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Kurze C, Le Conte Y, Dussaubat C, Erler S, Kryger P, Lewkowski O, Müller T, Widder M, Moritz RFA. Nosema Tolerant Honeybees (Apis mellifera) Escape Parasitic Manipulation of Apoptosis. PLoS One 2015; 10:e0140174. [PMID: 26445372 PMCID: PMC4596554 DOI: 10.1371/journal.pone.0140174] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 09/21/2015] [Indexed: 11/18/2022] Open
Abstract
Apoptosis is not only pivotal for development, but also for pathogen defence in multicellular organisms. Although numerous intracellular pathogens are known to interfere with the host’s apoptotic machinery to overcome this defence, its importance for host-parasite coevolution has been neglected. We conducted three inoculation experiments to investigate in the apoptotic respond during infection with the intracellular gut pathogen Nosema ceranae, which is considered as potential global threat to the honeybee (Apis mellifera) and other bee pollinators, in sensitive and tolerant honeybees. To explore apoptotic processes in the gut epithelium, we visualised apoptotic cells using TUNEL assays and measured the relative expression levels of subset of candidate genes involved in the apoptotic machinery using qPCR. Our results suggest that N. ceranae reduces apoptosis in sensitive honeybees by enhancing inhibitor of apoptosis protein-(iap)-2 gene transcription. Interestingly, this seems not be the case in Nosema tolerant honeybees. We propose that these tolerant honeybees are able to escape the manipulation of apoptosis by N. ceranae, which may have evolved a mechanism to regulate an anti-apoptotic gene as key adaptation for improved host invasion.
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Affiliation(s)
- Christoph Kurze
- Institute for Biology, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Yves Le Conte
- UR 406 Abeilles et Environnement, INRA, Avignon, France
| | | | - Silvio Erler
- Institute for Biology, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Per Kryger
- Department of Agroecology, Aarhus University, Flakkebjerg, Denmark
| | - Oleg Lewkowski
- Institute for Biology, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Thomas Müller
- Department of Internal Medicine IV, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Miriam Widder
- Department of Internal Medicine IV, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Robin F A Moritz
- Institute for Biology, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany; German Institute for Integrative Biodiversity Research (iDiv), Leipzig, Germany; University of Pretoria, Department of Zoology and Entomology, Pretoria, South Africa
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2
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Thomas SE, Malzer E, Ordóñez A, Dalton LE, van T Wout EFA, Liniker E, Crowther DC, Lomas DA, Marciniak SJ. p53 and translation attenuation regulate distinct cell cycle checkpoints during endoplasmic reticulum (ER) stress. J Biol Chem 2013; 288:7606-7617. [PMID: 23341460 PMCID: PMC3597802 DOI: 10.1074/jbc.m112.424655] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 01/04/2013] [Indexed: 01/25/2023] Open
Abstract
Cell cycle checkpoints ensure that proliferation occurs only under permissive conditions, but their role in linking nutrient availability to cell division is incompletely understood. Protein folding within the endoplasmic reticulum (ER) is exquisitely sensitive to energy supply and amino acid sources because deficiencies impair luminal protein folding and consequently trigger ER stress signaling. Following ER stress, many cell types arrest within the G(1) phase, although recent studies have identified a novel ER stress G(2) checkpoint. Here, we report that ER stress affects cell cycle progression via two classes of signal: an early inhibition of protein synthesis leading to G(2) delay involving CHK1 and a later induction of G(1) arrest associated both with the induction of p53 target genes and loss of cyclin D(1). We show that substitution of p53/47 for p53 impairs the ER stress G(1) checkpoint, attenuates the recovery of protein translation, and impairs induction of NOXA, a mediator of cell death. We propose that cell cycle regulation in response to ER stress comprises redundant pathways invoked sequentially first to impair G(2) progression prior to ultimate G(1) arrest.
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Affiliation(s)
- Sally E Thomas
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Elke Malzer
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom; Department of Genetics, University of Cambridge, Downing Site, Cambridge CB2 3EH, United Kingdom
| | - Adriana Ordóñez
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Lucy E Dalton
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Emily F A van T Wout
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Elizabeth Liniker
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Damian C Crowther
- Department of Genetics, University of Cambridge, Downing Site, Cambridge CB2 3EH, United Kingdom
| | - David A Lomas
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Stefan J Marciniak
- Department of Medicine and Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, United Kingdom.
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3
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A dp53/JNK-dependant feedback amplification loop is essential for the apoptotic response to stress in Drosophila. Cell Death Differ 2011; 19:451-60. [PMID: 21886179 DOI: 10.1038/cdd.2011.113] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Programmed cell death (apoptosis) is a conserved process aimed to eliminate unwanted cells. The key molecules are a group of proteases called caspases that cleave vital proteins, which leads to the death of cells. In Drosophila, the apoptotic pathway is usually represented as a cascade of events in which an initial stimulus activates one or more of the proapoptotic genes (hid, rpr, grim), which in turn activate caspases. In stress-induced apoptosis, the dp53 (Drosophila p53) gene and the Jun N-terminal kinase (JNK) pathway function upstream in the activation of the proapoptotic genes. Here we demonstrate that dp53 and JNK also function downstream of proapoptotic genes and the initiator caspase Dronc (Drosophila NEDD2-like caspase) and that they establish a feedback loop that amplifies the initial apoptotic stimulus. This loop plays a critical role in the apoptotic response because in its absence there is a dramatic decrease in the amount of cell death after a pulse of the proapoptotic proteins Hid and Rpr. Thus, our results indicate that stress-induced apoptosis in Drosophila is dependant on an amplification loop mediated by dp53 and JNK. Furthermore, they also demonstrate a mechanism of mutual activation of proapoptotic genes.
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4
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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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5
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Malzer E, Daly ML, Moloney A, Sendall TJ, Thomas SE, Ryder E, Ryoo HD, Crowther DC, Lomas DA, Marciniak SJ. Impaired tissue growth is mediated by checkpoint kinase 1 (CHK1) in the integrated stress response. J Cell Sci 2010; 123:2892-900. [PMID: 20682638 DOI: 10.1242/jcs.070078] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The integrated stress response (ISR) protects cells from numerous forms of stress and is involved in the growth of solid tumours; however, it is unclear how the ISR acts on cellular proliferation. We have developed a model of ISR signalling with which to study its effects on tissue growth. Overexpression of the ISR kinase PERK resulted in a striking atrophic eye phenotype in Drosophila melanogaster that could be rescued by co-expressing the eIF2alpha phosphatase GADD34. A genetic screen of 3000 transposon insertions identified grapes, the gene that encodes the Drosophila orthologue of checkpoint kinase 1 (CHK1). Knockdown of grapes by RNAi rescued eye development despite ongoing PERK activation. In mammalian cells, CHK1 was activated by agents that induce ER stress, which resulted in a G2 cell cycle delay. PERK was both necessary and sufficient for CHK1 activation. These findings indicate that non-genotoxic misfolded protein stress accesses DNA-damage-induced cell cycle checkpoints to couple the ISR to cell cycle arrest.
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Affiliation(s)
- Elke Malzer
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research (CIMR), Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK
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6
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Rosby R, Cui Z, Rogers E, deLivron MA, Robinson VL, DiMario PJ. Knockdown of the Drosophila GTPase nucleostemin 1 impairs large ribosomal subunit biogenesis, cell growth, and midgut precursor cell maintenance. Mol Biol Cell 2009; 20:4424-34. [PMID: 19710426 DOI: 10.1091/mbc.e08-06-0592] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Mammalian nucleostemin (NS) is a nucleolar guanosine triphosphate-binding protein implicated in cell cycle progression, stem cell proliferation, and ribosome assembly. Drosophila melanogaster contains a four-member nucleostemin family (NS1-4). NS1 is the closest orthologue to human NS; it shares 33% identity and 67% similarity with human NS. We show that NS1 has intrinsic GTPase and ATPase activity and that it is present within nucleoli of most larval and adult cells. Endogenous NS1 and lightly expressed green fluorescent protein (GFP)-NS1 enrich within the nucleolar granular regions as expected, whereas overexpressed GFP-NS1 localized throughout the nucleolus and nucleoplasm, and to several transcriptionally active interbands of polytene chromosomes. Severe overexpression correlated with the appearance of melanotic tumors and larval/pupal lethality. Depletion of 60% of NS1 transcripts also lead to larval and pupal lethality. NS1 protein depletion>95 correlated with the loss of imaginal island (precursor) cells in the larval midgut and to an apparent block in the nucleolar release of large ribosomal subunits in terminally differentiated larval midgut polyploid cells. Ultrastructural examination of larval Malpighian tubule cells depleted for NS1 showed a loss of cytoplasmic ribosomes and a concomitant appearance of cytoplasmic preautophagosomes and lysosomes. We interpret the appearance of these structures as indicators of cell stress response.
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Affiliation(s)
- Raphyel Rosby
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803-1715, USA
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7
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STAT92E is a positive regulator of Drosophila inhibitor of apoptosis 1 (DIAP/1) and protects against radiation-induced apoptosis. Proc Natl Acad Sci U S A 2008; 105:13805-10. [PMID: 18779571 DOI: 10.1073/pnas.0806291105] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The proapoptotic factors Reaper, Hid, Grim, and Sickle regulate apoptosis in Drosophila by inhibiting the antiapoptotic factor DIAP1 (Drosophila inhibitor of apoptosis 1). Heat, UV light, x-rays, and developmental signals can all increase the proapoptotic factors, but the control of transcription of the diap1 gene is unclear. We show that in imaginal discs the single Drosophila STAT protein (STAT92E) when activated can directly increase DIAP1 through binding to STAT DNA-binding sites in the diap1 promoter. The STAT92E contribution to DIAP1 production is required for cell survival after x-irradiation but not under unstressed conditions. Because DIAP1 prevents apoptosis after a variety of stresses, STAT92E may have a role in regulating stress responses in general.
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8
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Srinivasula SM, Gupta S, Datta P, Zhang Z, Hegde R, Cheong N, Fernandes-Alnemri T, Alnemri ES. Inhibitor of apoptosis proteins are substrates for the mitochondrial serine protease Omi/HtrA2. J Biol Chem 2003; 278:31469-72. [PMID: 12835328 DOI: 10.1074/jbc.c300240200] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mature serine protease Omi/HtrA2 is released from the mitochondria into the cytosol during apoptosis. Suppression of Omi/HtrA2 by RNA interference in human cell lines reduces cell death in response to TRAIL and etoposide. In contrast, ectopic expression of mature wildtype Omi/HtrA2, but not an active site mutant, induces potent caspase activation and apoptosis. In vitro assays demonstrated that Omi/HtrA2 could degrade inhibitor of apoptosis proteins (IAPs). Consistent with this observation, increased expression of Omi/HtrA2 in cells increases degradation of XIAP, while suppression of Omi/HtrA2 by RNA interference has an opposite effect. Combined, our data demonstrate that IAPs are substrates for Omi/HtrA2, and their degradation could be a mechanism by which the mitochondrially released Omi/HtrA2 activates caspases during apoptosis.
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Affiliation(s)
- Srinivasa M Srinivasula
- 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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9
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Abstract
Apoptosis, or programmed cell death, is a phenomenon that is integral to development and cellular homeostasis. In the last decade, many of the essential molecules and pathways that control this phenomenon have been elucidated. Because apoptosis is involved in almost all physiologic and pathologic processes, the understanding of its regulation has significant clinical ramifications. This article reviews the basic understanding of programmed cell death in terms of the effector molecules and pathways. Areas of interest to plastic surgeons are reviewed as they pertain to apoptosis. These areas include allotransplantation, craniofacial and limb development, flap survival, wound healing, stem cell science, and physiologic aging. These topics have not yet been studied extensively in the context of cell death. In this review article, other related and more comprehensively studied scientific areas are used to extrapolate their relevance to apoptosis. Apoptosis is an increasingly better understood process. With the knowledge of how programmed cell death is controlled, combined with the improved ability to effectively perform genetic manipulation and to design specific chemical approaches, apoptosis is gaining clinical relevance. In the next few years, practical clinical breakthroughs will help the medical community to understand the phenomenon of apoptosis and how it relates to the needs of patients.
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Affiliation(s)
- Brian R Gastman
- Department of Otolaryngology, University of Pittsburgh Shool of Medicine, Pa, USA.
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10
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Abstract
Cell death in Drosophila is regulated by many of the same signals that control apoptosis in mammalian systems. For all the three major cell death pathways that have been described in humans, homologous components have been identified in Drosophila. Here we report that distinct pathways mediate UV-induced apoptosis at different developmental stages in the Drosophila embryo. In midstage embryos, UVC irradiation induces reaper expression and cell death through a mei-41(dATM)-dependent pathway; UVB does not have the same effect. In contrast, in pregastrulation embryos, both UVB and UVC promote apoptosis via transcriptional induction of the Drosophila Apaf-1/ced-4 homolog. This early UV response requires E2F but not mei-41 function and appears to be independent of DNA damage.
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Affiliation(s)
- Lei Zhou
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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11
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Sathasivam S, Ince PG, Shaw PJ. Apoptosis in amyotrophic lateral sclerosis: a review of the evidence. Neuropathol Appl Neurobiol 2001; 27:257-74. [PMID: 11532157 DOI: 10.1046/j.0305-1846.2001.00332.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease primarily affecting the upper and lower motor neurones of the central nervous system. Recently, a lot of interest has been generated by the possibility that a mechanism of programmed cell death, termed apoptosis, is responsible for the motor neurone degeneration in this condition. Apoptosis is regulated through a variety of different pathways which interact and eventually lead to controlled cell death. Apart from genetic regulation, factors involved in the control of apoptosis include death receptors, caspases, Bcl-2 family of oncoproteins, inhibitor of apoptosis proteins (IAPs), inhibitors of IAPs, the p53 tumour suppressor protein and apoptosis-related molecules. The first part of this article will give an overview of the current knowledge of apoptosis. In the second part of this review, we will examine in detail the evidence for and against the contribution of apoptosis in motor neurone cell death in ALS, looking at cellular-, animal- and human post-mortem tissue-based models. In a chronic neurodegenerative disease such as ALS, conclusive evidence of apoptosis is likely to be difficult to detect, given the rapidity of the apoptotic cell death process in relation to the relatively slow time course of the disease. Although a complete picture of motor neurone death in ALS has not been fully elucidated, there is good and compelling evidence that a programmed cell death pathway operates in this disorder. The strongest body of evidence supporting this comes from the findings that, in ALS, changes in the levels of members of the Bcl-2 family of oncoproteins results in a predisposition towards apoptosis, there is increased expression or activation of caspases-1 and -3, and the dying motor neurones in human cases exhibit morphological features reminiscent of apoptosis. Further supporting evidence comes from the detection of apoptosis-related molecules and anti-Fas receptor antibodies in human cases of ALS. However, the role of the p53 protein in cell death in ALS is at present unclear. An understanding of the mechanism of programmed cell death in ALS may provide important clues for areas of potential therapeutic intervention for neuroprotection in this devastating condition.
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Affiliation(s)
- S Sathasivam
- Department of Neurology, University of Sheffield, Sheffield, UK
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12
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Kelley ML, Winge P, Heaney JD, Stephens RE, Farell JH, Van Beneden RJ, Reinisch CL, Lesser MP, Walker CW. Expression of homologues for p53 and p73 in the softshell clam (Mya arenaria), a naturally-occurring model for human cancer. Oncogene 2001; 20:748-58. [PMID: 11314008 DOI: 10.1038/sj.onc.1204144] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2000] [Revised: 11/22/2000] [Accepted: 11/29/2000] [Indexed: 01/10/2023]
Abstract
Homologues for human p53 (Hsp53) and p73 (Hsp73) genes were cloned and expression patterns for their corresponding proteins analysed in tissues from normal and leukemic softshell clams (Mya arenaria). These are the first structural and functional data for p53 and p73 cDNAs and gene products in a naturally occurring, non-mammalian disease model. Core sequence of the predicted clam p53 (Map53) and p73 (Map73) proteins is virtually identical and includes the following highly conserved regions: the transcriptional activation domain (TAD), MDM2 binding site, ATM phosphorylation site, proline rich domain, DNA binding domains (DBDs) II-V, nuclear import and export signals and the tetramerization domain. The core sequence is a structural mosaic of the corresponding human proteins, with the TAD and DBDs resembling Hsp53 and Hsp73, respectively. This suggests that Map53 and Map73 proteins may function similarly to human proteins. Clam proteins have either a short (Map53) or long (Map73) C-terminal extension. These features suggest that Map53 and Map73 may be alternate splice variants of a p63/p73-like ancestral gene. Map73 is significantly upregulated in hemocytes and adductor muscle from leukemic clams. In leukemic hemocytes, both proteins are absent from the nucleus and sequestered in the cytoplasm. This observation suggests that a non-mutational p53/p73-dependent mechanism may be involved in the clam disease. Further studies of these gene products in clams may reveal p53/p73-related molecular mechanisms that are held in common with Burkitt's lymphoma or other human cancers.
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Affiliation(s)
- M L Kelley
- Department of Biochemistry, Microbiology and Molecular Biology and School of Marine Science, University of Maine, Orono, ME 04469-5751, USA
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13
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Abstract
The past year has been a spectacular one for Drosophila research. The sequencing and annotation of the Drosophila melanogaster genome has allowed a comprehensive analysis of the first three eukaryotes to be sequenced-yeast, worm and fly-including an analysis of the fly's influences as a model for the study of human disease. This year has also seen the initiation of a full-length cDNA sequencing project and the first analysis of Drosophila development using high-density DNA microarrays containing several thousand Drosophila genes. For the first time homologous recombination has been demonstrated in flies and targeted gene disruptions may not be far off.
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Affiliation(s)
- S E Celniker
- Berkeley Drosophila Genome Project, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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14
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Abstract
Programmed cell death plays critical roles in a wide variety of physiological processes during fetal development and in adult tissues. In most cases, physiological cell death occurs by apoptosis as opposed to necrosis. Defects in apoptotic cell death regulation contribute to many diseases, including disorders where cell accumulation occurs (cancer, restenosis) or where cell loss ensues (stroke, heart failure, neurodegeneration, AIDS). In recent years, the molecular machinery responsible for apoptosis has been elucidated, revealing a family of intracellular proteases, the caspases, which are responsible directly or indirectly for the morphological and biochemical changes that characterize the phenomenon of apoptosis. Diverse regulators of the caspases have also been discovered, including activators and inhibitors of these cell death proteases. Inputs from signal transduction pathways into the core of the cell death machinery have also been identified, demonstrating ways of linking environmental stimuli to cell death responses or cell survival maintenance. Knowledge of the molecular mechanisms of apoptosis is providing insights into the causes of multiple pathologies where aberrant cell death regulation occurs and is beginning to provide new approaches to the treatment of human diseases.
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Affiliation(s)
- J C Reed
- Burnham Institute, La Jolla, California 92037, USA.
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15
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Abstract
Programmed cell death plays an important role in maintaining homeostasis during animal development, and has been conserved in animals as different as nematodes and humans. Recent studies of Drosophila have provided valuable information toward our understanding of genetic regulation of death. Different signals trigger the novel death regulators rpr, hid, and grim, that utilize the evolutionarily conserved iap and ark genes to modulate caspase function. Subsequent removal of dying cells also appears to be accomplished by conserved mechanisms. The similarity between Drosophila and human in cell death signaling pathways illustrate the promise of fruit flies as a model system to elucidate the mechanisms underlying regulation of programmed cell death.
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Affiliation(s)
- C Y Lee
- Center for Agricultural Biotechnology, University of Maryland Biotechnology Institute, Department of Biology, University of Maryland, College Park 20742, USA
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16
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17
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Abstract
Key components of the programmed cell death pathway are conserved between Caenorhabditis elegans, Drosophila melanogaster and humans. The search for additional homologs has been facilitated by the availability of the entire genomic sequence for each of these organisms.
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Affiliation(s)
- Jan N Tittel
- Howard Hughes Medical Institute, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Hermann Steller
- Howard Hughes Medical Institute, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA. E-mail:
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