University of Veterinary Medicine Vienna - Research portal

Diagrammed Link to Homepage University of Veterinary Medicine, Vienna

Germline and Steroid Regulation of Drosophila Aging

Abstract
In many organisms, from fruit flies to humans, reproduction shortens lifespan, but the underlying mechanisms remain unknown. Recent progress on this problem has been made in C. elegans. Ablation of germline precursor cells in this nematode worm extends lifespan by signaling through DAF-12, a nuclear receptor activated by steroids called dafachronic acids (DA). While germline ablation cannot extend lifespan in DA-deficient mutants, longevity is restored by application of DA. DA also increases activity of DAF-16, a transcription factor downstream of insulin/IGF-1 like signaling (IIS) which is required for germline loss to extend lifespan. Gonadal signals might thus regulate aging by modulating steroid hormone signaling and IIS. However, the details of this systemic regulation are not well understood, and it is unclear whether the observations in C. elegans also apply to other organisms. We have recently found that germline ablation can also extend lifespan and activate DAF-16 (dFOXO) in Drosophila melanogaster, suggesting that the gonadal regulation of aging might be evolutionarily conserved. Here we propose to investigate whether reproductive signals affect Drosophila lifespan by modulating steroid hormone signaling, as is the case in the worm. Interestingly, a steroid hormone (20-hydroxy-ecdysone, 20E) is known to affect lifespan in fruit flies by signaling through a nuclear receptor (ecdysone receptor, EcR) similar to DAF-12, but the exact mechanisms by which 20E/EcR regulate fly longevity have not yet been explored. We hypothesize that the DA/DAF-12 signaling pathway of C. elegans corresponds to the 20E/EcR pathway in Drosophila and that these endocrine systems have homologous effects on aging. Several facts lend support to our model: (1) the ligand binding domain of EcR shares 34% sequence identity with that of DAF-12; (2) the enzyme encoded by DAF-36 is required for DA production, whereas its Drosophila homolog neverland is required for 20E production; and (3) both DA and 20E affect DAF-16/dFOXO activity. Our research project will address this model in two specific aims, using the powerful tools of Drosophila genetics and endocrine physiology. Our first aim is to test whether and how the effects of germline ablation on lifespan depend on 20E/EcR signaling using epistasis analysis. Our second aim is to investigate whether and how 20E/EcR affects aging by modulating, or interacting with, the transcription factor DAF-16/dFOXO downstream of IIS. Research in this proposal will generate novel insights into the germline regulation of aging and help to unravel the mechanisms whereby steroid hormones affect lifespan.




Keywords
Alterung, Lebensspanne
Insulinstoffwechsel
Keimbahn
Reproduktion
Reproduktion
Steroidhormone
Lemma
FWF Drosophila Aging
Project leader
Flatt Thomas
Duration
01.07.09-30.06.12
Type of Research
Basic research
Vetmed Research Units
Institute of Population Genetics
Funded by
FWF - Fonds zur Förderung der wissenschaftlichen Forschung, Wien, Austria

Link To Project Finder
9 Publications

Durmaz, E; Rajpurohit, S; Betancourt, N; Fabian, DK; Kapun, M; Schmidt, P; Flatt, T (2019): A clinal polymorphism in the insulin signaling transcription factor foxo contributes to life-history adaptation in Drosophila. Evolution. 2019; 73(9):1774-1792
Open Access Logo

Fabian, DK; Garschall, K; Klepsatel, P; Santos-Matos, G; Sucena, É; Kapun, M; Lemaitre, B; Schlötterer, C; Arking, R; Flatt, T (2018): Evolution of longevity improves immunity in Drosophila . Evol Lett. 2018; 2(6):567-579
Open Access Logo

Garschall, K; Dellago, H; Gáliková, M; Schosserer, M; Flatt, T; Grillari, J (2017): Ubiquitous overexpression of the DNA repair factor dPrp19 reduces DNA damage and extends Drosophila life span. NPJ Aging Mech Dis. 2017; 3:5
Open Access Logo

Fabian, DK; Lack, JB; Mathur, V; Schlötterer, C; Schmidt, PS; Pool, JE; Flatt, T (2015): Spatially varying selection shapes life history clines among populations of Drosophila melanogaster from sub-Saharan Africa. J Evol Biol. 2015; 28(4):826-840
Open Access Logo

Klepsatel, P; Gáliková, M; Huber, CD; Flatt, T (2014): Similarities and differences in altitudinal versus latitudinal variation for morphological traits in Drosophila melanogaster. Evolution. 2014; 68(5):1385-1398

Klepsatel, P; Gáliková, M; De Maio, N; Huber, CD; Schlötterer, C; Flatt, T (2013): Variation in thermal performance and reaction norms among populations of Drosophila melanogaster. Evolution. 2013; 67(12):3573-3587

Klepsatel, P; Gáliková, M; De Maio, N; Ricci, S; Schlötterer, C; Flatt, T (2013): Reproductive and post-reproductive life history of wild-caught Drosophila melanogaster under laboratory conditions. J Evol Biol. 2013; 26(7):1508-1520

Fabian, DK; Kapun, M; Nolte, V; Kofler, R; Schmidt, PS; Schlötterer, C; Flatt, T (2012): Genome-wide patterns of latitudinal differentiation among populations of Drosophila melanogaster from North America. Mol Ecol. 2012; 21(19):4748-4769
Open Access Logo

Flatt, T (2011): Survival costs of reproduction in Drosophila. Exp Gerontol. 2011; 46(5):369-375

© University of Veterinary Medicine ViennaHelp and DownloadsAccessibility statement