromosomes. The resulting data and the analysis of puffing at specific gene sites, manifestations of enhanced transcriptional activity, have led to the use of the fruit fly as the most well-understood animal model for a plethora of cellular mechanisms and genetic defects. In recent years the fly data base has contributed greatly to the use of Drosophila as a remarkable model for the functional genomics of many human genes. Here I review briefly the diversity of "model genes" studied in this dipteran, ranging from mental acuity, sleep and development, to recent studies from our laboratory, and those of our collaborators, on steroid hormone biosynthesis and neurodegeneration.
Collapse
|
13
|
D'Ávila MF, Garcia RN, Loreto ELS, Valente VLDS. Analysis of phenotypes altered by temperature stress and hipermutability in Drosophila willistoni. IHERINGIA. SERIE ZOOLOGIA 2008. [DOI: 10.1590/s0073-47212008000300009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Drosophila willistoni (Sturtevant, 1916) is a species of the willistoni group of Drosophila having wide distribution from the South of USA (Florida) and Mexico to the North of Argentina. It has been subject of many evolutionary studies within the group, due to its considerable ability to successfully occupy a wide range of environments and also because of its great genetic variability expressed by different markers. The D. willistoni 17A2 strain was collected in 1991 in the state of Rio Grande do Sul, Brazil (30°05'S, 51°39'W), and has been maintained since then at the Drosophila laboratory of UFRGS. Different to the other D. willistoni strains maintained in the laboratory, the 17A2 strain spontaneously produced mutant males white-like (white eyes) and sepia-like (brown eyes) in stocks held at 17°C. In order to discover if this strain is potentially hypermutable, we submitted it to temperature stress tests. Eighteen isofemale strains were used in our tests and, after the first generation, all the individuals produced in each strain were maintained at 29°C. Different phenotype alterations were observed in subsequent generations, similar to mutations already well characterized in D. melanogaster (white, sepia, blistered and curly). In addition, an uncommon phenotype alteration with an apparent fusion of the antennae was observed, but only in the isofemale line nº 31. This last alteration has not been previously described as a mutation in the D. melanogaster species. Our results indicate that the D. willistoni 17A2 strain is a candidate for hypermutability, which presents considerable cryptic genetic variability. Different factors may be operating for the formation of this effect, such as the mobilization of transposable elements, effect of inbreeding and alteration of the heat-shock proteins functions.
Collapse
|
14
|
Talamillo A, Sánchez J, Cantera R, Pérez C, Martín D, Caminero E, Barrio R. Smt3 is required for Drosophila melanogaster metamorphosis. Development 2008; 135:1659-68. [PMID: 18367553 DOI: 10.1242/dev.020685] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Sumoylation, the covalent attachment of the small ubiquitin-related modifier SUMO to target proteins, regulates different cellular processes, although its role in the control of development remains unclear. We studied the role of sumoylation during Drosophila development by using RNAi to reduce smt3 mRNA levels in specific tissues. smt3 knockdown in the prothoracic gland, which controls key developmental processes through the synthesis and release of ecdysteroids, caused a 4-fold prolongation of larval life and completely blocked the transition from larval to pupal stages. The reduced ecdysteroid titer of smt3 knockdown compared with wild-type larvae explains this phenotype. In fact, after dietary administration of exogenous 20-hydroxyecdysone, knockdown larvae formed pupal cases. The phenotype is not due to massive cell death or degeneration of the prothoracic glands at the time when puparium formation should occur. Knockdown cells show alterations in expression levels and/or the subcellular localisation of enzymes and transcription factors involved in the regulation of ecdysteroid synthesis. In addition, they present reduced intracellular channels and a reduced content of lipid droplets and cholesterol, which could explain the deficit in steroidogenesis. In summary, our study indicates that Smt3 is required for the ecdysteroid synthesis pathway at the time of puparium formation.
Collapse
Affiliation(s)
- Ana Talamillo
- Functional Genomics Unit, CIC bioGUNE, Technology Park, Building 801-A, 48160 DERIO, Bizkaia, Spain
| | | | | | | | | | | | | |
Collapse
|
15
|
Lovato TL, Benjamin AR, Cripps RM. Transcription of Myocyte enhancer factor-2 in adult Drosophila myoblasts is induced by the steroid hormone ecdysone. Dev Biol 2005; 288:612-21. [PMID: 16325168 DOI: 10.1016/j.ydbio.2005.09.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2005] [Revised: 09/02/2005] [Accepted: 09/02/2005] [Indexed: 11/20/2022]
Abstract
The steroid hormone 20-hydroxyecdysone (ecdysone) activates a relatively small number of immediate-early genes during Drosophila pupal development, yet is able to orchestrate distinct differentiation events in a wide variety of tissues. Here, we demonstrate that expression of the muscle differentiation gene Myocyte enhancer factor-2 (Mef2) is normally delayed in twist-expressing adult myoblasts until the end of the third larval instar. The late up-regulation of Mef2 transcription in larval myoblasts is an ecdysone-dependent event which acts upon an identified Mef2 enhancer, and we identify enhancer sequences required for up-regulation. We also present evidence that the ecdysone-induced Broad Complex of zinc finger transcription factor genes is required for full activation of the myogenic program in these cells. Since forced early expression of Mef2 in adult myoblasts leads to premature muscle differentiation, our results explain how and why the adult muscle differentiation program is attenuated prior to pupal development. We propose a mechanism for the initiation of adult myogenesis, whereby twist expression in myoblasts provides a cellular context upon which an extrinsic signal builds to control muscle-specific differentiation events, and we discuss the general relevance of this model for gene regulation in animals.
Collapse
Affiliation(s)
- TyAnna L Lovato
- Department of Biology, University of New Mexico, Albuquerque, NM 87131-1091, USA
| | | | | |
Collapse
|
16
|
Jin X, Sun X, Song Q. Woc gene mutation causes 20E-dependent alpha-tubulin detyrosination in Drosophila melanogaster. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2005; 60:116-29. [PMID: 16235256 DOI: 10.1002/arch.20088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The mutation without children(rgl) (woc(rgl)) is a newly described ecdysone-deficient Drosophila mutant. The woc(rgl) mutant larvae show developmental arrestment at the late larval stage and fail to form a puparium due to the failure of the ring gland to secret normal levels of ecdysone. Although a 6.8-kb woc gene transcript encoding a 187-kDa potential transcription factor has been cloned and lack of a specific cholesterol 7,8-dehydrogenease that mediates the first step in the ecdysteroidogenic pathway is likely the cause for ecdysteroid deficiency, the cellular events controlled by the woc gene remain unclear. In the present study, we investigated the effect of the woc gene mutation on the expression and tyrosination of alpha-tubulin in the woc(rgl) mutant. Our results demonstrated that the mutation in the woc gene caused 20E-dependent alpha-tubulin detyrosination, but had no significant effect on the expression of total alpha- and beta-tubulin in the homozygous woc(rgl) mutant larvae. Immunocytochemical study revealed that 20E-induced alpha-tubulin detyrosination led to the diminishing of tyrosinated alpha-tubulin signals from microtubules, resulting in the disruption of microtubule structure. The composite data suggest that the woc gene may regulate 20E-dependent alpha-tubulin detyrosination and that microtubules may be involved in sterol transport and sterol utilization in insect.
Collapse
Affiliation(s)
- Xiaoyi Jin
- Department of Entomology, University of Missouri, Columbia, MO 65211, USA
| | | | | |
Collapse
|
17
|
The ecdysoneless 1 Gene Regulates Metabolism of the Juvenile Hormone and Dopamine in Drosophila melanogaster. RUSS J GENET+ 2005. [DOI: 10.1007/s11177-005-0222-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
18
|
Fluegel ML, Parker TJ, Pallanck LJ. Mutations of a Drosophila NPC1 gene confer sterol and ecdysone metabolic defects. Genetics 2005; 172:185-96. [PMID: 16079224 PMCID: PMC1456146 DOI: 10.1534/genetics.105.046565] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The molecular mechanisms by which dietary cholesterol is trafficked within cells are poorly understood. Previous work indicates that the NPC1 family of proteins plays an important role in this process, although the precise functions performed by this protein family remain elusive. We have taken a genetic approach to further explore the NPC1 family in the fruit fly Drosophila melanogaster. The Drosophila genome encodes two NPC1 homologs, designated NPC1a and NPC1b, that exhibit 42% and 35% identity to the human NPC1 protein, respectively. Here we describe the results of mutational analysis of the NPC1a gene. The NPC1a gene is ubiquitously expressed, and a null allele of NPC1a confers early larval lethality. The recessive lethal phenotype of NPC1a mutants can be partially rescued on a diet of high cholesterol or one that includes the insect steroid hormone 20-hydroxyecdysone. We also find that expression of NPC1a in the ring gland is sufficient to rescue the lethality associated with the loss of NPC1a and that cholesterol levels in NPC1a mutant larvae are unchanged relative to controls. Our results suggest that NPC1a promotes efficient intracellular trafficking of sterols in many Drosophila tissues including the ring gland where sterols must be delivered to sites of ecdysone synthesis.
Collapse
Affiliation(s)
- Megan L Fluegel
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, Washington 98195, USA
| | | | | |
Collapse
|
19
|
Neubueser D, Warren JT, Gilbert LI, Cohen SM. molting defective is required for ecdysone biosynthesis. Dev Biol 2005; 280:362-72. [PMID: 15882578 DOI: 10.1016/j.ydbio.2005.01.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2004] [Revised: 01/18/2005] [Accepted: 01/19/2005] [Indexed: 11/17/2022]
Abstract
20-hydroxyecdysone was discovered as the major biologically active insect steroid hormone half a century ago, yet much remains to be learned about its biosynthesis and its activities. 20-hydroxyecdysone controls many biological processes, including progression between larval stages, entry to pupariation and metamorphosis. A number of genes required for 20-hydroxyecdysone production have been identified, including those encoding enzymes that mediate four of the late steps of biosynthesis. A second smaller group of low ecdysone mutants do not encode enzymes. Here, we report identification of one such gene, which we call molting defective, on the basis of its lethal phenotype. molting defective encodes a nuclear zinc finger protein required for ecdysone biosynthesis.
Collapse
|
20
|
Berger EM, Dubrovsky EB. Juvenile hormone molecular actions and interactions during development of Drosophila melanogaster. VITAMINS AND HORMONES 2005; 73:175-215. [PMID: 16399411 DOI: 10.1016/s0083-6729(05)73006-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Edward M Berger
- Department Of Biology, Dartmouth College, Hanover, New Hampshire 03755, USA
| | | |
Collapse
|
21
|
Gaziova I, Bonnette PC, Henrich VC, Jindra M. Cell-autonomous roles of the ecdysoneless gene in Drosophila development and oogenesis. Development 2004; 131:2715-25. [PMID: 15128659 DOI: 10.1242/dev.01143] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Steroid signaling underlies developmental processes in animals. Mutations that impair steroidogenesis in the fruit fly Drosophila melanogaster provide tools to dissect steroid hormone action genetically. The widely used temperature-sensitive mutation ecdysoneless(1) (ecd(1)) disrupts production of the steroid hormone ecdysone, and causes developmental and reproductive defects. These defects cannot be satisfactorily interpreted without analysis of the ecd gene. Here, we show that ecd encodes an as yet functionally undescribed protein that is conserved throughout eukaryotes. The ecd(1) conditional allele contains an amino acid substitution, whereas three non-conditional larval lethal mutations result in truncated Ecd proteins. Consistent with its role in steroid synthesis, Ecd is expressed in the ecdysone-producing larval ring gland. However, development of ecd-null early larval lethal mutants cannot be advanced by Ecd expression targeted to the ring gland or by hormone feeding. Cell-autonomous ecd function, suggested by these experiments, is evidenced by the inability of ecd(-) clones to survive within developing imaginal discs. Ecd is also expressed in the ovary, and is required in both the follicle cells and the germline for oocyte development. These defects, induced by the loss of ecd, provide the first direct evidence for a cell-autonomous function of this evolutionarily conserved protein.
Collapse
Affiliation(s)
- Ivana Gaziova
- Department of Molecular Biology, University of South Bohemia, and Institute of Entomology ASCR, Ceske Budejovice 37005, Czech Republic
| | | | | | | |
Collapse
|
22
|
Niwa N, Hiromi Y, Okabe M. A conserved developmental program for sensory organ formation in Drosophila melanogaster. Nat Genet 2004; 36:293-7. [PMID: 14981517 DOI: 10.1038/ng1308] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2003] [Accepted: 01/23/2004] [Indexed: 11/10/2022]
Abstract
Different sensory organs, such the eye and ear, are widely thought to have separate origins, guided by distinct organ-specific factors that direct all aspects of their development. Previous studies of the D. melanogaster gene eyeless (ey) and its vertebrate homolog Pax6 suggested that this gene acts in such a manner and specifically drives eye development. But diverse sensory organs might instead arise by segment-specific modification of a developmental program that is involved more generally in sensory organ formation. In D. melanogaster, a common proneural gene called atonal (ato) functions in the initial process of development of a number of segment-specific organs, including the compound eye, the auditory organ and the stretch receptor, suggesting that these organs share an evolutionary origin. Here we show that D. melanogaster segment-specific sensory organs form through the integration of decapentaplegic (dpp), wingless (wg) and ecdysone signals into a single cis-regulatory element of ato. The induction of ectopic eyes by ey also depends on these signals for ato expression, and the ey mutant eye imaginal disc allows ato expression if cell death is blocked. These results imply that ey does not induce the entire eye morphogenetic program but rather modifies ato-dependent neuronal development. Our findings strongly suggest that various sensory organs evolved from an ato-dependent protosensory organ through segment specification by ey and Hox genes.
Collapse
Affiliation(s)
- Nao Niwa
- Division of Developmental Genetics, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | | | | |
Collapse
|
23
|
Abstract
The conversion of stationary epithelial cells into migratory, invasive cells is important for normal embryonic development and tumour metastasis. Border-cell migration in the ovary of Drosophila melanogaster has emerged as a simple, genetically tractable model for studying this process. Three distinct signals, which are also upregulated in cancer, control border-cell migration, so identifying further genes that are involved in border-cell migration could provide new insights into tumour invasion.
Collapse
Affiliation(s)
- Denise J Montell
- Department of Biological Chemistry, Johns Hopkins School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205-2185, USA.
| |
Collapse
|
24
|
Siviter RJ, Taylor CAM, Cottam DM, Denton A, Dani MP, Milner MJ, Shirras AD, Isaac RE. Ance, a Drosophila angiotensin-converting enzyme homologue, is expressed in imaginal cells during metamorphosis and is regulated by the steroid, 20-hydroxyecdysone. Biochem J 2002; 367:187-93. [PMID: 12093364 PMCID: PMC1222869 DOI: 10.1042/bj20020567] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2002] [Revised: 05/30/2002] [Accepted: 07/02/2002] [Indexed: 11/17/2022]
Abstract
Ance is a single domain homologue of mammalian angiotensin-converting enzyme (ACE) and is important for normal development and reproduction in Drosophila melanogaster. Mammalian ACE is responsible for the synthesis of angiotensin II and the inactivation of bradykinin and N -acetyl-Ser-Asp-Lys-Pro, but the absence of similar peptide hormones in insects suggests novel functions for Ance. We now provide evidence in support of a role for Ance during Drosophila metamorphosis. The transition of larva to pupa was accompanied by a 3-fold increase in ACE-like activity, which subsequently dropped to larval levels on adult eclosion. This increase was attributed to the induction of Ance expression during the wandering phase of the last larval instar in the imaginal cells (imaginal discs, abdominal histoblasts, gut imaginal cells and imaginal salivary gland). Ance expression was particularly strong in the presumptive adult midgut formed as a result of massive proliferation of the imaginal midgut cells soon after pupariation. No Ance transcripts were detected in the midgut of the fully differentiated adult intestine. Ance protein and mRNA were not detected in imaginal discs from wandering larvae of flies homozygous for the ecd ( 1 ) allele, a temperature-sensitive ecdysone-less mutant, suggesting that Ance expression is ecdysteroid-dependent. Physiological levels of 20-hydroxyecdysone induced the synthesis of ACE-like activity and Ance protein by a wing disc cell line (Cl.8+), confirming that Ance is an ecdysteroid-responsive gene. We propose that the expression of Ance in imaginal cells is co-ordinated by exposure to ecdysteroid (moulting hormone) during the last larval instar moult to increase levels of ACE-like activity during metamorphosis. The enzyme activity may be required for the processing of a developmental peptide hormone or may function in concert with other peptidases to provide amino acids for the synthesis of adult proteins.
Collapse
Affiliation(s)
- Richard J Siviter
- Molecular and Cellular Biosciences, Faculty of Biological Sciences, L. C. Miall Building, University of Leeds, Leeds, LS2 9JT, U.K
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Warren JT, Wismar J, Subrahmanyam B, Gilbert LI. Woc (without children) gene control of ecdysone biosynthesis in Drosophila melanogaster. Mol Cell Endocrinol 2001; 181:1-14. [PMID: 11476936 DOI: 10.1016/s0303-7207(01)00404-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The first step in ecdysteroidogenesis, i.e. the 7,8-dehydrogenation of dietary cholesterol (C) to 7-dehydrocholesterol (7dC), is blocked in Drosophila melanogaster homozygous woc (without children) third instar larval ring glands (source of ecdysone). Unlike ring glands from wild-type D. melanogaster larvae, glands from woc mutants cannot convert radiolabelled C or 25-hydroxycholesterol (25C) to 7dC or 7-dehydro-25-hydroxycholesterol (7d25C) in vitro, nor to ecdysone (E). Yet, when these same glands are incubated with synthetic tracer 7d25C, the rate of metabolism of this polar Delta(5,7)-sterol into E is identical to that observed with glands from comparably staged wild-type larvae. The absence of this enzymatic activity in vivo is probably the direct cause of the observed low whole-body ecdysteroid titers in late third instar homozygous mutant larvae, the low ecdysteroid secretory activity in vitro of brain-ring gland complexes from these animals, and the failure of the larvae to pupariate (undergo metamorphosis). Oral administration of 7dC, but not C, results in a dramatic increase in ecdysteroid production both in vivo and in vitro by the woc mutant brain-ring gland complexes and affects a partial rescue to the beginning of pupal-adult development, but no further, despite elevated whole-body ecdysteroid titers. Data previously reported (Wismar et al., 2000) indicate that the woc gene encodes a zinc-finger protein that apparently modulates the activity of the 7,8-dehydrogenase.
Collapse
Affiliation(s)
- J T Warren
- Department of Biology, Campus Box #3280, University of North Carolina at Chapel Hill, 27599-3280, USA
| | | | | | | |
Collapse
|
26
|
Biyasheva A, Do TV, Lu Y, Vaskova M, Andres AJ. Glue secretion in the Drosophila salivary gland: a model for steroid-regulated exocytosis. Dev Biol 2001; 231:234-51. [PMID: 11180965 DOI: 10.1006/dbio.2000.0126] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Small hydrophobic hormones like steroids control many tissue-specific physiological responses in higher organisms. Hormone response is characterized by changes in gene expression, but the molecular details connecting target-gene transcription to the physiology of responding cells remain elusive. The salivary glands of Drosophila provide an ideal model system to investigate gaps in our knowledge, because exposure to the steroid 20-hydroxyecdysone (20E) leads to a robust regulated secretion of glue granules after a stereotypical pattern of puffs (activated 20E-regulated genes) forms on the polytene chromosomes. Here, we describe a convenient bioassay for glue secretion and use it to analyze mutants in components of the puffing hierarchy. We show that 20E mediates secretion through the EcR/USP receptor, and two early-gene products, the rbp(+) function of BR-C and the Ca2+ binding protein E63-1, are involved. Furthermore, we demonstrate that 20E treatment of salivary glands leads to Ca2+ elevations by a genomic mechanism and that elevated Ca2+ levels are required for ectopically produced E63-1 to drive secretion. The results presented establish a connection between 20E exposure and changes in Ca2+ levels that are mediated by Ca2+ effector proteins, and thus establish a mechanistic framework for future studies.
Collapse
Affiliation(s)
- A Biyasheva
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, Chicago, Illinois 60611-3093, USA
| | | | | | | | | |
Collapse
|
27
|
Wismar J, Habtemichael N, Warren JT, Dai JD, Gilbert LI, Gateff E. The mutation without children(rgl) causes ecdysteroid deficiency in third-instar larvae of Drosophila melanogaster. Dev Biol 2000; 226:1-17. [PMID: 10993670 DOI: 10.1006/dbio.2000.9811] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Larvae homozygous for the recessive lethal allele without children(rgl) (woc(rgl)) fail to pupariate. Application of exogenous 20-hydroxyecdysone elicits puparium formation and pupation. Ecdysteroid titer measurements on mutant larvae show an endocrine deficiency in the brain-ring gland complex, which normally synthesizes ecdysone, resulting in a failure of the larvae to achieve a threshold whole body hormone titer necessary for molting. Ultrastructural investigation revealed extensive degeneration of the prothoracic cells of the ring gland in older larvae. The woc gene, located in polytene chromosomal region 97F, consists of 11 exons. A 6.8-kb transcript is expressed throughout development but is absent in the mutant woc(rgl) larvae. The woc gene encodes a protein of 187 kDa. Eight zinc fingers of the C2-C2 type point to a possible function as a transcription factor. The woc protein shows considerable homology to human proteins which have been implicated in both mental retardation and a leukemia/lymphoma syndrome.
Collapse
Affiliation(s)
- J Wismar
- Institut für Genetik, Johannes Gutenberg Universität, Saarstrasse 21a, Mainz, 55099, Germany
| | | | | | | | | | | |
Collapse
|
28
|
Affiliation(s)
- I F Zhimulev
- Institute of Cytology and Genetics, Siberian Division of Russian Academy of Sciences, Novosibirsk, Russia
| |
Collapse
|
29
|
Brennan CA, Ashburner M, Moses K. Ecdysone pathway is required for furrow progression in the developing Drosophila eye. Development 1998; 125:2653-64. [PMID: 9636080 DOI: 10.1242/dev.125.14.2653] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In Drosophila, secretion of the steroid hormone ecdysone from the prothoracic ring gland coordinates and triggers events such as molting and metamorphosis. In the developing Drosophila compound eye, pattern formation and cell-type specification initiate at a moving boundary known as the morphogenetic furrow. We have investigated the role of ecdysone in eye development and report here that the ecdysone signaling pathway is required for progression of the morphogenetic furrow in the eye imaginal disc of Drosophila. Genetic disruption both of the ecdysone signal in vivo with the ecdysoneless1 (ecd1) mutant and of ecdysone response with a Broad-Complex mutant result in disruption of morphogenetic furrow progression. In addition, we show that ecdysone-dependent gene expression, both of a reporter of transcriptional activity of the Ecdysone Receptor and of the Z1 isoform of the Broad Complex, are localized in and close to the furrow. These results suggest that, in the morphogenetic furrow, temporal hormonal signals are integrated into genetic pathways specifying spatial pattern.
Collapse
Affiliation(s)
- C A Brennan
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322-3030, USA
| | | | | |
Collapse
|
30
|
Awad TA, Truman JW. Postembryonic development of the midline glia in the CNS of Drosophila: proliferation, programmed cell death, and endocrine regulation. Dev Biol 1997; 187:283-97. [PMID: 9242424 DOI: 10.1006/dbio.1997.8587] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The development of Drosophila midline glia during larval and pupal stages was characterized by localizing beta-gal expression in enhancer trap lines, as well as with BrdU incorporation and pulse-chase experiments. At hatching about 40 to 50 glial cells are present along the midline of the ventral nerve cord (2 to 3 dorsal and 1 to 2 ventral cells per neuromere). The cells proliferate during the third larval instar and spread dorsoventrally within the midline, increasing in number to about 230 or more (around 20 cells per neuromere). Cell divisions cease shortly after pupariation, and the cells persist for the first half of pupal life with no apparent changes in numbers or positions. Between 50 and 80% of metamorphosis, however, virtually all of the midline glia undergo programmed cell death. Tissue culture experiments indicate that the peak of ecdysteroids occurring at pupariation is required for the cessation of proliferation of midline glia and their subsequent degeneration. Midline glia in central nervous systems (CNS) cultured with low or no ecdysteroids survive and continue to divide, whereas they cease proliferating and later degenerate with high ecdysteroids levels. The midline glial may play a role during CNS metamorphosis similar to that of their progenitors in the embryo, in stabilizing outgrowing neurites that cross or run along the midline.
Collapse
Affiliation(s)
- T A Awad
- Department of Zoology, University of Washington, Seattle 98195, USA
| | | |
Collapse
|
31
|
Warren JT, Bachmann JS, Dai JD, Gilbert LI. Differential incorporation of cholesterol and cholesterol derivatives into ecdysteroids by the larval ring glands and adult ovaries of Drosophila melanogaster: a putative explanation for the l(3)ecd1 mutation. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 1996; 26:931-943. [PMID: 9014338 DOI: 10.1016/s0965-1748(96)00059-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Studies in vitro revealed that intact ring glands of Drosophila melanogaster convert tritiated cholesterol (C) and 25-hydroxycholesterol (25C) via 7-dehydrocholesterol (7dC) and 7-dehydro-25-hydroxycholesterol (7d25C), respectively, to ecdysone (E) and 2-deoxyecdysone (2dE), while both intact and homogenized ovaries synthesize only 2dE from these precursors. Emulsified 7d25C was incorporated directly into ecdysteroids by these tissue preparations at a much greater rate than was 7d25C made in situ from 25C. To probe the basis of the biochemical defect in the ecdysteroid deficient conditional mutant ecdysoneless (ecd1), the differential incorporation into ecdysteroids of C (via 7dC), and particularly of 25C (via 7d25C), was measured relative to that observed after the incubation of 7d25C directly with both wild type and mutant tissues in vitro at 30 degrees C, the restrictive temperature. Both C and 25C were equally 7,8-dehydrogenated in situ to 7dC or 7d25C, respectively, by both wild type and mutant tissues at 30 degrees C. However, the rate of subsequent conversion of either of these delta 5,7-sterol intermediates synthesized in situ to ecdysteroids was reduced an average of 50% in the mutant tissues relative to the wild type. Yet, when emulsified 7d25C was incubated directly with either the wild type or mutant tissues at the restrictive temperature, the amplified rate of conversion of the freely available 7d25C to ecdysteroid by these tissues was identical. These data suggest that the defect in ecd1 tissue-mediated ecdysteroidogenesis does not involve a "hit" on any of the enzymes involved in either the 7,8-dehydrogenation of C or 25C or in the subsequent oxidation of 7d25C or 7dC to ecdysteroid. Rather, the mutation appears to affect the expression of a gene governing the translocation of delta 5,7-sterol intermediates from the subcellular compartment where they are synthesized and/or stored to the site of subsequent oxidation to ecdysteroid.
Collapse
Affiliation(s)
- J T Warren
- Department of Biology, University of North Carolina, Chapel Hill 27599-3280, USA
| | | | | | | |
Collapse
|
32
|
Sliter TJ, Sudhivoraseth K, McCarthy JL. Quantification of ecdysteroid biosynthesis during short-term organ culture. Methods Enzymol 1996; 272:292-304. [PMID: 8791789 DOI: 10.1016/s0076-6879(96)72035-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- T J Sliter
- Department of Biological Sciences, Southern Methodist University, Dallas, Texas 75275, USA
| | | | | |
Collapse
|
33
|
Henrich VC. Comparison of ecdysteroid production in Drosophila and Manduca: pharmacology and cross-species neural reactivity. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 1995; 30:239-254. [PMID: 7579574 DOI: 10.1002/arch.940300212] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In both Manduca sexta and Drosophila melanogaster, metamorphic events are driven by ecdysteroids whose production in prothoracic gland (PGs) is stimulated periodically by neural factors. Differences in the life cycle of moths and flies have made it difficult to compare the regulation of ecdysteroid biosynthesis in these two species. As in Manduca, at least two neural factors in the larval Drosophila BVG complex were separable by molecular weight, and they stimulated increased ecdysteroid biosynthesis from the ring gland, a composite organ that includes PG cells. Drosophila neural extracts accelerated ecdysteroid biosynthesis in Manduca PGs and, conversely, partially purified Manduca PTTH preparations elevated ecdysteroid biosynthesis in Drosophila ring glands, suggesting that the two species may share structurally similar prothoracicotropic factors. Drosophila ring glands required the presence of calcium ions to respond to neural extracts, but the phosphodiesterase inhibitor MIX and cAMP analogues exerted little, if any, positive effect on production. Mean ecdysteroid production rates of BVG-ring gland complexes taken from Drosophila larvae during various phases of the wandering period were often submaximal and highly variable, suggesting that they fluctuate widely prior to pupariation. Based on available data in Drosophila and the Manduca model for the control of ecdysteroid biosynthesis, a developmental scheme for neuroendocrine control in Drosophila is proposed.
Collapse
Affiliation(s)
- V C Henrich
- Department of Biology, University of North Carolina-Greensboro 27412, USA
| |
Collapse
|
34
|
Henrich VC, Livingston L, Gilbert LI. Developmental requirements for the ecdysoneless (ecd) locus in Drosophila melanogaster. DEVELOPMENTAL GENETICS 1993; 14:369-77. [PMID: 8293578 DOI: 10.1002/dvg.1020140506] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The ecdysoneless locus in Drosophila melanogaster has been defined previously by a single conditional mutation, I(3)ecd1, that causes an ecdysteroid deficit and larval death at the restrictive temperature, 29 degrees C, although the primary role of the mutation in developmental processes has been unclear. Gene dosage and complementation studies reported here for ecd1 and five nonconditional lethal alleles indicate that the ecd locus plays prezygotic and postzygotic roles essential for normal embryonic development, the successful completion of each larval molt, adult eclosion, and female fertility. The ecd locus is also required for normal macrochaete differentiation. For each observed phenotype, the severity of mutational effects was correlated with ecd mutant genotypes. In all cases, ecd1 homozygotes were least affected. Mutants heteroallelic for ecd1 and any one of four nonconditional recessive mutations were more severely affected than ecd1 homozygotes, revealing these as hypomorphic alleles. For all phenotypic effects, mutants heteroallelic for ecd1 and a dominant mutation (ecd3D) were most severely affected. These individuals died during embryogenesis at 29 degrees C and developed no macrochaetes on the dorsal thorax when transferred to 29 degrees C during the white prepupal stage. The ecd3D mutation also caused female semisterility in heterozygotes. Ecdysteroid regulation has been implicated previously in all the developmental processes disrupted by these ecd mutations except for macrochaete differentiation.
Collapse
Affiliation(s)
- V C Henrich
- Department of Biology, University of North Carolina at Greensboro 27412-5001
| | | | | |
Collapse
|
35
|
Segal D. Prospects of using Drosophila for insect neuroendocrine research. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 1993; 22:199-231. [PMID: 8431597 DOI: 10.1002/arch.940220116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Classical and in vitro approaches for the analysis of the molecular components of neuroendocrine systems often disrupt their close interaction with other bodily systems, which is a crucial aspect of their function in vivo. "Genetic dissection" is an alternative, noninvasive approach which involves the systematic generation of mutations in individual genes, followed by in vivo analysis of the phenotypic effects of altering a single protein at a time avoiding extraneous disruptions. Among insects Drosophila melanogaster is the most suitable model for this approach. This paper explores the application of genetic and molecular techniques available in Drosophila for studying its neuroendocrine system with special emphasis on the production of ecdysone and juvenile hormone. Strategies are described for the generation and identification of endocrine mutations, especially those affecting hormone synthesis and regulation. Once identified by a specific mutation, a gene in Drosophila can be cloned either by chromosomal microdissection and "chromosomal walk" or by transposon tagging. Methods for molecular analysis of the structure and function of a cloned gene and of the protein it encodes are available for further study. Alternatively, a gene can be cloned using heterologous DNA probes or oligonucleotides designed according to the amino acid sequence of a protein. Genes may also be cloned via their pattern of expression (using stage- or tissue-specific cDNA libraries or through transposon-mediated "enhancer detection." Anti-sense RNA, the replacement of the gene by in vitro manipulated versions, or mutagenesis of its endogenous copies can then be used for studying its function in vivo. Information about endocrine genes in Drosophila as well as material such as cloned genes and antibodies should be useful for the analysis of endocrine systems in other insects which are not amenable to genetic manipulations. Such information should be helpful in designing novel means for pest control based on the specific intervention with endocrine systems regulating insect development and reproduction.
Collapse
Affiliation(s)
- D Segal
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Israel
| |
Collapse
|
36
|
Dai JD, Henrich VC, Gilbert LI. An ultrastructural analysis of the ecdysoneless (l(3)ecd1ts) ring gland during the third larval instar of Drosophila melanogaster. Cell Tissue Res 1991; 265:435-45. [PMID: 1786592 DOI: 10.1007/bf00340866] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In the late third larval instar of Drosophila melanogaster, the prothoracic gland, an endocrine portion of the ring gland, synthesizes ecdysteroids at an accelerated rate. The resultant ecdysteroid titer peak initiates the events associated with metamorphosis. The normal prothoracic gland displays several ultrastructural features at this developmental stage that reflect increased steroidogenic activity, including extensive infoldings of the plasma membrane (membrane invaginations) and an increase in both the concentration of smooth endoplasmic reticulum (SER) (or transitional ER) and elongated mitochondria. By contrast, the prothoracic glands of larvae homozygous for a conditional larval lethal mutation, l(3)ecd1ts, not only fail to produce ecdysteroids at normal levels at the restrictive temperature (29 degrees C), but also acquire abnormal morphological features that reflect the disruptive effects of the mutation. These abnormalities include an accumulation of lipid droplets presumed to contain sterol precursors of ecdysteroids, a disappearance of SER and a drastic reduction of membrane invaginations in the peripheral area of the cell. These morphological defects are observed in prothoracic glands dissected from larvae transferred from 18 degrees C to 29 degrees C approximately 24 h before observation and also within 4 h of an in vitro transfer to 29 degrees C following dissection from wandering third instar larvae reared at 18 degrees C. No ultrastructural abnormalities were noted in the corpus allatum portion of mutant ring glands. These observations further indicate the direct involvement of the ecd gene product in ecdysteroid synthesis and suggest a role for the gene in the proper transport of precursors to the site where they can be utilized in ecdysteroid biosynthesis.
Collapse
Affiliation(s)
- J D Dai
- Department of Biology, University of North Carolina, Chapel Hill 27599-3280
| | | | | |
Collapse
|
37
|
Dai JD, Gilbert LI. Metamorphosis of the corpus allatum and degeneration of the prothoracic glands during the larval-pupal-adult transformation of Drosophila melanogaster: a cytophysiological analysis of the ring gland. Dev Biol 1991; 144:309-26. [PMID: 1901285 DOI: 10.1016/0012-1606(91)90424-2] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The degeneration of the prothoracic glands of Drosophila melanogaster during pupal-adult metamorphosis was analyzed by light microscopy, scanning, and transmission electron microscopy. The ultrastructural observations were correlated with the ability of the ring gland to synthesize ecdysteroids in vitro. The ring gland is prominent during larval life and is identifiable until just before adult eclosion but undergoes dramatic changes in location, shape, size, ultrastructure, and function during pupal-adult development. Prothoracic gland degeneration is characterized by: a gradual decrease in its ability to synthesize ecdysteroids; a decreasing quantity of smooth endoplasmic reticulum (SER) and mitochondria; the absence of intercellular channels; cytoplasmic fragmentation; and the separation of the prothoracic gland from the corpus allatum and corpus cardiacum. An ultrastructural analysis of the corpus allatum during larval-pupal-adult metamorphosis and adult life was also correlated with function, i.e., juvenile hormone biosynthesis, using a radiochemical assay of ring glands and adult corpora allata in vitro. A relatively high concentration of SER, mitochondria, and mitochondrion-scalariform junction complexes are typical features of an active corpus allatum cell. The migration of the corpus allatum from the ring gland to its position as a separate gland in the adult fly was studied in detail. The capacity of the corpus allatum to synthesize juvenile hormone is at its peak in the ring gland of the early wandering third instar larva, whereas the corpus allatum of 2-day-old female adults displayed the greatest synthetic activity during adult life. The physiological significance of the alterations in gland activity is discussed.
Collapse
Affiliation(s)
- J D Dai
- Department of Biology, University of North Carolina, Chapel Hill 27599
| | | |
Collapse
|
38
|
PÉTAVY GEORGES. Pleiotropic ovarian defects in ecd-1, a temperature-sensitive mutant of Drosophila melanogaster. INVERTEBR REPROD DEV 1991. [DOI: 10.1080/07924259.1991.9672166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
39
|
PÉTAVY GEORGES. Overall effects of the temperature-sensitiveecd-1mutation on fertility inDrosophila melanogaster. INVERTEBR REPROD DEV 1990. [DOI: 10.1080/07924259.1990.9672097] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
40
|
Deutsch J, Laval M, Lepesant JA, Maschat F, Pourrain F, Rat L. Larval fat body-specific gene expression in D. melanogaster. DEVELOPMENTAL GENETICS 1989; 10:220-31. [PMID: 2500286 DOI: 10.1002/dvg.1020100311] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The Pl gene, together with the LSP-1 alpha, -1 beta, and -1 gamma, LSP-2, and P6 genes, is expressed exclusively in the larval fat body of D. melanogaster during the third instar. In vivo mapping of the cis-acting regulatory sequences of the P1 gene was carried out using hybrid constructs with three different reporter genes and a combination of transient and germline transformation assays. This revealed that regulatory elements involved in the setting up of the temporal and spatial specificities of transcription of the P1 gene are located in a short DNA region immediately upstream of the mRNA transcription start. This region includes an element that behaves as a fat-body transcriptional enhancer and element(s) required for ecdysone inducibility of transcription of the P1 gene.
Collapse
Affiliation(s)
- J Deutsch
- Institut Jacques Monod, CNRS Université Paris, France
| | | | | | | | | | | |
Collapse
|
41
|
Sommé-Martin G, Colardeau J, Lafont R. Metabolism and biosynthesis of ecdysteroids in the Drosophila development mutant ecd1. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/0020-1790(88)90083-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
42
|
Henrich VC, Pak MD, Gilbert LI. Neural factors that stimulate ecdysteroid synthesis by the larval ring gland of Drosophila melanogaster. J Comp Physiol B 1987; 157:543-9. [PMID: 3121682 DOI: 10.1007/bf00700973] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The larval ring gland of Drosophila melanogaster is the source of ecdysteroids responsible for larval-larval and larval-pupal molting. An extract prepared from the Drosophila larval central nervous system, that presumably contains prothoracicotropic hormone, elicits a significant and dose-dependent in vitro increase in ecdysteroid synthesis by ring glands from wandering third instar larvae. The synthesis of all three ecdysteroids previously identified as ring gland products is elevated by more than two-fold in the presence of neural extract. The maximum response occurs within 30 min and can be sustained for at least two hours after a 30 min exposure to neural extract. No non-neural tissue extracts evoke a response and most of the prothoracicotropic activity originates in the ventral ganglion. However, while extract prepared from larval brains elicits only a slight increase in ecdysteroid synthesis, it enhances the activity of a submaximal dose of ventral ganglion extract. This suggests that two or more neural factors, at least one from the brain lobes and another from the ventral ganglion, interact to stimulate ecdysteroid synthesis by the larval ring gland.
Collapse
Affiliation(s)
- V C Henrich
- Department of Biology, University of North Carolina, Chapel Hill 27514
| | | | | |
Collapse
|