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Tyra LK, Nandi N, Tracy C, Krämer H. Yorkie Growth-Promoting Activity Is Limited by Atg1-Mediated Phosphorylation. Dev Cell 2020; 52:605-616.e7. [PMID: 32032548 DOI: 10.1016/j.devcel.2020.01.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 08/26/2019] [Accepted: 01/09/2020] [Indexed: 01/31/2023]
Abstract
The expression of multiple growth-promoting genes is coordinated by the transcriptional co-activator Yorkie with its major regulatory input provided by the Hippo-Warts kinase cascade. Here, we identify Atg1/ULK1-mediated phosphorylation of Yorkie as an additional inhibitory input independent of the Hippo-Warts pathway. Two serine residues in Yorkie, S74 and S97, are Atg1/ULK1 consensus target sites and are phosphorylated by ULK1 in vitro, thereby preventing its binding to Scalloped. In vivo, gain of function of Atg1, or its activator Acinus, caused elevated Yorkie phosphorylation and inhibited Yorkie's growth-promoting activity. Loss of function of Atg1 or Acinus raised expression of Yorkie target genes and increased tissue size. Unlike Atg1's role in autophagy, Atg1-mediated phosphorylation of Yorkie does not require Atg13. Atg1 is activated by starvation and other cellular stressors and therefore can impose temporary stress-induced constraints on the growth-promoting gene networks under the control of Hippo-Yorkie signaling.
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Affiliation(s)
- Lauren K Tyra
- Peter O'Donnell Jr. Brain Institute, Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390-9111, USA
| | - Nilay Nandi
- Peter O'Donnell Jr. Brain Institute, Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390-9111, USA
| | - Charles Tracy
- Peter O'Donnell Jr. Brain Institute, Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390-9111, USA
| | - Helmut Krämer
- Peter O'Donnell Jr. Brain Institute, Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390-9111, USA; Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390-9111, USA.
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2
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Eliason J, Afify A, Potter C, Matsumura I. A GAL80 Collection To Inhibit GAL4 Transgenes in Drosophila Olfactory Sensory Neurons. G3 (BETHESDA, MD.) 2018; 8:3661-3668. [PMID: 30262521 PMCID: PMC6222567 DOI: 10.1534/g3.118.200569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/17/2018] [Indexed: 01/16/2023]
Abstract
Fruit flies recognize hundreds of ecologically relevant odors and respond appropriately to them. The complexity, redundancy and interconnectedness of the olfactory machinery complicate efforts to pinpoint the functional contributions of any component neuron or receptor to behavior. Some contributions can only be elucidated in flies that carry multiple mutations and transgenes, but the production of such flies is currently labor-intensive and time-consuming. Here, we describe a set of transgenic flies that express the Saccharomyces cerevisiae GAL80 in specific olfactory sensory neurons (OrX-GAL80s). The GAL80s effectively and specifically subtract the activities of GAL4-driven transgenes that impart anatomical and physiological phenotypes. OrX-GAL80s can allow researchers to efficiently activate only one or a few types of functional neurons in an otherwise nonfunctional olfactory background. Such experiments will improve our understanding of the mechanistic connections between odorant inputs and behavioral outputs at the resolution of only a few functional neurons.
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Affiliation(s)
- Jessica Eliason
- Janelia Research Campus, Howard Hughes Medical Institute' Ashburn, VA, 20147
- Department of Biochemistry; Emory University School of Medicine; Atlanta, GA, 30322
| | - Ali Afify
- Solomon H. Snyder Department of Neuroscience; Johns Hopkins University School of Medicine; Baltimore, MD, 21205
| | - Christopher Potter
- Solomon H. Snyder Department of Neuroscience; Johns Hopkins University School of Medicine; Baltimore, MD, 21205
| | - Ichiro Matsumura
- Department of Biochemistry; Emory University School of Medicine; Atlanta, GA, 30322
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3
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Starfish Apaf-1 activates effector caspase-3/9 upon apoptosis of aged eggs. Sci Rep 2018; 8:1611. [PMID: 29371610 PMCID: PMC5785508 DOI: 10.1038/s41598-018-19845-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 01/09/2018] [Indexed: 11/29/2022] Open
Abstract
Caspase-3-related DEVDase activity is initiated upon apoptosis in unfertilized starfish eggs. In this study, we cloned a starfish procaspase-3 corresponding to mammalian effector caspase containing a CARD that is similar to the amino terminal CARD of mammalian capsase-9, and we named it procaspase-3/9. Recombinant procaspase-3/9 expressed at 15 °C was cleaved to form active caspase-3/9 which has DEVDase activity. Microinjection of the active caspase-3/9 into starfish oocytes/eggs induced apoptosis. An antibody against the recombinant protein recognized endogenous procaspase-3/9 in starfish oocytes, which was cleaved upon apoptosis in aged unfertilized eggs. These results indicate that caspase-3/9 is an effector caspase in starfish. To verify the mechanism of caspase-3/9 activation, we cloned starfish Apaf-1 containing a CARD, a NOD, and 11 WD40 repeat regions, and we named it sfApaf-1. Recombinant sfApaf-1 CARD interacts with recombinant caspase-3/9 CARD and with endogenous procaspase-3/9 in cell-free preparations made from starfish oocytes, causing the formation of active caspase-3/9. When the cell-free preparation without mitochondria was incubated with inactive recombinant procaspase-3/9 expressed at 37 °C, DEVDase activity increased and apoptosome-like complexes were formed in the high molecular weight fractions containing both sfApaf-1 and cleaved caspase-3/9. These results suggest that sfApaf-1 activation is not dependent on cytochrome c.
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4
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Garcia-Hughes G, Link N, Ghosh AB, Abrams JM. Hid arbitrates collective cell death in the Drosophila wing. Mech Dev 2015; 138 Pt 3:349-55. [PMID: 26226435 DOI: 10.1016/j.mod.2015.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 07/13/2015] [Accepted: 07/24/2015] [Indexed: 02/08/2023]
Abstract
Elimination of cells and tissues by apoptosis is a highly conserved and tightly regulated process. In Drosophila, the entire wing epithelium is completely removed shortly after eclosion. The cells that make up this epithelium are collectively eliminated through a highly synchronized form of apoptotic cell death, involving canonical apoptosome genes. Here we present evidence that collective cell death does not require cell-cell contact and show that transcription of the IAP antagonist, head involution defective, is acutely induced in wing epithelial cells prior to this process. hid mRNAs accumulate to levels that exceed a component of the ribosome and likewise, Hid protein becomes highly abundant in these same cells. hid function is required for collective cell death, since loss of function mutants shows persisting wing epithelial cells and, furthermore, silencing of the hormone bursicon in the CNS produced collective cell death defective phenotypes manifested in the wing epithelium. Taken together, our observations suggest that acute induction of Hid primes wing epithelial cells for collective cell death and that Bursicon is a strong candidate to trigger this process, possibly by activating the abundant pool of Hid protein already present.
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Affiliation(s)
- Gianella Garcia-Hughes
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390-9039, United States
| | - Nichole Link
- Baylor College of Medicine, Houston, TX 77030, United States
| | - Anwesha B Ghosh
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390-9039, United States
| | - John M Abrams
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390-9039, United States.
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5
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Ziraldo R, Link N, Abrams J, Ma L. Towards automatic image analysis and assessment of the multicellular apoptosis process. IET IMAGE PROCESSING 2015; 9:424-433. [PMID: 26500693 PMCID: PMC4613781 DOI: 10.1049/iet-ipr.2014.0531] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Apoptotic programmed cell death (PCD) is a fundamental aspect of developmental maturation. However, the authors' understanding of apoptosis, especially in the multi-cell regime, is incomplete because of the difficulty of identifying dying cells by conventional strategies. Real-time in vivo microscopy of Drosophila, an excellent model system for studying the PCD during development, has been used to uncover plausible collective apoptosis at the tissue level, although the dynamic regulation of the process remains to be deciphered. In this work, the authors have developed an image-analysis program that can quantitatively analyse time-lapse microscopy of live tissues undergoing apoptosis with a fluorescent nuclear marker, and subsequently extract the spatiotemporal patterns of multicellular response. The program can process a large number of cells (>103) automatically tracked across sets of image frames. It is applied to characterise the apoptosis of Drosophila wing epithelium at eclosion. Using the natural anatomic structures as reference, the authors identify dynamic patterns in the progression of PCD within the Drosophila tissues. The results not only confirm the previously observed collective multi-cell behaviour from a quantitative perspective, but also reveal a plausible role played by the anatomic structures, such as the wing veins, in the PCD propagation across the Drosophila wing.
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Affiliation(s)
- Riccardo Ziraldo
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX USA
| | - Nichole Link
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA
- Molecular and Human Genetics, Baylor College of Medicine, Houston, TX USA
| | - John Abrams
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Lan Ma
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX USA
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6
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Zimmermann M, Kugler SJ, Schulz A, Nagel AC. Loss of putzig Activity Results in Apoptosis during Wing Imaginal Development in Drosophila. PLoS One 2015; 10:e0124652. [PMID: 25894556 PMCID: PMC4403878 DOI: 10.1371/journal.pone.0124652] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 03/17/2015] [Indexed: 12/22/2022] Open
Abstract
The Drosophila gene putzig (pzg) encodes a nuclear protein that is an integral component of the Trf2/Dref complex involved in the transcription of proliferation-related genes. Moreover, Pzg is found in a complex together with the nucleosome remodeling factor NURF, where it promotes Notch target gene activation. Here we show that downregulation of pzg activity in the developing wing imaginal discs induces an apoptotic response, accompanied by the induction of the pro-apoptotic gene reaper, repression of Drosophila inhibitor of apoptosis protein accumulation and the activation of the caspases Drice, Caspase3 and Dcp1. As a further consequence ‘Apoptosis induced Proliferation’ (AiP) and ‘Apoptosis induced Apoptosis’ (AiA) are triggered. As expected, the activity of the stress kinase Jun N-terminal kinase (JNK), proposed to mediate both processes, is ectopically induced in response to pzg loss. In addition, the expression of the mitogen wingless (wg) but not of decapentaplegic (dpp) is observed. We present evidence that downregulation of Notch activates Dcp1 caspase and JNK signaling, however, neither induces ectopic wg nor dpp expression. In contrast, the consequences of Dref-RNAi were largely indistinguishable from pzg-RNAi with regard to apoptosis induction. Moreover, overexpression of Dref ameliorated the downregulation of pzg compatible with the notion that the two are required together to maintain cell and tissue homeostasis in Drosophila.
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Affiliation(s)
- Mirjam Zimmermann
- Institute of Genetics, University of Hohenheim, 70599 Stuttgart, Germany
| | - Sabrina J. Kugler
- Institute of Genetics, University of Hohenheim, 70599 Stuttgart, Germany
| | - Adriana Schulz
- Institute of Genetics, University of Hohenheim, 70599 Stuttgart, Germany
| | - Anja C. Nagel
- Institute of Genetics, University of Hohenheim, 70599 Stuttgart, Germany
- * E-mail:
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7
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Wangler MF, Yamamoto S, Bellen HJ. Fruit flies in biomedical research. Genetics 2015; 199:639-53. [PMID: 25624315 PMCID: PMC4349060 DOI: 10.1534/genetics.114.171785] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 12/09/2014] [Indexed: 12/13/2022] Open
Abstract
Many scientists complain that the current funding situation is dire. Indeed, there has been an overall decline in support in funding for research from the National Institutes of Health and the National Science Foundation. Within the Drosophila field, some of us question how long this funding crunch will last as it demotivates principal investigators and perhaps more importantly affects the long-term career choice of many young scientists. Yet numerous very interesting biological processes and avenues remain to be investigated in Drosophila, and probing questions can be answered fast and efficiently in flies to reveal new biological phenomena. Moreover, Drosophila is an excellent model organism for studies that have translational impact for genetic disease and for other medical implications such as vector-borne illnesses. We would like to promote a better collaboration between Drosophila geneticists/biologists and human geneticists/bioinformaticians/clinicians, as it would benefit both fields and significantly impact the research on human diseases.
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Affiliation(s)
- Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, Texas 77030 Department of Pediatrics, Baylor College of Medicine (BCM), Houston, Texas 77030 Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, Texas 77030 Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030 Program in Developmental Biology, Baylor College of Medicine (BCM), Texas 77030
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, Texas 77030 Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030 Program in Developmental Biology, Baylor College of Medicine (BCM), Texas 77030 Department of Neuroscience, Baylor College of Medicine (BCM), Texas 77030 Howard Hughes Medical Institute, Houston, Texas 77030
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8
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Kotkamp K, Kur E, Wendik B, Polok BK, Ben-Dor S, Onichtchouk D, Driever W. Pou5f1/Oct4 promotes cell survival via direct activation of mych expression during zebrafish gastrulation. PLoS One 2014; 9:e92356. [PMID: 24643012 PMCID: PMC3958507 DOI: 10.1371/journal.pone.0092356] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 02/17/2014] [Indexed: 01/29/2023] Open
Abstract
Myc proteins control cell proliferation, cell cycle progression, and apoptosis, and play important roles in cancer as well in establishment of pluripotency. Here we investigated the control of myc gene expression by the Pou5f1/Oct4 pluripotency factor in the early zebrafish embryo. We analyzed the expression of all known zebrafish Myc family members, myca, mycb, mych, mycl1a, mycl1b, and mycn, by whole mount in situ hybridization during blastula and gastrula stages in wildtype and maternal plus zygotic pou5f1 mutant (MZspg) embryos, as well as by quantitative PCR and in time series microarray data. We found that the broad blastula and gastrula stage mych expression, as well as late gastrula stage mycl1b expression, both depend on Pou5f1 activity. We analyzed ChIP-Seq data and found that both Pou5f1 and Sox2 bind to mych and mycl1b control regions. The regulation of mych by Pou5f1 appears to be direct transcriptional activation, as overexpression of a Pou5f1 activator fusion protein in MZspg embryos induced strong mych expression even when translation of zygotically expressed mRNAs was suppressed. We further showed that MZspg embryos develop enhanced apoptosis already during early gastrula stages, when apoptosis was not be detected in wildtype embryos. However, Mych knockdown alone did not induce early apoptosis, suggesting potentially redundant action of several early expressed myc genes, or combination of several pathways affected in MZspg. Experimental mych overexpression in MZspg embryos did significantly, but not completely suppress the apoptosis phenotype. Similarly, p53 knockdown only partially suppressed apoptosis in MZspg gastrula embryos. However, combined knockdown of p53 and overexpression of Mych completely rescued the MZspg apoptosis phenotype. These results reveal that Mych has anti-apoptotic activity in the early zebrafish embryo, and that p53-dependent and Myc pathways are likely to act in parallel to control apoptosis at these stages.
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Affiliation(s)
- Kay Kotkamp
- Developmental Biology, Institute Biology I, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Esther Kur
- Developmental Biology, Institute Biology I, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Björn Wendik
- Developmental Biology, Institute Biology I, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Bożena K. Polok
- Developmental Biology, Institute Biology I, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Shifra Ben-Dor
- Biological Services, Weizmann Institute of Science, Rehovot, Israel
| | - Daria Onichtchouk
- Developmental Biology, Institute Biology I, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- BIOSS - Centre for Biological Signalling Studies, Freiburg, Germany
| | - Wolfgang Driever
- Developmental Biology, Institute Biology I, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- BIOSS - Centre for Biological Signalling Studies, Freiburg, Germany
- * E-mail:
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9
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Suwannaboon R, Phiwsaiya K, Senapin S, Khunrae P, Rattanarojpong T. The identification and expression of the full-length HtrA2 gene from Penaeus monodon (black tiger shrimp). Protein Expr Purif 2013; 92:183-9. [DOI: 10.1016/j.pep.2013.09.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/14/2013] [Accepted: 09/18/2013] [Indexed: 11/29/2022]
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10
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Filipiak M, Tylko G, Pyza E. Zinc induces caspase-dependent mitochondrial pathway of the programmed cell death in haemocytes of Drosophila melanogaster. Biometals 2012; 25:507-16. [PMID: 22367497 PMCID: PMC3349848 DOI: 10.1007/s10534-012-9530-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 02/09/2012] [Indexed: 01/11/2023]
Abstract
Zinc is an essential trace element in cells. However, its high level in cytoplasm promotes activation of stress signaling pathways and may lead to cell death. In the present study we used Drosophila melanogaster blood cells (haemocytes), obtained from the third instar larvae, to study the effects of high concentrations of Zn(2+) on programmed cell death (PCD). We analyzed the activity of caspases, the level of caspase inhibitor protein DIAP1 and metallothioneins, as well as calcium concentrations and activity of mitochondria in haemocytes exposed to 0.35 and 1.7 mM concentrations of Zn. The obtained results showed that rapid increase of [Zn(2+)]( i ) in the cytoplasm up-regulates metallothionein MtnB but not MtnA gene expression in cells treated with Zn(2+) in both concentrations. Excess of Zn(2+) also induced activation of the initiator caspase Dronc, associated with the mitochondrial pathway of PCD, and the effector caspase DrICE. In turn, the activity of receptor-regulated Dredd caspase was not changed. The level of DIAP1 decreased significantly in haemocytes in the presence of high Zn(2+) concentration in comparison to untreated cells. Moreover, mitochondrial membrane potential was significantly decreased after exposure to Zn ions. These results indicate that high concentration of Zn(2+) in the cytoplasm of haemocytes induces PCD via a mitochondrial pathway and that caspases play a pivotal role in this process.
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Affiliation(s)
- Marta Filipiak
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
| | - Grzegorz Tylko
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
| | - Elzbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland
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11
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Schetelig MF, Nirmala X, Handler AM. Pro-apoptotic cell death genes, hid and reaper, from the tephritid pest species, Anastrepha suspensa. Apoptosis 2011; 16:759-68. [PMID: 21630017 DOI: 10.1007/s10495-011-0610-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Pro-apoptotic proteins from the reaper, hid, grim (RHG) family are primary regulators of programmed cell death in Drosophila due to their antagonistic effect on inhibitor of apoptosis (IAP) proteins, thereby releasing IAP-inhibition of caspases that effect apoptosis. Using a degenerate PCR approach to conserved domains from the 12 Drosophila species, we have identified the first reaper and hid orthologs from a tephritid, the Caribfly Anastrepha suspensa. As-hid is the first identified non-drosophilid homolog of hid, and As-rpr is the second non-drosophilid rpr homolog. Both genes share more than 50% amino acid sequence identity with their Drosophila homologs, suggesting that insect pro-apoptotic peptides may be more conserved than previously anticipated. Importantly, both genes encode the conserved IBM and GH3 motifs that are key for IAP-inhibition and mitochondrial localization. Functional verification of both genes as cell death effectors was demonstrated by cell death assays in A. suspensa embryonic cell culture, as well as in heterologous Drosophila melanogaster S2 cells. Notably, heterologous cell death activity was found to be higher for Anastrepha genes than their Drosophila counterparts. In common with the Drosophila cognates, As-hid and As-rpr negatively regulated the Drosophila inhibitor of apoptosis (DIAP1) gene to promote apoptosis, and both genes when used together effected increased cell death activity, indicating a co-operative function for As-hid and As-rpr. We show that these tephritid cell death genes are functional and potent as cell death effectors, and could be used to design improved transgenic lethality systems for insect population control.
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Affiliation(s)
- Marc F Schetelig
- USDA/ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL 32608, USA.
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12
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Chen S, Wei HM, Lv WW, Wang DL, Sun FL. E2 ligase dRad6 regulates DMP53 turnover in Drosophila. J Biol Chem 2011; 286:9020-30. [PMID: 21205821 PMCID: PMC3058994 DOI: 10.1074/jbc.m110.190314] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 12/27/2010] [Indexed: 11/06/2022] Open
Abstract
The turnover of tumor suppressor p53 is critical for its role in various cellular events. However, the pathway that regulates the turnover of the Drosophila melanogaster DMP53 is largely unknown. Here, we provide evidence for the first time that the E2 ligase, Drosophila homolog of Rad6 (dRad6/Dhr6), plays an important role in the regulation of DMP53 turnover. Depletion of dRad6 results in DMP53 accumulation, whereas overexpression of dRad6 causes enhanced DMP53 degradation. We show that dRad6 specifically interacts with DMP53 at the transcriptional activation domain and regulates DMP53 ubiquitination. Loss of dRad6 function in transgenic flies leads to lethalities and altered morphogenesis. The dRad6-induced defects in cell proliferation and apoptosis are found to be DMP53-dependent. The loss of dRad6 induces an accumulation of DMP53 that enhances the activation of apoptotic genes and leads to apoptosis in the presence of stress stimuli. In contrast to that, the E3 ligase is the primary factor that regulates p53 turnover in mammals, and this work demonstrates that the E2 ligase dRad6 is critical for the control of DMP53 degradation in Drosophila.
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Affiliation(s)
- Su Chen
- From the Institute of Epigenetics and Cancer Research, Medical Science Building C-315, School of Medicine, and
| | - Hui-Min Wei
- From the Institute of Epigenetics and Cancer Research, Medical Science Building C-315, School of Medicine, and
| | - Wen-Wen Lv
- From the Institute of Epigenetics and Cancer Research, Medical Science Building C-315, School of Medicine, and
| | - Da-Liang Wang
- From the Institute of Epigenetics and Cancer Research, Medical Science Building C-315, School of Medicine, and
| | - Fang-Lin Sun
- From the Institute of Epigenetics and Cancer Research, Medical Science Building C-315, School of Medicine, and
- School of Life Sciences, Tsinghua University, Beijing 100084, China
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13
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Shukla A, Tapadia MG. Differential localization and processing of apoptotic proteins in Malpighian tubules of Drosophila during metamorphosis. Eur J Cell Biol 2011; 90:72-80. [DOI: 10.1016/j.ejcb.2010.08.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 08/13/2010] [Accepted: 08/26/2010] [Indexed: 01/11/2023] Open
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14
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Kim YI, Ryu T, Lee J, Heo YS, Ahnn J, Lee SJ, Yoo O. A genetic screen for modifiers of Drosophila caspase Dcp-1 reveals caspase involvement in autophagy and novel caspase-related genes. BMC Cell Biol 2010; 11:9. [PMID: 20100334 PMCID: PMC2822743 DOI: 10.1186/1471-2121-11-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Accepted: 01/25/2010] [Indexed: 12/01/2022] Open
Abstract
Background Caspases are cysteine proteases with essential functions in the apoptotic pathway; their proteolytic activity toward various substrates is associated with the morphological changes of cells. Recent reports have described non-apoptotic functions of caspases, including autophagy. In this report, we searched for novel modifiers of the phenotype of Dcp-1 gain-of-function (GF) animals by screening promoter element- inserted Drosophila melanogaster lines (EP lines). Results We screened ~15,000 EP lines and identified 72 Dcp-1-interacting genes that were classified into 10 groups based on their functions and pathways: 4 apoptosis signaling genes, 10 autophagy genes, 5 insulin/IGF and TOR signaling pathway genes, 6 MAP kinase and JNK signaling pathway genes, 4 ecdysone signaling genes, 6 ubiquitination genes, 11 various developmental signaling genes, 12 transcription factors, 3 translation factors, and 11 other unclassified genes including 5 functionally undefined genes. Among them, insulin/IGF and TOR signaling pathway, MAP kinase and JNK signaling pathway, and ecdysone signaling are known to be involved in autophagy. Together with the identification of autophagy genes, the results of our screen suggest that autophagy counteracts Dcp-1-induced apoptosis. Consistent with this idea, we show that expression of eGFP-Atg5 rescued the eye phenotype caused by Dcp-1 GF. Paradoxically, we found that over-expression of full-length Dcp-1 induced autophagy, as Atg8b-GFP, an indicator of autophagy, was increased in the eye imaginal discs and in the S2 cell line. Taken together, these data suggest that autophagy suppresses Dcp-1-mediated apoptotic cell death, whereas Dcp-1 positively regulates autophagy, possibly through feedback regulation. Conclusions We identified a number of Dcp-1 modifiers that genetically interact with Dcp-1-induced cell death. Our results showing that Dcp-1 and autophagy-related genes influence each other will aid future investigations of the complicated relationships between apoptosis and autophagy.
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Affiliation(s)
- Young-Il Kim
- Bio Medical Research Center, Department of Biological Science, KAIST, 373-1, 305-701, Daejeon, Korea
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15
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Abstract
The last few years have witnessed a considerable expansion in the number of tools available to perform molecular and genetic studies on the genome of Anopheles mosquitoes, the vectors of human malaria. As a consequence, knowledge of aspects of the biology of mosquitoes, such as immunity, reproduction and behaviour, that are relevant to their ability to transmit disease is rapidly increasing, and could be translated into concrete benefits for malaria control strategies. Amongst the most important scientific advances, the development of transgenic technologies for Anopheles mosquitoes provides a crucial opportunity to improve current vector control measures or design novel ones. In particular, the use of genetic modification of the mosquito genome could provide for a more effective deployment of the sterile insect technique (SIT) against vector populations in the field. Currently, SIT relies on the release of radiation sterilized males, which compete with wild males for mating with wild females. The induction of sterility in males through the genetic manipulation of the mosquito genome, already achieved in a number of other insect species, could eliminate the need for radiation and increase the efficiency of SIT-based strategies. This paper provides an overview of the mechanisms already in use for inducing sterility by transgenesis in Drosophila and other insects, and speculates on possible ways to apply similar approaches to Anopheles mosquitoes.
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Affiliation(s)
- Flaminia Catteruccia
- Imperial College London, Division of Cell and Molecular Biology, Imperial College Road, London SW7 2AZ, UK.
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16
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Tiwari AK, Roy JK. Mutation in Rab11 results in abnormal organization of ommatidial cells and activation of JNK signaling in the Drosophila eye. Eur J Cell Biol 2009; 88:445-60. [PMID: 19473727 DOI: 10.1016/j.ejcb.2009.02.188] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2008] [Revised: 02/16/2009] [Accepted: 02/23/2009] [Indexed: 02/01/2023] Open
Abstract
Rab11(mo), a P insertion line of Rab11 showed degenerated ommatidia and excess cell death in larval/pupal eyes. Here, we demonstrate that Rab11 is essential for normal organization of ommatidial cells and their survival in Drosophila, and a mutation in this gene results in cytoskeleton disruption and activation of JNK signaling in the eye. The spatial organization of various cell types in compound eye, viz., cone, photoreceptor, pigment and bristle cells, were disrupted in Rab11 mutants as revealed by immunostaining of F-actin and adherens and septate junction proteins. Genetic interaction studies indicated that mutation in Rab11 upregulates Drosophila apoptotic genes, rpr, hid and grim. In order to study the pathway that causes excessive cell death in Rab11 mutants, the JNK pathway was chosen and genetic interaction analyses were carried out between Rab11 and candidates of the JNK signaling pathway. A downregulation of JNK signaling rescued the phenotype in Rab11 mutant eyes significantly while overexpression of JNK in the eyes using UAS-eiger, UAS-dtak1 or EP(2)0578, resulted in enhancement of the eye phenotype indicating a link between Rab11 and the JNK signaling pathway.
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Affiliation(s)
- Anand K Tiwari
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221005, India
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17
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Wang L, Zhang Q, Liu B, Han M, Shan B. Challenge and promise: roles for Livin in progression and therapy of cancer. Mol Cancer Ther 2008; 7:3661-9. [PMID: 19074843 DOI: 10.1158/1535-7163.mct-08-0480] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Ling Wang
- Cancer Research Center of the Fourth Hospital, Hebei Medical University, Jiankang Road 12th, Shijiazhuang, Hebei Province, PR China.
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18
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Link N, Chen P, Lu WJ, Pogue K, Chuong A, Mata M, Checketts J, Abrams JM. A collective form of cell death requires homeodomain interacting protein kinase. ACTA ACUST UNITED AC 2007; 178:567-74. [PMID: 17682052 PMCID: PMC2064464 DOI: 10.1083/jcb.200702125] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We examined post-eclosion elimination of the Drosophila wing epithelium in vivo where collective "suicide waves" promote sudden, coordinated death of epithelial sheets without a final engulfment step. Like apoptosis in earlier developmental stages, this unique communal form of cell death is controlled through the apoptosome proteins, Dronc and Dark, together with the IAP antagonists, Reaper, Grim, and Hid. Genetic lesions in these pathways caused intervein epithelial cells to persist, prompting a characteristic late-onset blemishing phenotype throughout the wing blade. We leveraged this phenotype in mosaic animals to discover relevant genes and establish here that homeodomain interacting protein kinase (HIPK) is required for collective death of the wing epithelium. Extra cells also persisted in other tissues, establishing a more generalized requirement for HIPK in the regulation of cell death and cell numbers.
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Affiliation(s)
- Nichole Link
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
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19
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Sato K, Hayashi Y, Ninomiya Y, Shigenobu S, Arita K, Mukai M, Kobayashi S. Maternal Nanos represses hid/skl-dependent apoptosis to maintain the germ line in Drosophila embryos. Proc Natl Acad Sci U S A 2007; 104:7455-60. [PMID: 17449640 PMCID: PMC1854842 DOI: 10.1073/pnas.0610052104] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Nanos (Nos) is an evolutionarily conserved protein essential for the survival of primordial germ cells. In Drosophila, maternal Nos partitions into pole cells and suppresses apoptosis to permit proper germ-line development. However, how this critical event is regulated by Nos has remained elusive. Here, we report that Nos represses apoptosis of pole cells by suppressing translation of head involution defective (hid), a member of the RHG gene family that is required for Caspase activation. In addition, we demonstrate that hid acts in concert with another RHG gene, sickle (skl), to induce apoptosis. Expression of skl is induced in pole cells by maternal tao-1, a ste20-like serine/threonine kinase. Tao-1-dependent skl expression is required to potentiate hid activity. However, skl expression is largely suppressed in normal pole cells. Once the pole cells lack maternal Nos, Tao-1-dependent skl expression is fully activated, suggesting that skl expression is also restricted by Nos. These findings provide the first evidence that the germ line is maintained through the regulated expression of RHG genes.
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Affiliation(s)
- Kimihiro Sato
- *Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Yoshiki Hayashi
- *Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Yuichi Ninomiya
- Division of Translational Research, Research Center for Genomic Medicine, Saitama Medical University, 1397-1 Yamane, Hidaka, Saitama 350-1241, Japan; and
| | - Shuji Shigenobu
- *Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Kayo Arita
- *Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Masanori Mukai
- *Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Satoru Kobayashi
- *Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, Higashiyama, Myodaiji, Okazaki 444-8787, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Honcho, Kawaguchi 332-0012, Japan
- To whom correspondence should be addressed. E-mail:
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20
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Kondo S, Senoo-Matsuda N, Hiromi Y, Miura M. DRONC coordinates cell death and compensatory proliferation. Mol Cell Biol 2006; 26:7258-68. [PMID: 16980627 PMCID: PMC1592896 DOI: 10.1128/mcb.00183-06] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Accidental cell death often leads to compensatory proliferation. In Drosophila imaginal discs, for example, gamma-irradiation induces extensive cell death, which is rapidly compensated by elevated proliferation. Excessive compensatory proliferation can be artificially induced by "undead cells" that are kept alive by inhibition of effector caspases in the presence of apoptotic stimuli. This suggests that compensatory proliferation is induced by dying cells as part of the apoptosis program. Here, we provide genetic evidence that the Drosophila initiator caspase DRONC governs both apoptosis execution and subsequent compensatory proliferation. We examined mutants of five Drosophila caspases and identified the initiator caspase DRONC and the effector caspase DRICE as crucial executioners of apoptosis. Artificial compensatory proliferation induced by coexpression of Reaper and p35 was completely suppressed in dronc mutants. Moreover, compensatory proliferation after gamma-irradiation was enhanced in drice mutants, in which DRONC is activated but the cells remain alive. These results show that the apoptotic pathway bifurcates at DRONC and that DRONC coordinates the execution of cell death and compensatory proliferation.
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Affiliation(s)
- Shu Kondo
- Department of Genetics, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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21
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Parker J. Control of Compartment Size by an EGF Ligand from Neighboring Cells. Curr Biol 2006; 16:2058-65. [PMID: 17055987 DOI: 10.1016/j.cub.2006.08.092] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 08/24/2006] [Accepted: 08/24/2006] [Indexed: 11/25/2022]
Abstract
Insect bodies are subdivided into anterior (A) and posterior (P) compartments: cohesive fields of distinct cell lineage and cell affinity . Like organs in many animal species, compartments can develop to normal sizes despite considerable variation in cell division . This implies that overall compartment dimensions are subject to genetic control, but the mechanisms are unknown. Here, studying Drosophila's embryonic segments, I show that P compartment dimensions depend on epidermal growth factor receptor (EGFR) signaling. I suggest the primary activating ligand is Spitz, emanating from neighboring A compartment cells. Spi/EGFR activity stimulates P compartment cell enlargement and survival, but evidence is presented that Spitz is secreted in limited amounts, so that increasing the number of cells within the P compartment causes the per-cell Spitz level to drop. This leads to compensatory apoptosis and cell-size reductions that preserve compartment dimensions. Conversely, I propose that lowering P compartment cell numbers enhances per-cell Spitz availability; this increases cell survival and cell size, again safeguarding compartment size. The results argue that the gauging of P compartment size is due, at least in part, to cells surviving and growing according to Spi availability. These data offer mechanistic insight into how diffusible molecules control organ size.
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Affiliation(s)
- Joseph Parker
- Division of Cell Biology, Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, United Kingdom.
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22
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Moon NS, Di Stefano L, Dyson N. A gradient of epidermal growth factor receptor signaling determines the sensitivity of rbf1 mutant cells to E2F-dependent apoptosis. Mol Cell Biol 2006; 26:7601-15. [PMID: 16954388 PMCID: PMC1636876 DOI: 10.1128/mcb.00836-06] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The inactivation of retinoblastoma (Rb) family members sensitizes cells to apoptosis. This cell death affects the development of mutant animals and also provides a critical constraint to the malignant potential of Rb mutant tumor cells. The extent of apoptosis caused by the inactivation of Rb is highly cell type and tissue specific, but the underlying reasons for this variation are poorly understood. Here, we characterize a specific time and place during Drosophila melanogaster development where rbf1 mutant cells are exquisitely sensitive to apoptosis. During the third larval instar, many rbf1 mutant cells undergo E2F-dependent cell death in the morphogenetic furrow. Surprisingly, this pattern of apoptosis is not caused by inappropriate cell cycle progression but instead involves the action of Argos, a secreted protein that negatively regulates Drosophila epidermal growth factor receptor (EGFR [DER]) activity. Apoptosis of rbf1 mutant cells is suppressed by the activation of DER, ras, or raf or by the inactivation of argos, sprouty, or gap1, and inhibition of DER strongly enhances apoptosis in rbf1 mutant discs. We show that RBF1 and a DER/ras/raf signaling pathway cooperate in vivo to suppress E2F-dependent apoptosis and that the loss of RBF1 alters a normal program of cell death that is controlled by Argos and DER. These results demonstrate that a gradient of DER/ras/raf signaling that occurs naturally during development provides the contextual signals that determine when and where the inactivation of rbf1 results in dE2F1-dependent apoptosis.
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Affiliation(s)
- Nam-Sung Moon
- Massachusetts General Hospital Cancer Research Center, Harvard Medical School, Building 149, Charlestown, MA 02129, USA
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23
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Means JC, Muro I, Clem RJ. Lack of involvement of mitochondrial factors in caspase activation in a Drosophila cell-free system. Cell Death Differ 2006; 13:1222-34. [PMID: 16322754 PMCID: PMC2575646 DOI: 10.1038/sj.cdd.4401821] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Although mitochondrial proteins play well-defined roles in caspase activation in mammalian cells, the role of mitochondrial factors in caspase activation in Drosophila is unclear. Using cell-free extracts, we demonstrate that mitochondrial factors play no apparent role in Drosophila caspase activation. Cytosolic extract from apoptotic S2 cells, in which caspases were inhibited, induced caspase activation in cytosolic extract from normal S2 cells. Mitochondrial extract did not activate caspases, nor did it influence caspase activation by cytosolic extract. Silencing of Hid, Reaper, or Grim reduced caspase activation by apoptotic cell extract. Furthermore, a peptide representing the amino terminus of Hid was sufficient to activate caspases in cytosolic extract, and this activity was not enhanced by addition of mitochondria or mitochondrial lysate. The Hid peptide also induced apoptosis when introduced into S2 cells. These results suggest that caspase activation in Drosophila is regulated solely by cytoplasmic factors and does not involve any mitochondrial factors.
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Affiliation(s)
- John C. Means
- Molecular, Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506
| | | | - Rollie J. Clem
- Molecular, Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506
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24
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Vazquez-Pianzola P, Hernández G, Suter B, Rivera-Pomar R. Different modes of translation for hid, grim and sickle mRNAs in Drosophila. Cell Death Differ 2006; 14:286-95. [PMID: 16794603 DOI: 10.1038/sj.cdd.4401990] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Protein synthesis is inhibited during apoptosis. However, the translation of many mRNAs still proceeds driven by internal ribosome entry sites (IRESs). Here we show that the 5'UTR of hid and grim mRNAs promote translation of uncapped-mRNA reporters in cell-free embryonic extracts and that hid and grim mRNA 5'UTRs drive IRES-mediated translation. The translation of capped-reporters proceeds in the presence of cap competitor and in extracts where cap-dependent translation is impaired. We show that the endogenous hid and grim mRNAs are present in polysomes of heat-shocked embryos, indicating that cap recognition is not required for translation. In contrast, sickle mRNA is translated in a cap-dependent manner in all these assays. Our results show that IRES-dependent initiation may play a role in the translation of Drosophila proapoptotic genes and suggest a variety of regulatory pathways.
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Affiliation(s)
- P Vazquez-Pianzola
- Max-Planck-Institut für biophysikalische Chemie, Abt. Molekulare Biologie, Am Fassberg 11, Göttingen, Germany
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25
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Adrain C, Brumatti G, Martin SJ. Apoptosomes: protease activation platforms to die from. Trends Biochem Sci 2006; 31:243-7. [PMID: 16595176 DOI: 10.1016/j.tibs.2006.03.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Revised: 02/14/2006] [Accepted: 03/22/2006] [Indexed: 11/23/2022]
Abstract
Apoptosis is orchestrated by members of the caspase family of cysteine proteases that exist as latent pro-enzymes in healthy cells. Caspase-activating platforms, called apoptosomes, initiate caspase activation in metazoans as diverse as nematodes and mammals. Several recent studies have generated new insights into the composition and assembly mechanisms of worm, fly and human apoptosomes.
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Affiliation(s)
- Colin Adrain
- Molecular Cell Biology Laboratory, Department of Genetics, The Smurfit Institute, Trinity College, Dublin 2, Ireland
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26
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Kanao T, Miyachi Y. Exposure to low-dose X-rays promotes peculiar autophagic cell death in Drosophila melanogaster, an effect that can be regulated by the inducible expression of Hml dsRNA. Mutat Res 2006; 595:60-8. [PMID: 16324723 DOI: 10.1016/j.mrfmmm.2005.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2004] [Revised: 09/12/2005] [Accepted: 10/15/2005] [Indexed: 10/25/2022]
Abstract
We previously reported that to induce an early emergence effect with low-dose X-irradiation in Drosophila, exposure during the prepupae stage is necessary. The present study examined the mechanism by which low-dose radiation rapidly eliminates larval cells and activates the formation of the imaginal discs during metamorphosis. Upon exposure to 0.5 Gy X-rays at 2 h after puparium formation (APF), the larval salivary glands swelled and were surrounded by remarkably thick structures containing an acid phosphatase (Acph) enzyme, implicating a peculiar autophagic cell death. TUNEL staining revealed the presence of DNA fragmentations compared with cells from sham controls which remained unchanged until 12 h APF. Additionally, the salivary glands of exposed flies were completely destroyed by 10 h APF. Furthermore, exposure to 0.5 Gy X-rays also facilitated the activity of the engulfment function of dendritic cells (DCs); they were generated in the larval salivary glands, engulfed the cell corpses and finally moved to the fat body. Data from an experiment demonstrating the inducible expression of Hml double-stranded RNA (dsRNA) indicate that a slow rate of engulfment of larval cells results in a longer time to emergence. Thus, the animals subjected to low-dose X-rays activated autophagic processes, resulting in significantly faster adult eclosion.
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Affiliation(s)
- Tomoko Kanao
- Department of Radiological Sciences, International University of Health and Welfare, Kitakanemaru 2600-1, Ohtawara-shi, Tochigi-ken 324-8501, Japan
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27
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Akdemir F, Farkas R, Chen P, Juhasz G, Medved'ová L, Sass M, Wang L, Wang X, Chittaranjan S, Gorski SM, Rodriguez A, Abrams JM. Autophagy occurs upstream or parallel to the apoptosome during histolytic cell death. Development 2006; 133:1457-65. [PMID: 16540507 DOI: 10.1242/dev.02332] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Histolysis refers to a widespread disintegration of tissues that is morphologically distinct from apoptosis and often associated with the stimulation of autophagy. Here, we establish that a component of the apoptosome, and pivotal regulator of apoptosis, is also required for histolytic cell death. Using in vivo and ex vivo assays, we demonstrate a global apoptogenic requirement for dark, the fly ortholog of Apaf1, and show that a required focus of dark(-) organismal lethality maps to the central nervous system. We further demonstrate that the Dark protein itself is a caspase substrate and find that alterations of this cleavage site produced the first hypermorphic point mutation within the Apaf1/Ced-4 gene family. In a model of ;autophagic cell death', dark was essential for histolysis but dispensable for characteristic features of the autophagic program, indicating that the induction of autophagy occurs upstream or parallel to histolytic cell death. These results demonstrate that stimulation of autophagy per se is not a ;killing event' and, at the same time, establish that common effector pathways, regulated by the apoptosome, can underlie morphologically distinct forms of programmed cell death.
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Affiliation(s)
- Fatih Akdemir
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
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28
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Nairz K, Rottig C, Rintelen F, Zdobnov E, Moser M, Hafen E. Overgrowth caused by misexpression of a microRNA with dispensable wild-type function. Dev Biol 2006; 291:314-24. [PMID: 16443211 DOI: 10.1016/j.ydbio.2005.11.047] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Accepted: 11/16/2005] [Indexed: 12/19/2022]
Abstract
MicroRNAs (miRNAs) represent an abundant class of non-coding RNAs that negatively regulate gene expression, primarily at the post-transcriptional level. miRNA genes are frequently located in proximity to fragile chromosomal sites associated with cancers and amplification of a miRNA cluster has been correlated with the etiology of lymphomas and solid tumors. The oncogenic potential of a miRNA polycistron has recently been demonstrated in vivo. Here, we show that misexpression of the Drosophila miRNA mirvana/mir-278 in the developing eye causes massive overgrowth, in part due to inhibition of apoptosis. A single base substitution affecting the mature miRNA blocks the gain-of-function phenotype but is not associated with a detectable reduction-of-function phenotype when homozygous. This result demonstrates that misexpressed miRNAs may acquire novel functions that cause unscheduled proliferation in vivo and thus exemplifies the potential of miRNAs to promote tumor formation.
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Affiliation(s)
- Knud Nairz
- Zoologisches Institut der Universität Zürich, Winterthurer Strasse 190, 8057 Zürich, Switzerland.
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29
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Kanuka H, Hiratou T, Igaki T, Kanda H, Kuranaga E, Sawamoto K, Aigaki T, Okano H, Miura M. Gain-of-function screen identifies a role of the Sec61alpha translocon in Drosophila postmitotic neurotoxicity. Biochim Biophys Acta Gen Subj 2005; 1726:225-37. [PMID: 16243437 DOI: 10.1016/j.bbagen.2005.06.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Revised: 06/06/2005] [Accepted: 06/06/2005] [Indexed: 12/20/2022]
Abstract
To elucidate the intrinsic mechanisms of neurotoxicity induction, including those underlying neural cell death and neurodegeneration, we developed a gain-of-function screen for gene products causing neural cell loss. To identify novel genes with a cell-death-related function in neurons, we screened 4,964 Drosophila GS lines, in which one or two genes from much of the Drosophila genome can be overexpressed. Approximately 0.68% of the GS lines produced phenotypes involving a loss of postmitotic neurons. Of these, we identified and characterized the endd2 gene, which encodes the Drosophila ortholog of Sec61alpha (DSec61alpha), an endoplasmic reticulum protein with protein translocation activity. Ectopic expression of DSec61alpha caused neural cell death accompanied by the accumulation of ubiquitinated proteins, which was mediated by DSec61alpha's translocon activity. This supported our previous observation that the DSec61alpha translocon contributes to expanded polyglutamine-mediated neuronal toxicity, which is also associated with ubiquitinated protein accumulation. These data suggest that the translocon may be a novel component of neural cell death and degeneration pathways. Our approach can be used to identify potential neurotoxic factors within the whole genome, which will increase our understanding of the molecular mechanisms of various types of cell death, including those associated with human neurodegenerative diseases.
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Affiliation(s)
- Hirotaka Kanuka
- Department of Genetics, Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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30
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Abstract
The elimination of cells by programmed cell death is a fundamental event in development where multicellular organisms regulate cell numbers or eliminate cells that are functionally redundant or potentially detrimental to the organism. The evolutionary conservation of the biochemical and genetic regulation of programmed cell death across species has allowed the genetic pathways of programmed cell death determined in lower species, such as the nematode Caenorhabditis elegans and the fruitfly Drosophila melanogaster to act as models to delineate the genetics and regulation of cell death in mammalian cells. These studies have identified cell autonomous and non-autonomous mechanisms that regulate of cell death and reveal that developmental cell death can either be a pre-determined cell fate or the consequence of insufficient cell interactions that normally promote cell survival.
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Affiliation(s)
- Ciara Twomey
- Signal Transduction Laboratory, Biochemistry Department, Biosciences Institute, University College Cork, Cork, Ireland
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31
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Vazquez-Pianzola P, Urlaub H, Rivera-Pomar R. Proteomic analysis of reaper 5' untranslated region-interacting factors isolated by tobramycin affinity-selection reveals a role for La antigen in reaper mRNA translation. Proteomics 2005; 5:1645-55. [PMID: 15789343 DOI: 10.1002/pmic.200401045] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Translational control is a key step in gene expression regulation during apoptosis. To understand the mechanisms of mRNA translation of a pro-apoptotic gene, reaper (rpr), we adapted the tobramycin-aptamer technique described by Hartmuth et al. (Proc. Natl. Acad. Sci. USA 2002, 99, 16719-16724) for the analysis of proteins interacting with rpr 5' untranslated region (UTR). We assembled ribonucleoprotein complexes in vitro using translation extracts derived from Drosophila embryos and purified the RNA-protein complexes for mas spectrometry analysis. We identified the proteins bound to the 5' UTR of rpr. One of them, the La antigen, was validated by RNA-crosslinking experiments using recombinant protein and by the translation efficiency of reporter mRNAs in Drosophila cells after RNAinterference experiments. Our data provide evidence of the involvement of La antigen in the translation of rpr and set a protocol for purification of tagged-RNA-protein complexes from cytoplasmic extracts.
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Affiliation(s)
- Paula Vazquez-Pianzola
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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32
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Abstract
Caspases, a unique family of cysteine proteases, execute programmed cell death (apoptosis). Caspases exist as inactive zymogens in cells and undergo a cascade of catalytic activation at the onset of apoptosis. The activated caspases are subject to inhibition by the inhibitor-of-apoptosis (IAP) family of proteins. This inhibition can be effectively removed by diverse proteins that share an IAP-binding tetrapeptide motif. Recent structural and biochemical studies have revealed the underlying molecular mechanisms for these processes in mammals and in Drosophila. This paper reviews these latest advances.
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Affiliation(s)
- Yigong Shi
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, New Jersey 08544, USA.
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33
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Sorensen EB, Mesner PW. IgH-2 cells: a reptilian model for apoptotic studies. Comp Biochem Physiol B Biochem Mol Biol 2005; 140:163-70. [PMID: 15621521 DOI: 10.1016/j.cbpc.2004.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Revised: 10/01/2004] [Accepted: 10/03/2004] [Indexed: 12/20/2022]
Abstract
Regulation of proper cell number in tissues depends upon a balance between cell proliferation and cell death. The process of apoptosis has thus far been studied in a variety of multicellular organisms from humans to higher plants. In order to broaden our perspective and identify another metazoan system with which to deepen our understanding of the function and evolution of the apoptotic machinery, we have characterized cell death in a reptilian cell line. We show that the death of IgH-2 Iguana (Iguana iguana) heart cells [Clark, H.F., Cohen, M.M., Karzon, D.T., 1970. Characterization of reptilian cell lines established at incubation temperatures of 23 to 36 degrees. Proc. Soc. Exp. Biol. Med. 133, 1039-1047.] is, in response to DNA damaging agents, accompanied by classic morphological changes of apoptosis including detachment from the substrate, cell shrinkage, nuclear pyknosis and externalization of the plasma membrane phospholipid phosphatidylserine. Our biochemical studies show that the death of IgH-2 cells is accompanied by internucleosomal DNA fragmentation and activation of caspases. Our studies with the pan-caspase inhibitor zVAD.fmk implicate caspases in the apoptotic process we observe. This work represents the first detailed molecular and biochemical analysis of apoptosis in cells of an organism of class Reptilia and establishes IgH-2 cells as a suitable model system with which to investigate the phenomenon of caspase dependent apoptosis and the apoptotic machinery in a reptilian model.
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Affiliation(s)
- Erika B Sorensen
- Department of Biological Sciences, University of Wisconsin-Whitewater, 800 W. Main St., Whitewater, WI 53190, USA
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34
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Abstract
Caspases, which are the executioners of apoptosis, comprise two distinct classes, the initiators and the effectors. Although general structural features are shared between the initiator and the effector caspases, their activation, inhibition and release of inhibition are differentially regulated. Biochemical and structural studies have led to important advances in understanding the underlying molecular mechanisms of caspase regulation. This article reviews these latest advances and describes our present understanding of caspase regulation during apoptosis.
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Affiliation(s)
- Stefan J Riedl
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, New Jersey 08544, USA
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35
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Chew SK, Akdemir F, Chen P, Lu WJ, Mills K, Daish T, Kumar S, Rodriguez A, Abrams JM. The Apical Caspase dronc Governs Programmed and Unprogrammed Cell Death in Drosophila. Dev Cell 2004; 7:897-907. [PMID: 15572131 DOI: 10.1016/j.devcel.2004.09.016] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2004] [Revised: 08/31/2004] [Accepted: 09/20/2004] [Indexed: 11/17/2022]
Abstract
Among the seven caspases encoded in the fly genome, only dronc contains a caspase recruitment domain. To assess the function of this gene in development, we produced a null mutation in dronc. Animals lacking zygotic dronc are defective for programmed cell death (PCD) and arrest as early pupae. These mutants present a range of defects, including extensive hyperplasia of hematopoietic tissues, supernumerary neuronal cells, and head involution failure. dronc genetically interacts with the Ced4/Apaf1 counterpart, Dark, and adult structures lacking dronc are disrupted for fine patterning. Furthermore, in diverse models of metabolic injury, dronc- cells are completely insensitive to induction of cell killing. These findings establish dronc as an essential regulator of cell number in development and illustrate broad requirements for this apical caspase in adaptive responses during stress-induced apoptosis.
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Affiliation(s)
- Su Kit Chew
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
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36
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Hernández G, Vázquez-Pianzola P, Sierra JM, Rivera-Pomar R. Internal ribosome entry site drives cap-independent translation of reaper and heat shock protein 70 mRNAs in Drosophila embryos. RNA (NEW YORK, N.Y.) 2004; 10:1783-97. [PMID: 15496524 PMCID: PMC1370666 DOI: 10.1261/rna.7154104] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Translation is a sensitive regulatory step during cellular stress and the apoptosis response. Under such conditions, cap-dependent translation is reduced and internal ribosome entry site (IRES)-dependent translation plays a major role. However, many aspects of how mRNAs are translated under stress remain to be elucidated. Here we report that reaper mRNA, a pro-apoptotic gene from Drosophila melanogaster, is translated in a cap-independent manner. In Drosophila mutant embryos devoid of the eukaryotic initiation factor 4E (eIF4E), reaper transcription is induced and apoptosis proceeds. In vitro translation experiments using wild-type and eIF4E mutant embryonic extracts show that reporter mRNA bearing reaper 5' untranslated region (UTR) is effectively translated in a cap-independent manner. The 5'UTR of reaper exhibits a high degree of similarity with that of Drosophila heat shock protein 70 mRNA, and both display IRES activity. Studies of mRNA association to polysomes in embryos indicate that both reaper and heat shock protein 70 mRNAs are recruited to polysomes under apoptosis or thermal stress. Our data suggest that heat shock protein 70 and reaper, two antagonizing factors in apoptosis, use a similar mechanism for protein synthesis.
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Affiliation(s)
- Greco Hernández
- Max-Planck-Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077-Göttingen, Germany
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37
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Seong YM, Choi JY, Park HJ, Kim KJ, Ahn SG, Seong GH, Kim IK, Kang S, Rhim H. Autocatalytic Processing of HtrA2/Omi Is Essential for Induction of Caspase-dependent Cell Death through Antagonizing XIAP. J Biol Chem 2004; 279:37588-96. [PMID: 15201285 DOI: 10.1074/jbc.m401408200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A mature form of nuclear-encoded mitochondrial serine protease HtrA2/Omi is pivotal in regulating apoptotic cell death; however, the underlying mechanism of the processing event of HtrA2/Omi and its relevant biological function remain to be clarified. Here, we describe that HtrA2/Omi is autocatalytically processed to the 36-kDa protein fragment, which is required for the cytochrome c-dependent caspase activation along with neutralizing XIAP-mediated inhibition of caspases through interaction with XIAP, eventually promoting apoptotic cell death. We have shown that the autocatalytic processing of HtrA2/Omi occurs via an intermolecular event, demonstrated by incubating an in vitro translated HtrA2/Omi (S306A) mutant with the enzymatically active glutathione S-transferase-HtrA2/Omi protein. Using N-terminal amino acid sequencing and mutational analysis, we identified that the autocatalytic cleavage site is the carboxyl side of alanine 133 of HtrA2/Omi, resulting in exposure of an inhibitor of apoptosis protein binding motif in its N terminus. Our study provides evidence that the autocatalytic processing of HtrA2/Omi is crucial for regulating HtrA2/Omi-mediated apoptotic cell death.
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Affiliation(s)
- Young-Mo Seong
- Graduate School of Biotechnology, Korea University, Seoul 136-701, Korea
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38
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Abstract
Apoptosis plays important roles in many facets of normal physiology in animal species, including programmed cell death associated with fetal development or metamorphosis, tissue homeostasis, immune cell education, and some aspects of aging. Defects in the regulation of apoptosis contribute to multiple diseases associated with either inappropriate cell loss or pathological cell accumulation. Host-pathogen interactions have additionally provided evolutionary pressure for apoptosis as a defense mechanism against viruses and microbes, sometimes linking apoptosis mechanisms with inflammatory responses. To a large extent, the apoptosis machinery can be viewed as a network, with different nodes connected by physical interactions of evolutionarily conserved domains. These domains can serve as signatures for identification of proteins involved in the network. In particular, the caspase recruitment domains (CARDs); death effector domains (DEDs); death domains (DDs); BIR (baculovirus IAP repeat) domains of inhibitor of apoptosis proteins (IAPs); Bcl-2 family proteins; caspase protease domains; and endonuclease-associated CIDE (cell death-inducing DFF45-like effector) domains are found in common in proteins involved in apoptosis. In the genomes of mammals, genes encoding proteins that carry one or more of these signature domains are often present in multiple copies, making up diverse gene families that permit tissue-specific and highly regulated control of cell life and death decisions through combinations of stimulus-specific gene expression and complex protein interaction networks. In this Review, we organize the repertoire of apoptosis proteins of humans into domain families, drawing comparisons with homologs in other vertebrate and invertebrate animal species, and discuss some of the functional implications of these findings.
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Affiliation(s)
- John C Reed
- The Burnham Institute, La Jolla, CA 92037, USA.
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Salvesen GS, Abrams JM. Caspase activation - stepping on the gas or releasing the brakes? Lessons from humans and flies. Oncogene 2004; 23:2774-84. [PMID: 15077141 DOI: 10.1038/sj.onc.1207522] [Citation(s) in RCA: 194] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The central components of the execution phase of apoptosis in worms, flies, and humans are members of the caspase protease family. Work in Drosophila and mammalian systems has revealed a web of interactions that govern the activity of these proteases, and two fundamental control points have been identified. These are zymogen activation - the process that converts a latent caspase into its active form, and inhibition of the resulting active protease. In humans, the driving force for caspase activity is activation of the zymogens, but in Drosophila, a major thrust is derepression of caspase inhibitors. In this review, we consider evidence for these two distinct events in terms of the regulation of caspase activity. This sets the scene for therapy to reinstate the normal death mechanisms that have been overcome in a cancer cell's quest for immortality.
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Affiliation(s)
- Guy S Salvesen
- Program in Apoptosis and Cell Death Research, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92122, USA.
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40
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Chen P, Ho SI, Shi Z, Abrams JM. Bifunctional killing activity encoded by conserved reaper proteins. Cell Death Differ 2004; 11:704-13. [PMID: 15002042 DOI: 10.1038/sj.cdd.4401406] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Drosophila activators of apoptosis mapping to the Reaper region function, in part, by antagonizing IAP proteins through a shared RHG motif. We isolated Reaper from the Blowfly L. cuprina, which triggered extensive apoptosis in Drosophila cells. Conserved regions of Reaper were tested in the context of GFP fusions and a second killing activity, distinct from the RHG, was identified. A 20 amino-acid peptide, designated R3, conferred targeting to a focal compartment and promoted membrane blebbing. Killing by the R3 fragment did not correlate with translational suppression or with reduced DIAP1 levels. Likewise, R3-induced cell deaths were only modestly suppressed by silencing of Dronc and involved no detectable association with DIAP1. Instead, a second IAP-binding domain, distinct from the R3, was identified at the C terminus of Reaper that bound to DIAP1 but failed to trigger apoptosis. Collectively, these findings are inconsistent with single effector models for cell killing by Reaper and suggest, instead, that Reaper encodes conserved bifunctional death activities that propagate through distinct effector pathways.
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Affiliation(s)
- P Chen
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
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41
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Deflorian G, Tiso N, Ferretti E, Meyer D, Blasi F, Bortolussi M, Argenton F. Prep1.1 has essential genetic functions in hindbrain development and cranial neural crest cell differentiation. Development 2004; 131:613-27. [PMID: 14711874 DOI: 10.1242/dev.00948] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In this study we analysed the function of the Meinox gene prep1.1 during zebrafish development. Meinox proteins form heterotrimeric complexes with Hox and Pbx members, increasing the DNA binding specificity of Hox proteins in vitro and in vivo. However, a role for a specific Meinox protein in the regulation of Hox activity in vivo has not been demonstrated. In situ hybridization showed that prep1.1 is expressed maternally and ubiquitously up to 24 hours post-fertilization (hpf), and restricted to the head from 48 hpf onwards. Morpholino-induced prep1.1 loss-of-function caused significant apoptosis in the CNS. Hindbrain segmentation and patterning was affected severely, as revealed by either loss or defective expression of several hindbrain markers (foxb1.2/mariposa, krox20, pax2.1 and pax6.1), including anteriorly expressed Hox genes (hoxb1a, hoxa2 and hoxb2), the impaired migration of facial nerve motor neurons, and the lack of reticulospinal neurons (RSNs) except Mauthner cells. Furthermore, the heads of prep1.1 morphants lacked all pharyngeal cartilages. This was not caused by the absence of neural crest cells or their impaired migration into the pharyngeal arches, as shown by expression of dlx2 and snail1, but by the inability of these cells to differentiate into chondroblasts. Our results indicate that prep1.1 has a unique genetic function in craniofacial chondrogenesis and, acting as a member of Meinox-Pbc-Hox trimers, it plays an essential role in hindbrain development.
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Affiliation(s)
- Gianluca Deflorian
- Dipartimento di Biologia, Universita' di Padova, Via U. Bassi 58/B, 35131 Padova, Italy
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42
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Claveria C, Martinez-A C, Torres M. A Bax/Bak-independent Mitochondrial Death Pathway Triggered by Drosophila Grim GH3 Domain in Mammalian Cells. J Biol Chem 2004; 279:1368-75. [PMID: 14551193 DOI: 10.1074/jbc.m309819200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Grim encodes a protein required for programmed cell death in Drosophila, whose proapoptotic activity is conserved in mammalian cells. Two proapoptotic domains are relevant for Grim killing function; the N-terminal region, which induces apoptosis by disrupting inhibitor of apoptosis protein (IAP) blockage of caspase activity, and the internal GH3 domain, which triggers a mitochondrial pathway. We explored the role of these two domains in heterologous killing of mammalian cells by Grim. The GH3 domain is essential for Grim proapoptotic activity in mouse cells, whereas the N-terminal domain is dispensable. The GH3 domain is required and sufficient for Grim targeting to mitochondria and for cytochrome c release in a caspase- and N-terminal-independent, IAP-insensitive manner. These Grim GH3 activities do not require Bax or Bak function, revealing GH3 activity as the first proapoptotic stimulus able to trigger the mitochondrial death pathway in mammalian cells in the absence of multidomain proapoptotic Bcl-2 proteins.
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Affiliation(s)
- Cristina Claveria
- Departamento de Inmunologiía y Oncología, Centro Nacional de Biotecnología/Consejo Superior de Investigaciones Cientiíficas, Universidad Autónoma de Madrid Campus de Cantoblanco, E-28049 Madrid, Spain
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43
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Jia J, Zhang W, Wang B, Trinko R, Jiang J. The Drosophila Ste20 family kinase dMST functions as a tumor suppressor by restricting cell proliferation and promoting apoptosis. Genes Dev 2003; 17:2514-9. [PMID: 14561774 PMCID: PMC218145 DOI: 10.1101/gad.1134003] [Citation(s) in RCA: 321] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In a genetic screen for mutations that restrict cell growth and organ size, we identified a new tumor suppressor gene, dMST, which encodes the Drosophila homolog of the mammalian Ste20 kinase family members MST1 and MST2. Loss-of-function mutations in dMST result in overgrown tissues containing more cells of normal size. dMST mutant cells exhibit elevated levels of Cyclin E and DIAP1, increased cell growth and proliferation, and impaired apoptosis. dMST forms a complex with Sav and Wts, two tumor suppressors also implicated in regulating both cell proliferation and apoptosis, suggesting that they act in common pathways.
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Affiliation(s)
- Jianhang Jia
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9133, USA.
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44
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Mergliano J, Minden JS. Caspase-independent cell engulfment mirrors cell death pattern in Drosophila embryos. Development 2003; 130:5779-89. [PMID: 14534140 DOI: 10.1242/dev.00824] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Programmed cell death plays an essential role during Drosophila embryonic development. A stereotypic series of cellular changes occur during apoptosis, most of which are initiated by a caspase cascade that is triggered by a trio of proteins, RPR, HID and GRIM. The final step in apoptosis is engulfment of the cell corpse. To monitor cell engulfment in vivo, we developed a fluorogenic beta-galactosidase substrate that is cleaved by an endogenous, lysosomal beta-galactosidase activity. The pattern of cell engulfment in wild-type embryos correlated well with the known pattern of apoptosis. Surprisingly, the pattern of cell engulfment persisted in apoptosis-deficient embryos. We provide evidence for a caspase-independent engulfment process that affects the majority of cells expected to die in developing Drosophila embryos.
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Affiliation(s)
- Jaime Mergliano
- Department of Biological Sciences and Science and Technology Center for Light Microscope Imaging and Biotechnology, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
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45
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Hegde R, Srinivasula SM, Datta P, Madesh M, Wassell R, Zhang Z, Cheong N, Nejmeh J, Fernandes-Alnemri T, Hoshino SI, Alnemri ES. The polypeptide chain-releasing factor GSPT1/eRF3 is proteolytically processed into an IAP-binding protein. J Biol Chem 2003; 278:38699-706. [PMID: 12865429 DOI: 10.1074/jbc.m303179200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Smac/Diablo and HtrA2/Omi are inhibitors of apoptosis (IAP)-binding proteins released from the mitochondria of human cells during apoptosis and regulate apoptosis by liberating caspases from IAP inhibition. Here we describe the identification of a proteolytically processed isoform of the polypeptide chain-releasing factor GSPT1/eRF3 protein, which functions in translation, as a new IAP-binding protein. In common with other IAP-binding proteins, the processed GSPT1 protein harbors a conserved N-terminal IAP-binding motif (AKPF). Additionally, processed GSPT1 interacts biochemically with IAPs and could promote caspase activation, IAP ubiquitination and apoptosis. The IAP-binding motif of the processed GSPT1 is absolutely required for these activities. Our findings are consistent with a model whereby processing of GSPT1 into the IAP-binding isoform could potentiate apoptosis by liberating caspases from IAP inhibition, or target IAPs and the processed GSPT1 for proteasome-mediated degradation.
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Affiliation(s)
- Ramesh Hegde
- Center for Apoptosis Research and the Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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46
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Chandrasekaran V, Beckendorf SK. senseless is necessary for the survival of embryonic salivary glands in Drosophila. Development 2003; 130:4719-28. [PMID: 12925597 DOI: 10.1242/dev.00677] [Citation(s) in RCA: 37] [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
Apoptosis in developing Drosophila embryos is rare and confined to specific groups of cells. We explain how one organ, salivary glands, of Drosophila embryos avoids apoptosis. senseless (sens), a Zn-finger transcription factor, is expressed in the salivary primordium and later in the differentiated salivary glands. The regulation of sens expression in the salivary placodes is more complex than observed in the embryonic PNS. We have shown that sens expression is initiated in the salivary placodes by fork head (fkh), a winged helix transcription factor. The expression of sens is maintained in the salivary glands by fkh and by daughterless (da), a bHLH family member. In this study, we have identified sage, a salivary-specific bHLH protein as a new heterodimeric partner for da protein in the salivary glands. In addition, our data suggest that sage RNAi embryos have a phenotype similar to sens and that sage is necessary to maintain expression of sens in the embryonic salivary glands. Furthermore, we show that in the salivary glands, sens acts as an anti-apoptotic protein by repressing reaper and possibly hid.
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Affiliation(s)
- Vidya Chandrasekaran
- Department of Molecular and Cell Biology, 401 Barker Hall, University of California, Berkeley, CA 94720, USA
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47
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Van Hoof C, Goris J. Phosphatases in apoptosis: to be or not to be, PP2A is in the heart of the question. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1640:97-104. [PMID: 12729918 DOI: 10.1016/s0167-4889(03)00029-6] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Protein phosphatase type 2A (PP2A) is a major Ser/Thr phosphatase involved in several cellular signal transduction pathways. In this review, we will focus on recent progress concerning the role of PP2A in apoptotic signalling. Since PP2A activates pro-apoptotic and inhibits anti-apoptotic proteins of the Bcl-2 family, we conclude that PP2A has a positive regulatory function in apoptosis. However, in Drosophila, a specific subset of the PP2A holoenzyme family, containing B'/PR61 as third regulatory subunit, is inhibitory for apoptosis, suggesting different regulatory mechanisms and substrates in different species. Moreover, PP2A acts not only upstream as a regulator of the apoptotic signal transduction pathway but also downstream as a substrate of effector caspases. Hence, PP2A is involved in the regulation as well as in the cellular response of apoptosis. Probably, various PP2A holoenzymes with distinct regulatory subunits specifically target different apoptotic substrates. This could explain the implication of PP2A at several levels of the apoptotic signal transduction pathway. Finally, some viral proteins such as adenovirus E4orf4 and simian virus small t target PP2A to alter its activity, resulting in induction of apoptosis as a regulatory mechanism to enhance virus spread.
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Affiliation(s)
- Christine Van Hoof
- Afdeling Biochemie, Faculteit Geneeskunde, Campus Gasthuisberg O&N, Katholieke Universiteit Leuven, Herestraat 49, B-3000 Leuven, Belgium
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48
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Abstract
Cell migration and programmed cell death are essential components of animal development and homeostasis, and the germ cells of Drosophila provide a simple genetic system to study the molecular mechanisms that govern these important cellular processes. Detailed descriptions of germ cell migration in Drosophila were accomplished long ago, but most genetic and molecular analyses of the process have occurred within the past 10 years. A few of the genes required for germ cell migration have been identified, and a very interesting picture is emerging. However, a process as complex as cell migration must involve the functions of many more molecules. In addition, cell migration and cell death mechanisms are often linked, as it is important to eliminate cells that are misplaced and could present a danger to the organism. In Drosophila, genes involved in germ cell migration can also affect programmed cell death. Currently, very little is known about how germ cells ectopic to the gonads are eliminated. To date, only four genes have been reported with roles in germ cell death, and three of these have additional functions in germ cell pathfinding. The nature of the cell death program has not been elucidated. Here, I provide a brief review of Drosophila germ cell migration and programmed cell death at both the descriptive and molecular levels. Many questions remain to be answered, but advances made in recent years are providing useful insights into these critical biological phenomena.
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Affiliation(s)
- Clark R Coffman
- Department of Zoology and Genetics, Iowa State University, Ames, Iowa 50011, USA.
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49
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Sogame N, Kim M, Abrams JM. Drosophila p53 preserves genomic stability by regulating cell death. Proc Natl Acad Sci U S A 2003; 100:4696-701. [PMID: 12672954 PMCID: PMC153618 DOI: 10.1073/pnas.0736384100] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
When animal cells are exposed to stressful conditions, the tumor suppressor protein p53 restrains growth by promoting an arrested cell cycle or initiating a cell death program. How these distinct fates are specified through the action of a single protein is not known. To study its functions in vivo we produced a targeted mutation at the Drosophila p53 (Dmp53) locus. We show that Dmp53 is required for damage-induced apoptosis but not for cell-cycle arrest. Dmp53 function is also required for damage-induced transcription of two tightly linked cell death activators, reaper and sickle. When challenged by ionizing radiation, Dmp53 mutants exhibit radiosensitivity and genomic instability. Hence, elevated mutant loads were not caused by defective checkpoint functions but instead correlated with failures in p53-associated cell death. Our studies support the notion that core ancestral functions of the p53 gene family are intimately coupled to cell death as an adaptive response to maintain genomic stability.
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Affiliation(s)
- Naoko Sogame
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9039, USA
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50
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Affiliation(s)
- Mireia Gómez-Angelats
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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