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Steenwinkel TE, Hamre KK, Werner T. The use of non-model Drosophila species to study natural variation in TOR pathway signaling. PLoS One 2022; 17:e0270436. [PMID: 36137094 PMCID: PMC9499319 DOI: 10.1371/journal.pone.0270436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 09/06/2022] [Indexed: 11/25/2022] Open
Abstract
Nutrition and growth are strongly linked, but not much is known about how nutrition leads to growth. To understand the connection between nutrition through the diet, growth, and proliferation, we need to study the phenotypes resulting from the activation and inhibition of central metabolic pathways. One of the most highly conserved metabolic pathways across eukaryotes is the Target of Rapamycin (TOR) pathway, whose primary role is to detect the availability of nutrients and to either induce or halt cellular growth. Here we used the model organism Drosophila melanogaster (D. mel.) and three non-model Drosophila species with different dietary needs, Drosophila guttifera (D. gut.), Drosophila deflecta (D. def.), and Drosophila tripunctata (D. tri.), to study the effects of dietary amino acid availability on fecundity and longevity. In addition, we inhibited the Target of Rapamycin (TOR) pathway, using rapamycin, to test how the inhibition interplays with the nutritional stimuli in these four fruit fly species. We hypothesized that the inhibition of the TOR pathway would reverse the phenotypes observed under conditions of overfeeding. Our results show that female fecundity increased with higher yeast availability in all four species but decreased in response to TOR inhibition. The longevity data were more varied: most species experienced an increase in median lifespan in both genders with an increase in yeast availability, while the lifespan of D. mel. females decreased. When exposed to the TOR inhibitor rapamycin, the life spans of most species decreased, except for D. tri, while we observed a major reduction in fecundity across all species. The obtained data can benefit future studies on the evolution of metabolism by showing the potential of using non-model species to track changes in metabolism. Particularly, our data show the possibility to use relatively closely related Drosophila species to gain insight on the evolution of TOR signaling.
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Affiliation(s)
- Tessa E. Steenwinkel
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, United States of America
| | - Kailee K. Hamre
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, United States of America
| | - Thomas Werner
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, United States of America
- * E-mail:
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Soni P, Ghufran MS, Olakkaran S, Puttaswamygowda GH, Duddukuri GR, Kanade SR. Epigenetic alterations induced by aflatoxin B 1: An in vitro and in vivo approach with emphasis on enhancer of zeste homologue-2/p21 axis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 762:143175. [PMID: 33131875 DOI: 10.1016/j.scitotenv.2020.143175] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/21/2020] [Accepted: 10/14/2020] [Indexed: 06/11/2023]
Abstract
The potent environmental toxicant aflatoxin B1 (AFB1), is a group I carcinogen reported to induce the expression of many cancer associated proteins. Epigenetic alterations such as DNA methylation and histone modifications play vital role in AFB1-mediated carcinogenesis. These epigenetic modifications may result in the recruitment of specific proteins and transcription factors to the promoter region and regulate gene expression. Here we show that AFB1, at lower concentrations (100 and 1000 nM) induced proliferation in L-132 and HaCaT cells with activation of the Akt pathway, which ultimately steered abnormal proliferation and transmission of survival signals. We demonstrated a significant reduction in the expression of p21 with a remarkable increase in the expression of cyclin D1 that correlated with increased methylation of CpG dinucleotides in p21 proximal promoter, while cyclin D1 promoter remained unmethylated. The chromatin immunoprecipitation results revealed the enrichment of DNMT3a and H3K27me3 repressive marks on the p21 proximal promoter where EZH2 mediated H3K27me3 mark enhanced the binding of DNMT3a at the promoter and further contributed to the transcriptional inactivation. The overall study provided the novel information on the impact of AFB1 on p21 inactivation via EZH2 and promoter methylation which is known to be a vital process in proliferation. Furthermore, AFB1 induced the expression of EZH2 analogue protein E(z), cyclin D1 analogue cyclin D and decreased the expression of p21 analogue Dacapo in Drosophila melanogaster. Interestingly, the aggressiveness in their expression upon re-exposure in successive generations suggested first hand perspectives on multigenerational epigenetic memory.
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Affiliation(s)
- Priyanka Soni
- Department of Biochemistry and Molecular Biology, School of Biological Sciences, Central University of Kerala, Tejaswini Hills, Periye, Kasargod 671316, Kerala, India
| | - Md Sajid Ghufran
- Department of Biochemistry and Molecular Biology, School of Biological Sciences, Central University of Kerala, Tejaswini Hills, Periye, Kasargod 671316, Kerala, India
| | - Shilpa Olakkaran
- Department of Zoology, School of Biological Sciences, Central University of Kerala, Tejaswini Hills, Periye, Kasargod 671316, Kerala, India
| | | | - Govinda Rao Duddukuri
- Department of Biochemistry and Molecular Biology, School of Biological Sciences, Central University of Kerala, Tejaswini Hills, Periye, Kasargod 671316, Kerala, India
| | - Santosh R Kanade
- Department of Plant Science, School of Life Science, University of Hyderabad, Prof. C. R. Rao Road Gachibowli, Hyderabad 500046, India.
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Mitchell CL, Latuszek CE, Vogel KR, Greenlund IM, Hobmeier RE, Ingram OK, Dufek SR, Pecore JL, Nip FR, Johnson ZJ, Ji X, Wei H, Gailing O, Werner T. α-amanitin resistance in Drosophila melanogaster: A genome-wide association approach. PLoS One 2017; 12:e0173162. [PMID: 28241077 PMCID: PMC5328632 DOI: 10.1371/journal.pone.0173162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/15/2017] [Indexed: 11/17/2022] Open
Abstract
We investigated the mechanisms of mushroom toxin resistance in the Drosophila Genetic Reference Panel (DGRP) fly lines, using genome-wide association studies (GWAS). While Drosophila melanogaster avoids mushrooms in nature, some lines are surprisingly resistant to α-amanitin—a toxin found solely in mushrooms. This resistance may represent a pre-adaptation, which might enable this species to invade the mushroom niche in the future. Although our previous microarray study had strongly suggested that pesticide-metabolizing detoxification genes confer α-amanitin resistance in a Taiwanese D. melanogaster line Ama-KTT, none of the traditional detoxification genes were among the top candidate genes resulting from the GWAS in the current study. Instead, we identified Megalin, Tequila, and widerborst as candidate genes underlying the α-amanitin resistance phenotype in the North American DGRP lines, all three of which are connected to the Target of Rapamycin (TOR) pathway. Both widerborst and Tequila are upstream regulators of TOR, and TOR is a key regulator of autophagy and Megalin-mediated endocytosis. We suggest that endocytosis and autophagy of α-amanitin, followed by lysosomal degradation of the toxin, is one of the mechanisms that confer α-amanitin resistance in the DGRP lines.
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Affiliation(s)
- Chelsea L Mitchell
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Catrina E Latuszek
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Kara R Vogel
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, 1300 University Ave., Madison, WI, United States of America
| | - Ian M Greenlund
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Rebecca E Hobmeier
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Olivia K Ingram
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Shannon R Dufek
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Jared L Pecore
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Felicia R Nip
- College of Human Medicine, Michigan State University, Clinical Center, East Lansing, MI, United States of America
| | - Zachary J Johnson
- U.S. Forest Service, Salt Lake Ranger District 6944 S, 3000 E, Salt Lake City, UT, United States of America
| | - Xiaohui Ji
- School of Forest Resources and Environmental Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Hairong Wei
- School of Forest Resources and Environmental Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Oliver Gailing
- School of Forest Resources and Environmental Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
| | - Thomas Werner
- Department of Biological Sciences, Michigan Technological University, 1400 Townsend Dr., Houghton, MI, United States of America
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