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Xiao W, Sun Y, Xu J, Zhang N, Dong L. uORF-Mediated Translational Regulation of ATF4 Serves as an Evolutionarily Conserved Mechanism Contributing to Non-Small-Cell Lung Cancer (NSCLC) and Stress Response. J Mol Evol 2022; 90:375-388. [PMID: 35962830 PMCID: PMC9375200 DOI: 10.1007/s00239-022-10068-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 07/20/2022] [Indexed: 11/30/2022]
Abstract
Diseases and environmental stresses are two distinct challenges for virtually all living organisms. In light of evolution, cellular responses to diseases and stresses might share similar molecular mechanisms, but the detailed regulation pathway is not reported yet. We obtained the transcriptomes and translatomes from several NSCLC (non-small-cell lung cancer) patients as well as from different species under normal or stress conditions. We found that the translation level of gene ATF4 is remarkably enhanced in NSCLC due to the reduced number of ribosomes binding to its upstream open reading frames (uORFs). We also showed the evolutionary conservation of this uORF-ATF4 regulation in the stress response of other species. Molecular experiments showed that knockdown of ATF4 reduced the cell growth rate while overexpression of ATF4 enhanced cell growth, especially for the ATF4 allele with mutated uORFs. Population genetics analyses in multiple species verified that the mutations that abolish uATGs (start codon of uORFs) are highly deleterious, suggesting the functional importance of uORFs. Our study proposes an evolutionarily conserved pattern that enhances the ATF4 translation by uORFs upon stress or disease. We generalized the concept of cellular response to diseases and stresses. These two biological processes may share similar molecular mechanisms.
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Affiliation(s)
- Wenjing Xiao
- Department of Radiotherapy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China.
| | - Yang Sun
- Department of Radiotherapy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Jinpeng Xu
- Department of Radiotherapy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Na Zhang
- Department of Radiotherapy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Lina Dong
- Department of Radiotherapy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
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2
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Huang Y, Cai P, Su X, Zheng M, Chi W, Lin S, Huang Z, Qin S, Zeng S. Hsian-Tsao ( Mesona chinensis Benth.) Extract Improves the Thermal Tolerance of Drosophila melanogaster. Front Nutr 2022; 9:819319. [PMID: 35614980 PMCID: PMC9124935 DOI: 10.3389/fnut.2022.819319] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 04/07/2022] [Indexed: 11/13/2022] Open
Abstract
Global warming has prompted scientific communities to consider how to alleviate thermal stress in humans and animals. The present study assessed the supplementation of hsian-tsao extract (HTE) on thermal stress in Drosophila melanogaster and preliminarily explicated its possible physiological and molecular mechanisms. Our results indicated that the lethal time for 50% of female flies fed on HTE was significantly longer than that of male flies at the same heat stress temperature. Under thermal stress, the survival time of females was remarkably increased in the HTE addition groups compared to the non-addition group. Thermal hardening by acute exposure to 36°C for 30 min (9:00 to 9:30 a.m.) every day could significantly prolong the longevity of females. Without thermal hardening, HTE increased the antioxidant capacity of females under heat stress, accompanied by an increment of catalase (CAT) activity, and the inhibition for hydroxyl radicals (OH⋅) and superoxide anions (⋅O2 -). Superoxide dismutase (SOD) activity and the inhibition for ⋅O2 - was significantly affected by thermal hardening in the non-HTE addition groups, and significant differences were shown in CAT and SOD activities, and the inhibition for ⋅O2 - among groups with thermal hardening. After heat exposure, heat shock protein 70 (Hsp70) was only up-regulated in the group with high levels of added HTE compared with the group without and this was similar in the thermal hardening group. It was concluded that the heat stress-relieving ability of HTE might be partly due to the enhancement of enzymatic activities of SOD and CAT, and the inhibition for OH⋅ and ⋅O2 -. However, the expression levels of Hsp70 were not well related to thermal tolerance or heat survival.
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Affiliation(s)
- Yan Huang
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Tea and Food Science, Wuyi University, Wuyishan, China
- Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Pumo Cai
- College of Tea and Food Science, Wuyi University, Wuyishan, China
| | - Xinxin Su
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Mingjing Zheng
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Ocean Food and Biological Engineering, Jimei University, Xiamen, China
| | - Wenwen Chi
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shaoling Lin
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhiwei Huang
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Si Qin
- College of Food Science and Technology, Hunan Agricultural University, Changsha, China
| | - Shaoxiao Zeng
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou, China
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3
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Gao P, Lu MX, Pan DD, Du YZ. Characterization of an inducible HSP70 gene in Chilo suppressalis and expression in response to environmental and biological stress. Cell Stress Chaperones 2020; 25:65-72. [PMID: 31792734 PMCID: PMC6985400 DOI: 10.1007/s12192-019-01047-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 10/09/2019] [Accepted: 10/22/2019] [Indexed: 12/11/2022] Open
Abstract
The highly conserved heat shock protein 70 (HSP70) contributes to survival at a cellular level and greatly enhances stress tolerance in many organisms. In this study, we isolate and characterize Cshsp702, which encodes an inducible form of HSP70 in the rice stem borer, Chilo suppressalis. Cshsp702 does not contain introns; the translational product is comprised of 629 amino acids with an isoelectric point of 5.69. Real-time quantitative PCR revealed that Cshsp702 was expressed at maximal levels in hemocytes and was minimally expressed in the midgut. Expression of Cshsp702 in response to a range of temperatures (-11 to 43 °C) indicated significant induction by extreme cold and hot temperatures, with maximum expression after 2 h at 42 °C. The induction of Cshsp702 in response to the endoparasite Cotesia chilonis was also studied; interestingly, Cshsp702 expression in C. suppressalis was significantly induced at 24 h and 5 days, which correspond to predicted times of C. chilonis feeding and growth, respectively. The potential induction of Cshsp702 as an inflammatory response due to parasitic stress is discussed. In conclusion, Cshsp702 is induced in response to both environmental and biotic stress and plays an important role in the physiological adaptation of C. suppressalis.
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Affiliation(s)
- Peng Gao
- School of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou, 225009, China
| | - Ming-Xing Lu
- School of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou, 225009, China.
| | - Dan-Dan Pan
- School of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou, 225009, China
| | - Yu-Zhou Du
- School of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou, 225009, China.
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China.
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4
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Hess K, Oliverio R, Nguyen P, Le D, Ellis J, Kdeiss B, Ord S, Chalkia D, Nikolaidis N. Concurrent action of purifying selection and gene conversion results in extreme conservation of the major stress-inducible Hsp70 genes in mammals. Sci Rep 2018; 8:5082. [PMID: 29572464 PMCID: PMC5865164 DOI: 10.1038/s41598-018-23508-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 03/14/2018] [Indexed: 12/28/2022] Open
Abstract
Several evolutionary mechanisms alter the fate of mutations and genes within populations based on their exhibited functional effects. To understand the underlying mechanisms involved in the evolution of the cellular stress response, a very conserved mechanism in the course of organismal evolution, we studied the patterns of natural genetic variation and functional consequences of polymorphisms of two stress-inducible Hsp70 genes. These genes, HSPA1A and HSPA1B, are major orchestrators of the cellular stress response and are associated with several human diseases. Our phylogenetic analyses revealed that the duplication of HSPA1A and HSPA1B originated in a lineage proceeding to placental mammals, and henceforth they remained in conserved synteny. Additionally, analyses of synonymous and non-synonymous changes suggest that purifying selection shaped the HSPA1 gene diversification, while gene conversion resulted in high sequence conservation within species. In the human HSPA1-cluster, the vast majority of mutations are synonymous and specific genic regions are devoid of mutations. Furthermore, functional characterization of several human polymorphisms revealed subtle differences in HSPA1A stability and intracellular localization. Collectively, the observable patterns of HSPA1A-1B variation describe an evolutionary pattern, in which purifying selection and gene conversion act simultaneously and conserve a major orchestrator of the cellular stress response.
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Affiliation(s)
- Kyle Hess
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA.,Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Ryan Oliverio
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA
| | - Peter Nguyen
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA
| | - Dat Le
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA
| | - Jacqueline Ellis
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA
| | - Brianna Kdeiss
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA
| | - Sara Ord
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA
| | - Dimitra Chalkia
- UCLA Center for Systems Biomedicine, Division of Digestive Diseases, School of Medicine, Los Angeles, CA, USA
| | - Nikolas Nikolaidis
- Department of Biological Science, Center for Applied Biotechnology Studies, and Center for Computational and Applied Mathematics, California State University, Fullerton, Fullerton, CA, 92834, USA.
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5
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Krebs RA, Feder ME, Lee J. HERITABILITY OF EXPRESSION OF THE 70KD HEAT-SHOCK PROTEIN IN DROSOPHILA MELANOGASTER AND ITS RELEVANCE TO THE EVOLUTION OF THERMOTOLERANCE. Evolution 2017; 52:841-847. [PMID: 28565246 DOI: 10.1111/j.1558-5646.1998.tb03708.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/1997] [Accepted: 03/06/1998] [Indexed: 11/30/2022]
Abstract
The principle inducible heat-shock protein of Drosophila melanogaster, Hsp70, contributes to thermotolerance throughout the entire life cycle of the species but may also reduce fitness in some life stages. In principle, selection might maximize the benefits of Hsp70 expression relative to its costs by adjusting the magnitude of Hsp70 expression for each life-cycle stage independently. Therefore we examined whether the magnitude of Hsp70 expression varied during the life cycle and the relationship of this variation to several life-history traits. For 28 isofemale lines derived from a single natural population, estimates of heritable variation in Hsp70 expression ranged between 0.25 and 0.49, and the association among variation in first- and third-instar larvae and in adults correlated highly. Thus, Hsp70 expression is genetically coupled at these developmental stages. A line engineered with extra copies of the hsp70 gene produced more Hsp70 and survived heat shock much better than did a control strain. Among natural lines, Hsp70 expression was only weakly related to tolerance of heat shock and to larva-to-adult survival and developmental time at permissive temperatures. Additionally, lines with high adult survival developed slowly as larvae, which is a possible trade-off. These and other findings suggest that trade-offs may maintain quantitative variation both in heat-shock protein expression and in life-history traits that associate with thermotolerance.
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Affiliation(s)
- Robert A Krebs
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, Illinois, 60637
| | - Martin E Feder
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, Illinois, 60637.,Committee on Evolutionary Biology, University of Chicago, 1027 East 57th Street, Chicago, Illinois, 60637
| | - Jeehyun Lee
- Department of Organismal Biology and Anatomy, University of Chicago, 1027 East 57th Street, Chicago, Illinois, 60637
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6
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Garbuz DG, Evgen’ev MB. The evolution of heat shock genes and expression patterns of heat shock proteins in the species from temperature contrasting habitats. RUSS J GENET+ 2017. [DOI: 10.1134/s1022795417010069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Andreeva NV, Zatsepina OG, Garbuz DG, Evgen'ev MB, Belyavsky AV. Recombinant HSP70 and mild heat shock stimulate growth of aged mesenchymal stem cells. Cell Stress Chaperones 2016; 21:727-33. [PMID: 27091568 PMCID: PMC4907997 DOI: 10.1007/s12192-016-0691-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 03/25/2016] [Accepted: 04/11/2016] [Indexed: 01/21/2023] Open
Abstract
Heat shock proteins including the major stress protein HSP70 support intracellular homeostasis and prevent protein damage after a temperature increase and other stressful environmental stimuli, as well as during aging. We have shown earlier that prolonged administration of recombinant human HSP70 to mice exhibiting Alzheimer's-like neurodegeneration as well as during sepsis reduces the clinical manifestations of these pathologies. Herein, we studied the action of recombinant human HSP70 on young and aged mouse mesenchymal stem cells (MSCs) in culture. The results obtained indicate that HSP70 at concentrations of 2 μg/ml and higher significantly stimulates growth of aged but not young MSCs. A similar effect is produced by application of a mild heat shock (42 °C 5 min) to the cells. Importantly, responses of young and aged MSCs to heat shock treatment of various durations differed drastically, and aged MSCs were significantly more sensitive to higher heat stress exposures than the young cells. Western blotting and protein labeling experiments demonstrated that neither mild heat shock nor exogenous HSP70 administration resulted in significant endogenous HSP70 induction in young and aged MSCs, whereas mild heat shock increased HSC70 levels in aged MSCs. The results of this study suggest that the administration of exogenous HSP70 and the application of mild heat stress may produce a certain "rejuvenating" effect on MSCs and possibly other cell types in vivo, and these interventions may potentially be used for life extension by delaying various manifestations of aging at the molecular and cellular level.
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Affiliation(s)
- N V Andreeva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991, Moscow, Vavilov Str. 32, Russian Federation
| | - O G Zatsepina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991, Moscow, Vavilov Str. 32, Russian Federation
| | - D G Garbuz
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991, Moscow, Vavilov Str. 32, Russian Federation
| | - M B Evgen'ev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991, Moscow, Vavilov Str. 32, Russian Federation.
| | - A V Belyavsky
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991, Moscow, Vavilov Str. 32, Russian Federation
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8
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Milton SL, Dawson-Scully K. Alleviating brain stress: what alternative animal models have revealed about therapeutic targets for hypoxia and anoxia. FUTURE NEUROLOGY 2013; 8:287-301. [PMID: 25264428 DOI: 10.2217/fnl.13.12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
While the mammalian brain is highly dependent on oxygen, and can withstand only a few minutes without air, there are both vertebrate and invertebrate examples of anoxia tolerance. One example is the freshwater turtle, which can withstand days without oxygen, thus providing a vertebrate model with which to examine the physiology of anoxia tolerance without the pathology seen in mammalian ischemia/reperfusion studies. Insect models such as Drosophila melanogaster have additional advantages, such as short lifespans, low cost and well-described genetics. These models of anoxia tolerance share two common themes that enable survival without oxygen: entrance into a state of deep hypometabolism, and the suppression of cellular injury during anoxia and upon restoration of oxygen. The study of such models of anoxia tolerance, adapted through millions of years of evolution, may thus suggest protective pathways that could serve as therapeutic targets for diseases characterized by oxygen deprivation and ischemic/reperfusion injuries.
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Affiliation(s)
- Sarah L Milton
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA
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9
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Bubliy OA, Kristensen TN, Loeschcke V. Stress-induced plastic responses in Drosophila simulans following exposure to combinations of temperature and humidity levels. J Exp Biol 2013; 216:4601-7. [DOI: 10.1242/jeb.092502] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
Plastic responses to heat and desiccation stress in insects have been studied in many laboratory experiments on Drosophila. However, in these studies the possible interaction between the corresponding stress factors in natural environments has not been taken into consideration. We investigated changes in heat and desiccation resistance of adult Drosophila simulans after short-term exposures to different temperatures (35ºC, 31ºC, 18ºC) in combination with high and low relative humidity (RH, ca. 90% and 20%, respectively). Hardening under extreme conditions (35ºC or 31ºC and low RH) commonly resulted in higher resistance to heat and desiccation as compared to other less stressful combinations of temperature and humidity levels. The concentration of the heat-shock protein Hsp70 in the experimental flies increased following almost all applied treatments. Life span of the hardened flies under non-stressful conditions was reduced irrespective of the stress dose indicating a fitness cost for the plastic responses. The results of the study show that hardening using combined heat-desiccation stress can be very efficient with regard to induction of plastic responses improving tolerance to both types of stress. This may favour adaptation to hot and dry climatic conditions, though the negative effects on fitness are likely to constrain evolution of such plastic responses.
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10
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Thorat LJ, Gaikwad SM, Nath BB. Trehalose as an indicator of desiccation stress in Drosophila melanogaster larvae: a potential marker of anhydrobiosis. Biochem Biophys Res Commun 2012; 419:638-42. [PMID: 22387478 DOI: 10.1016/j.bbrc.2012.02.065] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 02/09/2012] [Indexed: 11/18/2022]
Abstract
In the current scenario of global climate change, desiccation is considered as one of the major environmental stressors for the biota exposed to altered levels of ambient temperature and humidity. Drosophila melanogaster, a cosmopolitan terrestrial insect has been chosen as a humidity-sensitive bioindicator model for the present study since its habitat undergoes frequent stochastic and/or seasonally aggravated dehydration regimes. We report here for the first time the occurrence of anhydrobiosis in D. melanogaster larvae by subjecting them to desiccation stress under laboratory conditions. Larvae desiccated for ten hours at <5% relative humidity could enter anhydrobiosis and could revive upon rehydration followed by resumption of active metabolism. As revealed by FTIR and HPLC analyzes, our findings strongly indicated the synthesis and accumulation of trehalose in the desiccating larvae. Biochemical measurements pointed out the desiccation-responsive trehalose metabolic pathway that was found to be coordinated in concert with the enzymes trehalose 6-phosphate synthase and trehalase. Further, an inhibitor-based experimental approach using deoxynojirimycin, a specific trehalase inhibitor, demonstrated the pivotal role of trehalose in larval anhydrobiosis of D. melanogaster. We therefore propose trehalose as a potential marker for the assessment of anhydrobiosis in Drosophila. The present findings thus add to the growing list of novel biochemical markers in specific bioindicator organisms for fulfilling the urgent need of environmental biomonitoring of climate change.
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Affiliation(s)
- Leena J Thorat
- Centre for Advanced Studies, Department of Zoology, University of Pune, Pune 411007, India
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11
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Bubliy OA, Kristensen TN, Kellermann V, Loeschcke V. Plastic responses to four environmental stresses and cross-resistance in a laboratory population ofDrosophila melanogaster. Funct Ecol 2011. [DOI: 10.1111/j.1365-2435.2011.01928.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Chen A, Kramer EF, Purpura L, Krill JL, Zars T, Dawson-Scully K. The influence of natural variation at the foraging gene on thermotolerance in adult Drosophila in a narrow temperature range. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011; 197:1113-8. [PMID: 21861180 DOI: 10.1007/s00359-011-0672-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 07/08/2011] [Accepted: 07/30/2011] [Indexed: 11/26/2022]
Abstract
Poikilothermic organisms such as insects have mechanisms to protect neural function under high temperature stress. Natural variation at the foraging (for) locus of the fruit fly, Drosophila melanogaster, encoding a cGMP-dependent protein kinase (PKG), influences neural thermotolerance in Drosophila larvae. The current study re-examines thermotolerance of adult flies to account for inconsistencies in the documented role of for during hyperthermia. We found that adult for (R) (rover) flies with high PKG activity were incapacitated faster under hyperthermic conditions of 39°C compared to their lower PKG activity counterparts for (s) and for (s2) (sitters), but not at higher temperatures. This indicates that lowered PKG activity promotes tolerance to heat stress, and that the for gene influences thermotolerance for a narrow range of temperatures in adult flies.
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Affiliation(s)
- Adam Chen
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
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13
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Garbuz DG, Yushenova IA, Zatsepina OG, Przhiboro AA, Bettencourt BR, Evgen'ev MB. Organization and evolution of hsp70 clusters strikingly differ in two species of Stratiomyidae (Diptera) inhabiting thermally contrasting environments. BMC Evol Biol 2011; 11:74. [PMID: 21426536 PMCID: PMC3071340 DOI: 10.1186/1471-2148-11-74] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Accepted: 03/22/2011] [Indexed: 11/11/2022] Open
Abstract
Background Previously, we described the heat shock response in dipteran species belonging to the family Stratiomyidae that develop in thermally and chemically contrasting habitats including highly aggressive ones. Although all species studied exhibit high constitutive levels of Hsp70 accompanied by exceptionally high thermotolerance, we also detected characteristic interspecies differences in heat shock protein (Hsp) expression and survival after severe heat shock. Here, we analyzed genomic libraries from two Stratiomyidae species from thermally and chemically contrasting habitats and determined the structure and organization of their hsp70 clusters. Results Although the genomes of both species contain similar numbers of hsp70 genes, the spatial distribution of hsp70 copies differs characteristically. In a population of the eurytopic species Stratiomys singularior, which exists in thermally variable and chemically aggressive (hypersaline) conditions, the hsp70 copies form a tight cluster with approximately equal intergenic distances. In contrast, in a population of the stenotopic Oxycera pardalina that dwells in a stable cold spring, we did not find hsp70 copies in tandem orientation. In this species, the distance between individual hsp70 copies in the genome is very large, if they are linked at all. In O. pardalina we detected the hsp68 gene located next to a hsp70 copy in tandem orientation. Although the hsp70 coding sequences of S. singularior are highly homogenized via conversion, the structure and general arrangement of the hsp70 clusters are highly polymorphic, including gross aberrations, various deletions in intergenic regions, and insertion of incomplete Mariner transposons in close vicinity to the 3'-UTRs. Conclusions The hsp70 gene families in S. singularior and O. pardalina evolved quite differently from one another. We demonstrated clear evidence of homogenizing gene conversion in the S. singularior hsp70 genes, which form tight clusters in this species. In the case of the other species, O. pardalina, we found no clear trace of concerted evolution for the dispersed hsp70 genes. Furthermore, in the latter species we detected hsp70 pseudogenes, representing a hallmark of the birth-and-death process.
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Affiliation(s)
- David G Garbuz
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
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14
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Chen B, Shilova VY, Zatsepina OG, Evgen’ev MB, Feder ME. Location of P element insertions in the proximal promoter region of Hsp70A is consequential for gene expression and correlated with fecundity in Drosophila melanogaster. Cell Stress Chaperones 2008; 13:11-7. [PMID: 18347937 PMCID: PMC2666209 DOI: 10.1007/s12192-007-0002-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Revised: 06/15/2007] [Accepted: 06/22/2007] [Indexed: 01/29/2023] Open
Abstract
We compared a series of Drosophila strains with P element insertions from -28 to -144 nucleotides 5' to the transcription start site of the Hsp70A genes-corresponding to the range of naturally occurring P element insertion sites-to elucidate the consequences of insertion site for Hsp70A gene expression. Although all insertions reduced Hsp70A expression below that of a control strain, the magnitude of the reduction was inversely related to the number of nucleotides between the transcription start site and the insertion site. A pre-existing hypothesis is that naturally occurring transposable element insertions in Hsp promoters may be beneficial in some circumstances, which may account for their retention in natural populations. In the present study, in a control line heat shock reduced fecundity, whereas in lines with P element insertions heat shock typically increased fecundity. Finally, according to cluster-specific quantitative RT-PCR, expression of the Hsp70A cluster genes was typically greater than that of the Hsp70B gene cluster genes, although the latter are more numerous and, in this case, free of P element insertions.
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Affiliation(s)
- Bing Chen
- Department of Organismal Biology and Anatomy, The University of Chicago, 1027 E. 57th Street, Chicago, IL 60637 USA
- Institute of Zoology, Chinese Academy of Sciences, Beijing, 100080 China
| | - Victoria Y. Shilova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 117984 Moscow, Russia
| | - Olga G. Zatsepina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 117984 Moscow, Russia
| | - Michael B. Evgen’ev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov str. 32, 117984 Moscow, Russia
| | - Martin E. Feder
- Department of Organismal Biology and Anatomy, The University of Chicago, 1027 E. 57th Street, Chicago, IL 60637 USA
- The Committees on Evolutionary Biology, Genetics, and Molecular Medicine, The University of Chicago, 1027 E. 57th Street, Chicago, IL 60637 USA
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15
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Bettencourt BR, Hogan CC, Nimali M, Drohan BW. Inducible and constitutive heat shock gene expression responds to modification of Hsp70 copy number in Drosophila melanogaster but does not compensate for loss of thermotolerance in Hsp70 null flies. BMC Biol 2008; 6:5. [PMID: 18211703 PMCID: PMC2257928 DOI: 10.1186/1741-7007-6-5] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Accepted: 01/22/2008] [Indexed: 06/12/2024] Open
Abstract
Background The heat shock protein Hsp70 promotes inducible thermotolerance in nearly every organism examined to date. Hsp70 interacts with a network of other stress-response proteins, and dissecting the relative roles of these interactions in causing thermotolerance remains difficult. Here we examine the effect of Hsp70 gene copy number modification on thermotolerance and the expression of multiple stress-response genes in Drosophila melanogaster, to determine which genes may represent mechanisms of stress tolerance independent of Hsp70. Results Hsp70 copy number in four strains is positively associated with Hsp70 expression and inducible thermotolerance of severe heat shock. When assayed at carefully chosen temperatures, Hsp70 null flies are almost entirely deficient in thermotolerance. In contrast to expectations, increasing Hsp70 expression levels induced by thermal pretreatment are associated with increasing levels of seven other inducible Hsps across strains. In addition, complete Hsp70 loss causes upregulation of the inducible Hsps and six constitutive stress-response genes following severe heat shocks. Conclusion Modification of Hsp70 copy number quantitatively and qualitatively affects the expression of multiple other stress-response genes. A positive association between absolute expression levels of Hsp70 and other Hsps after thermal pretreatment suggests novel regulatory mechanisms. Severe heat shocks induce both novel gene expression patterns and almost total mortality in the Hsp70 null strain: alteration of gene expression in this strain does not compensate for Hsp70 loss but suggests candidates for overexpression studies.
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Affiliation(s)
- Brian R Bettencourt
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854, USA.
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16
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Gong WJ, Golic KG. Loss of Hsp70 in Drosophila is pleiotropic, with effects on thermotolerance, recovery from heat shock and neurodegeneration. Genetics 2005; 172:275-86. [PMID: 16204210 PMCID: PMC1456155 DOI: 10.1534/genetics.105.048793] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The heat-shock response is a programmed change in gene expression carried out by cells in response to environmental stress, such as heat. This response is universal and is characterized by the synthesis of a small group of conserved protein chaperones. In Drosophila melanogaster the Hsp70 chaperone dominates the profile of protein synthesis during the heat-shock response. We recently generated precise deletion alleles of the Hsp70 genes of D. melanogaster and have used those alleles to characterize the phenotypes of Hsp70-deficient flies. Flies with Hsp70 deletions have reduced thermotolerance. We find that Hsp70 is essential to survive a severe heat shock, but is not required to survive a milder heat shock, indicating that a significant degree of thermotolerance remains in the absence of Hsp70. However, flies without Hsp70 have a lengthened heat-shock response and an extended developmental delay after a non-lethal heat shock, indicating Hsp70 has an important role in recovery from stress, even at lower temperatures. Lack of Hsp70 also confers enhanced sensitivity to a temperature-sensitive lethal mutation and to the neurodegenerative effects produced by expression of a human polyglutamine disease protein.
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Affiliation(s)
- Wei J Gong
- Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA
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17
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Feder ME, Walser JC. The biological limitations of transcriptomics in elucidating stress and stress responses. J Evol Biol 2005; 18:901-10. [PMID: 16033562 DOI: 10.1111/j.1420-9101.2005.00921.x] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Global analysis of mRNA abundance via genomic arrays (i.e. transcriptomics or transcriptional profiling) is one approach to finding the genes that matter to organisms undergoing environmental stress. In evolutionary analyses of stress, mRNA abundance is often invoked as a proxy for the protein activity that may underlie variation in fitness. To provoke discussion of the utility and sensible application of this valuable approach, this manuscript examines the adequacy of mRNA abundance as a proxy for protein activity, fitness and stress. Published work to date suggests that mRNA abundance typically provides little information on protein activity and fitness and cannot substitute for detailed functional and ecological analyses of candidate genes. While the transcriptional profile can be an exquisitely sensitive indicator of stress, simpler indicators will often suffice. In view of this outcome, transcriptomics should undergo careful cost-benefit analysis before investigators deploy it in studies of stress responses and their evolution.
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Affiliation(s)
- M E Feder
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL 60637, USA.
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18
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Zatsepina OG, Karavanov AA, Garbuz DG, Shilova V, Tornatore P, Evgen'ev MB. Use of surface-enhanced laser desorption ionization-time-of-flight to identify heat shock protein 70 isoforms in closely related species of the virilis group of Drosophila. Cell Stress Chaperones 2005; 10:12-6. [PMID: 15832943 PMCID: PMC1074565 DOI: 10.1379/csc-71.1] [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] [Received: 07/16/2004] [Accepted: 10/28/2004] [Indexed: 11/24/2022] Open
Abstract
The 70-kDa heat shock protein (Hsp) family in all Drosophila species includes 2 environmentally inducible family members, Hsp70 and Hsp68. Two-dimensional gel electrophoresis revealed an unusual pattern of heat shock-inducible proteins in the species of the virilis group. Trypsin fingerprinting and microsequencing of tryptic peptides using ProteinChip Array technology identified the major isoelectric variants of Hsp70 family, including Hsp68 isoforms that differ in both molecular mass and isoelectric point from those in Drosophila melanogaster. The peculiar electrophoretic mobility is consistent with the deduced amino acid sequence of corresponding hsp genes from the species of the virilis group.
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19
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SARUP P, DAHLGAARD J, NORUP AM, JORGENSEN KT, HEBSGAARD MB, LOESCHCKE V. Down regulation of Hsp70 expression level prolongs the duration of heat-induced male sterility in Drosophila buzzatii. Funct Ecol 2004. [DOI: 10.1111/j.0269-8463.2004.00863.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Lighton JRB, Turner RJ. Thermolimit respirometry: an objective assessment of critical thermal maxima in two sympatric desert harvester ants,Pogonomyrmex rugosusandP. californicus. J Exp Biol 2004; 207:1903-13. [PMID: 15107444 DOI: 10.1242/jeb.00970] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYThe critical thermal maxima (CTmax) of two sympatric,diurnal, thermophilic harvester ants from the Mojave Desert, USA(Pogonomyrmex rugosus and P. californicus) were measured by ramping their temperature upwards at a rate of 0.25°C min-1during flow-through respirometry with optical activity detection. Rates of CO2 emission(V̇CO2) increased exponentially to plateau values that were twice as high in P. californicus as P. rugosus on a mass-specific basis. V̇CO2 then fell sharply, during which gross motor activity (measured optically) and spiracular control (measured from V̇CO2 variation)abruptly ceased, yielding two independent measures of CTmax. As determined by loss of muscular coordination, the CTmax of Pogonomyrmex rugosus was 51.57±0.38°C (mean ± s.d., while that of Pogonomyrmex californicus was 51.74±0.25°C. As determined by loss of spiracular control, the CTmax of Pogonomyrmex rugosus was 51.59±0.35°C, while that of Pogonomyrmex californicus was 51.78±0.37°C. In each species a pronounced post-mortal peak of V̇CO2 was observed. The major ecological and behavioral differences of the two species are not reflected in their CTmax values, which do not differ significantly. `Thermolimit respirometry' allows CTmax to be estimated objectively with coefficients of variation (s.d./mean) <1%, lending confidence to comparisons between species or treatment groups.
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Affiliation(s)
- John R B Lighton
- Department of Biological Sciences, University of Nevada at Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154-4004, USA.
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21
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Breuker CJ, Brakefield PM. Heat shock in the developmentally sensitive period of butterfly eyespots fails to increase fluctuating asymmetry. Evol Dev 2003; 5:231-9. [PMID: 12752762 DOI: 10.1046/j.1525-142x.2003.03031.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Fluctuating asymmetry (FA) is considered to provide a means of evaluating developmental stability and to reflect an individual's quality or the stress experienced during development. Stress is predicted to increase the phenotypic variation of both FA and trait size. In this study we examined the effect of a particular heat shock on both FA and size of eyespots in the butterfly, Bicyclus anynana. We also examined whether those eyespots thought to be involved in partner choice and sexual selection were particularly sensitive to stress. We applied a heat shock of 39.5 degrees C for 3 h before, during, and after a sensitive period in eyespot development. We examined the FA, variation in FA, size, and variation in size of five eyespots, two on the dorsal forewing (sexually selected traits), two on the ventral forewing, and one on the ventral hindwing (nonsexually selected traits). For each sex and treatment, the heat shock did not result in significant changes in mean trait size and FA nor in the variation of size and FA. There were no differences in the response to the heat shock between sexually and nonsexually selected traits. We discuss how the increased production of heat shock proteins, including HSP60, may have stabilized development and how this might explain the results.
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Affiliation(s)
- Casper J Breuker
- Evolutionary Biology, Institute of Evolutionary and Ecological Sciences, Leiden University, 2300 RA Leiden, The Netherlands.
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22
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Bettencourt BR, Kim I, Hoffmann AA, Feder ME. Response to natural and laboratory selection at the Drosophila hsp70 genes. Evolution 2002; 56:1796-801. [PMID: 12389724 DOI: 10.1111/j.0014-3820.2002.tb00193.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
To determine whether and how laboratory and natural selection act on the hsp70 (70-Kd heat-shock protein) genes of Drosophila melanogaster, we examined hsp70 allele frequencies in two sets of populations. First, five populations reared at different temperatures for more than 20 years differentially fixed both a large insertion/deletion (indel) polymorphism at the 87A7 hsp70 cluster ("56H8"/"122") and a single nucleotide polymorphism at the 87C1 hsp70 cluster. In both cases, the 18 degrees C and 25 degrees C populations fixed one allele and the 28 degrees C populations the other, consistent with previously described evolved differences among these populations in Hsp70 expression and thermotolerance. Second, we examined 56H8 and 122 frequencies in a set of 11 populations founded from flies collected along a latitudinal transect of eastern Australia. The 56H8 allele frequencies are positively associated with latitude, consistent with maintenance of the 56H8/122 polymorphism by natural selection. Thermal extremes and average values are negatively correlated with latitude. These results suggest that natural selection imposed by temperature and thermal variability may affect hsp70 allele frequencies.
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Affiliation(s)
- Brian R Bettencourt
- Department of Organismal Biology, University of Chicago, Illinois 60637, USA.
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23
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Roberts SP, Feder ME. Changing fitness consequences ofhsp70copy number in transgenicDrosophilalarvae undergoing natural thermal stress. Funct Ecol 2001. [DOI: 10.1046/j.1365-2435.2000.00429.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Bettencourt BR, Feder ME. Hsp70 duplication in the Drosophila melanogaster species group: how and when did two become five? Mol Biol Evol 2001; 18:1272-82. [PMID: 11420366 DOI: 10.1093/oxfordjournals.molbev.a003912] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
To determine how the modern copy number (5) of hsp70 genes in Drosophila melanogaster evolved, we localized the duplication events that created the genes in the phylogeny of the melanogaster group, examined D. melanogaster genomic sequence to investigate the mechanisms of duplication, and analyzed the hsp70 gene sequences of Drosophila orena and Drosophila mauritiana. The initial two-to-four hsp70 duplication occurred 10--15 MYA, according to fixed in situ hybridization to polytene chromosomes, before the origin and divergence of the melanogaster and five other species subgroups of the melanogaster group. Analysis of more than 30 kb of flanking sequence surrounding the hsp70 gene clusters suggested that this duplication was likely a retrotransposition. For the melanogaster subgroup, Southern hybridization and an hsp70 restriction map confirmed the conserved number (4) and arrangement of hsp70 genes in the seven species other than D. melanogaster. Drosophila melanogaster is unique; tandem duplication and gene conversion at the derived cluster yielded a fifth hsp70 gene. The four D. orena hsp70 genes are highly similar and concertedly evolving. In contrast, the D. mauritiana hsp70 genes are divergent, and many alleles are nonfunctional. The proliferation, concerted evolution, and maintenance of functionality in the D. melanogaster hsp70 genes is consistent with the action of natural selection in this species.
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Affiliation(s)
- B R Bettencourt
- Department of Organismal Biology and Anatomy, University of Chicago, Illinois 60637, USA.
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25
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Zatsepina OG, Velikodvorskaia VV, Molodtsov VB, Garbuz D, Lerman DN, Bettencourt BR, Feder ME, Evgenev MB. A DROSOPHILA MELANOGASTER Strain From Sub-Equatorial Africa Has Exceptional Thermotolerance But Decreased Hsp70 Expression. J Exp Biol 2001; 204:1869-81. [PMID: 11441029 DOI: 10.1242/jeb.204.11.1869] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
SUMMARY
Drosophila melanogaster collected in sub-equatorial Africa in the 1970s are remarkably tolerant of sustained laboratory culture above 30°C and of acute exposure to much warmer temperatures. Inducible thermotolerance of high temperatures, which in Drosophila melanogaster is due in part to the inducible molecular chaperone Hsp70, is only modest in this strain. Expression of Hsp70 protein and hsp70 mRNA is likewise reduced and has slower kinetics in this strain (T) than in a standard wild-type strain (Oregon R). These strains also differed in constitutive and heat-inducible levels of other molecular chaperones. The lower Hsp70 expression in the T strain apparently has no basis in the activation of the heat-shock transcription factor HSF, which is similar in T and Oregon R flies. Rather, the reduced expression may stem from insertion of two transposable elements, H.M.S. Beagle in the intergenic region of the 87A7 hsp70 gene cluster and Jockey in the hsp70Ba gene promoter. We hypothesize that the reduced Hsp70 expression in a Drosophila melanogaster strain living chronically at intermediate temperatures may represent an evolved suppression of the deleterious phenotypes of Hsp70.
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Affiliation(s)
- O G Zatsepina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, 117984 Moscow, Russia
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26
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Affiliation(s)
- Martin E. Feder
- Department of Organismal Biology & Anatomy and Committee on Evolutionary Biology, The University of Chicago, 1027 East 57th Street, Chicago, Illinois 60637; e-mail:
- Department of Ecology & Evolutionary Biology, University of California, Irvine, California 92697; e-mail:
- Department of Zoology, University of Washington, Seattle, Washington 98195-1800; e-mail:
| | - Albert F. Bennett
- Department of Organismal Biology & Anatomy and Committee on Evolutionary Biology, The University of Chicago, 1027 East 57th Street, Chicago, Illinois 60637; e-mail:
- Department of Ecology & Evolutionary Biology, University of California, Irvine, California 92697; e-mail:
- Department of Zoology, University of Washington, Seattle, Washington 98195-1800; e-mail:
| | - Raymond B. Huey
- Department of Organismal Biology & Anatomy and Committee on Evolutionary Biology, The University of Chicago, 1027 East 57th Street, Chicago, Illinois 60637; e-mail:
- Department of Ecology & Evolutionary Biology, University of California, Irvine, California 92697; e-mail:
- Department of Zoology, University of Washington, Seattle, Washington 98195-1800; e-mail:
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27
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Sørensen JG, Michalak P, Justesen J, Loeschcke V. Expression of the heat-shock protein HSP70 in Drosophila buzzatii lines selected for thermal resistance. Hereditas 2000; 131:155-64. [PMID: 10680297 DOI: 10.1111/j.1601-5223.1999.00155.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The level of HSP70 expression induced by a non-lethal high temperature was examined in lines selected for increased thermal resistance and in corresponding control lines of Drosophila buzzatii, in order to test if selection for high temperature resistance leads to an increased level of HSP70 expression. The lines used were selected for up to 64 generations either as adults or through all larval stages. In adult selection lines, hard selection was implemented every second generation after mild heat hardening. In larval selection lines, larvae were exposed each generation to laboratory "natural" selection. Generally lines selected as adults showed a higher HSP70 expression than did controls, both in third instar larvae and in adults. A strong negative response to selection of HSP70 expression was found in all lines that were selected at cycling temperatures during larval development. The results suggests that a trade off between heat resistance in form of HSP70 expression and fecundity/fertility are responsible for the level of HSP70 expression. The effect of the different methods of selection on HSP70 expression suggests that heat resistance constitutes more than one trait.
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Affiliation(s)
- J G Sørensen
- Department of Genetics and Ecology, University of Aarhus, Denmark
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28
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Abstract
Non-linear fitness gradients with maxima between extremes are expected for any environmental variable to which free-living populations are exposed. For exceedingly toxic agents, including ionizing radiation, such deviations from linearity are close to zero exposure and are conventionally called hormesis. Accordingly, hormesis is an extreme version of the non-linear fitness gradients for general environmental stresses such as temperature fluctuations, for which maximum fitness occurs at the moderate temperature fluctuations to which free-living populations are most commonly exposed. Some metabolic reserves should occur under moderate temperature stresses because of the need for pre-adaptation enabling survival during exposure to occasional periods of more extreme stress, especially at species borders where selection for stress resistance is likely to be most intense. Because heat shock proteins are induced by all stresses, adaptation to extreme temperatures should translate into adaptation to other stresses. Consequently, metabolic reserves from adaptation to extreme temperatures in the past should translate into protection from correlated abiotic stresses, especially in human populations where modern cultural processes are now ameliorating exposure to extreme stresses. Ambient and man-made radiations of non-catastrophic dimensions should therefore lead to stress-derived radiation hormesis. Other stresses can, in principle, be incorporated into this model. Accordingly, evolutionary and ecological considerations suggest two components of hormesis in relation to ionizing radiation: background radiation hormesis based upon the background exposure to which all organisms on earth are subjected; and stress-derived radiation hormesis. Exposure under stress-derived radiation hormesis is considerably larger than under background radiation hormesis, so significant deleterious effects from non-catastrophic radiation normally may be impossible to detect. Suggestions are provided for testing such postulated deviations from the commonly assumed linear no-threshold (LNT) hypothesis for the biological consequences of exposure to radiation.
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Affiliation(s)
- P A Parsons
- School of Genetics and Human Variation, La Trobe University, Bundoora, Victoria 3083, Australia
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29
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Abstract
Synapses are critical sites of information transfer in the nervous system, and it is important that their functionality be maintained under stressful conditions to prevent communication breakdown. Here we show that synaptic transmission at the Drosophila larval neuromuscular junction is protected by prior exposure to heat shock that strongly induces expression of heat shock proteins, in particular hsp70. Using a macropatch electrode to record synaptic activity at individual, visualized boutons, we found that prior heat shock sustains synaptic performance at high test temperatures through pre- and postsynaptic alterations. After heat shock, nerve impulses release more quantal units at high temperatures and exhibit fewer failures of release (presynaptic modification), whereas the amplitude of quantal currents remains more constant than does that in nonheat-shocked controls (postsynaptic modification). The time course of these physiological changes is similar to that of elevated hsp70. Thus, stress-induced neuroprotective mechanisms maintain function at synapses by modifying their properties.
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30
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Feder ME, Hofmann GE. Heat-shock proteins, molecular chaperones, and the stress response: evolutionary and ecological physiology. Annu Rev Physiol 1999; 61:243-82. [PMID: 10099689 DOI: 10.1146/annurev.physiol.61.1.243] [Citation(s) in RCA: 2527] [Impact Index Per Article: 101.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Molecular chaperones, including the heat-shock proteins (Hsps), are a ubiquitous feature of cells in which these proteins cope with stress-induced denaturation of other proteins. Hsps have received the most attention in model organisms undergoing experimental stress in the laboratory, and the function of Hsps at the molecular and cellular level is becoming well understood in this context. A complementary focus is now emerging on the Hsps of both model and nonmodel organisms undergoing stress in nature, on the roles of Hsps in the stress physiology of whole multicellular eukaryotes and the tissues and organs they comprise, and on the ecological and evolutionary correlates of variation in Hsps and the genes that encode them. This focus discloses that (a) expression of Hsps can occur in nature, (b) all species have hsp genes but they vary in the patterns of their expression, (c) Hsp expression can be correlated with resistance to stress, and (d) species' thresholds for Hsp expression are correlated with levels of stress that they naturally undergo. These conclusions are now well established and may require little additional confirmation; many significant questions remain unanswered concerning both the mechanisms of Hsp-mediated stress tolerance at the organismal level and the evolutionary mechanisms that have diversified the hsp genes.
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Affiliation(s)
- M E Feder
- Department of Organismal Biology and Anatomy and Committee on Evolutionary Biology, University of Chicago, Illinois 60637, USA.
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Krebs RA, Feder ME. Hsp70 and larval thermotolerance in Drosophila melanogaster: how much is enough and when is more too much? JOURNAL OF INSECT PHYSIOLOGY 1998; 44:1091-1101. [PMID: 12770408 DOI: 10.1016/s0022-1910(98)00059-6] [Citation(s) in RCA: 152] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Heat shock proteins (Hsps) and other molecular chaperones perform diverse cellular roles (e.g., inducible thermotolerance) whose functional consequences are concentration dependent. We manipulated Hsp70 concentration quantitatively in intact larvae of Drosophila melanogaster to examine its effect on survival, developmental time and tissue damage after heat shock. Larvae of an extra-copy strain, which has 22 hsp70 copies, produced Hsp70 more rapidly and to higher concentrations than larvae of a control strain, which has the wild-type 10 copies of the gene. Increasing the magnitude and duration of pretreatment increased Hsp70 concentrations, improved tolerance of more severe stress, and reduced delays in development. Pretreatment, however, did not protect against acute tissue damage. For larvae provided a brief or mild intensity pretreatment, faster expression of Hsp70 in the extra-copy strain improved survival to adult and reduced tissue damage 21h after heat shock. Negative effects on survival ensued in extra-copy larvae pretreated most intensely, but their overexpression of Hsp70 did not increase tissue damage. Because rapid expression to yield a low Hsp70 concentration benefits larvae but overexpression harms them, natural selection may balance benefits and costs of high and low expression levels in natural populations.
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Affiliation(s)
- R A. Krebs
- Department of Organismal Biology and Anatomy, The University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USAThe Committee on Evolutionary Biology, and the College, The University of Chicago, 1027 East 57th Street, Chicago, USA
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