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Jiang C, Storey KB, Yang H, Sun L. Aestivation in Nature: Physiological Strategies and Evolutionary Adaptations in Hypometabolic States. Int J Mol Sci 2023; 24:14093. [PMID: 37762394 PMCID: PMC10531719 DOI: 10.3390/ijms241814093] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/14/2023] [Accepted: 08/21/2023] [Indexed: 09/29/2023] Open
Abstract
Aestivation is considered to be one of the "purest" hypometabolic states in nature, as it involves aerobic dormancy that can be induced and sustained without complex factors. Animals that undergo aestivation to protect themselves from environmental stressors such as high temperatures, droughts, and food shortages. However, this shift in body metabolism presents new challenges for survival, including oxidative stress upon awakening from aestivation, accumulation of toxic metabolites, changes in energy sources, adjustments to immune status, muscle atrophy due to prolonged immobility, and degeneration of internal organs due to prolonged food deprivation. In this review, we summarize the physiological and metabolic strategies, key regulatory factors, and networks utilized by aestivating animals to address the aforementioned components of aestivation. Furthermore, we present a comprehensive overview of the advancements made in aestivation research across major species, including amphibians, fish, reptiles, annelids, mollusks, and echinoderms, categorized according to their respective evolutionary positions. This approach offers a distinct perspective for comparative analysis, facilitating an understanding of the shared traits and unique features of aestivation across different groups of organisms.
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Affiliation(s)
- Chunxi Jiang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences & Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (C.J.); (H.Y.)
- Laboratory for Marine Ecology and Environmental Science & Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kenneth B. Storey
- Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada;
| | - Hongsheng Yang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences & Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (C.J.); (H.Y.)
- Laboratory for Marine Ecology and Environmental Science & Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lina Sun
- CAS Key Laboratory of Marine Ecology and Environmental Sciences & Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (C.J.); (H.Y.)
- Laboratory for Marine Ecology and Environmental Science & Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Yang Y, Zheng Y, Sun L, Chen M. Genome-Wide DNA Methylation Signatures of Sea Cucumber Apostichopus japonicus during Environmental Induced Aestivation. Genes (Basel) 2020; 11:genes11091020. [PMID: 32877994 PMCID: PMC7565549 DOI: 10.3390/genes11091020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/21/2020] [Accepted: 08/28/2020] [Indexed: 02/07/2023] Open
Abstract
Organisms respond to severe environmental changes by entering into hypometabolic states, minimizing their metabolic rates, suspending development and reproduction, and surviving critical ecological changes. They come back to an active lifestyle once the environmental conditions are conducive. Marine invertebrates live in the aquatic environment and adapt to environmental changes in their whole life. Sea cucumbers and sponges are only two recently known types of marine organisms that aestivate in response to temperature change. Sea cucumber has become an excellent model organism for studies of environmentally-induced aestivation by marine invertebrates. DNA methylation, the most widely considered epigenetic marks, has been reported to contribute to phenotypic plasticity in response to environmental stress in aquatic organisms. Most of methylation-related enzymes, including DNA methyltransferases, Methyl-CpG binding domain proteins, and DNA demethylases, were up-regulated during aestivation. We conducted high-resolution whole-genome bisulfite sequencing of the intestine from sea cucumber at non-aestivation and deep-aestivation stages. Further DNA methylation profile analysis was also conducted across the distinct genomic features and entire transcriptional units. A different elevation in methylation level at internal exons was observed with clear demarcation of intron/exon boundaries during transcriptional unit scanning. The lowest methylation level occurs in the first exons, followed by the last exons and the internal exons. A significant increase in non-CpG methylation (CHG and CHH) was observed within the intron and mRNA regions in aestivation groups. A total of 1393 genes were annotated within hypermethylated DMRs (differentially methylated regions), and 749 genes were annotated within hypomethylated DMRs. Differentially methylated genes were enriched in the mRNA surveillance pathway, metabolic pathway, and RNA transport. Then, 24 hypermethylated genes and 15 hypomethylated genes were Retrovirus-related Pol polyprotein from transposon (RPPT) genes. This study provides further understanding of epigenetic control on environmental induced hypometabolism in aquatic organisms.
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Affiliation(s)
- Yujia Yang
- Laboratory for Evolution and Development, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China;
| | - Yingqiu Zheng
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266071, China;
| | - Lina Sun
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences (CAS), Qingdao 266003, China
- Correspondence: (L.S.); (M.C.)
| | - Muyan Chen
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266071, China;
- Correspondence: (L.S.); (M.C.)
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Capraro A, O'Meally D, Waters SA, Patel HR, Georges A, Waters PD. Waking the sleeping dragon: gene expression profiling reveals adaptive strategies of the hibernating reptile Pogona vitticeps. BMC Genomics 2019; 20:460. [PMID: 31170930 PMCID: PMC6555745 DOI: 10.1186/s12864-019-5750-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/29/2019] [Indexed: 12/30/2022] Open
Abstract
Background Hibernation is a physiological state exploited by many animals exposed to prolonged adverse environmental conditions associated with winter. Large changes in metabolism and cellular function occur, with many stress response pathways modulated to tolerate physiological challenges that might otherwise be lethal. Many studies have sought to elucidate the molecular mechanisms of mammalian hibernation, but detailed analyses are lacking in reptiles. Here we examine gene expression in the Australian central bearded dragon (Pogona vitticeps) using mRNA-seq and label-free quantitative mass spectrometry in matched brain, heart and skeletal muscle samples from animals at late hibernation, 2 days post-arousal and 2 months post-arousal. Results We identified differentially expressed genes in all tissues between hibernation and post-arousal time points; with 4264 differentially expressed genes in brain, 5340 differentially expressed genes in heart, and 5587 differentially expressed genes in skeletal muscle. Furthermore, we identified 2482 differentially expressed genes across all tissues. Proteomic analysis identified 743 proteins (58 differentially expressed) in brain, 535 (57 differentially expressed) in heart, and 337 (36 differentially expressed) in skeletal muscle. Tissue-specific analyses revealed enrichment of protective mechanisms in all tissues, including neuroprotective pathways in brain, cardiac hypertrophic processes in heart, and atrophy protective pathways in skeletal muscle. In all tissues stress response pathways were induced during hibernation, as well as evidence for gene expression regulation at transcription, translation and post-translation. Conclusions These results reveal critical stress response pathways and protective mechanisms that allow for maintenance of both tissue-specific function, and survival during hibernation in the central bearded dragon. Furthermore, we provide evidence for multiple levels of gene expression regulation during hibernation, particularly enrichment of miRNA-mediated translational repression machinery; a process that would allow for rapid and energy efficient reactivation of translation from mature mRNA molecules at arousal. This study is the first molecular investigation of its kind in a hibernating reptile, and identifies strategies not yet observed in other hibernators to cope stress associated with this remarkable state of metabolic depression. Electronic supplementary material The online version of this article (10.1186/s12864-019-5750-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alexander Capraro
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, UNSW Sydney, Sydney, NSW, 2052, Australia.
| | - Denis O'Meally
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia.,Present address: Center for Gene Therapy, Beckman Research Institute of the City of Hope, Duarte, CA, 91010, USA
| | - Shafagh A Waters
- School of Women's & Children's Health, Faculty of Medicine, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Hardip R Patel
- John Curtin School of Medical Research, Australian National University, Canberra, 2601, ACT, Australia
| | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia
| | - Paul D Waters
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, UNSW Sydney, Sydney, NSW, 2052, Australia
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Ishihara A, Sapon MA, Yamauchi K. Seasonal acclimatization and thermal acclimation induce global histone epigenetic changes in liver of bullfrog (Lithobates catesbeianus) tadpole. Comp Biochem Physiol A Mol Integr Physiol 2019; 230:39-48. [DOI: 10.1016/j.cbpa.2018.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 12/19/2018] [Accepted: 12/19/2018] [Indexed: 01/08/2023]
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Adamson KJ, Wang T, Rotgans BA, Kruangkum T, Kuballa AV, Storey KB, Cummins SF. Genes and associated peptides involved with aestivation in a land snail. Gen Comp Endocrinol 2017; 246:88-98. [PMID: 26497253 DOI: 10.1016/j.ygcen.2015.10.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 10/14/2015] [Accepted: 10/19/2015] [Indexed: 01/01/2023]
Abstract
Some animals can undergo a remarkable transition from active normal life to a dormant state called aestivation; entry into this hypometabolic state ensures that life continues even during long periods of environmental hardship. In this study, we aimed to identify those central nervous system (CNS) peptides that may regulate metabolic suppression leading to aestivation in land snails. Mass spectral-based neuropeptidome analysis of the CNS comparing active and aestivating states, revealed 19 differentially produced peptides; 2 were upregulated in active animals and 17 were upregulated in aestivated animals. Of those, the buccalin neuropeptide was further investigated since there is existing evidence in molluscs that buccalin modulates physiology by muscle contraction. The Theba pisana CNS contains two buccalin transcripts that encode precursor proteins that are capable of releasing numerous buccalin peptides. Of these, Tpi-buccalin-2 is most highly expressed within our CNS transcriptome derived from multiple metabolic states. No significant difference was observed at the level of gene expression levels for Tpi-buccalin-2 between active and aestivated animals, suggesting that regulation may reside at the level of post-translational control of peptide abundance. Spatial gene and peptide expression analysis of aestivated snail CNS demonstrated that buccalin-2 has widespread distribution within regions that control several physiological roles. In conclusion, we provide the first detailed molecular analysis of the peptides and associated genes that are related to hypometabolism in a gastropod snail known to undergo extended periods of aestivation.
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Affiliation(s)
- K J Adamson
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia
| | - T Wang
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia
| | - B A Rotgans
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia
| | - T Kruangkum
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia
| | - A V Kuballa
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia
| | - K B Storey
- Institute of Biochemistry & Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - S F Cummins
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia.
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Abstract
Freeze tolerance is an amazing winter survival strategy used by various amphibians and reptiles living in seasonally cold environments. These animals may spend weeks or months with up to ∼65% of their total body water frozen as extracellular ice and no physiological vital signs, and yet after thawing they return to normal life within a few hours. Two main principles of animal freeze tolerance have received much attention: the production of high concentrations of organic osmolytes (glucose, glycerol, urea among amphibians) that protect the intracellular environment, and the control of ice within the body (the first putative ice-binding protein in a frog was recently identified), but many other strategies of biochemical adaptation also contribute to freezing survival. Discussed herein are recent advances in our understanding of amphibian and reptile freeze tolerance with a focus on cell preservation strategies (chaperones, antioxidants, damage defense mechanisms), membrane transporters for water and cryoprotectants, energy metabolism, gene/protein adaptations, and the regulatory control of freeze-responsive hypometabolism at multiple levels (epigenetic regulation of DNA, microRNA action, cell signaling and transcription factor regulation, cell cycle control, and anti-apoptosis). All are providing a much more complete picture of life in the frozen state.
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Affiliation(s)
| | - Janet M. Storey
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
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Zhu A, Chen M, Zhang X, Storey KB. Gene structure, expression, and DNA methylation characteristics of sea cucumber cyclin B gene during aestivation. Gene 2016; 594:82-88. [PMID: 27601256 DOI: 10.1016/j.gene.2016.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/30/2016] [Accepted: 09/02/2016] [Indexed: 10/21/2022]
Abstract
The sea cucumber, Apostichopus japonicus, is a good model for studying environmentally-induced aestivation by a marine invertebrate. One of the central requirements of aestivation is the repression of energy-expensive cellular processes such as cell cycle progression. The present study identified the gene structure of the cell cycle regulator, cyclin B, and detected the expression levels of this gene over three stages of the annual aestivation-arousal cycle. Furthermore, the DNA methylation characteristics of cyclin B were analyzed in non-aestivation and deep-aestivation stages of sea cucumbers. We found that the cyclin B promoter contains a CpG island, three CCAAT-boxes and three cell cycle gene homology regions (CHRs). Application of qRT-PCR analysis showed significant downregulation of cyclin B transcript levels during deep-aestivation in comparison with non-aestivation in both intestine and longitudinal muscle, and these returned to basal levels after arousal from aestivation. Methylation analysis of the cyclin B core promoter revealed that its methylation level showed significant differences between non-aestivation and deep-aestivation stages (p<0.05) and interestingly, a positive correlation between Cyclin B transcripts expression and methylation levels of the core promoter was also observed. Our findings suggest that cell cycle progression may be reversibly arrested during aestivation as indicated by the changes in cyclin B expression levels and we propose that DNA methylation is one of the regulatory mechanisms involved in cyclin B transcriptional variation.
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Affiliation(s)
- Aijun Zhu
- Fisheries College, Ocean University of China, Qingdao, PR China; The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, PR China
| | - Muyan Chen
- Fisheries College, Ocean University of China, Qingdao, PR China; The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, PR China.
| | - Xiumei Zhang
- Fisheries College, Ocean University of China, Qingdao, PR China; The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, PR China
| | - Kenneth B Storey
- Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
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Reynolds JA, Bautista-Jimenez R, Denlinger DL. Changes in histone acetylation as potential mediators of pupal diapause in the flesh fly, Sarcophaga bullata. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2016; 76:29-37. [PMID: 27350056 DOI: 10.1016/j.ibmb.2016.06.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 06/23/2016] [Accepted: 06/23/2016] [Indexed: 06/06/2023]
Abstract
The growing appreciation that epigenetic processes are integral to the responses of many organisms to changes in the environment suggests a possible role for epigenetics in coordination of insect diapause. The results we present suggest that histone modification may be one type of epigenetic process that contributes to regulation of pupal diapause in the flesh fly, Sarcophaga bullata. Reduction in total histone H3 acetylation in diapausing pupae, shifts in mRNA expression profiles of genes encoding histone acetyltransferase (HAT) and histone deacetylase (HDAC) in pre-diapause, diapause and post-diapause flies compared to their nondiapause counterparts, and alterations in HDAC enzyme activity during and post-diapause lend support to the hypothesis that this specific type of histone modification is involved in regulating diapause programming, maintenance, and termination. Transcription of genes encoding HDAC1, HDAC3, HDAC6, and Sirtuin2 were all upregulated in photosensitive first instar larvae programmed to enter pupal diapause, suggesting that histone deacetylation may be linked to the early decision to enter diapause. A 50% reduction in transcription of hdac3 and a corresponding 30% reduction in HDAC activity during diapause suggest that removal of acetyl groups from histones primarily occurs prior to diapause entry and that further histone deacetylation is not necessary to maintain diapause. Transcription of the HDAC genes was quickly elevated when diapause was terminated, followed by an increase in enzyme activity after a short delay. A maternal effect operating in these flies prevents pupal diapause in progeny whose mothers experienced pupal diapause, even if the progeny are reared in strong diapause-inducing short-day conditions. Such nondiapausing pupae had HDAC transcription profiles nearly identical to the profiles seen in nondiapausing pupae generated under a long-day photoperiod. Together, these results provide consistent evidence for histone acetylation and deacetylation as regulators of this insect's developmental trajectory.
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Affiliation(s)
- J A Reynolds
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH 43210, USA.
| | - Robin Bautista-Jimenez
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH 43210, USA
| | - D L Denlinger
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH 43210, USA; Department of Entomology, The Ohio State University, Columbus, OH 43210, USA
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Adamson KJ, Wang T, Rotgans BA, Kuballa AV, Storey KB, Cummins SF. Differential peptide expression in the central nervous system of the land snail Theba pisana, between active and aestivated. Peptides 2016; 80:61-71. [PMID: 26303007 DOI: 10.1016/j.peptides.2015.08.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Revised: 08/16/2015] [Accepted: 08/17/2015] [Indexed: 12/25/2022]
Abstract
Hypometabolism is a physiological state of dormancy entered by many animals in times of environmental stress. There are gaps in our understanding of the molecular components used by animals to achieve this metabolic state. The availability of genomic and transcriptome data can be useful to study the process of hypometabolism at the molecular level. In this study, we use the land snail Theba pisana to identify peptides that may be involved in the hypometabolic state known as aestivation. We found a total of 22 neuropeptides in the central nervous system (CNS) that were differentially produced during activity and aestivation based on mass spectral-based neuropeptidome analysis. Of these, 4 were upregulated in active animals and 18 were upregulated in aestivation. A neuropeptide known to regulate muscle contractions in a variety of molluscs, the small cardioactive peptide A (sCAPA), and a peptide of yet unknown function (termed Aestivation Associated Peptide 12) were chosen for further investigation using temporal and spatial expression analysis of the precursor gene and peptide. Both peptides share expression within regions of the CNS cerebral ganglia and suboesophageal ganglia. Relative transcript abundance suggests that regulation of peptide synthesis and secretion is post-transcriptional. In summary, we provide new insights into the molecular basis of the regulation of aestivation in land snails through CNS peptide control.
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Affiliation(s)
- K J Adamson
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia
| | - T Wang
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia
| | - B A Rotgans
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia
| | - A V Kuballa
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia
| | - K B Storey
- Institute of Biochemistry & Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - S F Cummins
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore DC, Queensland 4558, Australia.
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10
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Hammond SA, Nelson CJ, Helbing CC. Environmental influences on the epigenomes of herpetofauna and fish. Biochem Cell Biol 2016; 94:95-100. [DOI: 10.1139/bcb-2015-0111] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Herpetofauna (amphibians and reptiles) and fish represent important sentinel and indicator species for environmental and ecosystem health. It is widely accepted that the epigenome plays an important role in gene expression regulation. Environmental stimuli, including temperature and pollutants, influence gene activity, and there is growing evidence demonstrating that an important mechanism is through modulation of the epigenome. This has been primarily studied in human and mammalian models; relatively little is known about the impact of environmental conditions or pollutants on herpetofauna or fish epigenomes and the regulatory consequences of these changes on gene expression. Herein we review recent studies that have begun to address this deficiency, which have mainly focused on limited specific epigenetic marks and individual genes or large-scale global changes in DNA methylation, owing to the comparative ease of measurement. Greater understanding of the epigenetic influences of these environmental factors will depend on increased availability of relevant species-specific genomic sequence information to facilitate chromatin immunoprecipitation and DNA methylation experiments.
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Affiliation(s)
- S. Austin Hammond
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700, STN CSC, Victoria, BC V8W 2Y2, Canada
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700, STN CSC, Victoria, BC V8W 2Y2, Canada
| | - Christopher J. Nelson
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700, STN CSC, Victoria, BC V8W 2Y2, Canada
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700, STN CSC, Victoria, BC V8W 2Y2, Canada
| | - Caren C. Helbing
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700, STN CSC, Victoria, BC V8W 2Y2, Canada
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700, STN CSC, Victoria, BC V8W 2Y2, Canada
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11
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Abstract
For many animals, survival of severe environmental stress (e.g. to extremes of heat or cold, drought, oxygen limitation, food deprivation) is aided by entry into a hypometabolic state. Strong depression of metabolic rate, often to only 1–20% of normal resting rate, is a core survival strategy of multiple forms of hypometabolism across the animal kingdom, including hibernation, anaerobiosis, aestivation and freeze tolerance. Global biochemical controls are needed to suppress and reprioritize energy use; one such well-studied control is reversible protein phosphorylation. Recently, we turned our attention to the idea that mechanisms previously associated mainly with epigenetic regulation can also contribute to reversible suppression of gene expression in hypometabolic states. Indeed, situations as diverse as mammalian hibernation and turtle anoxia tolerance show coordinated changes in histone post-translational modifications (acetylation, phosphorylation) and activities of histone deacetylases, consistent with their use as mechanisms for suppressing gene expression during hypometabolism. Other potential mechanisms of gene silencing in hypometabolic states include altered expression of miRNAs that can provide post-transcriptional suppression of mRNA translation and the formation of ribonuclear protein bodies in the nucleus and cytoplasm to allow storage of mRNA transcripts until animals rouse themselves again. Furthermore, mechanisms first identified in epigenetic regulation (e.g. protein acetylation) are now proving to apply to many central metabolic enzymes (e.g. lactate dehydrogenase), suggesting a new layer of regulatory control that can contribute to coordinating the depression of metabolic rate.
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Affiliation(s)
- Kenneth B. Storey
- Institute of Biochemistry and Departments of Biology and Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
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12
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Zhao Y, Chen M, Storey KB, Sun L, Yang H. DNA methylation levels analysis in four tissues of sea cucumber Apostichopus japonicus based on fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) during aestivation. Comp Biochem Physiol B Biochem Mol Biol 2014; 181:26-32. [PMID: 25461675 DOI: 10.1016/j.cbpb.2014.11.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 11/04/2014] [Accepted: 11/07/2014] [Indexed: 10/24/2022]
Abstract
DNA methylation plays an important role in regulating transcriptional change in response to environmental stimuli. In the present study, DNA methylation levels of tissues of the sea cucumber Apostichopus japonicus were analyzed by the fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) technique over three stages of the aestivation cycle. Overall, a total of 26,963 fragments were amplified including 9112 methylated fragments among four sea cucumber tissues using 18 pairs of selective primers. Results indicated an average DNA methylation level of 33.79% for A. japonicus. The incidence of DNA methylation was different across tissue types in the non-aestivation stage: intestine (30.16%), respiratory tree (27.61%), muscle (27.94%) and body wall (56.25%). Our results show that hypermethylation accompanied deep-aestivation in A. japonicus, which suggests that DNA methylation may have an important role in regulating global transcriptional suppression during aestivation. Further analysis indicated that the main DNA modification sites were focused on intestine and respiratory tree tissues and that full-methylation but not hemi-methylation levels exhibited significant increases in the deep-aestivation stage.
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Affiliation(s)
- Ye Zhao
- Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Muyan Chen
- Fisheries College, Ocean University of China, Qingdao 266003, PR China.
| | - Kenneth B Storey
- Institute of Biochemistry, Carleton University, Ottawa, ON, Canada, K1S 5B6
| | - Lina Sun
- Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China
| | - Hongsheng Yang
- Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China.
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Zhao Y, Chen M, Su L, Wang T, Liu S, Yang H. Molecular cloning and expression-profile analysis of sea cucumber DNA (Cytosine-5)-methyltransferase 1 and methyl-CpG binding domain type 2/3 genes during aestivation. Comp Biochem Physiol B Biochem Mol Biol 2013; 165:26-35. [DOI: 10.1016/j.cbpb.2013.02.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 02/22/2013] [Accepted: 02/25/2013] [Indexed: 10/27/2022]
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Abstract
Aestivation is a survival strategy used by many vertebrates and invertebrates to endure arid environmental conditions. Key features of aestivation include strong metabolic rate suppression, strategies to retain body water, conservation of energy and body fuel reserves, altered nitrogen metabolism, and mechanisms to preserve and stabilize organs, cells and macromolecules over many weeks or months of dormancy. Cell signaling is crucial to achieving both a hypometabolic state and reorganizing multiple metabolic pathways to optimize long-term viability during aestivation. This commentary examines the current knowledge about cell signaling pathways that participate in regulating aestivation, including signaling cascades mediated by the AMP-activated kinase, Akt, ERK, and FoxO1.
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Affiliation(s)
- Kenneth B Storey
- Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON, Canada, K1S 5B6.
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Krivoruchko A, Storey KB. Epigenetics in anoxia tolerance: a role for histone deacetylases. Mol Cell Biochem 2010; 342:151-61. [PMID: 20437082 DOI: 10.1007/s11010-010-0479-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 04/17/2010] [Indexed: 11/24/2022]
Abstract
The importance of epigenetics has been established in many key biological processes but the relevance of this regulatory mechanism to animal survival of low oxygen conditions has never been examined. To establish whether epigenetic mechanisms could be involved in natural anoxia tolerance, we have examined the anoxia-responsive expression of the transcriptional silencers, histone deacetylases (HDACs), in tissues of a unique model for anoxia tolerance, the freshwater turtle Trachemys scripta elegans. Transcript and protein levels of all five HDACs rose by 1.3-4.6 and 1.7-3.5-fold, respectively, in skeletal muscle in response to 20 h of anoxia exposure. In addition, HDAC activity in the muscle increased by 1.5-fold in response to 20 h of anoxia and levels of acetylated histone H3 (Lys 9 or Lys 23) decreased to 40-60% of control values. The liver displayed a milder response with HDAC1, -4, and -5 protein levels increasing by 1.6-2.1-fold after 5 h anoxia exposure; acetylated histone H3 levels also decreased to 50-75% of control values. Only HDAC5 responded to anoxia exposure in the heart; Hdac5 transcript levels increased 2.1-2.3-fold and HDAC5 protein rose by 3.3-fold. Overall, our results show a tissue-specific pattern of HDAC upregulation in response to anoxia exposure in T.s. elegans, suggesting that these enzymes play a key role in anoxia tolerance, probably by contributing to the transcriptional silencing necessary in this hypometabolic state.
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Aubin-Horth N, Renn SCP. Genomic reaction norms: using integrative biology to understand molecular mechanisms of phenotypic plasticity. Mol Ecol 2009; 18:3763-80. [PMID: 19732339 DOI: 10.1111/j.1365-294x.2009.04313.x] [Citation(s) in RCA: 256] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phenotypic plasticity is the development of different phenotypes from a single genotype, depending on the environment. Such plasticity is a pervasive feature of life, is observed for various traits and is often argued to be the result of natural selection. A thorough study of phenotypic plasticity should thus include an ecological and an evolutionary perspective. Recent advances in large-scale gene expression technology make it possible to also study plasticity from a molecular perspective, and the addition of these data will help answer long-standing questions about this widespread phenomenon. In this review, we present examples of integrative studies that illustrate the molecular and cellular mechanisms underlying plastic traits, and show how new techniques will grow in importance in the study of these plastic molecular processes. These techniques include: (i) heterologous hybridization to DNA microarrays; (ii) next generation sequencing technologies applied to transcriptomics; (iii) techniques for studying the function of noncoding small RNAs; and (iv) proteomic tools. We also present recent studies on genetic model systems that uncover how environmental cues triggering different plastic responses are sensed and integrated by the organism. Finally, we describe recent work on changes in gene expression in response to an environmental cue that persist after the cue is removed. Such long-term responses are made possible by epigenetic molecular mechanisms, including DNA methylation. The results of these current studies help us outline future avenues for the study of plasticity.
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Affiliation(s)
- Nadia Aubin-Horth
- Département de Sciences biologiques, Université de Montréal, Québec, Canada.
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Berner NJ, Else PL, Hulbert AJ, Mantle BL, Cramp RL, Franklin CE. Metabolic depression during aestivation does not involve remodelling of membrane fatty acids in two Australian frogs. J Comp Physiol B 2009; 179:857-66. [DOI: 10.1007/s00360-009-0368-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 04/28/2009] [Accepted: 05/01/2009] [Indexed: 11/28/2022]
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