1
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Gordon K, Gonzales P, Lee C, Marcin J, Takashima Y, Lazzaro B, Wolfner M. Drosophila Arc1 is not required for male fertility or sperm competition success. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.001053. [PMID: 38089935 PMCID: PMC10714220 DOI: 10.17912/micropub.biology.001053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 11/27/2023] [Accepted: 11/27/2023] [Indexed: 02/01/2024]
Abstract
Activity-regulated cytoskeleton associated protein (Arc1), which is required for synaptic plasticity and metabolism in Drosophila , self-assembles into capsid-like structures that transport mRNAs in extracellular vesicles. In addition to expression in the brain and nervous system, Arc1 is expressed in the male accessory glands, an endothelial tissue that produces male seminal proteins and exosomes that impact male fertility. We thus hypothesized that Arc1 might impact male fertility. We measured the fertility, mating latency, mating duration, and sperm competition performance of Arc1 males relative to controls and found no evidence that Arc1 is required for any of these measures of male fertility.
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Affiliation(s)
- Kathleen Gordon
- Department of Entomology, Cornell University, Ithaca, New York, United States
| | - Patrick Gonzales
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States
| | - Caroline Lee
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States
| | - Jeremy Marcin
- Department of Entomology, Cornell University, Ithaca, New York, United States
| | - Yoko Takashima
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States
| | - Brian Lazzaro
- Department of Entomology, Cornell University, Ithaca, New York, United States
| | - Mariana Wolfner
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States
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2
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Shi J, Xu J, Ma J, He F. tRNA-derived small RNAs are embedded in the gene regulatory program instructing Drosophila metamorphosis. Genome Res 2023; 33:gr.278128.123. [PMID: 37973194 PMCID: PMC10760521 DOI: 10.1101/gr.278128.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 11/08/2023] [Indexed: 11/19/2023]
Abstract
A class of noncoding RNAs, referred to as tsRNAs, is emerging with a potential to exert a new layer in gene regulation. These RNAs are breakdown products of tRNAs, either through active processing or passive cleavage or both. Since tRNAs are part of the general machinery for translation, their expression levels and activities are tightly controlled, raising the possibility that their breakdown products, tsRNAs, may provide a link between the overall translational status of a cell to specific changes in gene regulatory network. We hypothesize that Drosophila pupation, being a special developmental stage during which there is a global limitation of nutrients, represents a system in which such a link may readily reveal itself. We show that specific tsRNAs indeed exhibit a dynamic accumulation upon entering the pupal stage. We describe experiments to characterize the mode of tsRNA action and, through the use of such gained knowledge, conduct a genome-wide analysis to assess the functions of dynamically expressed tsRNAs. Our results show that the predicted target genes are highly enriched in biological processes specific to this stage of development including metamorphosis. We further show that tsRNA action is required for successful pupation, providing direct support to the hypothesis that tsRNAs accumulated during this stage are critical to the gene expression program at this stage of development.
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Affiliation(s)
| | - Jiaqi Xu
- Zhejiang University School of Medicine
| | - Jun Ma
- Zhejiang University School of Medicine
| | - Feng He
- Zhejiang University School of Medicine
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3
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Diaz AV, Stephenson D, Nemkov T, D’Alessandro A, Reis T. Spenito-dependent metabolic sexual dimorphism intrinsic to fat storage cells. Genetics 2023; 225:iyad164. [PMID: 37738330 PMCID: PMC10627258 DOI: 10.1093/genetics/iyad164] [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: 06/05/2023] [Accepted: 08/16/2023] [Indexed: 09/24/2023] Open
Abstract
Metabolism in males and females is distinct. Differences are usually linked to sexual reproduction, with circulating signals (e.g. hormones) playing major roles. In contrast, sex differences prior to sexual maturity and intrinsic to individual metabolic tissues are less understood. We analyzed Drosophila melanogaster larvae and find that males store more fat than females, the opposite of the sexual dimorphism in adults. We show that metabolic differences are intrinsic to the major fat storage tissue, including many differences in the expression of metabolic genes. Our previous work identified fat storage roles for Spenito (Nito), a conserved RNA-binding protein and regulator of sex determination. Nito knockdown specifically in the fat storage tissue abolished fat differences between males and females. We further show that Nito is required for sex-specific expression of the master regulator of sex determination, Sex-lethal (Sxl). "Feminization" of fat storage cells via tissue-specific overexpression of a Sxl target gene made larvae lean, reduced the fat differences between males and females, and induced female-like metabolic gene expression. Altogether, this study supports a model in which Nito autonomously controls sexual dimorphisms and differential expression of metabolic genes in fat cells in part through its regulation of the sex determination pathway.
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Affiliation(s)
- Arely V Diaz
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Daniel Stephenson
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Travis Nemkov
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Angelo D’Alessandro
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Tânia Reis
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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4
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Swope SD, Jones TW, Mellina KN, Nichols SJ, DiAngelo JR. Arc1 : a regulator of triglyceride homeostasis in male Drosophila. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000945. [PMID: 37675078 PMCID: PMC10477910 DOI: 10.17912/micropub.biology.000945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 08/09/2023] [Accepted: 08/17/2023] [Indexed: 09/08/2023]
Abstract
Achieving metabolic homeostasis is necessary for survival, and many genes are required to control organismal metabolism. A genetic screen in Drosophila larvae identified putative fat storage genes including Arc1 . Arc1 has been shown to act in neurons to regulate larval lipid storage; however, whether Arc1 functions to regulate adult metabolism is unknown. Arc1 esm18 males store more fat than controls while both groups eat similar amounts. Arc1 esm18 flies express more brummer lipase and less of the glycolytic enzyme triose phosphate isomerase, which may contribute to excess fat observed in these mutants. These results suggest that Arc1 regulates adult Drosophila lipid homeostasis.
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Affiliation(s)
| | - Tyler W. Jones
- Pennsylvania State University, Berks Campus, Reading, PA
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5
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Diaz AV, Matheny T, Stephenson D, Nemkov T, D’Alessandro A, Reis T. Spenito-dependent metabolic sexual dimorphism intrinsic to fat storage cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.17.528952. [PMID: 36824729 PMCID: PMC9949119 DOI: 10.1101/2023.02.17.528952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Metabolism in males and females is distinct. Differences are usually linked to sexual reproduction, with circulating signals (e.g. hormones) playing major roles. By contrast, sex differences prior to sexual maturity and intrinsic to individual metabolic tissues are less understood. We analyzed Drosophila melanogaster larvae and find that males store more fat than females, the opposite of the sexual dimorphism in adults. We show that metabolic differences are intrinsic to the major fat storage tissue, including many differences in the expression of metabolic genes. Our previous work identified fat storage roles for Spenito (Nito), a conserved RNA-binding protein and regulator of sex determination. Nito knockdown specifically in the fat storage tissue abolished fat differences between males and females. We further show that Nito is required for sex-specific expression of the master regulator of sex determination, Sex-lethal (Sxl). "Feminization" of fat storage cells via tissue-specific overexpression of a Sxl target gene made larvae lean, reduced the fat differences between males and females, and induced female-like metabolic gene expression. Altogether, this study supports a model in which Nito autonomously controls sexual dimorphisms and differential expression of metabolic genes in fat cells in part through its regulation of the sex determination pathway.
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Affiliation(s)
- Arely V. Diaz
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Tyler Matheny
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Daniel Stephenson
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Travis Nemkov
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Angelo D’Alessandro
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Tânia Reis
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
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6
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Zhao X, Wang W, Yao Y, Li X, Huang X, Wang Y, Ding M, Huang X. An RDH‐Plin2 axis modulates lipid droplet size by antagonizing Bmm lipase. EMBO Rep 2022; 23:e52669. [PMID: 35132760 PMCID: PMC8892243 DOI: 10.15252/embr.202152669] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 12/04/2021] [Accepted: 12/21/2021] [Indexed: 12/18/2022] Open
Abstract
The size of lipid droplets varies greatly in vivo and is determined by both intrinsic and extrinsic factors. From an RNAi screen in Drosophila, we found that knocking down subunits of COP9 signalosome (CSN) results in enlarged lipid droplets under high‐fat, but not normal, conditions. We identified CG2064, a retinol dehydrogenase (RDH) homolog, as the proteasomal degradation target of CSN in regulating lipid droplet size. RDH/CG2064 interacts with the lipid droplet‐resident protein Plin2 and the RDH/CG2064‐Plin2 axis acts to reduce the overall level and lipid droplet localization of Bmm/ATGL lipase. This axis is important for larval survival under prolonged starvation. Thus, we discovered an RDH‐Plin2 axis modulates lipid droplet size.
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Affiliation(s)
- Xuefan Zhao
- State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental Biology Innovation Academy for Seed Design Chinese Academy of Sciences Beijing China
- University of Chinese Academy of Sciences Beijing China
| | - Wei Wang
- State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental Biology Innovation Academy for Seed Design Chinese Academy of Sciences Beijing China
| | - Yan Yao
- State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental Biology Innovation Academy for Seed Design Chinese Academy of Sciences Beijing China
| | - Xia Li
- State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental Biology Innovation Academy for Seed Design Chinese Academy of Sciences Beijing China
| | - Xiahe Huang
- State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental Biology Innovation Academy for Seed Design Chinese Academy of Sciences Beijing China
| | - Yingchun Wang
- State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental Biology Innovation Academy for Seed Design Chinese Academy of Sciences Beijing China
| | - Mei Ding
- State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental Biology Innovation Academy for Seed Design Chinese Academy of Sciences Beijing China
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental Biology Innovation Academy for Seed Design Chinese Academy of Sciences Beijing China
- University of Chinese Academy of Sciences Beijing China
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7
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Wat LW, Chowdhury ZS, Millington JW, Biswas P, Rideout EJ. Sex determination gene transformer regulates the male-female difference in Drosophila fat storage via the adipokinetic hormone pathway. eLife 2021; 10:e72350. [PMID: 34672260 PMCID: PMC8594944 DOI: 10.7554/elife.72350] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/07/2021] [Indexed: 12/17/2022] Open
Abstract
Sex differences in whole-body fat storage exist in many species. For example, Drosophila females store more fat than males. Yet, the mechanisms underlying this sex difference in fat storage remain incompletely understood. Here, we identify a key role for sex determination gene transformer (tra) in regulating the male-female difference in fat storage. Normally, a functional Tra protein is present only in females, where it promotes female sexual development. We show that loss of Tra in females reduced whole-body fat storage, whereas gain of Tra in males augmented fat storage. Tra's role in promoting fat storage was largely due to its function in neurons, specifically the Adipokinetic hormone (Akh)-producing cells (APCs). Our analysis of Akh pathway regulation revealed a male bias in APC activity and Akh pathway function, where this sex-biased regulation influenced the sex difference in fat storage by limiting triglyceride accumulation in males. Importantly, Tra loss in females increased Akh pathway activity, and genetically manipulating the Akh pathway rescued Tra-dependent effects on fat storage. This identifies sex-specific regulation of Akh as one mechanism underlying the male-female difference in whole-body triglyceride levels, and provides important insight into the conserved mechanisms underlying sexual dimorphism in whole-body fat storage.
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Affiliation(s)
- Lianna W Wat
- Department of Cellular and Physiological Sciences, The University of British ColumbiaVancouverCanada
| | - Zahid S Chowdhury
- Department of Cellular and Physiological Sciences, The University of British ColumbiaVancouverCanada
| | - Jason W Millington
- Department of Cellular and Physiological Sciences, The University of British ColumbiaVancouverCanada
| | - Puja Biswas
- Department of Cellular and Physiological Sciences, The University of British ColumbiaVancouverCanada
| | - Elizabeth J Rideout
- Department of Cellular and Physiological Sciences, The University of British ColumbiaVancouverCanada
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8
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Keith SA, Bishop C, Fallacaro S, McCartney BM. Arc1 and the microbiota together modulate growth and metabolic traits in Drosophila. Development 2021; 148:271091. [PMID: 34323271 DOI: 10.1242/dev.195222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 07/01/2021] [Indexed: 12/20/2022]
Abstract
Perturbations to animal-associated microbial communities (the microbiota) have deleterious effects on various aspects of host fitness, but the molecular processes underlying these impacts are poorly understood. Here, we identify a connection between the microbiota and the neuronal factor Arc1 that affects growth and metabolism in Drosophila. We find that Arc1 exhibits tissue-specific microbiota-dependent expression changes, and that germ-free flies bearing a null mutation of Arc1 exhibit delayed and stunted larval growth, along with a variety of molecular, cellular and organismal traits indicative of metabolic dysregulation. Remarkably, we show that the majority of these phenotypes can be fully suppressed by mono-association with a single Acetobacter sp. isolate, through mechanisms involving both bacterial diet modification and live bacteria. Additionally, we provide evidence that Arc1 function in key neuroendocrine cells of the larval brain modulates growth and metabolic homeostasis under germ-free conditions. Our results reveal a role for Arc1 in modulating physiological responses to the microbial environment, and highlight how host-microbe interactions can profoundly impact the phenotypic consequences of genetic mutations in an animal host.
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Affiliation(s)
- Scott A Keith
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Cassandra Bishop
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Samantha Fallacaro
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Brooke M McCartney
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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9
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Hantak MP, Einstein J, Kearns RB, Shepherd JD. Intercellular Communication in the Nervous System Goes Viral. Trends Neurosci 2021; 44:248-259. [PMID: 33485691 PMCID: PMC8041237 DOI: 10.1016/j.tins.2020.12.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/19/2020] [Accepted: 12/30/2020] [Indexed: 12/20/2022]
Abstract
Viruses and transposable elements are major drivers of evolution and make up over half the sequences in the human genome. In some cases, these elements are co-opted to perform biological functions for the host. Recent studies made the surprising observation that the neuronal gene Arc forms virus-like protein capsids that can transfer RNA between neurons to mediate a novel intercellular communication pathway. Phylogenetic analyses showed that mammalian Arc is derived from an ancient retrotransposon of the Ty3/gypsy family and contains homology to the retroviral Gag polyproteins. The Drosophila Arc homologs, which are independently derived from the same family of retrotransposons, also mediate cell-to-cell signaling of RNA at the neuromuscular junction; a striking example of convergent evolution. Here we propose an Arc 'life cycle', based on what is known about retroviral Gag, and discuss how elucidating these biological processes may lead to novel insights into brain plasticity and memory.
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Affiliation(s)
- Michael P Hantak
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT, USA
| | - Jenifer Einstein
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT, USA
| | - Rachel B Kearns
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT, USA
| | - Jason D Shepherd
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT, USA.
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10
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Erlendsson S, Morado DR, Cullen HB, Feschotte C, Shepherd JD, Briggs JAG. Structures of virus-like capsids formed by the Drosophila neuronal Arc proteins. Nat Neurosci 2020; 23:172-175. [PMID: 31907439 PMCID: PMC7032958 DOI: 10.1038/s41593-019-0569-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 12/05/2019] [Indexed: 11/13/2022]
Abstract
Arc, a neuronal gene critical for synaptic plasticity, originated through
domestication of retrotransposon Gag genes and mediates
intercellular mRNA transfer. We report high-resolution structures of
retrovirus-like capsids formed by Drosophila dArc1 and dArc2
that have surface spikes and putative internal RNA-binding domains. These data
demonstrate that virus-like capsid-forming properties of Arc are evolutionarily
conserved and provide a structural basis for understanding their function in
intercellular communication.
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Affiliation(s)
- Simon Erlendsson
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Dustin R Morado
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Harrison B Cullen
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, USA
| | - Cedric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, USA
| | - Jason D Shepherd
- Department of Neurobiology and Anatomy, The University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - John A G Briggs
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, UK.
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11
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Abstract
Excess adipose fat accumulation, or obesity, is a growing problem worldwide in terms of both the rate of incidence and the severity of obesity-associated metabolic disease. Adipose tissue evolved in animals as a specialized dynamic lipid storage depot: adipose cells synthesize fat (a process called lipogenesis) when energy is plentiful and mobilize stored fat (a process called lipolysis) when energy is needed. When a disruption of lipid homeostasis favors increased fat synthesis and storage with little turnover owing to genetic predisposition, overnutrition or sedentary living, complications such as diabetes and cardiovascular disease are more likely to arise. The vinegar fly Drosophila melanogaster (Diptera: Drosophilidae) is used as a model to better understand the mechanisms governing fat metabolism and distribution. Flies offer a wealth of paradigms with which to study the regulation and physiological effects of fat accumulation. Obese flies accumulate triacylglycerols in the fat body, an organ similar to mammalian adipose tissue, which specializes in lipid storage and catabolism. Discoveries in Drosophila have ranged from endocrine hormones that control obesity to subcellular mechanisms that regulate lipogenesis and lipolysis, many of which are evolutionarily conserved. Furthermore, obese flies exhibit pathophysiological complications, including hyperglycemia, reduced longevity and cardiovascular function - similar to those observed in obese humans. Here, we review some of the salient features of the fly that enable researchers to study the contributions of feeding, absorption, distribution and the metabolism of lipids to systemic physiology.
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Affiliation(s)
- Laura Palanker Musselman
- Department of Biological Sciences, Binghamton University, State University of New York, Binghamton, NY 13902, USA
| | - Ronald P Kühnlein
- Department of Biochemistry 1, Institute of Molecular Biosciences, University of Graz, Humboldtstraβe 50/II, A-8010 Graz, Austria.,BioTechMed-Graz, Graz, Austria
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12
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Hazegh KE, Nemkov T, D’Alessandro A, Diller JD, Monks J, McManaman JL, Jones KL, Hansen KC, Reis T. An autonomous metabolic role for Spen. PLoS Genet 2017. [PMID: 28640815 PMCID: PMC5501677 DOI: 10.1371/journal.pgen.1006859] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Preventing obesity requires a precise balance between deposition into and mobilization from fat stores, but regulatory mechanisms are incompletely understood. Drosophila Split ends (Spen) is the founding member of a conserved family of RNA-binding proteins involved in transcriptional regulation and frequently mutated in human cancers. We find that manipulating Spen expression alters larval fat levels in a cell-autonomous manner. Spen-depleted larvae had defects in energy liberation from stores, including starvation sensitivity and major changes in the levels of metabolic enzymes and metabolites, particularly those involved in β-oxidation. Spenito, a small Spen family member, counteracted Spen function in fat regulation. Finally, mouse Spen and Spenito transcript levels scaled directly with body fat in vivo, suggesting a conserved role in fat liberation and catabolism. This study demonstrates that Spen is a key regulator of energy balance and provides a molecular context to understand the metabolic defects that arise from Spen dysfunction. All animals need energy to fuel development and survive as adults. Excess energy stored as fat provides a means to endure periods when external energy is unavailable, but there is a delicate balance between accumulating sufficient fat stores and becoming obese. While the enzymes that mediate energy deposition into and mobilization from fat stores are well studied, the complex upstream regulatory pathways have not been fully worked out. We report here that two members of a conserved family of RNA-binding proteins, Spen and Nito, operate in fat storage cells in fruit fly larvae to control the expression of genes that mediate energy liberation from fat stores. Manipulating Spen or Spenito function grossly perturbs larval energy metabolism, including imbalances in the amounts of stored fats, key metabolites, and metabolic enzymes, and resulting in defects in survival under starvation conditions. Interestingly, Nito opposes Spen functions, indicative of a regulatory mechanism that helps keep energy balance in check. We find that the mouse homologs of Spen and Nito, which were known to regulate gene expression in other pathways, respond similarly to changes in body fat induced by a high-fat diet, suggesting that the balancing effect of these two proteins also prevents mammalian obesity.
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Affiliation(s)
- Kelsey E. Hazegh
- Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO United States of America
| | - Travis Nemkov
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO United States of America
| | - Angelo D’Alessandro
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO United States of America
| | - John D. Diller
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO United States of America
| | - Jenifer Monks
- Department of Obstetrics and Gynecology, Division of Reproductive Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO United States of America
| | - James L. McManaman
- Department of Obstetrics and Gynecology, Division of Reproductive Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO United States of America
| | - Kenneth L. Jones
- Department of Pediatrics, Section of Hematology, Oncology, and Bone Marrow Transplant, University of Colorado Anschutz Medical Campus, Aurora, CO United States of America
| | - Kirk C. Hansen
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO United States of America
| | - Tânia Reis
- Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO United States of America
- * E-mail:
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13
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Hazegh KE, Reis T. A Buoyancy-based Method of Determining Fat Levels in Drosophila. J Vis Exp 2016. [PMID: 27842367 DOI: 10.3791/54744] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Drosophila melanogaster is a key experimental system in the study of fat regulation. Numerous techniques currently exist to measure levels of stored fat in Drosophila, but most are expensive and/or laborious and have clear limitations. Here, we present a method to quickly and cheaply determine organismal fat levels in L3 Drosophila larvae. The technique relies on the differences in density between fat and lean tissues and allows for rapid detection of fat and lean phenotypes. We have verified the accuracy of this method by comparison to body fat percentage as determined by neutral lipid extraction and gas chromatography coupled with mass spectrometry (GCMS). We furthermore outline detailed protocols for the collection and synchronization of larvae as well as relevant experimental recipes. The technique presented below overcomes the major shortcomings in the most widely used lipid quantitation methods and provides a powerful way to quickly and sensitively screen L3 larvae for fat regulation phenotypes while maintaining the integrity of the larvae. This assay has wide applications for the study of metabolism and fat regulation using Drosophila.
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Affiliation(s)
- Kelsey E Hazegh
- Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus
| | - Tânia Reis
- Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus;
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