201
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Drosophila brca2 is required for mitotic and meiotic DNA repair and efficient activation of the meiotic recombination checkpoint. PLoS Genet 2008; 4:e31. [PMID: 18266476 PMCID: PMC2233675 DOI: 10.1371/journal.pgen.0040031] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Accepted: 12/21/2007] [Indexed: 11/19/2022] Open
Abstract
Heterozygous mutations in the tumor suppressor BRCA2 confer a high risk of breast and other cancers in humans. BRCA2 maintains genome stability in part through the regulation of Rad51-dependent homologous recombination. Much about its precise function in the DNA damage responses is, however, not yet known. We have made null mutations in the Drosophila homolog of BRCA2 and measured the levels of homologous recombination, non-homologous end-joining, and single-strand annealing in the pre-meiotic germline of Drosophila males. We show that repair by homologous recombination is dramatically decreased in Drosophila brca2 mutants. Instead, large flanking deletions are formed, and repair by the non-conservative single-strand annealing pathway predominates. We further show that during meiosis, Drosophila Brca2 has a dual role in the repair of meiotic double-stranded breaks and the efficient activation of the meiotic recombination checkpoint. The eggshell patterning defects that result from activation of the meiotic recombination checkpoint in other meiotic DNA repair mutants can be strongly suppressed by mutations in brca2. In addition, Brca2 co-immunoprecipitates with the checkpoint protein Rad9, suggesting a direct role for Brca2 in the transduction of the meiotic recombination checkpoint signal.
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202
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Abstract
There is increasing support for the idea that aging and cancer are intimately connected by the activity of specific genes and the cellular responses to potentially oncogenic insults. This Hot Topics review discusses some recently published articles that shed light on both the commonalities--and intricacies--of the cancer-aging relationship. These articles reveal the expected complexities, but also surprising conservation, in mechanisms that link cancer and aging.
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Affiliation(s)
- Judith Campisi
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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203
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Mauri F, McNamee LM, Lunardi A, Chiacchiera F, Del Sal G, Brodsky MH, Collavin L. Modification of Drosophila p53 by SUMO modulates its transactivation and pro-apoptotic functions. J Biol Chem 2008; 283:20848-56. [PMID: 18492669 DOI: 10.1074/jbc.m710186200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Conjugation to SUMO is a reversible post-translational modification that regulates several transcription factors involved in cell proliferation, differentiation, and disease. The p53 tumor suppressor can be modified by SUMO-1 in mammalian cells, but the functional consequences of this modification are unclear. Here, we demonstrate that the Drosophila homolog of human p53 can be efficiently sumoylated in insect cells. We identify two lysine residues involved in SUMO attachment, one at the C terminus, between the DNA binding and oligomerization domains, and one at the N terminus of the protein. We find that sumoylation helps recruit Drosophila p53 to nuclear dot-like structures that can be marked by human PML and the Drosophila homologue of Daxx. We demonstrate that mutation of both sumoylation sites dramatically reduces the transcriptional activity of p53 and its ability to induce apoptosis in transgenic flies, providing in vivo evidence that sumoylation is critical for Drosophila p53 function.
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Affiliation(s)
- Federico Mauri
- Laboratorio Nazionale Consorzio Interuniversitario Biotecnologie, AREA Science Park, Padriciano 99, Trieste, Italy
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204
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Zhang Y, Lin N, Carroll PM, Chan G, Guan B, Xiao H, Yao B, Wu SS, Zhou L. Epigenetic blocking of an enhancer region controls irradiation-induced proapoptotic gene expression in Drosophila embryos. Dev Cell 2008; 14:481-93. [PMID: 18410726 DOI: 10.1016/j.devcel.2008.01.018] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 11/29/2007] [Accepted: 01/31/2008] [Indexed: 11/25/2022]
Abstract
Drosophila embryos are highly sensitive to gamma-ray-induced apoptosis at early but not later, more differentiated stages during development. Two proapoptotic genes, reaper and hid, are upregulated rapidly following irradiation. However, in post-stage-12 embryos, in which most cells have begun differentiation, neither proapoptotic gene can be induced by high doses of irradiation. Our study indicates that the sensitive-to-resistant transition is due to epigenetic blocking of the irradiation-responsive enhancer region (IRER), which is located upstream of reaper but is also required for the induction of hid in response to irradiation. This IRER, but not the transcribed regions of reaper/hid, becomes enriched for trimethylated H3K27/H3K9 and forms a heterochromatin-like structure during the sensitive-to-resistant transition. The functions of histone-modifying enzymes Hdac1(rpd3) and Su(var)3-9 and PcG proteins Su(z)12 and Polycomb are required for this process. Thus, direct epigenetic regulation of two proapoptotic genes controls cellular sensitivity to cytotoxic stimuli.
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Affiliation(s)
- Yanping Zhang
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
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205
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Abstract
Insects have made major contributions to understanding the regulation of cell death, dating back to the pioneering work of Lockshin and Williams on death of muscle cells during postembryonic development of Manduca. A physically smaller cousin of moths, the fruit fly Drosophila melanogaster, offers unique advantages for studying the regulation of cell death in response to different apoptotic stimuli in situ. Different signaling pathways converge in Drosophila to activate a common death program through transcriptional activation of reaper, hid and grim. Reaper-family proteins induce apoptosis by binding to and antagonizing inhibitor of apoptosis proteins (IAPs), which in turn inhibit caspases. This switch from life to death relies extensively on targeted degradation of cell death proteins by the ubiquitin-proteasome pathway. Drosophila IAP-1 (Diap1) functions as an E3-ubiquitin ligase to protect cells from unwanted death by promoting the degradation of the initiator caspase Dronc. However, in response to apoptotic signals, Reaper-family proteins are produced, which promote the auto-ubiquitination and degradation of Diap1, thereby removing the 'brakes on death' in cells that are doomed to die. More recently, several other ubiquitin pathway proteins were found to play important roles for caspase regulation, indicating that the control of cell survival and death relies extensively on targeted degradation by the ubiquitin-proteasome pathway.
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206
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Ujfaludi Z, Boros IM, Bálint E. Different sets of genes are activated by p53 upon UV or ionizing radiation in Drosophila melanogaster. ACTA BIOLOGICA HUNGARICA 2008; 58 Suppl:65-79. [PMID: 18297795 DOI: 10.1556/abiol.58.2007.suppl.6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The p53 tumour suppressor plays central role in the maintenance of genome integrity. P53 deficient fruit flies are highly sensitive to ionizing radiation (IR) and show genome instability suggesting that the Drosophila melanogaster p53 (Dmp53) is necessary for the proper damage response upon IR. We found that Dmp53 null fruit flies are highly sensitive to ultraviolet radiation (UV) as well. We analyzed the expression levels of apoptotic genes in wild type and Dmp53 null mutant animals after UV or IR using quantitative real-time RT-PCR. Ark (Apaf-1 related killer) was induced in a Dmp53-dependent way upon UV treatment but not by IR, hid (head involution defective/wrinkled) was induced upon both types of DNA damage, while reaper was induced only upon IR but not UV treatment. Using microarray analysis we identified several further genes that are activated upon UV irradiation in the presence of wild type Dmp53 only. Some but not all of these genes show Dmp53-dependent activation upon IR treatment as well. These results suggest that Dmp53 activates distinct cellular pathways through regulation of different target genes after different types of DNA damage.
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Affiliation(s)
- Zsuzsanna Ujfaludi
- Department of Biochemistry and Molecular Biology, University of Szeged, Hungary
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207
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Langton PF, Colombani J, Aerne BL, Tapon N. Drosophila ASPP regulates C-terminal Src kinase activity. Dev Cell 2008; 13:773-82. [PMID: 18061561 DOI: 10.1016/j.devcel.2007.11.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Revised: 10/02/2007] [Accepted: 11/09/2007] [Indexed: 12/20/2022]
Abstract
Src-family kinases (SFKs) control a variety of biological processes, from cell proliferation and differentiation to cytoskeletal rearrangements. Abnormal activation of SFKs has been implicated in a wide variety of cancers and is associated with metastatic behavior (Yeatman, 2004). SFKs are maintained in an inactive state by inhibitory phosphorylation of their C-terminal region by C-terminal Src kinase (Csk). We have identified Drosophila Ankyrin-repeat, SH3-domain, and Proline-rich-region containing Protein (dASPP) as a regulator of Drosophila Csk (dCsk) activity. dASPP is the homolog of the mammalian ASPP proteins, which are known to bind to and stimulate the proapoptotic function of p53. We show that dASPP is a positive regulator of dCsk. First, dASPP loss-of-function strongly enhances the specific phenotypes of dCsk mutants in wing epithelial cells. Second, dASPP interacts physically with dCsk to potentiate the inhibitory phosphorylation of Drosophila Src (dSrc). Our results suggest a role for dASPP in maintaining epithelial integrity through dCsk regulation.
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Affiliation(s)
- Paul F Langton
- Apoptosis and Proliferation Control Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3PX, United Kingdom
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208
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209
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Yamada Y, Davis KD, Coffman CR. Programmed cell death of primordial germ cells in Drosophila is regulated by p53 and the Outsiders monocarboxylate transporter. Development 2007; 135:207-16. [PMID: 18057102 DOI: 10.1242/dev.010389] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Primordial germ cell development uses programmed cell death to remove abnormal, misplaced or excess cells. Precise control of this process is essential to maintain the continuity and integrity of the germline, and to prevent germ cells from colonizing locations other than the gonads. Through careful analyses of primordial germ cell distribution in developing Drosophila melanogaster embryos, we show that normal germ cell development involves extensive programmed cell death during stages 10-12 of embryogenesis. This germ cell death is mediated by Drosophila p53 (p53). Mutations in p53 result in excess primordial germ cells that are ectopic to the gonads. Initial movements of the germ cells appear normal, and wild-type numbers of germ cells populate the gonads, indicating that p53 is required for germ cell death, but not migration. To our knowledge, this is the first report of a loss-of-function phenotype for Drosophila p53 in a non-sensitized background. The p53 phenotype is remarkably similar to that of outsiders (out) mutants. Here, we show that the out gene encodes a putative monocarboxylate transporter. Mutations in p53 and out show nonallelic noncomplementation. Interestingly, overexpression of p53 in primordial germ cells of out mutant embryos partially suppresses the out germ cell death phenotype, suggesting that p53 functions in germ cells either downstream of out or in a closely linked pathway. These findings inform models in which signaling between p53 and cellular metabolism are integrated to regulate programmed cell death decisions.
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Affiliation(s)
- Yukiko Yamada
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011-3260, USA
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210
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Bodai L, Pardi N, Ujfaludi Z, Bereczki O, Komonyi O, Balint E, Boros IM. Daxx-like protein of Drosophila interacts with Dmp53 and affects longevity and Ark mRNA level. J Biol Chem 2007; 282:36386-93. [PMID: 17933869 DOI: 10.1074/jbc.m705547200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Daxx-like protein (DLP), the Drosophila homolog of Daxx, binds Drosophila melanogaster p53 (Dmp53) through its C-terminal region. We generated DLP mutants and found that although DLP expression is developmentally regulated, it is not essential for the execution of the developmental program. The effects DLP mutations show in the loss of heterozygosity assay and on phenotypes resulting from Dmp53 overexpression indicate a genetic interaction between DLP and Dmp53. In contrast to Dmp53 mutants, however, loss of DLP does not result in radiosensitivity indicating that it does not play an essential role in the activation of Dmp53-dependent response after ionizing radiation, and DLP is also not required for the irradiation-induced activation of reaper. In contrast, DLP is involved in the transcriptional regulation of Ark, because Ark mRNA level is decreased in DLP mutants and increased upon ectopic overexpression of DLP. Interestingly, DLP mutants have reduced longevity and reduced female fertility. Altogether, our data suggest complex functions for DLP, which include an anti-apoptotic effect exerted through repression of some Dmp53 functions, and activation of some proapoptotic genes.
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Affiliation(s)
- László Bodai
- Chromatin Research Group of USZ-HAS, Department of Biochemistry and Molecular Biology, University of Szeged, Szeged, H-6726 Hungary
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211
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Villiard É, Brinkmann H, Moiseeva O, Mallette FA, Ferbeyre G, Roy S. Urodele p53 tolerates amino acid changes found in p53 variants linked to human cancer. BMC Evol Biol 2007; 7:180. [PMID: 17903248 PMCID: PMC2072957 DOI: 10.1186/1471-2148-7-180] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Accepted: 09/28/2007] [Indexed: 11/18/2022] Open
Abstract
Background Urodele amphibians like the axolotl are unique among vertebrates in their ability to regenerate and their resistance to develop cancers. It is unknown whether these traits are linked at the molecular level. Results Blocking p53 signaling in axolotls using the p53 inhibitor, pifithrin-α, inhibited limb regeneration and the expression of p53 target genes such as Mdm2 and Gadd45, suggesting a link between tumor suppression and regeneration. To understand this relationship we cloned the p53 gene from axolotl. When comparing its sequence with p53 from other organisms, and more specifically human we observed multiple amino acids changes found in human tumors. Phylogenetic analysis of p53 protein sequences from various species is in general agreement with standard vertebrate phylogeny; however, both mice-like rodents and teleost fishes are fast evolving. This leads to long branch attraction resulting in an artefactual basal emergence of these groups in the phylogenetic tree. It is tempting to assume a correlation between certain life style traits (e.g. lifespan) and the evolutionary rate of the corresponding p53 sequences. Functional assays of the axolotl p53 in human or axolotl cells using p53 promoter reporters demonstrated a temperature sensitivity (ts), which was further confirmed by performing colony assays at 37°C. In addition, axolotl p53 was capable of efficient transactivation at the Hmd2 promoter but has moderate activity at the p21 promoter. Endogenous axolotl p53 was activated following UV irradiation (100 j/m2) or treatment with an alkylating agent as measured using serine 15 phosphorylation and the expression of the endogenous p53 target Gadd45. Conclusion Urodele p53 may play a role in regeneration and has evolved to contain multiple amino acid changes predicted to render the human protein defective in tumor suppression. Some of these mutations were probably selected to maintain p53 activity at low temperature. However, other significant changes in the axolotl proteins may play more subtle roles on p53 functions, including DNA binding and promoter specificity and could represent useful adaptations to ensure p53 activity and tumor suppression in animals able to regenerate or subject to large variations in oxygen levels or temperature.
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Affiliation(s)
- Éric Villiard
- Department of Biochemistry, Faculty of Medicine, Université de Montréal, Montréal, QC, H3C 3J7, Canada
| | - Henner Brinkmann
- Department of Biochemistry, Faculty of Medicine, Université de Montréal, Montréal, QC, H3C 3J7, Canada
| | - Olga Moiseeva
- Department of Biochemistry, Faculty of Medicine, Université de Montréal, Montréal, QC, H3C 3J7, Canada
| | - Frédérick A Mallette
- Department of Biochemistry, Faculty of Medicine, Université de Montréal, Montréal, QC, H3C 3J7, Canada
| | - Gerardo Ferbeyre
- Department of Biochemistry, Faculty of Medicine, Université de Montréal, Montréal, QC, H3C 3J7, Canada
| | - Stéphane Roy
- Department of Biochemistry, Faculty of Medicine, Université de Montréal, Montréal, QC, H3C 3J7, Canada
- Department of Stomatology, Faculty of Dentistry, Université de Montréal, Montréal, QC, H3C 3J7, Canada
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212
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Pankow S, Bamberger C. The p53 tumor suppressor-like protein nvp63 mediates selective germ cell death in the sea anemone Nematostella vectensis. PLoS One 2007; 2:e782. [PMID: 17848985 PMCID: PMC1964547 DOI: 10.1371/journal.pone.0000782] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Accepted: 07/22/2007] [Indexed: 11/29/2022] Open
Abstract
Here we report the identification and molecular function of the p53 tumor suppressor-like protein nvp63 in a non-bilaterian animal, the starlet sea anemone Nematostella vectensis. So far, p53-like proteins had been found in bilaterians only. The evolutionary origin of p53-like proteins is highly disputed and primordial p53-like proteins are variably thought to protect somatic cells from genotoxic stress. Here we show that ultraviolet (UV) irradiation at low levels selectively induces programmed cell death in early gametes but not somatic cells of adult N. vectensis polyps. We demonstrate with RNA interference that nvp63 mediates this cell death in vivo. Nvp63 is the most archaic member of three p53-like proteins found in N. vectensis and in congruence with all known p53-like proteins, nvp63 binds to the vertebrate p53 DNA recognition sequence and activates target gene transcription in vitro. A transactivation inhibitory domain at its C-terminus with high homology to the vertebrate p63 may regulate nvp63 on a molecular level. The genotoxic stress induced and nvp63 mediated apoptosis in N. vectensis gametes reveals an evolutionary ancient germ cell protective pathway which relies on p63-like proteins and is conserved from cnidarians to vertebrates.
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Affiliation(s)
- Sandra Pankow
- Department of Cell Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Casimir Bamberger
- Sundgauallee 64, Freiburg, Germany
- * To whom correspondence should be addressed. E-mail:
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213
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Peterson JS, Bass BP, Jue D, Rodriguez A, Abrams JM, McCall K. Noncanonical cell death pathways act during Drosophila oogenesis. Genesis 2007; 45:396-404. [PMID: 17506088 DOI: 10.1002/dvg.20306] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Programmed cell death (PCD) is a highly conserved process that occurs during development and in response to adverse conditions. In Drosophila, most PCDs require the genes within the H99 deficiency, the adaptor molecule Ark, and caspases. Here we investigate 10 cell death genes for their potential roles in two distinct types of PCD that occur in oogenesis: developmental nurse cell PCD and starvation-induced PCD. Most of the genes investigated were found to have little effect on late stage developmental PCD in oogenesis, although ark mutants showed a partial inhibition. Mid-stage starvation-induced germline PCD was found to be independent of the upstream activators and ark although it requires caspases, suggesting an apoptosome-independent mechanism of caspase activation in mid-oogenesis. These results indicate that novel pathways must control PCD in the ovary.
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Affiliation(s)
- Jeanne S Peterson
- Department of Biology, Boston University, Boston, Massachusetts 02115, USA
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214
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Bauer JH, Chang C, Morris SNS, Hozier S, Andersen S, Waitzman JS, Helfand SL. Expression of dominant-negative Dmp53 in the adult fly brain inhibits insulin signaling. Proc Natl Acad Sci U S A 2007; 104:13355-60. [PMID: 17686972 PMCID: PMC1948898 DOI: 10.1073/pnas.0706121104] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In Drosophila melanogaster, p53 (Dmp53) is an important mediator of longevity. Expression of dominant-negative (DN) forms of Dmp53 in adult neurons, but not in muscle or fat body cells, extends lifespan. The lifespan of calorie-restricted flies is not further extended by simultaneously expressing DN-Dmp53 in the nervous system, indicating that a decrease in Dmp53 activity may be a part of the CR lifespan-extending pathway in flies. In this report, we show that selective expression of DN-Dmp53 in only the 14 insulin-producing cells (IPCs) in the brain extends lifespan to the same extent as expression in all neurons and this lifespan extension is not additive with CR. DN-Dmp53-dependent lifespan extension is accompanied by reduction of Drosophila insulin-like peptide 2 (dILP2) mRNA levels and reduced insulin signaling (IIS) in the fat body, which suggests that Dmp53 may affect lifespan by modulating insulin signaling in the fly.
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Affiliation(s)
- Johannes H. Bauer
- Department of Molecular Biology, Cell Biology and Biochemistry, Division of Biology and Medicine, Brown University, Providence, RI 02903
| | - Chengyi Chang
- Department of Molecular Biology, Cell Biology and Biochemistry, Division of Biology and Medicine, Brown University, Providence, RI 02903
| | - Siti Nur Sarah Morris
- Department of Molecular Biology, Cell Biology and Biochemistry, Division of Biology and Medicine, Brown University, Providence, RI 02903
| | - Suzanne Hozier
- Department of Molecular Biology, Cell Biology and Biochemistry, Division of Biology and Medicine, Brown University, Providence, RI 02903
| | - Sandra Andersen
- Department of Molecular Biology, Cell Biology and Biochemistry, Division of Biology and Medicine, Brown University, Providence, RI 02903
| | - Joshua S. Waitzman
- Department of Molecular Biology, Cell Biology and Biochemistry, Division of Biology and Medicine, Brown University, Providence, RI 02903
| | - Stephen L. Helfand
- Department of Molecular Biology, Cell Biology and Biochemistry, Division of Biology and Medicine, Brown University, Providence, RI 02903
- *To whom correspondence should be addressed. E-mail:
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215
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Murray-Zmijewski F, Lane DP, Bourdon JC. p53/p63/p73 isoforms: an orchestra of isoforms to harmonise cell differentiation and response to stress. Cell Death Differ 2007; 13:962-72. [PMID: 16601753 DOI: 10.1038/sj.cdd.4401914] [Citation(s) in RCA: 387] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
p63, p73 and p53 compose a family of transcription factors involved in cell response to stress and development. p53 is the most frequently mutated gene in cancer (50%) and loss of p53 activity is considered to be ubiquitous to all cancers. Recent publications may have a profound impact on our understanding of p53 tumour suppressor activity. p63, p73 and p53 genes have a dual gene structure conserved in drosophila, zebrafish and man. They encode for multiple p63, p73 or p53 proteins containing different protein domains (isoforms) due to multiple splicing, alternative promoter and alternative initiation of translation. In this review, we describe the different isoforms of p63, p73, p53 and their roles in development and cancer. The changes in the interactions between p53, p63 and p73 isoforms are likely to be fundamental to our understanding in the transition between normal cell cycling and the onset of tumour formation.
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Affiliation(s)
- F Murray-Zmijewski
- Department of Surgery and Molecular Oncology, University of Dundee, Ninewells Hospital, CR-UK Cell Transformation Research Group, Dundee DD19SY, UK
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216
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Ou HD, Löhr F, Vogel V, Mäntele W, Dötsch V. Structural evolution of C-terminal domains in the p53 family. EMBO J 2007; 26:3463-73. [PMID: 17581633 PMCID: PMC1933395 DOI: 10.1038/sj.emboj.7601764] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Accepted: 05/23/2007] [Indexed: 11/09/2022] Open
Abstract
The tetrameric state of p53, p63, and p73 has been considered one of the hallmarks of this protein family. While the DNA binding domain (DBD) is highly conserved among vertebrates and invertebrates, sequences C-terminal to the DBD are highly divergent. In particular, the oligomerization domain (OD) of the p53 forms of the model organisms Caenorhabditis elegans and Drosophila cannot be identified by sequence analysis. Here, we present the solution structures of their ODs and show that they both differ significantly from each other as well as from human p53. CEP-1 contains a composite domain of an OD and a sterile alpha motif (SAM) domain, and forms dimers instead of tetramers. The Dmp53 structure is characterized by an additional N-terminal beta-strand and a C-terminal helix. Truncation analysis in both domains reveals that the additional structural elements are necessary to stabilize the structure of the OD, suggesting a new function for the SAM domain. Furthermore, these structures show a potential path of evolution from an ancestral dimeric form over a tetrameric form, with additional stabilization elements, to the tetramerization domain of mammalian p53.
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Affiliation(s)
- Horng Der Ou
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance (BMRZ), JW Goethe University of Frankfurt, Frankfurt/Main, Germany
- Graduate Group in Biophysics, University of California San Francisco, San Francisco, CA, USA
| | - Frank Löhr
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance (BMRZ), JW Goethe University of Frankfurt, Frankfurt/Main, Germany
| | - Vitali Vogel
- Institute of Biophysics, JW Goethe University of Frankfurt, Frankfurt/Main, Germany
| | - Werner Mäntele
- Institute of Biophysics, JW Goethe University of Frankfurt, Frankfurt/Main, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance (BMRZ), JW Goethe University of Frankfurt, Frankfurt/Main, Germany
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, University of Frankfurt, Max-von-Laue-Strasse 9, Frankfurt, Hessen 60438, Germany. Tel.: +49 69 798 29631; Fax: +49 69 798 29632; E-mail:
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217
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Miguel NCDO, Wajsenzon IJR, Takiya CM, de Andrade LR, Tortelote GG, Einicker-Lamas M, Allodi S. Catalase, Bax and p53 expression in the visual system of the crab Ucides cordatus following exposure to ultraviolet radiation. Cell Tissue Res 2007; 329:159-68. [PMID: 17406897 DOI: 10.1007/s00441-007-0410-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Accepted: 03/02/2007] [Indexed: 12/20/2022]
Abstract
In invertebrates, a few studies have suggested apoptosis as the mechanism of choice to protect the retina after exposure to ultraviolet (UV) radiation. We demonstrated previously, by electron microscopy, that the retina and lamina ganglionaris (or lamina) cells of the crab Ucides cordatus displayed subcellular signs of apoptosis after exposure to UVB and UVC. Here, we first ascertained, by the TdT-mediated dUTP-biotin nick end-labeling (TUNEL) technique, that UV irradiation indeed produced the previously reported results. We next tested, in the visual system of U. cordatus, whether the expression (as analyzed by immunohistochemistry and observed with laser scanning microscopy) and levels (as examined by Western blotting) of catalase, Bax, and p53 were affected by the same dose of UV radiation as that used previously. Our data revealed that the intensity of catalase, Bax, and p53 labeling was stronger in irradiated retina and lamina cells than in non-irradiated retina and lamina. However, no significant difference was observed in the concentrations of these proteins isolated from the whole optic lobe. The results thus suggest that UVB and UVC induce apoptosis in the crustacean retina and lamina by increasing catalase expression and activating the Bax- and p53-mediated apoptosis pathways.
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Affiliation(s)
- Nadia Campos de Oliveira Miguel
- Departamento de Histologia e Embriologia, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
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218
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Abstract
Intense research over the past four years has led to the discovery and characterization of a novel signalling network, known as the Salvador-Warts-Hippo (SWH) pathway, involved in tissue growth control in Drosophila melanogaster. At present, eleven proteins have been implicated as members of this pathway, and several downstream effector genes have been characterized. The importance of this pathway is emphasized by its evolutionary conservation, and by increasing evidence that its deregulation occurs in human tumours. Here, we review the main findings from Drosophila and the implications that these have for tumorigenesis in mammals.
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Affiliation(s)
- Kieran Harvey
- Peter MacCallum Cancer Centre, St Andrew's Place, East Melbourne, Victoria 3002 Australia.
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219
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Akdemir F, Christich A, Sogame N, Chapo J, Abrams JM. p53 directs focused genomic responses in Drosophila. Oncogene 2007; 26:5184-93. [PMID: 17310982 DOI: 10.1038/sj.onc.1210328] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
p53 is a fundamental determinant of cancer susceptibility and other age-related pathologies. Similar to mammalian counterparts, Drosophila p53 integrates stress signals and elicits apoptotic responses that maintain genomic stability. To illuminate core-adaptive functions controlled by this gene family, we examined the Drosophila p53 regulatory network at a genomic scale. In development, the absence of p53 impacted constitutive expression for a surprisingly broad scope of genes. By contrast, stimulus-dependent responses governed by Drosophila p53 were limited in scope. The vast majority of stress responders were induced and p53 dependent (RIPD) genes. The signature set of 29 'high stringency' RIPD genes identified here were enriched for intronless loci, with a non-uniform distribution that includes a recently evolved cluster unique to Drosophila melanogaster. Two RIPD genes, with known and unknown biochemical activities, were functionally examined. One RIPD gene, designated XRP1, maintains genome stability after genotoxic challenge and prevents cell proliferation upon induced expression. A second gene, RnrL, is an apoptogenic effector required for caspase activation in a model of p53-dependent killing. Together, these studies identify ancient and convergent features of the p53 regulatory network.
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Affiliation(s)
- F Akdemir
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
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220
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Singh A, Shi X, Choi KW. Lobe and Serrate are required for cell survival during early eye development in Drosophila. Development 2007; 133:4771-81. [PMID: 17090721 DOI: 10.1242/dev.02686] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Organogenesis involves an initial surge of cell proliferation, leading to differentiation. This is followed by cell death in order to remove extra cells. During early development, there is little or no cell death. However, there is a lack of information concerning the genes required for survival during the early cell-proliferation phase. Here, we show that Lobe (L) and the Notch (N) ligand Serrate (Ser), which are both involved in ventral eye growth, are required for cell survival in the early eye disc. We observed that the loss-of-ventral-eye phenotype in L or Ser mutants is due to the induction of cell death and the upregulation of secreted Wingless (Wg). This loss-of-ventral-eye phenotype can be rescued by (i) increasing the levels of cell death inhibitors, (ii) reducing the levels of Hid-Reaper-Grim complex, or (iii) reducing canonical Wg signaling components. Blocking Jun-N-terminal kinase (JNK) signaling, which can induce caspase-independent cell death, significantly rescued ventral eye loss in L or Ser mutants. However, blocking both caspase-dependent cell death and JNK signaling together showed stronger rescues of the L- or Ser-mutant eye at a 1.5-fold higher frequency. This suggests that L or Ser loss-of-function triggers both caspase-dependent and -independent cell death. Our studies thus identify a mechanism responsible for cell survival in the early eye.
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Affiliation(s)
- Amit Singh
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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221
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Tang Y, Luo J, Zhang W, Gu W. Tip60-dependent acetylation of p53 modulates the decision between cell-cycle arrest and apoptosis. Mol Cell 2007; 24:827-39. [PMID: 17189186 DOI: 10.1016/j.molcel.2006.11.021] [Citation(s) in RCA: 550] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Revised: 09/11/2006] [Accepted: 11/21/2006] [Indexed: 01/17/2023]
Abstract
Upon DNA damage and other types of stress, p53 induces either cell-cycle arrest or apoptosis depending on the cellular context. However, the molecular mechanisms that govern the choice between cell-cycle arrest and apoptosis are not well understood. Here, we show that Tip60 is required for both cell growth arrest and apoptosis mediated by p53 and also induces its acetylation specifically at lysine 120 (K120) within the DNA-binding domain. Interestingly, this modification is crucial for p53-dependent apoptosis but is dispensable for its mediated growth arrest. K120 is a recurrent site for p53 mutation in human cancer, and the corresponding acetylation-defective tumor mutant (K120R) abrogates p53-mediated apoptosis, but not growth arrest. Thus, our study demonstrates that Tip60-dependent acetylation of p53 at K120 modulates the decision between cell-cycle arrest and apoptosis, and it reveals that the DNA-binding core domain is an important target for p53 regulation by posttranslational modifications.
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Affiliation(s)
- Yi Tang
- Institute for Cancer Genetics, Surgeons, Columbia University, 1150 St. Nicholas Ave, New York, New York 10032, USA
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222
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Derry WB, Bierings R, van Iersel M, Satkunendran T, Reinke V, Rothman JH. Regulation of developmental rate and germ cell proliferation in Caenorhabditis elegans by the p53 gene network. Cell Death Differ 2006; 14:662-70. [PMID: 17186023 DOI: 10.1038/sj.cdd.4402075] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Caenorhabditis elegans CEP-1 activates germline apoptosis in response to genotoxic stress, similar to its mammalian counterpart, tumor suppressor p53. In mammals, there are three p53 family members (p53, p63, and p73) that activate and repress many distinct and overlapping sets of genes, revealing a complex transcriptional regulatory network. Because CEP-1 is the sole p53 family member in C. elegans, analysis of this network is greatly simplified in this organism. We found that CEP-1 functions during normal development in the absence of stress to repress many (331) genes and activate only a few (28) genes. In response to genotoxic stress, 1394 genes are activated and 942 are repressed, many of which contain p53-binding sites. Comparison of the CEP-1 transcriptional network with transcriptional targets of the human p53 family reveals considerable overlap between CEP-1-regulated genes and homologues regulated by human p63 and p53, suggesting a composite p53/p63 action for CEP-1. We found that phg-1, the C. elegans Gas1 (growth arrest-specific 1) homologue, is activated by CEP-1 and is a negative regulator of cell proliferation in the germline in response to genotoxic stress. Further, we find that CEP-1 and PHG-1 mediate the decreased developmental rate and embryonic viability of mutations in the clk-2/TEL2 gene, which regulates lifespan and checkpoint responses.
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Affiliation(s)
- W B Derry
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA.
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223
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Yamasaki S, Yagishita N, Sasaki T, Nakazawa M, Kato Y, Yamadera T, Bae E, Toriyama S, Ikeda R, Zhang L, Fujitani K, Yoo E, Tsuchimochi K, Ohta T, Araya N, Fujita H, Aratani S, Eguchi K, Komiya S, Maruyama I, Higashi N, Sato M, Senoo H, Ochi T, Yokoyama S, Amano T, Kim J, Gay S, Fukamizu A, Nishioka K, Tanaka K, Nakajima T. Cytoplasmic destruction of p53 by the endoplasmic reticulum-resident ubiquitin ligase 'Synoviolin'. EMBO J 2006; 26:113-22. [PMID: 17170702 PMCID: PMC1782373 DOI: 10.1038/sj.emboj.7601490] [Citation(s) in RCA: 164] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Accepted: 11/07/2006] [Indexed: 11/09/2022] Open
Abstract
Synoviolin, also called HRD1, is an E3 ubiquitin ligase and is implicated in endoplasmic reticulum -associated degradation. In mammals, Synoviolin plays crucial roles in various physiological and pathological processes, including embryogenesis and the pathogenesis of arthropathy. However, little is known about the molecular mechanisms of Synoviolin in these actions. To clarify these issues, we analyzed the profile of protein expression in synoviolin-null cells. Here, we report that Synoviolin targets tumor suppressor gene p53 for ubiquitination. Synoviolin sequestrated and metabolized p53 in the cytoplasm and negatively regulated its cellular level and biological functions, including transcription, cell cycle regulation and apoptosis. Furthermore, these p53 regulatory functions of Synoviolin were irrelevant to other E3 ubiquitin ligases for p53, such as MDM2, Pirh2 and Cop1, which form autoregulatory feedback loops. Our results provide novel insights into p53 signaling mediated by Synoviolin.
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Affiliation(s)
- Satoshi Yamasaki
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Naoko Yagishita
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Takeshi Sasaki
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Minako Nakazawa
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Yukihiro Kato
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Tadayuki Yamadera
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Eunkyung Bae
- GenExl, Inc. Biomedical Research Center, Taejon, South Korea
| | - Sayumi Toriyama
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Rie Ikeda
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Lei Zhang
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Kazuko Fujitani
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Eunkyung Yoo
- GenExl, Inc. Biomedical Research Center, Taejon, South Korea
| | - Kaneyuki Tsuchimochi
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Tomohiko Ohta
- Division of Breast and Endocrine Surgery, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Natsumi Araya
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Hidetoshi Fujita
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Satoko Aratani
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Katsumi Eguchi
- The First Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan
| | - Setsuro Komiya
- Department of Orthopedic Surgery, Kagoshima University, Faculty of Medicine, Kagoshima, Japan
| | - Ikuro Maruyama
- Department of Dermatology and Laboratory of Molecular Medicine, Kagoshima University, Faculty of Medicine, Kagoshima, Japan
| | - Nobuyo Higashi
- Department of Anatomy, Akita University School of Medicine, Akita, Japan
| | - Mitsuru Sato
- Department of Anatomy, Akita University School of Medicine, Akita, Japan
| | - Haruki Senoo
- Department of Anatomy, Akita University School of Medicine, Akita, Japan
| | - Takahiro Ochi
- National Hospital Organization Sagamihara National Hospital, Kanagawa, Japan
| | - Shigeyuki Yokoyama
- Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Tokyo, Japan; Protein Research Group, RIKEN Genomic Sciences Center, Yokohama, Japan
| | - Tetsuya Amano
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Jaeseob Kim
- GenExl, Inc. Biomedical Research Center, Taejon, South Korea
| | - Steffen Gay
- Department of Rheumatology, University Hospital Zürich, Zürich, Switzerland
| | - Akiyoshi Fukamizu
- Aspect of Functional Genomic Biology, Center of Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Japan
| | - Kusuki Nishioka
- Rheumatology, Immunology and Genetics Program, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
| | - Keiji Tanaka
- Laboratory of Frontier Science, The Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Toshihiro Nakajima
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, Kawasaki, Japan
- Department of Genome Science, Institute of Medical Science, St Marianna University School of Medicine, 2-16-1 Sugao Miyamae-ku, Kawasaki, Kanagawa 216-8512, Japan. Tel.: +81 44 977 8111 (ext. 4111); Fax: +81 44 977 10712; E-mail:
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224
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Liu W, Silverstein AM, Shu H, Martinez B, Mumby MC. A functional genomics analysis of the B56 isoforms of Drosophila protein phosphatase 2A. Mol Cell Proteomics 2006; 6:319-32. [PMID: 17121811 DOI: 10.1074/mcp.m600272-mcp200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Members of the B56 family of protein phosphatase 2A (PP2A) regulatory subunits play crucial roles in Drosophila cell survival. Distinct functions of two B56 subunits were investigated using a combination of RNA interference, DNA microarrays, and proteomics. RNA interference-mediated knockdown of the B56-1 subunit (PP2A-B') but not the catalytic (mts) or B56-2 subunit (wdb) of PP2A resulted in increased expression of the apoptotic inducers reaper and sickle. Co-knockdown of B56-1 with reaper, but not with sickle, reduced the apoptosis caused by depletion of the B56 subunits. Two-dimensional gel electrophoresis and mass spectrometry identified proteins modified in cells depleted of PP2A subunits. These included generation of caspase-dependent cleavage products, increases in protein abundance, and covalent modifications. Results suggested that up-regulation of the ribosome-associated protein stubarista can serve as a sensitive marker of apoptosis. Up-regulation of transcripts for multiple glutathione transferases and other proteins suggested that loss of PP2A affected pathways involved in the response to oxidative stress. Knockdown of PP2A elevated basal JNK activity and substantially decreased activation of ERK in response to oxidative stress. The results reveal that the B56-containing isoform of PP2A functions within multiple signaling pathways, including those that regulate expression of reaper and the response to oxidative stress, thus promoting cell survival in Drosophila.
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Affiliation(s)
- Wei Liu
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390-9041, USA
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225
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Wells BS, Yoshida E, Johnston LA. Compensatory proliferation in Drosophila imaginal discs requires Dronc-dependent p53 activity. Curr Biol 2006; 16:1606-15. [PMID: 16920621 PMCID: PMC1764442 DOI: 10.1016/j.cub.2006.07.046] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 07/12/2006] [Accepted: 07/14/2006] [Indexed: 12/17/2022]
Abstract
BACKGROUND The p53 transcription factor directs a transcriptional program that determines whether a cell lives or dies after DNA damage. Animal survival after extensive cellular damage often requires that lost tissue be replaced through compensatory growth or regeneration. In Drosophila, damaged imaginal disc cells can induce the proliferation of neighboring viable cells, but how this is controlled is not clear. Here we provide evidence that Drosophila p53 (dp53) has a previously unidentified role in coordinating the compensatory growth response to tissue damage. RESULTS We find that dp53, the sole p53 ortholog in Drosophila, is required for each component of the response to cellular damage, including two separate cell-cycle arrests, changes in patterning gene expression, cell proliferation, and growth. We demonstrate that these processes are regulated by dp53 in a manner that is independent of DNA-damage sensing but that requires the initiator caspase Dronc. Our results indicate that once induced, dp53 amplifies and sustains the response through a positive feedback loop with Dronc and the apoptosis-inducing factors Hid and Reaper. CONCLUSIONS How cell death and cell proliferation are coordinated during development and after stress is a fundamental question that is critical for an understanding of growth regulation. Our data suggest that dp53 may carry out an ancestral function that promotes animal survival through the coordination of responses leading to compensatory growth after tissue damage.
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Affiliation(s)
- Brent S Wells
- Department of Genetics and Development, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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226
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Suh EK, Yang A, Kettenbach A, Bamberger C, Michaelis AH, Zhu Z, Elvin JA, Bronson RT, Crum CP, McKeon F. p63 protects the female germ line during meiotic arrest. Nature 2006; 444:624-8. [PMID: 17122775 DOI: 10.1038/nature05337] [Citation(s) in RCA: 413] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Accepted: 10/12/2006] [Indexed: 11/09/2022]
Abstract
Meiosis in the female germ line of mammals is distinguished by a prolonged arrest in prophase of meiosis I between homologous chromosome recombination and ovulation. How DNA damage is detected in these arrested oocytes is poorly understood, but it is variably thought to involve p53, a central tumour suppressor in mammals. While the function of p53 in monitoring the genome of somatic cells is clear, a consensus for the importance of p53 for germ line integrity has yet to emerge. Here we show that the p53 homologue p63 (refs 5, 6), and specifically the TAp63 isoform, is constitutively expressed in female germ cells during meiotic arrest and is essential in a process of DNA damage-induced oocyte death not involving p53. We also show that DNA damage induces both the phosphorylation of p63 and its binding to p53 cognate DNA sites and that these events are linked to oocyte death. Our data support a model whereby p63 is the primordial member of the p53 family and acts in a conserved process of monitoring the integrity of the female germ line, whereas the functions of p53 are restricted to vertebrate somatic cells for tumour suppression. These findings have implications for understanding female germ line fidelity, the regulation of fertility and the evolution of tumour suppressor mechanisms.
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Affiliation(s)
- Eun-Kyung Suh
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
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227
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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: 8.1] [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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228
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Smolik S, Jones K. Drosophila dCBP is involved in establishing the DNA replication checkpoint. Mol Cell Biol 2006; 27:135-46. [PMID: 17043110 PMCID: PMC1800657 DOI: 10.1128/mcb.01283-06] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The CBP/p300 family of proteins comprises related acetyltransferases that coactivate signal-responsive transcription. Recent evidence suggests that p300/CBP may also interact directly with complexes that mediate different aspects of DNA metabolism such as replication and repair. In this report, we show that loss of dCBP in Drosophila cells and eye discs results in a defect in the cell cycle arrest induced by stalled DNA replication. We show that dCBP and the checkpoint kinase Mei-41 can be found together in a complex and, furthermore, that dCBP has a genetic interaction with mei-41 in the response to stalled DNA replication. These observations suggest a broader role for the p300/CBP acetyltransferases in the modulation of chromatin structure and function during DNA metabolic events as well as for transcription.
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Affiliation(s)
- Sarah Smolik
- Oregon Health and Sciences University, NRC3, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
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229
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Jaklevic B, Uyetake L, Lemstra W, Chang J, Leary W, Edwards A, Vidwans S, Sibon O, Tin Su T. Contribution of growth and cell cycle checkpoints to radiation survival in Drosophila. Genetics 2006; 174:1963-72. [PMID: 17028317 PMCID: PMC1698627 DOI: 10.1534/genetics.106.064477] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cell cycle checkpoints contribute to survival after exposure to ionizing radiation (IR) by arresting the cell cycle and permitting repair. As such, yeast and mammalian cells lacking checkpoints are more sensitive to killing by IR. We reported previously that Drosophila larvae mutant for grp (encoding a homolog of Chk1) survive IR as well as wild type despite being deficient in cell cycle checkpoints. This discrepancy could be due to differences either among species or between unicellular and multicellular systems. Here, we provide evidence that Grapes is needed for survival of Drosophila S2 cells after exposure to similar doses of IR, suggesting that multicellular organisms may utilize checkpoint-independent mechanisms to survive irradiation. The dispensability of checkpoints in multicellular organisms could be due to replacement of damaged cells by regeneration through increased nutritional uptake and compensatory proliferation. In support of this idea, we find that inhibition of nutritional uptake (by starvation or onset of pupariation) or inhibition of growth factor signaling and downstream targets (by mutations in cdk4, chico, or dmyc) reduced the radiation survival of larvae. Further, some of these treatments are more detrimental for grp mutants, suggesting that the need for compensatory proliferation is greater for checkpoint mutants. The difference in survival of grp and wild-type larvae allowed us to screen for small molecules that act as genotype-specific radiation sensitizers in a multicellular context. A pilot screen of a small molecule library from the National Cancer Institute yielded known and approved radio-sensitizing anticancer drugs. Since radiation is a common treatment option for human cancers, we propose that Drosophila may be used as an in vivo screening tool for genotype-specific drugs that enhance the effect of radiation therapy.
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Affiliation(s)
- Burnley Jaklevic
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder 80309-0347, USA
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230
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Römer L, Klein C, Dehner A, Kessler H, Buchner J. p53 – ein natürlicher Krebskiller: Einsichten in die Struktur und Therapiekonzepte. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200600611] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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231
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Römer L, Klein C, Dehner A, Kessler H, Buchner J. p53—A Natural Cancer Killer: Structural Insights and Therapeutic Concepts. Angew Chem Int Ed Engl 2006; 45:6440-60. [PMID: 16983711 DOI: 10.1002/anie.200600611] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Every single day, the DNA of each cell in the human body is mutated thousands of times, even in absence of oncogenes or extreme radiation. Many of these mutations could lead to cancer and, finally, death. To fight this, multicellular organisms have evolved an efficient control system with the tumor-suppressor protein p53 as the central element. An intact p53 network ensures that DNA damage is detected early on. The importance of p53 for preventing cancer is highlighted by the fact that p53 is inactivated in more than 50 % of all human tumors. Thus, for good reason, p53 is one of the most intensively studied proteins. Despite the great effort that has been made to characterize this protein, the complex function and the structural properties of p53 are still only partially known. This review highlights basic concepts and recent progress in understanding the structure and regulation of p53, focusing on emerging new mechanistic and therapeutic concepts.
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Affiliation(s)
- Lin Römer
- Department Chemie, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany
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232
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Abstract
Compensatory growth, or regeneration, is used to replace damaged tissue during animal development. Recent work has revealed a new role for Drosophila p53 in the compensatory proliferation of cells that are needed to repair damaged tissues, a role that requires the non-apoptotic function of the caspase protease Dronc.
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Affiliation(s)
- Eric H Baehrecke
- Center for Biosystems Research, University of Maryland Biotechnology Institute, College Park, Maryland 20742, USA.
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233
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Abstract
As guardian of the genome the tumor suppressor p53 controls a crucial point in protection from cellular damage and response to stressors. Activation of p53 can have beneficial (DNA repair) or detrimental (apoptosis) consequences for individual cells. In either case activation of p53 is thought to safeguard the organism at large from the deleterious effects of various stresses. Recent data suggest that the function of p53 might also play a role in the regulation of organismal lifespan. Increased p53 activity leads to lifespan shortening in mice, while apparent reduction of p53 activity in flies leads to lifespan extension. Although the mechanism by which p53 regulates lifespan remains to be determined, these findings highlight the possibility that careful manipulation of p53 activity during adult life may result in beneficial effects on healthy lifespan.
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Affiliation(s)
- Johannes H Bauer
- Department of Molecular Biology, Cell Biology and Biochemistry, Division of Biology and Medicine, Brown University, Laboratories for Molecular Medicine, Providence, Rhode Island 02903, USA
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234
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Knights CD, Catania J, Di Giovanni S, Muratoglu S, Perez R, Swartzbeck A, Quong AA, Zhang X, Beerman T, Pestell RG, Avantaggiati ML. Distinct p53 acetylation cassettes differentially influence gene-expression patterns and cell fate. ACTA ACUST UNITED AC 2006; 173:533-44. [PMID: 16717128 PMCID: PMC2063863 DOI: 10.1083/jcb.200512059] [Citation(s) in RCA: 203] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The activity of the p53 gene product is regulated by a plethora of posttranslational modifications. An open question is whether such posttranslational changes act redundantly or dependently upon one another. We show that a functional interference between specific acetylated and phosphorylated residues of p53 influences cell fate. Acetylation of lysine 320 (K320) prevents phosphorylation of crucial serines in the NH2-terminal region of p53; only allows activation of genes containing high-affinity p53 binding sites, such as p21/WAF; and promotes cell survival after DNA damage. In contrast, acetylation of K373 leads to hyperphosphorylation of p53 NH2-terminal residues and enhances the interaction with promoters for which p53 possesses low DNA binding affinity, such as those contained in proapoptotic genes, leading to cell death. Further, acetylation of each of these two lysine clusters differentially regulates the interaction of p53 with coactivators and corepressors and produces distinct gene-expression profiles. By analogy with the “histone code” hypothesis, we propose that the multiple biological activities of p53 are orchestrated and deciphered by different “p53 cassettes,” each containing combination patterns of posttranslational modifications and protein–protein interactions.
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Affiliation(s)
- Chad D Knights
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA
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235
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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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236
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Wichmann A, Jaklevic B, Su TT. Ionizing radiation induces caspase-dependent but Chk2- and p53-independent cell death in Drosophila melanogaster. Proc Natl Acad Sci U S A 2006; 103:9952-7. [PMID: 16785441 PMCID: PMC1502560 DOI: 10.1073/pnas.0510528103] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ionizing radiation (IR) can induce apoptosis via p53, which is the most commonly mutated gene in human cancers. Loss of p53, however, can render cancer cells refractory to therapeutic effects of IR. Alternate p53-independent pathways exist but are not as well understood as p53-dependent apoptosis. Studies of how IR induces p53-independent cell death could benefit from the existence of a genetically tractable model. In Drosophila melanogaster, IR induces apoptosis in the imaginal discs of larvae, typically assayed at 4-6 hr after exposure to a LD(50) dose. In mutants of Drosophila Chk2 or p53 homologs, apoptosis is severely diminished in these assays, leading to the widely held belief that IR-induced apoptosis depends on these genes in Drosophila. In this article, we show that IR-induced apoptosis still occurs in the imaginal discs of chk2 and p53 mutant larvae, albeit with a delay. We demonstrate that this phenomenon is a true apoptotic response because it requires caspase activity and the chromosomal locus that encodes the pro-apoptotic genes reaper, hid, and grim. We also show that Chk2- and p53-independent apoptosis is IR dose-dependent and is therefore probably triggered by a DNA damage signal. We conclude that Drosophila has Chk2- and p53-independent pathways to activate caspases and induce apoptosis in response to IR. This work establishes Drosophila as a model for p53-independent apoptosis, which is of potential therapeutic importance for inducing cell death in p53-deficient cancer cells.
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Affiliation(s)
- Anita Wichmann
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347
| | - Burnley Jaklevic
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347
| | - Tin Tin Su
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347
- To whom correspondence should be addressed. E-mail:
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237
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Yamada Y, Coffman CR. DNA damage-induced programmed cell death: potential roles in germ cell development. Ann N Y Acad Sci 2006; 1049:9-16. [PMID: 15965102 DOI: 10.1196/annals.1334.002] [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: 11/12/2022]
Abstract
The detection of DNA damage is necessary to protect against proliferation of potentially harmful cells and often results in cell cycle arrest and programmed cell death. Key components of DNA damage signaling networks include ATM, CHK2, p53, and Bax. Mutations in these damage signaling systems are linked to tumorigenesis and developmental abnormalities. Expression of some of these genes in primordial germ cells (PGCs) argues that PGCs may utilize DNA damage-induced signaling mechanisms to select against germ cells that are genetically defective, thus maintaining the integrity of the germline. This paper summarizes the roles of these DNA damage signaling molecules and addresses their potential involvement in germ cell development.
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Affiliation(s)
- Yukiko Yamada
- Department of Genetics, Development and Cell Biology, Iowa State University, 3238 Molecular Biology Building, Ames, IA 50011-3260, USA.
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238
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Oikemus SR, Queiroz-Machado J, Lai K, McGinnis N, Sunkel C, Brodsky MH. Epigenetic telomere protection by Drosophila DNA damage response pathways. PLoS Genet 2006; 2:e71. [PMID: 16710445 PMCID: PMC1463044 DOI: 10.1371/journal.pgen.0020071] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Accepted: 03/27/2006] [Indexed: 12/21/2022] Open
Abstract
Analysis of terminal deletion chromosomes indicates that a sequence-independent mechanism regulates protection of Drosophila telomeres. Mutations in Drosophila DNA damage response genes such as atm/tefu, mre11, or rad50 disrupt telomere protection and localization of the telomere-associated proteins HP1 and HOAP, suggesting that recognition of chromosome ends contributes to telomere protection. However, the partial telomere protection phenotype of these mutations limits the ability to test if they act in the epigenetic telomere protection mechanism. We examined the roles of the Drosophila atm and atr-atrip DNA damage response pathways and the nbs homolog in DNA damage responses and telomere protection. As in other organisms, the atm and atr-atrip pathways act in parallel to promote telomere protection. Cells lacking both pathways exhibit severe defects in telomere protection and fail to localize the protection protein HOAP to telomeres. Drosophila nbs is required for both atm- and atr-dependent DNA damage responses and acts in these pathways during DNA repair. The telomere fusion phenotype of nbs is consistent with defects in each of these activities. Cells defective in both the atm and atr pathways were used to examine if DNA damage response pathways regulate telomere protection without affecting telomere specific sequences. In these cells, chromosome fusion sites retain telomere-specific sequences, demonstrating that loss of these sequences is not responsible for loss of protection. Furthermore, terminally deleted chromosomes also fuse in these cells, directly implicating DNA damage response pathways in the epigenetic protection of telomeres. We propose that recognition of chromosome ends and recruitment of HP1 and HOAP by DNA damage response proteins is essential for the epigenetic protection of Drosophila telomeres. Given the conserved roles of DNA damage response proteins in telomere function, related mechanisms may act at the telomeres of other organisms.
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Affiliation(s)
- Sarah R Oikemus
- Program in Gene Function and Expression and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Joana Queiroz-Machado
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Faculdade de Ciências da Saúde, Universidade Fernando Pessoa, Porto, Portugal
| | - KuanJu Lai
- Program in Gene Function and Expression and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Nadine McGinnis
- Program in Gene Function and Expression and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Claudio Sunkel
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Michael H Brodsky
- Program in Gene Function and Expression and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail:
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239
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Affiliation(s)
- W-J Lu
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
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240
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Abstract
Although early studies have suggested that the oncoprotein Mdm2 is the primary E3 ubiquitin ligase for the p53 tumor suppressor, an increasing amount of data suggests that p53 ubiquitination and degradation are more complex than once thought. The discoveries of MdmX, HAUSP, ARF, COP1, Pirh2, and ARF-BP1 continue to uncover the multiple facets of this pathway. There is no question that Mdm2 plays a pivotal role in downregulating p53 activities in numerous cellular settings. Nevertheless, growing evidence challenges the conventional view that Mdm2 is essential for p53 turnover.
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Affiliation(s)
- Christopher L. Brooks
- Institute for Cancer Genetics and Department of Pathology, College of Physicians and Surgeons, Columbia University, 1150 St. Nicholas Avenue, New York, New York 10032
| | - Wei Gu
- Institute for Cancer Genetics and Department of Pathology, College of Physicians and Surgeons, Columbia University, 1150 St. Nicholas Avenue, New York, New York 10032
- Correspondence:
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241
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Abstract
The complexity of the p53 protein, coupled with the vast cellular responses to p53, is simply astonishing. As new isoforms, functional domains and protein-protein interactions are described; each morsel of information forces us to think (and re-think) about how it 'fits' into the current p53 paradigm. One aspect of p53 signaling that is under refinement is the mechanism(s) leading to apoptosis. Here we discuss what is known about p53-induced apoptosis, what proteins and protein-protein interactions are responsible for regulating apoptosis, how can this cascade be genetically dissected, and what pharmacological tools are available to modulate p53-dependent apoptosis. While everything may not comfortably fit into our understanding of p53, all of these data will certainly broaden our viewpoint on the complexity and significance of the p53-induced apoptotic pathway. Here, our discussion is primarily focused on the works presented at the 12th International p53 Workshop, except where appropriate background is required.
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Affiliation(s)
- J E Chipuk
- Department of Immunology, Saint Jude Children's Research Hospital, 332 North Lauderdale Street, Suite E7015, Memphis, Tennessee 38105, USA.
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242
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Liu Y, Lehmann M. FOXO-independent suppression of programmed cell death by the PI3K/Akt signaling pathway in Drosophila. Dev Genes Evol 2006; 216:531-5. [PMID: 16520939 DOI: 10.1007/s00427-006-0063-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2005] [Accepted: 01/27/2006] [Indexed: 10/24/2022]
Abstract
Signaling through the PI3K/Akt/FOXO pathway plays an important role in vertebrates in protecting cells from programmed cell death. PI3K and Akt have been similarly shown to be involved in survival signaling in the invertebrate model organism Drosophila. However, it is not known whether PI3K and Akt execute this function by controlling a pro-apoptotic activity of Drosophila FOXO. In this study, we show that elevated signaling through PI3K and Akt can prevent developmentally controlled death in the salivary glands of the fruit fly. We further show that Drosophila FOXO is not required for normal salivary gland death and that the rescue of salivary gland death by PI3K occurs independent of FOXO. These results give support to the notion that FOXOs have acquired pro-apoptotic functions after separation of the vertebrate and invertebrate lineages.
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Affiliation(s)
- Yanling Liu
- Department of Biological Sciences, University of Arkansas, 601 Science Engineering, Fayetteville, AR 72701, USA
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243
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Brun S, Rincheval-Arnold A, Colin J, Risler Y, Mignotte B, Guénal I. The myb-related gene stonewall induces both hyperplasia and cell death in Drosophila: rescue of fly lethality by coexpression of apoptosis inducers. Cell Death Differ 2006; 13:1752-62. [PMID: 16456582 DOI: 10.1038/sj.cdd.4401861] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We carried out gain-of-function mutagenesis screening and identified a mutant in which GAL4 induction led to both hyperplasia and apoptosis. The gene involved was identified as stonewall (stwl), a myb-related gene involved in germ cell proliferation and differentiation during oogenesis. As observed with dmyb, the ectopic expression of stwl(UY823) inhibited endoreplication in salivary glands. We also found that stwl(UY823) overexpression, like overexpression of the wild-type gene, activated G1/S transition and apoptosis. The apoptosis triggered by stwl(UY823) expression is correlated to induction of the proapoptotic gene reaper. Finally, the death of flies induced by ectopic stwl(UY823) expression is efficiently prevented in vivo by triggering cell death in stwl(UY823)-expressing cells. Our results suggest that stwl(UY823) kills flies by causing inappropriate cell cycle entry, and that triggering the death of these overproliferating cells or slowing their proliferation restores viability.
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Affiliation(s)
- S Brun
- Laboratoire de Génétique et Biologie Cellulaire, CNRS MR 8159, Université de Versailles-St. Quentin en Yvelines, 45 avenue des Etats-Unis, F-78035 Versailles cedex, France
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244
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Mandal S, Guptan P, Owusu-Ansah E, Banerjee U. Mitochondrial regulation of cell cycle progression during development as revealed by the tenured mutation in Drosophila. Dev Cell 2006; 9:843-54. [PMID: 16326395 DOI: 10.1016/j.devcel.2005.11.006] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Revised: 11/02/2005] [Accepted: 11/10/2005] [Indexed: 12/28/2022]
Abstract
The precise control of the cell cycle requires regulation by many intrinsic and extrinsic factors. Whether the metabolic status of the cell exerts a direct control over cell cycle checkpoints is not well understood. We isolated a mutation, tenured (tend), in a gene encoding cytochrome oxidase subunit Va. This mutation causes a drop in intracellular ATP to levels sufficient to maintain cell survival, growth, and differentiation, but not to enable progression through the cell cycle. Analysis of this gene in vivo and in cell lines shows that a specific pathway involving AMPK and p53 is activated that causes elimination of Cyclin E, resulting in cell cycle arrest. We demonstrate that in multiple tissues the mitochondrion has a direct and specific role in enforcing a G1-S cell cycle checkpoint during periods of energy deprivation.
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Affiliation(s)
- Sudip Mandal
- Department of Molecular, Cell, and Developmental Biology, Department of Biological Chemistry and Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California 90095, USA
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245
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Rebollar E, Valadez-Graham V, Vázquez M, Reynaud E, Zurita M. Role of the p53 homologue fromDrosophila melanogasterin the maintenance of histone H3 acetylation and response to UV-light irradiation. FEBS Lett 2006; 580:642-8. [PMID: 16412438 DOI: 10.1016/j.febslet.2005.12.083] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Revised: 12/20/2005] [Accepted: 12/27/2005] [Indexed: 01/01/2023]
Abstract
It has been demonstrated that the human tumor suppressor p53 has an important role in modulating histone modifications after UV light irradiation. In this work we explored if the p53 Drosophila homologue has a similar role. Taking advantage of the existence of polytene chromosomes in the salivary glands of third instar larvae, we analyzed K9 and K14 H3 acetylation patterns in situ after UV irradiation of wild-type and Dmp53 null flies. As in human cells, after UV damage there is an increase in H3 acetylation in wild-type organisms. In Dmp53 mutant flies, this response is significantly affected at the K9 position. These results are similar to those found in human p53 mutant tumor cells with one interesting difference, only the basal H3 acetylation of K14 is reduced in Dmp53 mutant flies, while the basal H3-K9 acetylation is not affected. This work shows, that the presence of Dmp53 is necessary to maintain normal H3-K14 acetylation levels in Drosophila chromatin and that the function of p53 to maintaining histone modifications, is conserved in Drosophila and humans.
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Affiliation(s)
- Eria Rebollar
- Department of Developmental Genetics and Molecular Physiology, Institute of Biotechnology, National University of México, Cuernavaca, Morelos 62250, Mexico
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246
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Pérez-Garijo A, Martín FA, Struhl G, Morata G. Dpp signaling and the induction of neoplastic tumors by caspase-inhibited apoptotic cells in Drosophila. Proc Natl Acad Sci U S A 2005; 102:17664-9. [PMID: 16314564 PMCID: PMC1308921 DOI: 10.1073/pnas.0508966102] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In Drosophila, stresses such as x-irradiation or severe heat shock can cause most epidermal cells to die by apoptosis. Yet, the remaining cells recover from such assaults and form normal adult structures, indicating that they undergo extra growth to replace the lost cells. Recent studies of cells in which the cell death pathway is blocked by expression of the caspase inhibitor P35 have raised the possibility that dying cells normally regulate this compensatory growth by serving as transient sources of mitogenic signals. Caspase-inhibited cells that initiate apoptosis do not die. Instead, they persist in an "undead" state in which they ectopically express the signaling genes decapentaplegic (dpp) and wingless (wg) and induce abnormal growth and proliferation of surrounding tissue. Here, using mutations to abolish Dpp and/or Wg signaling by such undead cells, we show that Dpp and Wg constitute opposing stimulatory and inhibitory signals that regulate this excess growth and proliferation. Strikingly, we also found that, when Wg signaling is blocked, unfettered Dpp signaling by undead cells transforms their neighbors into neoplastic tumors, provided that caspase activity is also blocked in the responding cells. This phenomenon may provide a paradigm for the formation of neoplastic tumors in mammalian tissues that are defective in executing the cell death pathway. Specifically, we suggest that stress events (exposure to chemical mutagens, viral infection, or irradiation) that initiate apoptosis in such tissues generate undead cells, and that imbalances in growth regulatory signals sent by these cells can induce the oncogenic transformation of neighboring cells.
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Affiliation(s)
- Ainhoa Pérez-Garijo
- Centro de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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247
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Werz C, Lee TV, Lee PL, Lackey M, Bolduc C, Stein DS, Bergmann A. Mis-specified cells die by an active gene-directed process, and inhibition of this death results in cell fate transformation in Drosophila. Development 2005; 132:5343-52. [PMID: 16280349 PMCID: PMC2760325 DOI: 10.1242/dev.02150] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Incorrectly specified or mis-specified cells often undergo cell death or are transformed to adopt a different cell fate during development. The underlying cause for this distinction is largely unknown. In many developmental mutants in Drosophila, large numbers of mis-specified cells die synchronously, providing a convenient model for analysis of this phenomenon. The maternal mutant bicoid is particularly useful model with which to address this issue because its mutant phenotype is a combination of both transformation of tissue (acron to telson) and cell death in the presumptive head and thorax regions. We show that a subset of these mis-specified cells die through an active gene-directed process involving transcriptional upregulation of the cell death inducer hid. Upregulation of hid also occurs in oskar mutants and other segmentation mutants. In hid bicoid double mutants, mis-specified cells in the presumptive head and thorax survive and continue to develop, but they are transformed to adopt a different cell fate. We provide evidence that the terminal torso signaling pathway protects the mis-specified telson tissue in bicoid mutants from hid-induced cell death, whereas mis-specified cells in the head and thorax die, presumably because equivalent survival signals are lacking. These data support a model whereby mis-specification can be tolerated if a survival pathway is provided, resulting in cellular transformation.
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Affiliation(s)
- Christian Werz
- The University of Texas M.D. Anderson Cancer Center, Department of Biochemistry and Molecular Biology, 1515 Holcombe Boulevard, Unit 1000, Houston, TX 77030, USA
| | - Tom V. Lee
- The University of Texas M.D. Anderson Cancer Center, Department of Biochemistry and Molecular Biology, 1515 Holcombe Boulevard, Unit 1000, Houston, TX 77030, USA
- The Genes and Development Graduate Program (http://www.mdanderson.org/genedev)
| | - Peter L. Lee
- The University of Texas M.D. Anderson Cancer Center, Department of Biochemistry and Molecular Biology, 1515 Holcombe Boulevard, Unit 1000, Houston, TX 77030, USA
| | - Melinda Lackey
- The University of Texas M.D. Anderson Cancer Center, Department of Biochemistry and Molecular Biology, 1515 Holcombe Boulevard, Unit 1000, Houston, TX 77030, USA
| | - Clare Bolduc
- The University of Texas M.D. Anderson Cancer Center, Department of Biochemistry and Molecular Biology, 1515 Holcombe Boulevard, Unit 1000, Houston, TX 77030, USA
| | - David S. Stein
- The University of Texas at Austin, Patterson labs 532, Section of Molecular Cell and Developmental Biology, Institute for Cellular and Molecular Biology, 2401 W24th and Speedway, Austin, TX 78712, USA
| | - Andreas Bergmann
- The University of Texas M.D. Anderson Cancer Center, Department of Biochemistry and Molecular Biology, 1515 Holcombe Boulevard, Unit 1000, Houston, TX 77030, USA
- The Genes and Development Graduate Program (http://www.mdanderson.org/genedev)
- Author for correspondence (e-mail: )
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248
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Lee JH, Koh H, Kim M, Park J, Lee SY, Lee S, Chung J. JNK pathway mediates apoptotic cell death induced by tumor suppressor LKB1 in Drosophila. Cell Death Differ 2005; 13:1110-22. [PMID: 16273080 DOI: 10.1038/sj.cdd.4401790] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Although recent progresses have unveiled the diverse in vivo functions of LKB1, detailed molecular mechanisms governing these processes still remain enigmatic. Here, we showed that Drosophila LKB1 negatively regulates organ growth by caspase-dependent apoptosis, without affecting cell size and cell cycle progression. Through genetic screening for LKB1 modifiers, we discovered the JNK pathway as a novel component of LKB1 signaling; the JNK pathway was activated by LKB1 and mediated the LKB1-dependent apoptosis. Consistently, LKB1-null mutant was defective in embryonic apoptosis and displayed a drastic hyperplasia in the central nervous system; these phenotypes were fully rescued by ectopic JNK activation as well as wild-type LKB1 expression. Furthermore, inhibition of LKB1 resulted in epithelial morphogenesis failure, which was associated with a decrease in JNK activity. Collectively, our studies unprecedentedly elucidate JNK as the downstream mediator of the LKB1-dependent apoptosis, and provide a new paradigm for understanding the diverse LKB1 functions in vivo.
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Affiliation(s)
- J H Lee
- National Creative Research Initiatives Center for Cell Growth Regulation and Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong, Taejon, Korea
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249
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Bauer JH, Poon PC, Glatt-Deeley H, Abrams JM, Helfand SL. Neuronal Expression of p53 Dominant-Negative Proteins in Adult Drosophila melanogaster Extends Life Span. Curr Biol 2005; 15:2063-8. [PMID: 16303568 DOI: 10.1016/j.cub.2005.10.051] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Revised: 10/06/2005] [Accepted: 10/10/2005] [Indexed: 11/24/2022]
Abstract
Hyperactivation of p53 leads to a reduction in tumor formation and an unexpected shortening of life span in two different model systems . The decreased life span occurs with signs of accelerated aging, such as osteoporosis, reduction in body weight, atrophy of organs, decreased stress resistance, and depletion of hematopoietic stem cells. These observations suggest a role for p53 in the determination of life span and the speculation that decreasing p53 activity may result in positive effects on some aging phenotypes . In this report, we show that expression of dominant-negative versions of Drosophila melanogaster p53 in adult neurons extends life span and increases genotoxic stress resistance in the fly. Consistent with this, a naturally occurring allele with decreased p53 activity has been associated with extended survival in humans . Expression of the dominant-negative Drosophila melanogaster p53 constructs does not further increase the extended life span of flies that are calorie restricted, suggesting that a decrease in p53 activity may mediate a component of the calorie-restriction life span-extending pathway in flies.
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Affiliation(s)
- Johannes H Bauer
- University of Connecticut Health Center, Department of Genetics and Developmental Biology, 263 Farmington Avenue, Farmington, Connecticut 06073, USA
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250
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Müller D, Kugler SJ, Preiss A, Maier D, Nagel AC. Genetic modifier screens on Hairless gain-of-function phenotypes reveal genes involved in cell differentiation, cell growth and apoptosis in Drosophila melanogaster. Genetics 2005; 171:1137-52. [PMID: 16118195 PMCID: PMC1456817 DOI: 10.1534/genetics.105.044453] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Accepted: 07/29/2005] [Indexed: 11/18/2022] Open
Abstract
Overexpression of Hairless (H) causes a remarkable degree of tissue loss and apoptosis during imaginal development. H functions as antagonist in the Notch-signaling pathway in Drosophila, and the link to growth and apoptosis is poorly understood. To further our insight into H-mediated apoptosis, we performed two large-scale screens for modifiers of a small rough eye phenotype caused by H overexpression. Both loss- and gain-of-function screens revealed known and new genetic interactors representing diverse cellular functions. Many of them did not cause eye phenotypes on their own, emphasizing a specific genetic interaction with H. As expected, we also identified components of different signaling pathways supposed to be involved in the regulation of cell growth and cell death. Accordingly, some of them also acted as modifiers of proapoptotic genes, suggesting a more general involvement in the regulation of apoptosis. Overall, these screens highlight the importance of H and the Notch pathway in mediating cell death in response to developmental and environmental cues and emphasize their role in maintaining developmental cellular homeostasis.
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Affiliation(s)
- Dominik Müller
- University of Hohenheim, Institute of Genetics (240), 70599 Stuttgart, Germany
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