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Frydrychová RČ, Konopová B, Peska V, Brejcha M, Sábová M. Telomeres and telomerase: active but complex players in life-history decisions. Biogerontology 2024; 25:205-226. [PMID: 37610666 DOI: 10.1007/s10522-023-10060-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 08/01/2023] [Indexed: 08/24/2023]
Abstract
Studies on human telomeres have established that telomeres exert a significant influence on lifespan and health of organisms. However, recent research has indicated that the original idea that telomeres affect lifespan in a universal and central manner across all eukaryotic species is an oversimplification. Indeed, findings from a variety of animal species revealed that the role of telomere biology in aging is more subtle and intricate than previously recognized. Here, we show how telomere biology varies depending on the taxon. We also show how telomere biology corresponds to basic life history traits and affects the life table of a species and investments in growth, body size, reproduction, and lifespan; telomeres are hypothesized to shape evolutionary perspectives for species in an active but complex manner. Our evaluation is based on telomere biology data from many examples from throughout the animal kingdom that vary according to the degree of organismal complexity and life history strategies.
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Affiliation(s)
- Radmila Čapková Frydrychová
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic.
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, Ceske Budejovice, Czech Republic.
| | - Barbora Konopová
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
| | - Vratislav Peska
- Department of Cell Biology and Radiobiology, Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 00, Brno, Czech Republic
| | - Miloslav Brejcha
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, Ceske Budejovice, Czech Republic
| | - Michala Sábová
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
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Telomeres and Their Neighbors. Genes (Basel) 2022; 13:genes13091663. [PMID: 36140830 PMCID: PMC9498494 DOI: 10.3390/genes13091663] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 11/21/2022] Open
Abstract
Telomeres are essential structures formed from satellite DNA repeats at the ends of chromosomes in most eukaryotes. Satellite DNA repeat sequences are useful markers for karyotyping, but have a more enigmatic role in the eukaryotic cell. Much work has been done to investigate the structure and arrangement of repetitive DNA elements in classical models with implications for species evolution. Still more is needed until there is a complete picture of the biological function of DNA satellite sequences, particularly when considering non-model organisms. Celebrating Gregor Mendel’s anniversary by going to the roots, this review is designed to inspire and aid new research into telomeres and satellites with a particular focus on non-model organisms and accessible experimental and in silico methods that do not require specialized equipment or expensive materials. We describe how to identify telomere (and satellite) repeats giving many examples of published (and some unpublished) data from these techniques to illustrate the principles behind the experiments. We also present advice on how to perform and analyse such experiments, including details of common pitfalls. Our examples are a selection of recent developments and underexplored areas of research from the past. As a nod to Mendel’s early work, we use many examples from plants and insects, especially as much recent work has expanded beyond the human and yeast models traditional in telomere research. We give a general introduction to the accepted knowledge of telomere and satellite systems and include references to specialized reviews for the interested reader.
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Bilateral telomerase-associated impacts of Spirulina platensis extracts: Activation versus inhibition. Eur J Integr Med 2021. [DOI: 10.1016/j.eujim.2021.101303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Engin AB, Engin A. The Connection Between Cell Fate and Telomere. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1275:71-100. [PMID: 33539012 DOI: 10.1007/978-3-030-49844-3_3] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Abolition of telomerase activity results in telomere shortening, a process that eventually destabilizes the ends of chromosomes, leading to genomic instability and cell growth arrest or death. Telomere shortening leads to the attainment of the "Hayflick limit", and the transition of cells to state of senescence. If senescence is bypassed, cells undergo crisis through loss of checkpoints. This process causes massive cell death concomitant with further telomere shortening and spontaneous telomere fusions. In functional telomere of mammalian cells, DNA contains double-stranded tandem repeats of TTAGGG. The Shelterin complex, which is composed of six different proteins, is required for the regulation of telomere length and stability in cells. Telomere protection by telomeric repeat binding protein 2 (TRF2) is dependent on DNA damage response (DDR) inhibition via formation of T-loop structures. Many protein kinases contribute to the DDR activated cell cycle checkpoint pathways, and prevent DNA replication until damaged DNA is repaired. Thereby, the connection between cell fate and telomere length-associated telomerase activity is regulated by multiple protein kinase activities. Contrarily, inactivation of DNA damage checkpoint protein kinases in senescent cells can restore cell-cycle progression into S phase. Therefore, telomere-initiated senescence is a DNA damage checkpoint response that is activated with a direct contribution from dysfunctional telomeres. In this review, in addition to the above mentioned, the choice of main repair pathways, which comprise non-homologous end joining and homologous recombination in telomere uncapping telomere dysfunctions, are discussed.
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Affiliation(s)
- Ayse Basak Engin
- Department of Toxicology, Faculty of Pharmacy, Gazi University, Ankara, Turkey.
| | - Atilla Engin
- Department of General Surgery, Faculty of Medicine, Gazi University, Ankara, Turkey
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Louzon M, Zahn S, Capelli N, Massemin S, Coeurdassier M, Pauget B, Gimbert F, de Vaufleury A. Impact of ageing and soil contaminants on telomere length in the land snail. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 201:110766. [PMID: 32531572 DOI: 10.1016/j.ecoenv.2020.110766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 06/11/2023]
Abstract
Telomeres (TLs) are non-coding DNA sequences that are usually shortened with ageing and/or chemical exposure. Bioindicators such as the land snail can be used to assess the environmental risk of contaminated soils. As for most invertebrates, the evolution of TLs with ageing or exposure to contaminants is unknown in this mollusc. The aims of this study were to explore the relationships between ageing, contaminant exposure, sublethal effects and TL length in the terrestrial gastropod Cantareus aspersus. TL length was investigated in haemocytes from five age classes of C. aspersus. The impact of contaminants on sub-adult snails exposed to Cd, Hg or a mixture of polycyclic aromatic hydrocarbons (PAHs) in soils for one or two months was studied. Bioaccumulation, growth, sexual maturity and TLs were measured. TL attrition was significant for the juvenile and sub-adult stages, but not later. Exposure to Cd increased the mortality (around 30%). Exposure to polluted soils inhibited growth (19-40%) and sexual maturity (6-100%). Although the health of the snails exposed to Cd, Hg and PAHs was altered, TL length in haemocytes was not disturbed, suggesting a high capacity of this snail species to maintain its TLs in haemocytes under chemical stress. These results first address TL length in snails and reveal that the relationship commonly proposed for vertebrates between TL shortening and ageing or exposure to contaminants cannot be generalized.
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Affiliation(s)
- Maxime Louzon
- UMR CNRS 6249 Chrono-Environnement, University of Franche-Comté, 16 Route de Gray, 25030, Besançon Cedex, France
| | - Sandrine Zahn
- IPHC UMR 7178 DEPE CNRS, University of Strasbourg, 23 Rue du loess, 67087, Strasbourg, Cedex 3, France
| | - Nicolas Capelli
- UMR CNRS 6249 Chrono-Environnement, University of Franche-Comté, 16 Route de Gray, 25030, Besançon Cedex, France
| | - Sylvie Massemin
- IPHC UMR 7178 DEPE CNRS, University of Strasbourg, 23 Rue du loess, 67087, Strasbourg, Cedex 3, France
| | - Michaël Coeurdassier
- UMR CNRS 6249 Chrono-Environnement, University of Franche-Comté, 16 Route de Gray, 25030, Besançon Cedex, France
| | | | - Frédéric Gimbert
- UMR CNRS 6249 Chrono-Environnement, University of Franche-Comté, 16 Route de Gray, 25030, Besançon Cedex, France
| | - Annette de Vaufleury
- UMR CNRS 6249 Chrono-Environnement, University of Franche-Comté, 16 Route de Gray, 25030, Besançon Cedex, France.
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Sánchez-Montes G, Martínez-Solano Í, Díaz-Paniagua C, Vilches A, Ariño AH, Gomez-Mestre I. Telomere attrition with age in a wild amphibian population. Biol Lett 2020; 16:20200168. [PMID: 32673551 PMCID: PMC7423040 DOI: 10.1098/rsbl.2020.0168] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 06/16/2020] [Indexed: 12/16/2022] Open
Abstract
Telomere shortening with age has been documented in many organisms, but few studies have reported telomere length measurements in amphibians, and no information is available for growth after metamorphosis, nor in wild populations. We provide both cross-sectional and longitudinal evidence of net telomere attrition with age in a wild amphibian population of natterjack toads (Epidalea calamita). Based on age-estimation by skeletochronology and qPCR telomere length measurements in the framework of an individual-based monitoring programme, we confirmed telomere attrition in recaptured males. Our results support that toads experience telomere attrition throughout their ontogeny, and that most attrition occurs during the first 1-2 years. We did not find associations between telomere length and inbreeding or body condition. Our results on telomere length dynamics under natural conditions confirm telomere shortening with age in amphibians and provide quantification of wide telomere length variation within and among age-classes in a wild breeding population.
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Affiliation(s)
- Gregorio Sánchez-Montes
- Museo Nacional de Ciencias Naturales, CSIC, c/ José Gutiérrez Abascal, 2, 28006 Madrid, Spain
| | - Íñigo Martínez-Solano
- Museo Nacional de Ciencias Naturales, CSIC, c/ José Gutiérrez Abascal, 2, 28006 Madrid, Spain
| | - Carmen Díaz-Paniagua
- Ecology, Evolution, and Development Group, Doñana Biological Station, CSIC, c/ Américo Vespucio 26, 41092 Seville, Spain
| | - Antonio Vilches
- Department of Environmental Biology, University of Navarra, c/ Irunlarrea, 1, 31008 Pamplona, Spain
| | - Arturo H. Ariño
- Department of Environmental Biology, University of Navarra, c/ Irunlarrea, 1, 31008 Pamplona, Spain
| | - Ivan Gomez-Mestre
- Ecology, Evolution, and Development Group, Doñana Biological Station, CSIC, c/ Américo Vespucio 26, 41092 Seville, Spain
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Ho EKH, Macrae F, Latta LC, Benner MJ, Sun C, Ebert D, Schaack S. Intraspecific Variation in Microsatellite Mutation Profiles in Daphnia magna. Mol Biol Evol 2020; 36:1942-1954. [PMID: 31077327 PMCID: PMC6934441 DOI: 10.1093/molbev/msz118] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Microsatellite loci (tandem repeats of short nucleotide motifs) are highly abundant in eukaryotic genomes and often used as genetic markers because they can exhibit variation both within and between populations. Although widely recognized for their mutability and utility, the mutation rates of microsatellites have only been empirically estimated in a few species, and have rarely been compared across genotypes and populations within a species. Here, we investigate the dynamics of microsatellite mutation over long- and short-time periods by quantifying the starting abundance and mutation rates for microsatellites for six different genotypes of Daphnia magna, an aquatic microcrustacean, collected from three populations (Finland, Germany, and Israel). Using whole-genome sequences of these six starting genotypes, descendent mutation accumulation (MA) lines, and large population controls (non-MA lines), we find each genotype exhibits a distinctive initial microsatellite profile which clusters according to the population-of-origin. During the period of MA, we observe motif-specific, highly variable, and rapid microsatellite mutation rates across genotypes of D. magna, the average of which is order of magnitude greater than the recently reported rate observed in a single genotype of the congener, Daphnia pulex. In our experiment, genotypes with more microsatellites starting out exhibit greater losses and those with fewer microsatellites starting out exhibit greater gains—a context-dependent mutation bias that has not been reported previously. We discuss how genotype-specific mutation rates and spectra, in conjunction with evolutionary forces, can shape both the differential accumulation of repeat content in the genome and the evolution of mutation rates.
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Affiliation(s)
- Eddie K H Ho
- Department of Biology, Reed College, Portland, OR
| | | | - Leigh C Latta
- Department of Biology, Reed College, Portland, OR
- Division of Natural Sciences and Mathematics, Lewis-Clark State College, Lewiston, ID
| | | | - Cheng Sun
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
| | - Sarah Schaack
- Department of Biology, Reed College, Portland, OR
- Corresponding author: E-mail:
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Louzon M, Coeurdassier M, Gimbert F, Pauget B, de Vaufleury A. Telomere dynamic in humans and animals: Review and perspectives in environmental toxicology. ENVIRONMENT INTERNATIONAL 2019; 131:105025. [PMID: 31352262 DOI: 10.1016/j.envint.2019.105025] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 06/19/2019] [Accepted: 07/15/2019] [Indexed: 06/10/2023]
Abstract
Telomeres (TLs) play major roles in stabilizing the genome and are usually shortened with ageing. The maintenance of TLs is ensured by two mechanisms involving telomerase (TA) enzyme and alternative lengthening telomeres (ALT). TL shortening and/or TA inhibition have been related to health effects on organisms (leading to reduced reproductive lifespan and survival), suggesting that they could be key processes in toxicity mechanisms (at molecular and cellular levels) and relevant as an early warning of exposure and effect of chemicals on human health and animal population dynamics. Consequently, a critical analysis of knowledge about relationships between TL dynamic and environmental pollution is essential to highlight the relevance of TL measurement in environmental toxicology. The first objective of this review is to provide a survey on the basic knowledge about TL structure, roles, maintenance mechanisms and causes of shortening in both vertebrates (including humans) and invertebrates. Overall, TL length decreases with ageing but some unexpected exceptions are reported (e.g., in species with different lifespans, such as the nematode Caenorhabditis elegans or the crustacean Homarus americanus). Inconsistent results reported in various biological groups or even between species of the same genus (e.g., the microcrustacean Daphnia sp.) indicate that the relation usually proposed between TL shortening and a decrease in TA activity cannot be generalized and depends on the species, stage of development or lifespan. Although the scientific literature provides evidence of the effect of ageing on TL shortening, much less information on the relationships between shortening, maintenance of TLs, influence of other endogenous and environmental drivers, including exposure to chemical pollutants, is available, especially in invertebrates. The second objective of this review is to connect knowledge on TL dynamic and exposure to contaminants. Most of the studies published on humans rely on correlative epidemiological approaches and few in vitro experiments. They have shown TL attrition when exposed to contaminants, such as polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), pesticides and metallic elements (ME). In other vertebrates, the studies we found deals mainly with birds and, overall, report a disturbance of TL dynamic consecutively to exposure to chemicals, including metals and organic compounds. In invertebrates, no data are available and the potential of TL dynamic in environmental risk assessment remains to be explored. On the basis of the main gaps identified some research perspectives (e.g., impact of endogenous and environmental drivers, dose response effects, link between TL length, TA activity, longevity and ageing) are proposed to better understand the potential of TL and TA measurements in humans and animals in environmental toxicology.
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Affiliation(s)
- Maxime Louzon
- Department Chrono-Environnement, UMR UFC/CNRS 6249 USC INRA University of Bourgogne Franche-Comté, 16 route de Gray, 25000 Besançon, France
| | - Michael Coeurdassier
- Department Chrono-Environnement, UMR UFC/CNRS 6249 USC INRA University of Bourgogne Franche-Comté, 16 route de Gray, 25000 Besançon, France
| | - Frédéric Gimbert
- Department Chrono-Environnement, UMR UFC/CNRS 6249 USC INRA University of Bourgogne Franche-Comté, 16 route de Gray, 25000 Besançon, France
| | - Benjamin Pauget
- TESORA, Le Visium, 22 avenue Aristide Briand, 94110 Arcueil, France
| | - Annette de Vaufleury
- Department Chrono-Environnement, UMR UFC/CNRS 6249 USC INRA University of Bourgogne Franche-Comté, 16 route de Gray, 25000 Besançon, France.
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Constantinou J, Sullivan J, Mirbahai L. Ageing differently: Sex-dependent ageing rates in Daphnia magna. Exp Gerontol 2019; 121:33-45. [PMID: 30922945 DOI: 10.1016/j.exger.2019.03.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/08/2019] [Accepted: 03/23/2019] [Indexed: 01/08/2023]
Abstract
Ageing is defined as the gradual decline of normal physiological functions in a time-dependent manner. Significant progress has been made in characterising the regulatory processes involved in the mechanisms of ageing which would have been hindered without the use of model organisms. Use of alternative model organisms greatly diversifies our understanding of different factors underpinning the ageing process and the potential translation for human application. Unique characteristics make Daphnia an attractive model organism for research into mechanisms underlying ageing, such as transparent body, short generation time, well-characterised methylome, regenerative capabilities and available naturally occurring ecotypes. Most interestingly, genetically identical female and male Daphnia have evolved different average lifespans, providing a unique opportunity for understanding the underlying mechanisms of ageing and regulation of lifespan. Investigating sex differences in longevity could provide insight into principal mechanisms of ageing and lifespan regulation. In this study we provide evidence in support of establishing genetically identical female and male Daphnia as unique and valuable resources for research into mechanisms of ageing and begin to delineate the mechanisms involved in sex differences in lifespan. We identify significant differences between genders in physiological markers such as lifespan, growth rate, heart rate and swimming speed in addition to molecular markers such as lipid peroxidation product accumulation, thiol content decline and age-dependent decline in DNA damage repair efficiency. Overall, our data indicates that investigating sex differences in longevity in the clonal organism Daphnia under controlled laboratory conditions can provide insight into principal mechanisms of ageing and lifespan regulation.
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Affiliation(s)
- Julia Constantinou
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - Jack Sullivan
- MRC-ARUK Centre for Musculoskeletal Ageing Research, Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2TT, UK; NIHR Surgical Reconstruction and Microbiology Research Centre, University Hospital Birmingham, Birmingham B15 2WB, UK
| | - Leda Mirbahai
- Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK.
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A telomerase with novel non-canonical roles: TERT controls cellular aggregation and tissue size in Dictyostelium. PLoS Genet 2019; 15:e1008188. [PMID: 31237867 PMCID: PMC6592521 DOI: 10.1371/journal.pgen.1008188] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/10/2019] [Indexed: 11/19/2022] Open
Abstract
Telomerase, particularly its main subunit, the reverse transcriptase, TERT, prevents DNA erosion during eukaryotic chromosomal replication, but also has poorly understood non-canonical functions. Here, in the model social amoeba Dictyostelium discoideum, we show that the protein encoded by tert has telomerase-like motifs, and regulates, non-canonically, important developmental processes. Expression levels of wild-type (WT) tert were biphasic, peaking at 8 and 12 h post-starvation, aligning with developmental events, such as the initiation of streaming (~7 h) and mound formation (~10 h). In tert KO mutants, however, aggregation was delayed until 16 h. Large, irregular streams formed, then broke up, forming small mounds. The mound-size defect was not induced when a KO mutant of countin (a master size-regulating gene) was treated with TERT inhibitors, but anti-countin antibodies did rescue size in the tert KO. Although, conditioned medium (CM) from countin mutants failed to rescue size in the tert KO, tert KO CM rescued the countin KO phenotype. These and additional observations indicate that TERT acts upstream of smlA/countin: (i) the observed expression levels of smlA and countin, being respectively lower and higher (than WT) in the tert KO; (ii) the levels of known size-regulation intermediates, glucose (low) and adenosine (high), in the tert mutant, and the size defect's rescue by supplemented glucose or the adenosine-antagonist, caffeine; (iii) the induction of the size defect in the WT by tert KO CM and TERT inhibitors. The tert KO's other defects (delayed aggregation, irregular streaming) were associated with changes to cAMP-regulated processes (e.g. chemotaxis, cAMP pulsing) and their regulatory factors (e.g. cAMP; acaA, carA expression). Overexpression of WT tert in the tert KO rescued these defects (and size), and restored a single cAMP signaling centre. Our results indicate that TERT acts in novel, non-canonical and upstream ways, regulating key developmental events in Dictyostelium.
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Fischer KE, Riddle NC. Sex Differences in Aging: Genomic Instability. J Gerontol A Biol Sci Med Sci 2019; 73:166-174. [PMID: 28575157 DOI: 10.1093/gerona/glx105] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 05/26/2017] [Indexed: 11/13/2022] Open
Abstract
Aging is characterized by decreasing physiological integration, reduced function, loss of resilience, and increased risk of death. Paradoxically, although women live longer, they suffer greater morbidity particularly late in life. These sex differences in human lifespan and healthspan are consistently observed in all countries and during every era for which reliable data exist. While these differences are ubiquitous in humans, evidence of sex differences in longevity and health for other species is more equivocal. Among fruit flies, nematodes, and mice, sex differences in lifespan vary depending on strain and treatment. In this review, we focus on sex differences in age-related alterations in DNA damage and mutation rates, telomere attrition, epigenetics, and nuclear architecture. We find that robust sex differences exist, eg, the higher incidence of DNA damage in men compared to women, but sex differences are not often conserved between species. For most mechanisms reviewed here, there are insufficient data to make a clear determination regarding the impact of sex, largely because sex differences have not been analyzed. Overall, our findings reveal an urgent need for well-designed studies that explicitly examine sex differences in molecular drivers of aging.
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Affiliation(s)
| | - Nicole C Riddle
- Department of Biology, The University of Alabama at Birmingham
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Olsson M, Wapstra E, Friesen C. Ectothermic telomeres: it's time they came in from the cold. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2016.0449. [PMID: 29335373 PMCID: PMC5784069 DOI: 10.1098/rstb.2016.0449] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2017] [Indexed: 12/17/2022] Open
Abstract
We review the evolutionary ecology and genetics of telomeres in taxa that cannot elevate their body temperature to a preferred level through metabolism but do so by basking or seeking out a warm environment. This group of organisms contains all living things on earth, apart from birds and mammals. One reason for our interest in this synthetic group is the argument that high, stable body temperature increases the risk of malignant tumours if long, telomerase-restored telomeres make cells 'live forever'. If this holds true, ectotherms should have significantly lower cancer frequencies. We discuss to what degree there is support for this 'anti-cancer' hypothesis in the current literature. Importantly, we suggest that ectothermic taxa, with variation in somatic telomerase expression across tissue and taxa, may hold the key to understanding ongoing selection and evolution of telomerase dynamics in the wild. We further review endotherm-specific effects of growth on telomeres, effects of autotomy ('tail dropping') on telomere attrition, and costs of maintaining sexual displays measured in telomere attrition. Finally, we cover plant ectotherm telomeres and life histories in a separate 'mini review'.This article is part of the theme issue 'Understanding diversity in telomere dynamics'.
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Affiliation(s)
- Mats Olsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Medicinaregatan 18, Box 463, 405 30 Gothenburg, Sweden .,School of Biological Sciences, The University of Wollongong, 2522 Wollongong, New South Wales, Australia
| | - Erik Wapstra
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart 7001, Tasmania, Australia
| | - Christopher Friesen
- School of Life and Environmental Sciences, University of Sydney, Heydon-Laurence Bldg A08, Science Road, Sydney, NSW 2006, Australia
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Telomere maintenance during anterior regeneration and aging in the freshwater annelid Aeolosoma viride. Sci Rep 2018; 8:18078. [PMID: 30584242 PMCID: PMC6305377 DOI: 10.1038/s41598-018-36396-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 11/20/2018] [Indexed: 12/13/2022] Open
Abstract
Aging is a complex process involving declines in various cellular and physical functionalities, including regenerative ability. Telomere maintenance is thought to be necessary for regeneration, and telomere attrition is one mechanism that contributes to aging. However, it is unclear if aging affects regeneration owing to deterioration of telomeric maintenance. We introduce Aeolosoma viride—a freshwater annelid with strong regenerative abilities—as a new model for studying the effects of aging on telomere functions and regeneration. We show that the anterior regenerative ability of A. viride declines with age. We characterized the A. viride telomere sequence as being composed of TTAGGG repeats and identifyied the telomerase gene Avi-tert. In adult A. viride, telomerase was constantly active and telomere lengths were similar among different body sections and stably maintained with age. Notably, we found that regeneration did not result in telomere shortening at regenerating sites. Moreover, transient up-regulation of Avi-tert expression and telomerase activity was observed at regenerating sites, which might promote telomere lengthening to counteract telomere erosion resulting from cell proliferation. Our study suggests that although aging affects A. viride regeneration independent of steady-state telomere length, timely regulation of telomerase functions is critical for the regeneration process in A. viride.
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Kvist J, Gonçalves Athanàsio C, Shams Solari O, Brown JB, Colbourne JK, Pfrender ME, Mirbahai L. Pattern of DNA Methylation in Daphnia: Evolutionary Perspective. Genome Biol Evol 2018; 10:1988-2007. [PMID: 30060190 PMCID: PMC6097596 DOI: 10.1093/gbe/evy155] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2018] [Indexed: 02/06/2023] Open
Abstract
DNA methylation is an evolutionary ancient epigenetic modification that is phylogenetically widespread. Comparative studies of the methylome across a diverse range of non-conventional and conventional model organisms is expected to help reveal how the landscape of DNA methylation and its functions have evolved. Here, we explore the DNA methylation profile of two species of the crustacean Daphnia using whole genome bisulfite sequencing. We then compare our data with the methylomes of two insects and two mammals to achieve a better understanding of the function of DNA methylation in Daphnia. Using RNA-sequencing data for all six species, we investigate the correlation between DNA methylation and gene expression. DNA methylation in Daphnia is mainly enriched within the coding regions of genes, with the highest methylation levels observed at exons 2–4. In contrast, vertebrate genomes are globally methylated, and increase towards the highest methylation levels observed at exon 2, and maintained across the rest of the gene body. Although DNA methylation patterns differ among all species, their methylation profiles share a bimodal distribution across the genomes. Genes with low levels of CpG methylation and gene expression are mainly enriched for species specific genes. In contrast, genes associated with high methylated CpG sites are highly transcribed and evolutionary conserved across all species. Finally, the positive correlation between internal exons and gene expression potentially points to an evolutionary conserved mechanism, whereas the negative regulation of gene expression via methylation of promoters and exon 1 is potentially a secondary mechanism that has been evolved in vertebrates.
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Affiliation(s)
- Jouni Kvist
- School of Biosciences, University of Birmingham, United Kingdom
| | | | | | - James B Brown
- Department of Statistics, University of California, Berkeley.,Centre for Computational Biology (CCB), University of Birmingham, United Kingdom
| | | | - Michael E Pfrender
- Department of Biological Sciences and Environmental Change Initiative, University of Notre Dame
| | - Leda Mirbahai
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
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15
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Saiz E, Calbet A, Griffell K. Sex-Dependent Effects of Caloric Restriction on the Ageing of an Ambush Feeding Copepod. Sci Rep 2017; 7:12662. [PMID: 28978933 PMCID: PMC5627296 DOI: 10.1038/s41598-017-12661-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 09/18/2017] [Indexed: 01/25/2023] Open
Abstract
Planktonic copepods are a very successful group in marine pelagic environments, with a key role in biogeochemical cycles. Among them, the genus Oithona is one of the more abundant and ubiquitous. We report here on the effects of caloric (food) restriction on the ageing patterns of the copepod Oithona davisae. The response of O. davisae to caloric restriction was sex dependent: under food limitation, females have lower age-specific mortality rates and longer lifespans and reproductive periods; male mortality rates and life expectancy were not affected. Males are more active swimmers than females, and given their higher energetic demands presumably generate reactive oxygen species at higher rates. That was confirmed by starvation experiments, which showed that O. davisae males burn through body reserves much faster, resulting in shorter life expectancy. Compared with common, coastal calanoid copepods, the effects of caloric restriction on O. davisae appeared less prominent. We think this difference in the magnitude of the responses is a consequence of the distinct life-history traits associated with the genus Oithona (ambush feeder, egg-carrier), with much lower overall levels of metabolism and reproductive effort.
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Affiliation(s)
- Enric Saiz
- Institut de Ciències del Mar - CSIC, Pg. Marítim de la Barceloneta 37-49, 08003, Barcelona, Catalonia, Spain.
| | - Albert Calbet
- Institut de Ciències del Mar - CSIC, Pg. Marítim de la Barceloneta 37-49, 08003, Barcelona, Catalonia, Spain
| | - Kaiene Griffell
- Institut de Ciències del Mar - CSIC, Pg. Marítim de la Barceloneta 37-49, 08003, Barcelona, Catalonia, Spain
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16
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Lai AG, Pouchkina-Stantcheva N, Di Donfrancesco A, Kildisiute G, Sahu S, Aboobaker AA. The protein subunit of telomerase displays patterns of dynamic evolution and conservation across different metazoan taxa. BMC Evol Biol 2017; 17:107. [PMID: 28441946 PMCID: PMC5405514 DOI: 10.1186/s12862-017-0949-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 04/04/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Most animals employ telomerase, which consists of a catalytic subunit known as the telomerase reverse transcriptase (TERT) and an RNA template, to maintain telomere ends. Given the importance of TERT and telomere biology in core metazoan life history traits, like ageing and the control of somatic cell proliferation, we hypothesised that TERT would have patterns of sequence and regulatory evolution reflecting the diverse life histories across the Animal Kingdom. RESULTS We performed a complete investigation of the evolutionary history of TERT across animals. We show that although TERT is almost ubiquitous across Metazoa, it has undergone substantial sequence evolution within canonical motifs. Beyond the known canonical motifs, we also identify and compare regions that are highly variable between lineages, but show conservation within phyla. Recent data have highlighted the importance of alternative splice forms of TERT in non-canonical functions and although animals may share some conserved introns, we find that the selection of exons for alternative splicing appears to be highly variable, and regulation by alternative splicing appears to be a very dynamic feature of TERT evolution. We show that even within a closely related group of triclad flatworms, where alternative splicing of TERT was previously correlated with reproductive strategy, we observe highly diverse splicing patterns. CONCLUSIONS Our work establishes that the evolutionary history and structural evolution of TERT involves previously unappreciated levels of change and the emergence of lineage specific motifs. The sequence conservation we describe within phyla suggests that these new motifs likely serve essential biological functions of TERT, which along with changes in splicing, underpin diverse functions of TERT important for animal life histories.
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Affiliation(s)
- Alvina G Lai
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
| | | | | | - Gerda Kildisiute
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - Sounak Sahu
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - A Aziz Aboobaker
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
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17
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Abstract
The ability to appropriately respond to proteotoxic stimuli is a major determinant of longevity and involves induction of various heat shock response (HSR) genes, which are essential to cope with cellular and organismal insults throughout lifespan. The activity of NAD+-dependent deacetylase Sir2, originally discovered in yeast, is known to be essential for effective HSR and longevity. Our previous work on HSR inDaphnia pulicaria indicated a drastic reduction of the HSR in older organisms. In this report we investigate the role of Sir2 in regulating HSR during the lifespan of D. pulicaria. We cloned Daphnia Sir2 open reading frame (ORF) to characterize the enzyme activity and confirmed that the overall function of Sir2 was conserved in Daphnia. The Sir2 mRNA levels increased while the enzyme activity declined with age and considering that Sir2 activity regulates HSR, this explains the previously observed age-dependent decline in HSR. Finally, we tested the effect of Sir2 knockdown throughout adult life by using our new RNA interference (RNAi) method by feeding. Sir2 knockdown severely reduced both the median lifespan as well as significantly increased mortality following heat shock. Our study provides the first characterization and functional study of Daphnia Sir2.
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18
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Abstract
Using data from 83 isolates from a single population, the population genomics of the microcrustacean Daphnia pulex are described and compared to current knowledge for the only other well-studied invertebrate, Drosophila melanogaster These two species are quite similar with respect to effective population sizes and mutation rates, although some features of recombination appear to be different, with linkage disequilibrium being elevated at short ([Formula: see text] bp) distances in D. melanogaster and at long distances in D. pulex The study population adheres closely to the expectations under Hardy-Weinberg equilibrium, and reflects a past population history of no more than a twofold range of variation in effective population size. Fourfold redundant silent sites and a restricted region of intronic sites appear to evolve in a nearly neutral fashion, providing a powerful tool for population genetic analyses. Amino acid replacement sites are predominantly under strong purifying selection, as are a large fraction of sites in UTRs and intergenic regions, but the majority of SNPs at such sites that rise to frequencies [Formula: see text] appear to evolve in a nearly neutral fashion. All forms of genomic sites (including replacement sites within codons, and intergenic and UTR regions) appear to be experiencing an [Formula: see text] higher level of selection scaled to the power of drift in D. melanogaster, but this may in part be a consequence of recent demographic changes. These results establish D. pulex as an excellent system for future work on the evolutionary genomics of natural populations.
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Ujvari B, Biro PA, Charters JE, Brown G, Heasman K, Beckmann C, Madsen T. Curvilinear telomere length dynamics in a squamate reptile. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12764] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Beata Ujvari
- Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University Waurn Ponds Victoria3218 Australia
| | - Peter A. Biro
- Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University Waurn Ponds Victoria3218 Australia
| | - Jordan E. Charters
- Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University Waurn Ponds Victoria3218 Australia
- School of Biological Sciences University of Queensland Brisbane Queensland4072 Australia
| | - Gregory Brown
- School of Biological Sciences University of Sydney Sydney New South Wales2006 Australia
| | - Kim Heasman
- Faculty of Veterinary Science University of Sydney Sydney New South Wales2006 Australia
| | - Christa Beckmann
- Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University Waurn Ponds Victoria3218 Australia
| | - Thomas Madsen
- Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University Waurn Ponds Victoria3218 Australia
- School of Molecular Biosciences University of Sydney Sydney New South Wales2006 Australia
- School of Biological Sciences University of Wollongong Wollongong New South Wales2522 Australia
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20
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Peška V, Sitová Z, Fajkus P, Fajkus J. BAL31-NGS approach for identification of telomeres de novo in large genomes. Methods 2016; 114:16-27. [PMID: 27595912 DOI: 10.1016/j.ymeth.2016.08.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 08/22/2016] [Accepted: 08/31/2016] [Indexed: 10/21/2022] Open
Abstract
This article describes a novel method to identify as yet undiscovered telomere sequences, which combines next generation sequencing (NGS) with BAL31 digestion of high molecular weight DNA. The method was applied to two groups of plants: i) dicots, genus Cestrum, and ii) monocots, Allium species (e.g. A. ursinum and A. cepa). Both groups consist of species with large genomes (tens of Gb) and a low number of chromosomes (2n=14-16), full of repeat elements. Both genera lack typical telomeric repeats and multiple studies have attempted to characterize alternative telomeric sequences. However, despite interesting hypotheses and suggestions of alternative candidate telomeres (retrotransposons, rDNA, satellite repeats) these studies have not resolved the question. In a novel approach based on the two most general features of eukaryotic telomeres, their repetitive character and sensitivity to BAL31 nuclease digestion, we have taken advantage of the capacity and current affordability of NGS in combination with the robustness of classical BAL31 nuclease digestion of chromosomal termini. While representative samples of most repeat elements were ensured by low-coverage (less than 5%) genomic shot-gun NGS, candidate telomeres were identified as under-represented sequences in BAL31-treated samples.
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Affiliation(s)
- Vratislav Peška
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic; Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, CZ-61265 Brno, Czech Republic
| | - Zdeňka Sitová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
| | - Petr Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic; Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, CZ-61265 Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic; Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, CZ-61265 Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic.
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21
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Kepinska M, Szyller J, Milnerowicz H. The influence of oxidative stress induced by iron on telomere length. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 40:931-935. [PMID: 26513689 DOI: 10.1016/j.etap.2015.10.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 10/07/2015] [Accepted: 10/10/2015] [Indexed: 06/05/2023]
Abstract
Oxidative stress can be induced by increased concentrations of iron in the body and consequently can cause shortening of telomeres. Telomeres, called mitotic clocks, are non-coding fragments at the end of chromosomes. During the replication of genetic material they are shortened, playing the role of ageing biomarkers in eukaryotes. In human endothelial cells, oxidative stress causes a decrease in telomerase activity. Shortening of chromosomes in telomeric parts was found in patients with primary hemochromatosis and in patients taking supplements containing iron. Increased level of transferrin saturation is associated with the presence of shorter telomeres in the chromosomes of leukocytes. The relationship between iron status and telomere length is still not fully understood.
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Affiliation(s)
- Marta Kepinska
- Department of Biomedical and Environmental Analysis, Faculty of Pharmacy, Wroclaw Medical University, Borowska 211, 50-556 Wrocław, Poland.
| | - Jakub Szyller
- Students Scientific Society at the Department of Biomedical Environmental Analysis, Faculty of Pharmacy, Wroclaw Medical University, Borowska 211, 50-556 Wrocław, Poland
| | - Halina Milnerowicz
- Department of Biomedical and Environmental Analysis, Faculty of Pharmacy, Wroclaw Medical University, Borowska 211, 50-556 Wrocław, Poland
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22
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Schumpert CA, Dudycha JL, Patel RC. Development of an efficient RNA interference method by feeding for the microcrustacean Daphnia. BMC Biotechnol 2015; 15:91. [PMID: 26446824 PMCID: PMC4597761 DOI: 10.1186/s12896-015-0209-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 10/01/2015] [Indexed: 12/18/2022] Open
Abstract
Background RNA interference (RNAi) is an important molecular tool for analysis of gene function in vivo. Daphnia, a freshwater microcrustacean, is an emerging model organism for studying cellular and molecular processes involved in aging, development, and ecotoxicology especially in the context of environmental variation. However, in spite of the availability of a fully sequenced genome of Daphnia pulex, meaningful mechanistic studies have been hampered by a lack of molecular techniques to alter gene expression. A microinjection method for gene knockdown by RNAi has been described but the need for highly specialized equipment as well as technical expertise limits the wider application of this technique. In addition to being expensive and technically challenging, microinjections can only target genes expressed during embryonic stages, thus making it difficult to achieve effective RNAi in adult organisms. Results In our present study we present a bacterial feeding method for RNAi in Daphnia. We used a melanic Daphnia species (Daphnia melanica) that exhibits dark pigmentation to target phenoloxidase, a key enzyme in the biosynthesis of melanin. We demonstrate that our RNAi method results in a striking phenotype and that the phenoloxidase mRNA expression and melanin content, as well as survival following UV insults, are diminished as a result of RNAi. Conclusions Overall, our results establish a new method for RNAi in Daphnia that significantly advances further use of Daphnia as a model organism for functional genomics studies. The method we describe is relatively simple and widely applicable for knockdown of a variety of genes in adult organisms.
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Affiliation(s)
- Charles A Schumpert
- Department of Biological Sciences, University of South Carolina, 700 Sumter Street, Columbia, SC, 29208, USA
| | - Jeffry L Dudycha
- Department of Biological Sciences, University of South Carolina, 700 Sumter Street, Columbia, SC, 29208, USA
| | - Rekha C Patel
- Department of Biological Sciences, University of South Carolina, 700 Sumter Street, Columbia, SC, 29208, USA.
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Impaired telomerase activity hinders proliferation and in vitro transformation of Penaeus monodon lymphoid cells. Cytotechnology 2015; 68:1301-14. [PMID: 26084784 DOI: 10.1007/s10616-015-9890-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 05/19/2015] [Indexed: 12/16/2022] Open
Abstract
Retaining terminal transferase activity of telomerase, the ribonucleoprotein enzyme which add telomeric repeats on chromosome end is thought to be required to prevent cellular ageing. Additionally, telomerase considered as a marker for cell proliferation and immortalization in eukaryotes. We examined telomerase activity in tissues and lymphoid cell culture of Penaeus monodon. Along with telomerase activity, telomere repeats and an attempt on identification of telomerase reverse transcriptase (PmTERT) were made. Telomeric repeat amplification protocol revealed that telomerase-dependent telomeric lengthening has been taking place in P. monodon and the adult tissues were retaining this capacity throughout their lifespan with the highest activity in ovary, testis and lymphoid organ. However, telomerase activity could not be detected in lymphoid cells in culture. The canonical telomeric repeats added by telomerase of lymphoid tissue extract were identified as TTAGG, but pentameric repeats GGTTA and AGGTT were also added by the telomerase. PmTERT protein sequence (partial) shared 100 % identity with the TERT sequence of Daphnia pulex, 27 % sequence identity with Purple sea urchin and 24-25 % with Zebra fish. Undetectable telomerase activity in lymphoid cell culture supports the hypothesis that the inadequate telomerase activity or gene expression may be a reason that prevents neoplastic transformation and spontaneous immortalization of the cells in vitro. Thus, it is envisaged that telomerase activation in lymphoid cells may surmount cellular ageing for in vitro transformation and cell line establishment.
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