1
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Diao F, Vasudevan D, Heckscher ES, White BH. Hox gene-specific cellular targeting using split intein Trojan exons. Proc Natl Acad Sci U S A 2024; 121:e2317083121. [PMID: 38602904 PMCID: PMC11047080 DOI: 10.1073/pnas.2317083121] [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: 10/07/2023] [Accepted: 03/07/2024] [Indexed: 04/13/2024] Open
Abstract
The Trojan exon method, which makes use of intronically inserted T2A-Gal4 cassettes, has been widely used in Drosophila to create thousands of gene-specific Gal4 driver lines. These dual-purpose lines provide genetic access to specific cell types based on their expression of a native gene while simultaneously mutating one allele of the gene to enable loss-of-function analysis in homozygous animals. While this dual use is often an advantage, the truncation mutations produced by Trojan exons are sometimes deleterious in heterozygotes, perhaps by creating translation products with dominant negative effects. Such mutagenic effects can cause developmental lethality as has been observed with genes encoding essential transcription factors. Given the importance of transcription factors in specifying cell type, alternative techniques for generating specific Gal4 lines that target them are required. Here, we introduce a modified Trojan exon method that retains the targeting fidelity and plug-and-play modularity of the original method but mitigates its mutagenic effects by exploiting the self-splicing capabilities of split inteins. "Split Intein Trojan exons" (siTrojans) ensure that the two truncation products generated from the interrupted allele of the native gene are trans-spliced to create a full-length native protein. We demonstrate the efficacy of siTrojans by generating a comprehensive toolkit of Gal4 and Split Gal4 lines for the segmentally expressed Hox transcription factors and illustrate their use in neural circuit mapping by targeting neurons according to their position along the anterior-posterior axis. Both the method and the Hox gene-specific toolkit introduced here should be broadly useful.
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Affiliation(s)
- Fengqiu Diao
- Laboratory of Molecular Biology, Section on Neural Function, National Institute of Mental Health, NIH, Bethesda, MD20892
| | - Deeptha Vasudevan
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL60637
| | - Ellie S. Heckscher
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL60637
| | - Benjamin H. White
- Laboratory of Molecular Biology, Section on Neural Function, National Institute of Mental Health, NIH, Bethesda, MD20892
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2
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Oliveira-Ferreira C, Gaspar M, Vasconcelos ML. Neuronal substrates of egg-laying behaviour at the abdominal ganglion of Drosophila melanogaster. Sci Rep 2023; 13:21941. [PMID: 38081887 PMCID: PMC10713638 DOI: 10.1038/s41598-023-48109-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
Egg-laying in Drosophila is the product of post-mating physiological and behavioural changes that culminate in a stereotyped sequence of actions. Egg-laying harbours a great potential as a paradigm to uncover how the appropriate motor circuits are organized and activated to generate behaviour. To study this programme, we first describe the different phases of the egg-laying programme and the specific actions associated with each phase. Using a combination of neuronal activation and silencing experiments, we identify neurons (OvAbg) in the abdominal ganglion as key players in egg-laying. To generate and functionally characterise subsets of OvAbg, we used an intersectional approach with neurotransmitter specific lines-VGlut, Cha and Gad1. We show that OvAbg/VGlut neurons promote initiation of egg deposition in a mating status dependent way. OvAbg/Cha neurons are required in exploration and egg deposition phases, though activation leads specifically to egg expulsion. Experiments with the OvAbg/Gad1 neurons show they participate in egg deposition. We further show a functional connection of OvAbg neurons with brain neurons. This study provides insight into the organization of neuronal circuits underlying complex motor behaviour.
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Affiliation(s)
| | - Miguel Gaspar
- Neuroscience Programme, Champalimaud Foundation, Lisbon, Portugal
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3
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Amin H, Nolte SS, Swain B, von Philipsborn AC. GABAergic signaling shapes multiple aspects of Drosophila courtship motor behavior. iScience 2023; 26:108069. [PMID: 37860694 PMCID: PMC10583093 DOI: 10.1016/j.isci.2023.108069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 09/06/2023] [Accepted: 09/25/2023] [Indexed: 10/21/2023] Open
Abstract
Inhibitory neurons are essential for orchestrating and structuring behavior. We use one of the best studied behaviors in Drosophila, male courtship, to analyze how inhibitory, GABAergic neurons shape the different steps of this multifaceted motor sequence. RNAi-mediated knockdown of the GABA-producing enzyme GAD1 and the ionotropic receptor Rdl in sex specific, fruitless expressing neurons in the ventral nerve cord causes uncoordinated and futile copulation attempts, defects in wing extension choice and severe alterations of courtship song. Altered song of GABA depleted males fails to stimulate female receptivity, but rescue of song patterning alone is not sufficient to rescue male mating success. Knockdown of GAD1 and Rdl in male brain circuits abolishes courtship conditioning. We characterize the around 220 neurons coexpressing GAD1 and Fruitless in the Drosophila male nervous system and propose inhibitory circuit motifs underlying key features of courtship behavior based on the observed phenotypes.
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Affiliation(s)
- Hoger Amin
- Department of Molecular Biology and Genetics and Department of Biomedicine, Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus University, 8000 Aarhus, Denmark
| | - Stella S. Nolte
- Department of Molecular Biology and Genetics and Department of Biomedicine, Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus University, 8000 Aarhus, Denmark
| | - Bijayalaxmi Swain
- Department of Molecular Biology and Genetics and Department of Biomedicine, Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus University, 8000 Aarhus, Denmark
| | - Anne C. von Philipsborn
- Department of Molecular Biology and Genetics and Department of Biomedicine, Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus University, 8000 Aarhus, Denmark
- Department of Neuroscience and Movement Science, Medicine Section, University of Fribourg, 1700 Fribourg, Switzerland
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4
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Cury KM, Axel R. Flexible neural control of transition points within the egg-laying behavioral sequence in Drosophila. Nat Neurosci 2023:10.1038/s41593-023-01332-5. [PMID: 37217726 DOI: 10.1038/s41593-023-01332-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/13/2023] [Indexed: 05/24/2023]
Abstract
Innate behaviors are frequently comprised of ordered sequences of component actions that progress to satisfy essential drives. Progression is governed by specialized sensory cues that induce transitions between components within the appropriate context. Here we have characterized the structure of the egg-laying behavioral sequence in Drosophila and found significant variability in the transitions between component actions that affords the organism an adaptive flexibility. We identified distinct classes of interoceptive and exteroceptive sensory neurons that control the timing and direction of transitions between the terminal components of the sequence. We also identified a pair of motor neurons that enact the final transition to egg expulsion. These results provide a logic for the organization of innate behavior in which sensory information processed at critical junctures allows for flexible adjustments in component actions to satisfy drives across varied internal and external environments.
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Affiliation(s)
- Kevin M Cury
- The Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY, USA.
| | - Richard Axel
- The Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY, USA.
- Howard Hughes Medical Institute, Columbia University, New York, NY, USA.
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5
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Yamanouchi HM, Tanaka R, Kamikouchi A. Piezo-mediated mechanosensation contributes to stabilizing copulation posture and reproductive success in Drosophila males. iScience 2023; 26:106617. [PMID: 37250311 PMCID: PMC10214400 DOI: 10.1016/j.isci.2023.106617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/13/2023] [Accepted: 04/04/2023] [Indexed: 05/31/2023] Open
Abstract
In internal fertilization animals, reproductive success depends on maintaining copulation until gametes are transported from male to female. In Drosophila melanogaster, mechanosensation in males likely contributes to copulation maintenance, but its molecular underpinning remains to be identified. Here we show that the mechanosensory gene piezo and its' expressing neurons are responsible for copulation maintenance. An RNA-seq database search and subsequent mutant analysis revealed the importance of piezo for maintaining male copulation posture. piezo-GAL4-positive signals were found in the sensory neurons of male genitalia bristles, and optogenetic inhibition of piezo-expressing neurons in the posterior side of the male body during copulation destabilized posture and terminated copulation. Our findings suggest that the mechanosensory system of male genitalia through Piezo channels plays a key role in copulation maintenance and indicate that Piezo may increase male fitness during copulation in flies.
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Affiliation(s)
| | - Ryoya Tanaka
- Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Azusa Kamikouchi
- Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, Aichi 464-8602, Japan
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6
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The doublesex gene regulates dimorphic sexual and aggressive behaviors in Drosophila. Proc Natl Acad Sci U S A 2022; 119:e2201513119. [PMID: 36067320 PMCID: PMC9477402 DOI: 10.1073/pnas.2201513119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Most animal species display dimorphic sexual behaviors and male-biased aggressiveness. Current models have focused on the male-specific product from the fruitless (fruM) gene, which controls male courtship and male-specific aggression patterns in fruit flies, and describe a male-specific mechanism underlying sexually dimorphic behaviors. Here we show that the doublesex (dsx) gene, which expresses male-specific DsxM and female-specific DsxF transcription factors, functions in the nervous system to control both male and female sexual and aggressive behaviors. We find that Dsx is not only required in central brain neurons for male and female sexual behaviors, but also functions in approximately eight pairs of male-specific neurons to promote male aggressiveness and approximately two pairs of female-specific neurons to inhibit female aggressiveness. DsxF knockdown females fight more frequently, even with males. Our findings reveal crucial roles of dsx, which is broadly conserved from worms to humans, in a small number of neurons in both sexes to establish dimorphic sexual and aggressive behaviors.
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7
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Casado-Navarro R, Serrano-Saiz E. DMRT Transcription Factors in the Control of Nervous System Sexual Differentiation. Front Neuroanat 2022; 16:937596. [PMID: 35958734 PMCID: PMC9361473 DOI: 10.3389/fnana.2022.937596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Sexual phenotypic differences in the nervous system are one of the most prevalent features across the animal kingdom. The molecular mechanisms responsible for sexual dimorphism throughout metazoan nervous systems are extremely diverse, ranging from intrinsic cell autonomous mechanisms to gonad-dependent endocrine control of sexual traits, or even extrinsic environmental cues. In recent years, the DMRT ancient family of transcription factors has emerged as being central in the development of sex-specific differentiation in all animals in which they have been studied. In this review, we provide an overview of the function of Dmrt genes in nervous system sexual regulation from an evolutionary perspective.
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8
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Neural Control of Action Selection Among Innate Behaviors. Neurosci Bull 2022; 38:1541-1558. [PMID: 35633465 DOI: 10.1007/s12264-022-00886-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 04/10/2022] [Indexed: 10/18/2022] Open
Abstract
Nervous systems must not only generate specific adaptive behaviors, such as reproduction, aggression, feeding, and sleep, but also select a single behavior for execution at any given time, depending on both internal states and external environmental conditions. Despite their tremendous biological importance, the neural mechanisms of action selection remain poorly understood. In the past decade, studies in the model animal Drosophila melanogaster have demonstrated valuable neural mechanisms underlying action selection of innate behaviors. In this review, we summarize circuit mechanisms with a particular focus on a small number of sexually dimorphic neurons in controlling action selection among sex, fight, feeding, and sleep behaviors in both sexes of flies. We also discuss potentially conserved circuit configurations and neuromodulation of action selection in both the fly and mouse models, aiming to provide insights into action selection and the sexually dimorphic prioritization of innate behaviors.
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9
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Jois S, Chan YB, Fernandez MP, Pujari N, Janz LJ, Parker S, Leung AKW. Sexually dimorphic peripheral sensory neurons regulate copulation duration and persistence in male Drosophila. Sci Rep 2022; 12:6177. [PMID: 35418584 PMCID: PMC9007984 DOI: 10.1038/s41598-022-10247-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 04/04/2022] [Indexed: 12/20/2022] Open
Abstract
Peripheral sensory neurons are the gateway to the environment across species. In Drosophila, olfactory and gustatory senses are required to initiate courtship, as well as for the escalation of courtship patterns that lead to copulation. To be successful, copulation must last long enough to ensure the transfer of sperm and seminal fluid that ultimately leads to fertilization. The peripheral sensory information required to regulate copulation duration is unclear. Here, we employed genetic manipulations that allow driving gene expression in the male genitalia as a tool to uncover the role of these genitalia specific neurons in copulation. The fly genitalia contain sex-specific bristle hairs innervated by mechanosensory neurons. To date, the role of the sensory information collected by these peripheral neurons in male copulatory behavior is unknown. We confirmed that these MSNs are cholinergic and co-express both fru and dsx. We found that the sensory information received by the peripheral sensory neurons from the front legs (GRNs) and mechanosensory neurons (MSNs) at the male genitalia contribute to the regulation of copulation duration. Moreover, our results show that their function is required for copulation persistence, which ensures copulation is undisrupted in the presence of environmental stress before sperm transfer is complete.
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Affiliation(s)
- Shreyas Jois
- Department of Veterinary Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, SK, S7N 5B4, Canada
| | - Yick-Bun Chan
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Maria Paz Fernandez
- Department of Neuroscience and Behavior, Barnard College, New York City, NY, 10027, USA
| | - Narsimha Pujari
- Department of Veterinary Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, SK, S7N 5B4, Canada
| | - Lea Joline Janz
- Department of Veterinary Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, SK, S7N 5B4, Canada
| | - Sarah Parker
- Centre for Applied Epidemiology, Large Animal Clinical Science, WCVM, University of Saskatchewan, Saskatoon, SK, S7N 5B4, Canada
| | - Adelaine Kwun-Wai Leung
- Department of Veterinary Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, SK, S7N 5B4, Canada.
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10
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Nässel DR, Wu SF. Cholecystokinin/sulfakinin peptide signaling: conserved roles at the intersection between feeding, mating and aggression. Cell Mol Life Sci 2022; 79:188. [PMID: 35286508 PMCID: PMC8921109 DOI: 10.1007/s00018-022-04214-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/19/2022] [Accepted: 02/21/2022] [Indexed: 12/27/2022]
Abstract
Neuropeptides are the most diverse messenger molecules in metazoans and are involved in regulation of daily physiology and a wide array of behaviors. Some neuropeptides and their cognate receptors are structurally and functionally well conserved over evolution in bilaterian animals. Among these are peptides related to gastrin and cholecystokinin (CCK). In mammals, CCK is produced by intestinal endocrine cells and brain neurons, and regulates gall bladder contractions, pancreatic enzyme secretion, gut functions, satiety and food intake. Additionally, CCK plays important roles in neuromodulation in several brain circuits that regulate reward, anxiety, aggression and sexual behavior. In invertebrates, CCK-type peptides (sulfakinins, SKs) are, with a few exceptions, produced by brain neurons only. Common among invertebrates is that SKs mediate satiety and regulate food ingestion by a variety of mechanisms. Also regulation of secretion of digestive enzymes has been reported. Studies of the genetically tractable fly Drosophila have advanced our understanding of SK signaling mechanisms in regulation of satiety and feeding, but also in gustatory sensitivity, locomotor activity, aggression and reproductive behavior. A set of eight SK-expressing brain neurons plays important roles in regulation of these competing behaviors. In males, they integrate internal state and external stimuli to diminish sex drive and increase aggression. The same neurons also diminish sugar gustation, induce satiety and reduce feeding. Although several functional roles of CCK/SK signaling appear conserved between Drosophila and mammals, available data suggest that the underlying mechanisms differ.
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Affiliation(s)
- Dick R Nässel
- Department of Zoology, Stockholm University, 10691, Stockholm, Sweden.
| | - Shun-Fan Wu
- College of Plant Protection/Laboratory of Bio-Interactions and Crop Health, Nanjing Agricultural University, Nanjing, 210095, China
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11
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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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12
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Goodwin SF, Hobert O. Molecular Mechanisms of Sexually Dimorphic Nervous System Patterning in Flies and Worms. Annu Rev Cell Dev Biol 2021; 37:519-547. [PMID: 34613817 DOI: 10.1146/annurev-cellbio-120319-115237] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Male and female brains display anatomical and functional differences. Such differences are observed in species across the animal kingdom, including humans, but have been particularly well-studied in two classic animal model systems, the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans. Here we summarize recent advances in understanding how the worm and fly brain acquire sexually dimorphic features during development. We highlight the advantages of each system, illustrating how the precise anatomical delineation of sexual dimorphisms in worms has enabled recent analysis into how these dimorphisms become specified during development, and how focusing on sexually dimorphic neurons in the fly has enabled an increasingly detailed understanding of sex-specific behaviors.
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Affiliation(s)
- Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, United Kingdom;
| | - Oliver Hobert
- Department of Biological Sciences and Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA;
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13
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Mank JE, Rideout EJ. Developmental mechanisms of sex differences: from cells to organisms. Development 2021; 148:272484. [PMID: 34647574 DOI: 10.1242/dev.199750] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Male-female differences in many developmental mechanisms lead to the formation of two morphologically and physiologically distinct sexes. Although this is expected for traits with prominent differences between the sexes, such as the gonads, sex-specific processes also contribute to traits without obvious male-female differences, such as the intestine. Here, we review sex differences in developmental mechanisms that operate at several levels of biological complexity - molecular, cellular, organ and organismal - and discuss how these differences influence organ formation, function and whole-body physiology. Together, the examples we highlight show that one simple way to gain a more accurate and comprehensive understanding of animal development is to include both sexes.
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Affiliation(s)
- Judith E Mank
- Department of Zoology, Biodiversity Research Centre, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.,Biosciences, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK
| | - Elizabeth J Rideout
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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14
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Salim S, Banu A, Alwa A, Gowda SBM, Mohammad F. The gut-microbiota-brain axis in autism: what Drosophila models can offer? J Neurodev Disord 2021; 13:37. [PMID: 34525941 PMCID: PMC8442445 DOI: 10.1186/s11689-021-09378-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/06/2021] [Indexed: 12/28/2022] Open
Abstract
The idea that alterations in gut-microbiome-brain axis (GUMBA)-mediated communication play a crucial role in human brain disorders like autism remains a topic of intensive research in various labs. Gastrointestinal issues are a common comorbidity in patients with autism spectrum disorder (ASD). Although gut microbiome and microbial metabolites have been implicated in the etiology of ASD, the underlying molecular mechanism remains largely unknown. In this review, we have summarized recent findings in human and animal models highlighting the role of the gut-brain axis in ASD. We have discussed genetic and neurobehavioral characteristics of Drosophila as an animal model to study the role of GUMBA in ASD. The utility of Drosophila fruit flies as an amenable genetic tool, combined with axenic and gnotobiotic approaches, and availability of transgenic flies may reveal mechanistic insight into gut-microbiota-brain interactions and the impact of its alteration on behaviors relevant to neurological disorders like ASD.
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Affiliation(s)
- Safa Salim
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, 34110, Qatar
| | - Ayesha Banu
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, 34110, Qatar
| | - Amira Alwa
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, 34110, Qatar
| | - Swetha B M Gowda
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, 34110, Qatar
| | - Farhan Mohammad
- Division of Biological and Biomedical Sciences (BBS), College of Health & Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Doha, 34110, Qatar.
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15
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Drosophila Corazonin Neurons as a Hub for Regulating Growth, Stress Responses, Ethanol-Related Behaviors, Copulation Persistence and Sexually Dimorphic Reward Pathways. J Dev Biol 2021; 9:jdb9030026. [PMID: 34287347 PMCID: PMC8293205 DOI: 10.3390/jdb9030026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/30/2021] [Accepted: 07/01/2021] [Indexed: 12/11/2022] Open
Abstract
The neuronal mechanisms by which complex behaviors are coordinated and timed often involve neuropeptidergic regulation of stress and reward pathways. Recent studies of the neuropeptide Corazonin (Crz), a homolog of the mammalian Gonadotrophin Releasing Hormone (GnRH), have suggested its crucial role in the regulation of growth, internal states and behavioral decision making. We focus this review on Crz neurons with the goal to (1) highlight the diverse roles of Crz neuron function, including mechanisms that may be independent of the Crz peptide, (2) emphasize current gaps in knowledge about Crz neuron functions, and (3) propose exciting ideas of novel research directions involving the use of Crz neurons. We describe the different developmental fates of distinct subsets of Crz neurons, including recent findings elucidating the molecular regulation of apoptosis. Crz regulates systemic growth, food intake, stress responses and homeostasis by interacting with the short Neuropeptide F (sNPF) and the steroid hormone ecdysone. Additionally, activation of Crz neurons is shown to be pleasurable by interacting with the Neuropeptide F (NPF) and regulates reward processes such as ejaculation and ethanol-related behaviors in a sexually dimorphic manner. Crz neurons are proposed to be a motivational switch regulating copulation duration using a CaMKII-dependent mechanism described as the first neuronal interval timer lasting longer than a few seconds. Lastly, we propose ideas to use Crz neuron-induced ejaculation to study the effects of fictive mating and sex addiction in flies, as well as to elucidate dimorphic molecular mechanisms underlying reward behaviors and feeding disorders.
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16
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Male courtship song drives escape responses that are suppressed for successful mating. Sci Rep 2021; 11:9227. [PMID: 33927291 PMCID: PMC8084941 DOI: 10.1038/s41598-021-88691-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/12/2021] [Indexed: 11/08/2022] Open
Abstract
Persuasion is a crucial component of the courtship ritual needed to overcome contact aversion. In fruit flies, it is well established that the male courtship song prompts receptivity in female flies, in part by causing sexually mature females to slow down and pause, allowing copulation. Whether the above receptivity behaviours require the suppression of contact avoidance or escape remains unknown. Here we show, through genetic manipulation of neurons we identified as required for female receptivity, that male song induces avoidance/escape responses that are suppressed in wild type flies. First, we show that silencing 70A09 neurons leads to an increase in escape, as females increase their walking speed during courtship together with an increase in jumping and a reduction in pausing. The increase in escape response is specific to courtship, as escape to a looming threat is not intensified. Activation of 70A09 neurons leads to pausing, confirming the role of these neurons in escape modulation. Finally, we show that the escape displays by the female result from the presence of a courting male and more specifically from the song produced by a courting male. Our results suggest that courtship song has a dual role, promoting both escape and pause in females and that escape is suppressed by the activity of 70A09 neurons, allowing mating to occur.
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17
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Nojima T, Rings A, Allen AM, Otto N, Verschut TA, Billeter JC, Neville MC, Goodwin SF. A sex-specific switch between visual and olfactory inputs underlies adaptive sex differences in behavior. Curr Biol 2021; 31:1175-1191.e6. [PMID: 33508219 PMCID: PMC7987718 DOI: 10.1016/j.cub.2020.12.047] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/15/2020] [Accepted: 12/24/2020] [Indexed: 01/05/2023]
Abstract
Although males and females largely share the same genome and nervous system, they differ profoundly in reproductive investments and require distinct behavioral, morphological, and physiological adaptations. How can the nervous system, while bound by both developmental and biophysical constraints, produce these sex differences in behavior? Here, we uncover a novel dimorphism in Drosophila melanogaster that allows deployment of completely different behavioral repertoires in males and females with minimum changes to circuit architecture. Sexual differentiation of only a small number of higher order neurons in the brain leads to a change in connectivity related to the primary reproductive needs of both sexes-courtship pursuit in males and communal oviposition in females. This study explains how an apparently similar brain generates distinct behavioral repertoires in the two sexes and presents a fundamental principle of neural circuit organization that may be extended to other species.
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Affiliation(s)
- Tetsuya Nojima
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Annika Rings
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Aaron M Allen
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Nils Otto
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Thomas A Verschut
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - Jean-Christophe Billeter
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - Megan C Neville
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK.
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK.
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18
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Nakata M, Kikuchi Y, Iwami M, Takayanagi-Kiya S, Kiya T. Identification and characterization of sexually dimorphic neurons that express the sex-determining gene doublesex in the brain of silkmoth Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 129:103518. [PMID: 33421546 DOI: 10.1016/j.ibmb.2021.103518] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/21/2020] [Accepted: 01/01/2021] [Indexed: 06/12/2023]
Abstract
Sexual differences in behavior are generated by sexually dimorphic neural circuits in animals. In insects, a highly conserved sex-determining gene doublesex (dsx) plays essential roles in the development of sexual dimorphisms. In the present study, to elucidate the neural basis of sexual differences in behaviors of silkmoth Bombyx mori, we investigated Bombyx mori dsx (Bmdsx) expression in the brains through development. In the brain, Bmdsx was differentially expressed in sex- and developmental stage-dependent manners. BmDSX protein-expressing cells were located in the dorsomedial region of the pupal and adult brains, and constituted two and one neural clusters in males and females, respectively. The number of BmDSX-positive cells was developmentally regulated and peaked at the early to middle pupal stages, suggesting that the sexually dimorphic neural circuits are established during this period. The detection of a neural activity marker protein BmHR38 suggested that the BmDSX-positive cells are not active during sexual behavior in both male and female moths, even though the cells in the vicinity of the BmDSX-positive cell clusters are active. These results imply that Bmdsx plays roles in the development of sexually dimorphic neural circuits, but the neural circuits are not related to sexual behavior in silkmoths.
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Affiliation(s)
- Masami Nakata
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Japan
| | - Yusuke Kikuchi
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Japan
| | - Masafumi Iwami
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Japan
| | - Seika Takayanagi-Kiya
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Japan
| | - Taketoshi Kiya
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Japan.
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19
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Chiu H, Hoopfer ED, Coughlan ML, Pavlou HJ, Goodwin SF, Anderson DJ. A circuit logic for sexually shared and dimorphic aggressive behaviors in Drosophila. Cell 2021; 184:507-520.e16. [PMID: 33382967 PMCID: PMC7856078 DOI: 10.1016/j.cell.2020.11.048] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 10/27/2020] [Accepted: 11/25/2020] [Indexed: 12/11/2022]
Abstract
Aggression involves both sexually monomorphic and dimorphic actions. How the brain implements these two types of actions is poorly understood. We have identified three cell types that regulate aggression in Drosophila: one type is sexually shared, and the other two are sex specific. Shared common aggression-promoting (CAP) neurons mediate aggressive approach in both sexes, whereas functionally downstream dimorphic but homologous cell types, called male-specific aggression-promoting (MAP) neurons in males and fpC1 in females, control dimorphic attack. These symmetric circuits underlie the divergence of male and female aggressive behaviors, from their monomorphic appetitive/motivational to their dimorphic consummatory phases. The strength of the monomorphic → dimorphic functional connection is increased by social isolation in both sexes, suggesting that it may be a locus for isolation-dependent enhancement of aggression. Together, these findings reveal a circuit logic for the neural control of behaviors that include both sexually monomorphic and dimorphic actions, which may generalize to other organisms.
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Affiliation(s)
- Hui Chiu
- Division of Biology and Biological Engineering 156-29, Tianqiao and Chrissy Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Eric D Hoopfer
- Carleton College, 1 N. College St., Northfield, MN 55057, USA
| | - Maeve L Coughlan
- Mount Holyoke College, 50 College St., South Hadley, MA 01075, USA
| | - Hania J Pavlou
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - David J Anderson
- Division of Biology and Biological Engineering 156-29, Tianqiao and Chrissy Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA.
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20
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Millington JW, Brownrigg GP, Chao C, Sun Z, Basner-Collins PJ, Wat LW, Hudry B, Miguel-Aliaga I, Rideout EJ. Female-biased upregulation of insulin pathway activity mediates the sex difference in Drosophila body size plasticity. eLife 2021; 10:e58341. [PMID: 33448263 PMCID: PMC7864645 DOI: 10.7554/elife.58341] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 01/11/2021] [Indexed: 12/14/2022] Open
Abstract
Nutrient-dependent body size plasticity differs between the sexes in most species, including mammals. Previous work in Drosophila showed that body size plasticity was higher in females, yet the mechanisms underlying increased female body size plasticity remain unclear. Here, we discover that a protein-rich diet augments body size in females and not males because of a female-biased increase in activity of the conserved insulin/insulin-like growth factor signaling pathway (IIS). This sex-biased upregulation of IIS activity was triggered by a diet-induced increase in stunted mRNA in females, and required Drosophila insulin-like peptide 2, illuminating new sex-specific roles for these genes. Importantly, we show that sex determination gene transformer promotes the diet-induced increase in stunted mRNA via transcriptional coactivator Spargel to regulate the male-female difference in body size plasticity. Together, these findings provide vital insight into conserved mechanisms underlying the sex difference in nutrient-dependent body size plasticity.
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Affiliation(s)
- Jason W Millington
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British ColumbiaVancouverCanada
| | - George P Brownrigg
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British ColumbiaVancouverCanada
| | - Charlotte Chao
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British ColumbiaVancouverCanada
| | - Ziwei Sun
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British ColumbiaVancouverCanada
| | - Paige J Basner-Collins
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British ColumbiaVancouverCanada
| | - Lianna W Wat
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British ColumbiaVancouverCanada
| | - Bruno Hudry
- MRC London Institute of Medical Sciences, and Institute of Clinical Sciences, Faculty of Medicine, Imperial College LondonLondonUnited Kingdom
| | - Irene Miguel-Aliaga
- MRC London Institute of Medical Sciences, and Institute of Clinical Sciences, Faculty of Medicine, Imperial College LondonLondonUnited Kingdom
| | - Elizabeth J Rideout
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British ColumbiaVancouverCanada
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21
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Deutsch D, Pacheco D, Encarnacion-Rivera L, Pereira T, Fathy R, Clemens J, Girardin C, Calhoun A, Ireland E, Burke A, Dorkenwald S, McKellar C, Macrina T, Lu R, Lee K, Kemnitz N, Ih D, Castro M, Halageri A, Jordan C, Silversmith W, Wu J, Seung HS, Murthy M. The neural basis for a persistent internal state in Drosophila females. eLife 2020; 9:e59502. [PMID: 33225998 PMCID: PMC7787663 DOI: 10.7554/elife.59502] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 11/18/2020] [Indexed: 12/13/2022] Open
Abstract
Sustained changes in mood or action require persistent changes in neural activity, but it has been difficult to identify the neural circuit mechanisms that underlie persistent activity and contribute to long-lasting changes in behavior. Here, we show that a subset of Doublesex+ pC1 neurons in the Drosophila female brain, called pC1d/e, can drive minutes-long changes in female behavior in the presence of males. Using automated reconstruction of a volume electron microscopic (EM) image of the female brain, we map all inputs and outputs to both pC1d and pC1e. This reveals strong recurrent connectivity between, in particular, pC1d/e neurons and a specific subset of Fruitless+ neurons called aIPg. We additionally find that pC1d/e activation drives long-lasting persistent neural activity in brain areas and cells overlapping with the pC1d/e neural network, including both Doublesex+ and Fruitless+ neurons. Our work thus links minutes-long persistent changes in behavior with persistent neural activity and recurrent circuit architecture in the female brain.
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Affiliation(s)
- David Deutsch
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Diego Pacheco
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | | | - Talmo Pereira
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Ramie Fathy
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Jan Clemens
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Cyrille Girardin
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Adam Calhoun
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Elise Ireland
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Austin Burke
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Sven Dorkenwald
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Department of Computer Science, Princeton UniversityPrincetonUnited States
| | - Claire McKellar
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Thomas Macrina
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Department of Computer Science, Princeton UniversityPrincetonUnited States
| | - Ran Lu
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Kisuk Lee
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Brain & Cognitive Science Department, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Nico Kemnitz
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Dodam Ih
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Manuel Castro
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Akhilesh Halageri
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Chris Jordan
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - William Silversmith
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Jingpeng Wu
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - H Sebastian Seung
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Department of Computer Science, Princeton UniversityPrincetonUnited States
| | - Mala Murthy
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
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22
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Molina-García L, Lloret-Fernández C, Cook SJ, Kim B, Bonnington RC, Sammut M, O'Shea JM, Gilbert SPR, Elliott DJ, Hall DH, Emmons SW, Barrios A, Poole RJ. Direct glia-to-neuron transdifferentiation gives rise to a pair of male-specific neurons that ensure nimble male mating. eLife 2020; 9:e48361. [PMID: 33138916 PMCID: PMC7609048 DOI: 10.7554/elife.48361] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 10/02/2020] [Indexed: 12/20/2022] Open
Abstract
Sexually dimorphic behaviours require underlying differences in the nervous system between males and females. The extent to which nervous systems are sexually dimorphic and the cellular and molecular mechanisms that regulate these differences are only beginning to be understood. We reveal here a novel mechanism by which male-specific neurons are generated in Caenorhabditis elegans through the direct transdifferentiation of sex-shared glial cells. This glia-to-neuron cell fate switch occurs during male sexual maturation under the cell-autonomous control of the sex-determination pathway. We show that the neurons generated are cholinergic, peptidergic, and ciliated putative proprioceptors which integrate into male-specific circuits for copulation. These neurons ensure coordinated backward movement along the mate's body during mating. One step of the mating sequence regulated by these neurons is an alternative readjustment movement performed when intromission becomes difficult to achieve. Our findings reveal programmed transdifferentiation as a developmental mechanism underlying flexibility in innate behaviour.
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Affiliation(s)
- Laura Molina-García
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Carla Lloret-Fernández
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Steven J Cook
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of MedicineNew YorkUnited States
| | - Byunghyuk Kim
- Department of Genetics, Albert Einstein College of MedicineNew YorkUnited States
| | - Rachel C Bonnington
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Michele Sammut
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Jack M O'Shea
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Sophie PR Gilbert
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - David J Elliott
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - David H Hall
- Department of Genetics, Albert Einstein College of MedicineNew YorkUnited States
| | - Scott W Emmons
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of MedicineNew YorkUnited States
- Department of Genetics, Albert Einstein College of MedicineNew YorkUnited States
| | - Arantza Barrios
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
| | - Richard J Poole
- Department of Cell and Developmental Biology, University College LondonLondonUnited Kingdom
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23
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Mezzera C, Brotas M, Gaspar M, Pavlou HJ, Goodwin SF, Vasconcelos ML. Ovipositor Extrusion Promotes the Transition from Courtship to Copulation and Signals Female Acceptance in Drosophila melanogaster. Curr Biol 2020; 30:3736-3748.e5. [PMID: 32795437 DOI: 10.1016/j.cub.2020.06.071] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/05/2020] [Accepted: 06/22/2020] [Indexed: 10/23/2022]
Abstract
Communication between male and female fruit flies during courtship is essential for successful mating, but, as with many other species, it is the female who decides whether to mate. Here, we show a novel role for ovipositor extrusion in promoting male copulation attempts in virgin and mated females and signaling acceptance in virgins. We first show that ovipositor extrusion is only displayed by sexually mature females, exclusively during courtship and in response to the male song. We identified a pair of descending neurons that controls ovipositor extrusion in mated females. Genetic silencing of the descending neurons shows that ovipositor extrusion stimulates the male to attempt copulation. A detailed behavioral analysis revealed that during courtship, the male repeatedly licks the female genitalia, independently of ovipositor extrusion, and that licking an extruded ovipositor prompts a copulation attempt. However, if the ovipositor is not subsequently retracted, copulation is prevented, as it happens with mated females. In this study, we reveal a dual function of the ovipositor: while its extrusion is necessary for initiating copulation by the male, its retraction signals female acceptance. We thus uncover the significance of the communication between male and female that initiates the transition from courtship to copulation.
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Affiliation(s)
- Cecilia Mezzera
- Champalimaud Center for the Unknown, Lisbon 1400-038, Portugal
| | | | - Miguel Gaspar
- Champalimaud Center for the Unknown, Lisbon 1400-038, Portugal
| | - Hania J Pavlou
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
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24
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Lee SS, Wu MN. Neural circuit mechanisms encoding motivational states in Drosophila. Curr Opin Neurobiol 2020; 64:135-142. [PMID: 32563845 PMCID: PMC7669672 DOI: 10.1016/j.conb.2020.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 05/08/2020] [Indexed: 01/05/2023]
Abstract
Animals engage in motivated behaviors, such as feeding and mating behaviors, to ensure their own survival and the survival of their species. However, the neural circuits mediating the generation and persistence of these motivational drives remain poorly understood. Here we review recent studies on the circuit mechanisms underlying motivational states in Drosophila, with a focus on feeding, courtship, and aggression. These studies shed light on the molecular and cellular mechanisms by, which key drive neurons receive relevant input signals, integrate information, and decide on a specific behavioral output. We also discuss conceptual models for integrating these circuit mechanisms, distinguishing between those for homeostatically-regulated versus non-homeostatically-regulated motivated behaviors. We suggest that the ability to trigger persistence of a motivated behavior may be a feature of integrator or apex/command neurons.
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Affiliation(s)
- Sang Soo Lee
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Mark N Wu
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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25
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Court R, Namiki S, Armstrong JD, Börner J, Card G, Costa M, Dickinson M, Duch C, Korff W, Mann R, Merritt D, Murphey RK, Seeds AM, Shirangi T, Simpson JH, Truman JW, Tuthill JC, Williams DW, Shepherd D. A Systematic Nomenclature for the Drosophila Ventral Nerve Cord. Neuron 2020; 107:1071-1079.e2. [PMID: 32931755 PMCID: PMC7611823 DOI: 10.1016/j.neuron.2020.08.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/30/2020] [Accepted: 08/05/2020] [Indexed: 11/30/2022]
Abstract
Drosophila melanogaster is an established model for neuroscience research with relevance in biology and medicine. Until recently, research on the Drosophila brain was hindered by the lack of a complete and uniform nomenclature. Recognizing this, Ito et al. (2014) produced an authoritative nomenclature for the adult insect brain, using Drosophila as the reference. Here, we extend this nomenclature to the adult thoracic and abdominal neuromeres, the ventral nerve cord (VNC), to provide an anatomical description of this major component of the Drosophila nervous system. The VNC is the locus for the reception and integration of sensory information and involved in generating most of the locomotor actions that underlie fly behaviors. The aim is to create a nomenclature, definitions, and spatial boundaries for the Drosophila VNC that are consistent with other insects. The work establishes an anatomical framework that provides a powerful tool for analyzing the functional organization of the VNC.
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Affiliation(s)
- Robert Court
- School of Informatics, University of Edinburgh, Edinburgh, EH8 9AB, UK
| | - Shigehiro Namiki
- HHMI-Janelia Research Campus, Ashburn, VA 20147, USA; RCAST, University of Tokyo, Tokyo 153-8904, Japan
| | | | - Jana Börner
- Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Gwyneth Card
- HHMI-Janelia Research Campus, Ashburn, VA 20147, USA
| | - Marta Costa
- Virtual Fly Brain, University of Cambridge, Cambridge, CB2 3EJ, UK
| | - Michael Dickinson
- Division of Biology and Biological Engineering, The California Institute of Technology, Pasadena, CA 91125, USA
| | - Carsten Duch
- iDN, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Wyatt Korff
- HHMI-Janelia Research Campus, Ashburn, VA 20147, USA
| | - Richard Mann
- Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10027, USA
| | - David Merritt
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Rod K Murphey
- Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Andrew M Seeds
- Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico
| | - Troy Shirangi
- Department of Biology, Villanova University, Villanova, PA 19085, USA
| | - Julie H Simpson
- Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - James W Truman
- HHMI-Janelia Research Campus, Ashburn, VA 20147, USA; Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
| | - John C Tuthill
- Department of Physiology & Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Darren W Williams
- Centre for Developmental Neurobiology, King's College London, London WC2R 2LS, UK
| | - David Shepherd
- School of Natural Sciences, Bangor University, Bangor LL57 2UW, Bangor, UK.
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26
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Chen S, Liu Y, Yang X, Liu Z, Luo X, Xu J, Huang Y. Dysfunction of dimorphic sperm impairs male fertility in the silkworm. Cell Discov 2020; 6:60. [PMID: 32963806 PMCID: PMC7477584 DOI: 10.1038/s41421-020-00194-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 07/13/2020] [Indexed: 11/17/2022] Open
Abstract
Sperm, which have a vital role in sexual reproduction in the animal kingdom, can display heteromorphism in some species. The regulation of sperm dichotomy remains a longstanding puzzle even though the phenomenon has been widely documented for over a century. Here we use Bombyx mori as a model to study a form of sperm dimorphism (eupyrene and apyrene sperm), which is nearly universal among Lepidoptera. We demonstrate that B. mori Sex-lethal (BmSxl) is crucial for apyrene sperm development, and that B. mori poly(A)-specific ribonuclease-like domain-containing 1 (BmPnldc1) is required for eupyrene sperm development. BmSXL is distributed in the nuclei and cytoplasm of somatic cyst cells in a mesh-like pattern and in the cytoplasm of germ cells enclosed in spermatocysts and sperm bundles. Cytological analyses of dimorphic sperm in BmSxl mutants (∆BmSxl) showed deficient apyrene sperm with abnormal nuclei, as well as loss of motility associated with malformed mitochondrial derivatives. We define the crucial function of apyrene sperm in the process of fertilization as assisting the migration of eupyrene spermatozoa from bursa copulatrix to spermatheca. By contrast, BmPnldc1 deficiency (∆BmPnldc1) caused eupyrene sperm abnormalities and impaired the release of eupyrene sperm bundles during spermiation. Although apyrene or eupyrene sperm defects impaired fertility of the mutated males, double copulation of a wild-type female with ∆BmSxl and ∆BmPnldc1 males could rescue the sterility phenotypes induced by single copulation with either gene-deficient male. Our findings demonstrate the crucial functions of BmSxl and BmPnldc1 in the development of sperm dimorphism and the indispensable roles of nonfertile apyrene sperm in fertilization.
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Affiliation(s)
- Shuqing Chen
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032 Shanghai, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Yujia Liu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032 Shanghai, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Xu Yang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032 Shanghai, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Zulian Liu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032 Shanghai, China
| | - Xingyu Luo
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032 Shanghai, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Jun Xu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032 Shanghai, China
- Present Address: Department of Genetics, Harvard Medical School, Boston, MA 02115 USA
| | - Yongping Huang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032 Shanghai, China
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27
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Allen AM, Neville MC, Birtles S, Croset V, Treiber CD, Waddell S, Goodwin SF. A single-cell transcriptomic atlas of the adult Drosophila ventral nerve cord. eLife 2020; 9:e54074. [PMID: 32314735 PMCID: PMC7173974 DOI: 10.7554/elife.54074] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 04/03/2020] [Indexed: 02/07/2023] Open
Abstract
The Drosophila ventral nerve cord (VNC) receives and processes descending signals from the brain to produce a variety of coordinated locomotor outputs. It also integrates sensory information from the periphery and sends ascending signals to the brain. We used single-cell transcriptomics to generate an unbiased classification of cellular diversity in the VNC of five-day old adult flies. We produced an atlas of 26,000 high-quality cells, representing more than 100 transcriptionally distinct cell types. The predominant gene signatures defining neuronal cell types reflect shared developmental histories based on the neuroblast from which cells were derived, as well as their birth order. The relative position of cells along the anterior-posterior axis could also be assigned using adult Hox gene expression. This single-cell transcriptional atlas of the adult fly VNC will be a valuable resource for future studies of neurodevelopment and behavior.
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Affiliation(s)
- Aaron M Allen
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Megan C Neville
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Sebastian Birtles
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Vincent Croset
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | | | - Scott Waddell
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
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28
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Ishii K, Wohl M, DeSouza A, Asahina K. Sex-determining genes distinctly regulate courtship capability and target preference via sexually dimorphic neurons. eLife 2020; 9:e52701. [PMID: 32314964 PMCID: PMC7173972 DOI: 10.7554/elife.52701] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 04/03/2020] [Indexed: 11/17/2022] Open
Abstract
For successful mating, a male animal must execute effective courtship behaviors toward a receptive target sex, which is female. Whether the courtship execution capability and upregulation of courtship toward females are specified through separable sex-determining genetic pathways remains uncharacterized. Here, we found that one of the two Drosophila sex-determining genes, doublesex (dsx), specifies a male-specific neuronal component that serves as an execution mechanism for courtship behavior, whereas fruitless (fru) is required for enhancement of courtship behavior toward females. The dsx-dependent courtship execution mechanism includes a specific subclass within a neuronal cluster that co-express dsx and fru. This cluster contains at least another subclass that is specified cooperatively by both dsx and fru. Although these neuronal populations can also promote aggressive behavior toward male flies, this capacity requires fru-dependent mechanisms. Our results uncover how sex-determining genes specify execution capability and female-specific enhancement of courtship behavior through separable yet cooperative neurogenetic mechanisms.
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Affiliation(s)
- Kenichi Ishii
- Molecular Neurobiology Laboratory, Salk Institute for Biological StudiesLa JollaUnited States
| | - Margot Wohl
- Molecular Neurobiology Laboratory, Salk Institute for Biological StudiesLa JollaUnited States
- Neuroscience Graduate Program, University of California, San DiegoSan DiegoUnited States
| | - Andre DeSouza
- Molecular Neurobiology Laboratory, Salk Institute for Biological StudiesLa JollaUnited States
- Neuroscience Graduate Program, University of California, San DiegoSan DiegoUnited States
| | - Kenta Asahina
- Molecular Neurobiology Laboratory, Salk Institute for Biological StudiesLa JollaUnited States
- Neuroscience Graduate Program, University of California, San DiegoSan DiegoUnited States
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29
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Lenschow C, Lima SQ. In the mood for sex: neural circuits for reproduction. Curr Opin Neurobiol 2020; 60:155-168. [DOI: 10.1016/j.conb.2019.12.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 12/01/2019] [Accepted: 12/04/2019] [Indexed: 12/31/2022]
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30
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Neurons that Function within an Integrator to Promote a Persistent Behavioral State in Drosophila. Neuron 2019; 105:322-333.e5. [PMID: 31810837 DOI: 10.1016/j.neuron.2019.10.028] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 10/08/2019] [Accepted: 10/18/2019] [Indexed: 01/19/2023]
Abstract
Innate behaviors involve both reflexive motor programs and enduring internal states, but how these responses are coordinated by the brain is not clear. In Drosophila, male-specific P1 interneurons promote courtship song, as well as a persistent internal state that prolongs courtship and enhances aggressiveness. However, P1 neurons themselves are not persistently active. Here, we identify pCd neurons as persistently active, indirect P1 targets that are required for P1-evoked persistent courtship and aggression. Acute activation of pCd neurons alone is inefficacious but enhances and prolongs courtship or aggression promoted by female cues. Brief female exposure induces a persistent increase in male aggressiveness, an effect abrogated by interruption of pCd activity. pCd activity is not sufficient but necessary for persistent physiological activity, implying an essential role in a persistence network. Thus, P1 neurons coordinate both command-like control of courtship song and a persistent internal state of social arousal mediated by pCd neurons.
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31
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Massey JH, Chung D, Siwanowicz I, Stern DL, Wittkopp PJ. The yellow gene influences Drosophila male mating success through sex comb melanization. eLife 2019; 8:49388. [PMID: 31612860 PMCID: PMC6794089 DOI: 10.7554/elife.49388] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 09/06/2019] [Indexed: 12/28/2022] Open
Abstract
Drosophila melanogaster males perform a series of courtship behaviors that, when successful, result in copulation with a female. For over a century, mutations in the yellow gene, named for its effects on pigmentation, have been known to reduce male mating success. Prior work has suggested that yellow influences mating behavior through effects on wing extension, song, and/or courtship vigor. Here, we rule out these explanations, as well as effects on the nervous system more generally, and find instead that the effects of yellow on male mating success are mediated by its effects on pigmentation of male-specific leg structures called sex combs. Loss of yellow expression in these modified bristles reduces their melanization, which changes their structure and causes difficulty grasping females prior to copulation. These data illustrate why the mechanical properties of anatomy, not just neural circuitry, must be considered to fully understand the development and evolution of behavior. More than 100 years ago, Nobel-prize winning geneticist Thomas Hunt Morgan and his colleagues discovered that some fruit flies inherited genetic mutations that caused their body color to change. The yellow flies had a mutation in one specific gene and these mutants did not only look different from normal flies, they behaved differently too. Specifically, yellow males were far less successful at mating than normal males, demonstrating for the first time that some behaviors had a genetic basis. Since then it has remained a mystery how the genetic mutations that cause yellow coloration in fruit flies lead to unsuccessful mating attempts. Geneticists have long suggested that mutations in insect pigment genes cause changes in the fly’s brain because these pigments are made from dopamine, a chemical messenger that acts in the brain. They proposed that yellow flies must have altered levels of dopamine in their brains which was causing them to fail at mating. To solve this mystery, Massey et al. used a series of genetic experiments and high speed-videos to assess how mutations in male yellow fruit flies affected their mating behavior. The experiments showed that yellow fruit flies mated poorly not because of changes in their brain but because of changes in specialized structures on their legs called sex combs. The yellow males lack melanin pigments in their sex combs, which changes their structure. As a result, the yellow males would court female flies but were then unable to grab and mount them. This explains why yellow flies often fail to mate and why fruit flies have sex combs in the first place. The study reveals the importance of scientists considering that genes that affect behavior may do so by changing anatomy rather than by altering the brain. The results also may benefit those working to control insect pests. For example, they could help insect pest managers to develop strategies that prevent reproduction in other insects that spread disease or destroy crops.
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Affiliation(s)
- Jonathan H Massey
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, United States.,Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Daayun Chung
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, United States
| | - Igor Siwanowicz
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - David L Stern
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Patricia J Wittkopp
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, United States.,Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States
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32
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Asahina K. Sex differences in Drosophila behavior: Qualitative and Quantitative Dimorphism. CURRENT OPINION IN PHYSIOLOGY 2018; 6:35-45. [PMID: 30386833 PMCID: PMC6205217 DOI: 10.1016/j.cophys.2018.04.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The importance of sex as a biological variable is being recognized by more and more researchers, including those using Drosophila melanogaster as a model organism. Differences between the two sexes are not confined to well-known reproductive behaviors, but include other behaviors and physiological characteristics that are considered "common" to both sexes. It is possible to categorize sexual dimorphisms into "qualitative" and "quantitative" differences, and this review focuses on recent advances in elucidating genetic and neurophysiological basis of both qualitative and quantitative sex differences in Drosophila behavior. While sex-specific behaviors are often mediated by sexually dimorphic neural circuits, quantitative sexual dimorphism is caused by sex-specific modulation of a common neuronal substrate.
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Affiliation(s)
- Kenta Asahina
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, MNL-KA, La Jolla, California 92037, United States of America
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33
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Jois S, Chan YB, Fernandez MP, Leung AKW. Characterization of the Sexually Dimorphic fruitless Neurons That Regulate Copulation Duration. Front Physiol 2018; 9:780. [PMID: 29988589 PMCID: PMC6026680 DOI: 10.3389/fphys.2018.00780] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 06/04/2018] [Indexed: 11/13/2022] Open
Abstract
Male courtship in Drosophila melanogaster is a sexually dimorphic innate behavior that is hardwired in the nervous system. Understanding the neural mechanism of courtship behavior requires the anatomical and functional characterization of all the neurons involved. Courtship involves a series of distinctive behavioral patterns, culminating in the final copulation step, where sperms from the male are transferred to the female. The duration of this process is tightly controlled by multiple genes. The fruitless (fru) gene is one of the factors that regulate the duration of copulation. Using several intersectional genetic combinations to restrict the labeling of GAL4 lines, we found that a subset of a serotonergic cluster of fru neurons co-express the dopamine-synthesizing enzyme, tyrosine hydroxylase, and provide behavioral and immunological evidence that these neurons are involved in the regulation of copulation duration.
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Affiliation(s)
- Shreyas Jois
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Yick Bun Chan
- Department of Neurobiology, Harvard Medical School, Boston, MA, United States
| | - Maria Paz Fernandez
- Department of Neurobiology, Harvard Medical School, Boston, MA, United States
| | - Adelaine Kwun-Wai Leung
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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34
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Zer-Krispil S, Zak H, Shao L, Ben-Shaanan S, Tordjman L, Bentzur A, Shmueli A, Shohat-Ophir G. Ejaculation Induced by the Activation of Crz Neurons Is Rewarding to Drosophila Males. Curr Biol 2018; 28:1445-1452.e3. [PMID: 29681474 DOI: 10.1016/j.cub.2018.03.039] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 02/03/2018] [Accepted: 03/16/2018] [Indexed: 11/29/2022]
Abstract
The reward system is a collection of circuits that reinforce behaviors necessary for survival [1, 2]. Given the importance of reproduction for survival, actions that promote successful mating induce pleasurable feeling and are positively reinforced [3, 4]. This principle is conserved in Drosophila, where successful copulation is naturally rewarding to male flies, induces long-term appetitive memories [5], increases brain levels of neuropeptide F (NPF, the fly homolog of neuropeptide Y), and prevents ethanol, known otherwise as rewarding to flies [6, 7], from being rewarding [5]. It is not clear which of the multiple sensory and motor responses performed during mating induces perception of reward. Sexual interactions with female flies that do not reach copulation are not sufficient to reduce ethanol consumption [5], suggesting that only successful mating encounters are rewarding. Here, we uncoupled the initial steps of mating from its final steps and tested the ability of ejaculation to mimic the rewarding value of full copulation. We induced ejaculation by activating neurons that express the neuropeptide corazonin (CRZ) [8] and subsequently measured different aspects of reward. We show that activating Crz-expressing neurons is rewarding to male flies, as they choose to reside in a zone that triggers optogenetic stimulation of Crz neurons and display conditioned preference for an odor paired with the activation. Reminiscent of successful mating, repeated activation of Crz neurons increases npf levels and reduces ethanol consumption. Our results demonstrate that ejaculation stimulated by Crz/Crz-receptor signaling serves as an essential part of the mating reward mechanism in Drosophila. VIDEO ABSTRACT.
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Affiliation(s)
- Shir Zer-Krispil
- The Mina & Everard Goodman Faculty of Life Sciences and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002 Ramat-Gan, Israel
| | - Hila Zak
- The Mina & Everard Goodman Faculty of Life Sciences and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002 Ramat-Gan, Israel
| | - Lisha Shao
- HHMI Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Shir Ben-Shaanan
- The Mina & Everard Goodman Faculty of Life Sciences and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002 Ramat-Gan, Israel
| | - Lea Tordjman
- The Mina & Everard Goodman Faculty of Life Sciences and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002 Ramat-Gan, Israel
| | - Assa Bentzur
- The Mina & Everard Goodman Faculty of Life Sciences and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002 Ramat-Gan, Israel
| | - Anat Shmueli
- The Mina & Everard Goodman Faculty of Life Sciences and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002 Ramat-Gan, Israel
| | - Galit Shohat-Ophir
- The Mina & Everard Goodman Faculty of Life Sciences and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002 Ramat-Gan, Israel.
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35
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Thompson KJ. Oviposition-like central pattern generators in pregenital segments of male and female grasshoppers. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:419-433. [PMID: 29423751 DOI: 10.1007/s00359-018-1249-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/27/2018] [Accepted: 01/31/2018] [Indexed: 10/18/2022]
Abstract
Grasshoppers produce an extraordinary oviposition behavior that is associated with multiple specializations of the skeletal and neuromuscular systems in the posterior abdomen, including a central pattern generator (CPG) in the female's terminal abdominal ganglion. Two pairs of shovel-shaped appendages, the ovipositor valves on the abdomen tip, excavate the soil for deposition of eggs. By contrast, the sexually monomorphic pregenital region of the abdomen is without appendages. Morphological homologues of ovipositor muscles and efferent neurons in the eighth abdominal segment are nevertheless present in pregenital segments of males and females. In both sexes, a robust rhythmic motor program was induced in pregenital segments by the same experimental methods used to elicit oviposition digging. The activity, recorded extracellularly, was oviposition-like in burst period (5-6 s) and homologous muscle phase relationships, and it persisted after sensory inputs were removed, indicating the presence of pregenital CPGs. The abdomen exhibited posterior-going waves of activity with an intersegmental phase delay of approximately 1 s. These results indicate that serially homologous motor systems, including functional CPGs, provided the foundation for the evolution of oviposition behavior.
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Affiliation(s)
- Karen J Thompson
- Department of Biology, Agnes Scott College, 141 E College Ave., Decatur, 30030, GA, USA.
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36
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Sayin S, Boehm AC, Kobler JM, De Backer JF, Grunwald Kadow IC. Internal State Dependent Odor Processing and Perception-The Role of Neuromodulation in the Fly Olfactory System. Front Cell Neurosci 2018; 12:11. [PMID: 29440990 PMCID: PMC5797598 DOI: 10.3389/fncel.2018.00011] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 01/08/2018] [Indexed: 12/21/2022] Open
Abstract
Animals rely heavily on their sense of olfaction to perform various vital interactions with an ever-in-flux environment. The turbulent and combinatorial nature of air-borne odorant cues demands the employment of various coding strategies, which allow the animal to attune to its internal needs and past or present experiences. Furthermore, these internal needs can be dependent on internal states such as hunger, reproductive state and sickness. Neuromodulation is a key component providing flexibility under such conditions. Understanding the contributions of neuromodulation, such as sensory neuron sensitization and choice bias requires manipulation of neuronal activity on a local and global scale. With Drosophila's genetic toolset, these manipulations are feasible and even allow a detailed look on the functional role of classical neuromodulators such as dopamine, octopamine and neuropeptides. The past years unraveled various mechanisms adapting chemosensory processing and perception to internal states such as hunger and reproductive state. However, future research should also investigate the mechanisms underlying other internal states including the modulatory influence of endogenous microbiota on Drosophila behavior. Furthermore, sickness induced by pathogenic infection could lead to novel insights as to the neuromodulators of circuits that integrate such a negative postingestive signal within the circuits governing olfactory behavior and learning. The enriched emporium of tools Drosophila provides will help to build a concrete picture of the influence of neuromodulation on olfaction and metabolism, adaptive behavior and our overall understanding of how a brain works.
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Affiliation(s)
- Sercan Sayin
- Neural Circuits and Metabolism, School of Life Sciences, Technische Universität München, Munich, Germany
| | - Ariane C Boehm
- Neural Circuits and Metabolism, School of Life Sciences, Technische Universität München, Munich, Germany.,Chemosensory Coding, Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Johanna M Kobler
- Neural Circuits and Metabolism, School of Life Sciences, Technische Universität München, Munich, Germany.,Chemosensory Coding, Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Jean-François De Backer
- Neural Circuits and Metabolism, School of Life Sciences, Technische Universität München, Munich, Germany
| | - Ilona C Grunwald Kadow
- Neural Circuits and Metabolism, School of Life Sciences, Technische Universität München, Munich, Germany.,Chemosensory Coding, Max Planck Institute of Neurobiology, Martinsried, Germany
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37
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Mishra A, Salari A, Berigan BR, Miguel KC, Amirshenava M, Robinson A, Zars BC, Lin JL, Milescu LS, Milescu M, Zars T. The Drosophila Gr28bD product is a non-specific cation channel that can be used as a novel thermogenetic tool. Sci Rep 2018; 8:901. [PMID: 29343813 PMCID: PMC5772361 DOI: 10.1038/s41598-017-19065-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 12/21/2017] [Indexed: 11/23/2022] Open
Abstract
Extrinsic control of single neurons and neuronal populations is a powerful approach for understanding how neural circuits function. Adding new thermogenetic tools to existing optogenetic and other forms of intervention will increase the complexity of questions that can be addressed. A good candidate for developing new thermogenetic tools is the Drosophila gustatory receptor family, which has been implicated in high-temperature avoidance behavior. We examined the five members of the Gr28b gene cluster for temperature-dependent properties via three approaches: biophysical characterization in Xenopus oocytes, functional calcium imaging in Drosophila motor neurons, and behavioral assays in adult Drosophila. Our results show that Gr28bD expression in Xenopus oocytes produces a non-specific cationic current that is activated by elevated temperatures. This current is non-inactivating and non-voltage dependent. When expressed in Drosophila motor neurons, Gr28bD can be used to change the firing pattern of individual cells in a temperature-dependent fashion. Finally, we show that pan-neuronal or motor neuron expression of Gr28bD can be used to alter fruit fly behavior with elevated temperatures. Together, these results validate the potential of the Gr28bD gene as a founding member of a new class of thermogenetic tools.
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Affiliation(s)
- Aditi Mishra
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Autoosa Salari
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Benton R Berigan
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Kayla C Miguel
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Marzie Amirshenava
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Abbey Robinson
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Benjamin C Zars
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Jenna L Lin
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Lorin S Milescu
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA.
| | - Mirela Milescu
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA.
| | - Troy Zars
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA.
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38
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Ellendersen BE, von Philipsborn AC. Neuronal modulation of D. melanogaster sexual behaviour. CURRENT OPINION IN INSECT SCIENCE 2017; 24:21-28. [PMID: 29208219 DOI: 10.1016/j.cois.2017.08.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/20/2017] [Accepted: 08/24/2017] [Indexed: 06/07/2023]
Abstract
Drosophila melanogaster sexual behaviour relies on well-studied genetically determined neuronal circuits. At the same time, it can be flexible and is modulated by multiple external and internal factors. This review focuses on how physiological state, behavioural context and social experience impact sexual circuits in the two sexes. We discuss how females tune receptivity and other behaviours depending on mating status and how males adjust courtship intensity based on sexual satiety, age and the conflicting drive for aggression. Neuronal mechanisms for behavioural modulation include changes in sensory and central processing. Activity of modulatory neurons can enhance, suppress or reverse the behavioural response to sensory cues. In summary, fly sexual behaviour is an excellent model to study mechanisms of neuromodulation of complex innate behaviour on the circuit level.
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Affiliation(s)
- Bárður Eyjólfsson Ellendersen
- Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus University, Ole Worms Alle 3, Building 1170, DK-8000 Aarhus C, Denmark
| | - Anne C von Philipsborn
- Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus University, Ole Worms Alle 3, Building 1170, DK-8000 Aarhus C, Denmark.
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39
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Chauhan V, Srikumar S, Aamer S, Pandareesh MD, Chauhan A. Methylmercury Exposure Induces Sexual Dysfunction in Male and Female Drosophila Melanogaster. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14101108. [PMID: 28946640 PMCID: PMC5664609 DOI: 10.3390/ijerph14101108] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 09/19/2017] [Accepted: 09/20/2017] [Indexed: 12/20/2022]
Abstract
Mercury, an environmental health hazard, is a neurotoxic heavy metal. In this study, the effect of methylmercury (MeHg) exposure was analyzed on sexual behavior in Drosophila melanogaster (fruit fly), because neurons play a vital role in sexual functions. The virgin male and female flies were fed a diet mixed with different concentrations of MeHg (28.25, 56.5, 113, 226, and 339 µM) for four days, and the effect of MeHg on copulation of these flies was studied. While male and female control flies (no MeHg) and flies fed with lower concentrations of MeHg (28.25, 56.5 µM) copulated in a normal manner, male and female flies exposed to higher concentrations of MeHg (113, 226, and 339 µM) did not copulate. When male flies exposed to higher concentrations of MeHg were allowed to copulate with control female flies, only male flies fed with 113 µM MeHg were able to copulate. On the other hand, when female flies exposed to higher concentrations of MeHg were allowed to copulate with control male flies, none of the flies could copulate. After introduction of male and female flies in the copulation chamber, duration of wing flapping by male flies decreased in a MeHg-concentration-dependent manner from 101 ± 24 seconds (control) to 100.7 ± 18, 96 ±12, 59 ± 44, 31 ± 15, and 3.7 ± 2.7 seconds at 28.25, 56.5, 113, 226, and 339 µM MeHg, respectively. On the other hand, grooming in male and female flies increased in a MeHg-concentration-dependent manner. These findings suggest that MeHg exposure causes sexual dysfunction in male and female Drosophila melanogaster. Further studies showed that MeHg exposure increased oxidative stress and decreased triglyceride levels in a concentration–dependent manner in both male and female flies, suggesting that MeHg-induced oxidative stress and decreased triglyceride levels may partly contribute to sexual dysfunction in fruit flies.
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Affiliation(s)
- Ved Chauhan
- New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA.
| | - Syian Srikumar
- New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA.
| | - Sarah Aamer
- New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA.
| | - Mirazkar D Pandareesh
- New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA.
| | - Abha Chauhan
- New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA.
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40
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Abstract
Neural circuits that control copulation in male flies have been identified.
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Affiliation(s)
- Joel Levine
- Department of Biology, University of Toronto Mississauga, Mississauga, Canada
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