1
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Sokolowski DJ, Vasquez OE, Wilson MD, Sokolowski MB, Anreiter I. Transcriptomic effects of the foraging gene shed light on pathways of pleiotropy and plasticity. Ann N Y Acad Sci 2023; 1526:99-113. [PMID: 37350250 DOI: 10.1111/nyas.15015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023]
Abstract
Genes are often pleiotropic and plastic in their expression, features which increase and diversify the functionality of the genome. The foraging (for) gene in Drosophila melanogaster is highly pleiotropic and a long-standing model for studying individual differences in behavior and plasticity from ethological, evolutionary, and genetic perspectives. Its pleiotropy is known to be linked to its complex molecular structure; however, the downstream pathways and interactors remain mostly elusive. To uncover these pathways and interactors and gain a better understanding of how pleiotropy and plasticity are achieved at the molecular level, we explore the effects of different for alleles on gene expression at baseline and in response to 4 h of food deprivation, using RNA sequencing analysis in different Drosophila larval tissues. The results show tissue-specific transcriptomic dynamics influenced by for allelic variation and food deprivation, as well as genotype by treatment interactions. Differentially expressed genes yielded pathways linked to previously described for phenotypes and several potentially novel phenotypes. Together, these findings provide putative genes and pathways through which for might regulate its varied phenotypes in a pleiotropic, plastic, and gene-structure-dependent manner.
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Affiliation(s)
- Dustin J Sokolowski
- Genetics and Genome Biology, SickKids Research Institute, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Oscar E Vasquez
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Michael D Wilson
- Genetics and Genome Biology, SickKids Research Institute, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Marla B Sokolowski
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
- Program in Child and Brain Development, Canadian Institute for Advanced Research, Toronto, Ontario, Canada
| | - Ina Anreiter
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
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2
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Xu H, Yu Y, Gao Y, Hassan A, Jia B, Huang Q. The cGMP-dependent protein kinase gene can regulate trail-following behaviour and locomotion in the termite Reticulitermes chinensis Snyder. INSECT MOLECULAR BIOLOGY 2022; 31:585-592. [PMID: 35506165 DOI: 10.1111/imb.12781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/28/2022] [Indexed: 06/14/2023]
Abstract
Social behaviours in termites are closely related to the chemical communication between individuals. It is well known that foraging worker termites can use trail pheromones to orient and locomote along trails so as to take food resources back to the nest. However, it is still unclear how termites recognize trail pheromones. Here, we cloned and sequenced the cGMP-dependent protein kinase (PKG) gene from the termite Reticulitermes chinensis Snyder, and then examined the response of termites to trail pheromones after silencing PKG through RNA interference. We found that PKG knockdown impaired termite ability to follow trail pheromones accurately and exhibited irregular behavioural trajectories in response to the trail pheromone in the termite R. chinensis. Our locomotion assays further showed that PKG knockdown significantly increased the turn angle and angular velocity in the termite R. chinensis. These findings help us better understanding the molecular regulatory mechanism of foraging communications in termites.
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Affiliation(s)
- Huan Xu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yichun Yu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yongyong Gao
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Ali Hassan
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Bao Jia
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan, Hubei, China
- Nanning Institute of Termite Control, Nanning, Guangxi, China
| | - Qiuying Huang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan, Hubei, China
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3
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Chen M, Sokolowski MB. How Social Experience and Environment Impacts Behavioural Plasticity in Drosophila. Fly (Austin) 2021; 16:68-84. [PMID: 34852730 DOI: 10.1080/19336934.2021.1989248] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
An organism's behaviour is influenced by its social environment. Experiences such as social isolation or crowding may have profound short or long-term effects on an individual's behaviour. The composition of the social environment also depends on the genetics and previous experiences of the individuals present, leading to additional potential outcomes from each social interaction. In this article, we review selected literature related to the social environment of the model organism Drosophila melanogaster, and how Drosophila respond to variation in their social experiences throughout their lifetimes. We focus on the effects of social environment on behavioural phenotypes such as courtship, aggression, and group dynamics, as well as other phenotypes such as development and physiology. The consequences of phenotypic plasticity due to social environment are discussed with respect to the ecology and evolution of Drosophila. We also relate these studies to laboratory research practices involving Drosophila and other animals.
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Affiliation(s)
- Molly Chen
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada.,Current Affiliation: Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1 Canada
| | - Marla B Sokolowski
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Ontario M5G 1Z8, Canada
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4
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Dason JS, Anreiter I, Wu CF. Transcending boundaries: from quantitative genetics to single genes. J Neurogenet 2021; 35:95-98. [PMID: 34544325 DOI: 10.1080/01677063.2021.1960519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Jeffrey S Dason
- Department of Biomedical Sciences, University of Windsor, Windsor, Canada
| | - Ina Anreiter
- Department of Neurobiology, Stanford University, Stanford, CA, USA
| | - Chun-Fang Wu
- Department of Biology, University of Iowa, Iowa City, IA, USA
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5
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Lucas C, Ben-Shahar Y. The foraging gene as a modulator of division of labour in social insects. J Neurogenet 2021; 35:168-178. [PMID: 34151702 DOI: 10.1080/01677063.2021.1940173] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The social ants, bees, wasps, and termites include some of the most ecologically-successful groups of animal species. Their dominance in most terrestrial environments is attributed to their social lifestyle, which enable their colonies to exploit environmental resources with remarkable efficiency. One key attribute of social insect colonies is the division of labour that emerges among the sterile workers, which represent the majority of colony members. Studies of the mechanisms that drive division of labour systems across diverse social species have provided fundamental insights into the developmental, physiological, molecular, and genomic processes that regulate sociality, and the possible genetic routes that may have led to its evolution from a solitary ancestor. Here we specifically discuss the conserved role of the foraging gene, which encodes a cGMP-dependent protein kinase (PKG). Originally identified as a behaviourally polymorphic gene that drives alternative foraging strategies in the fruit fly Drosophila melanogaster, changes in foraging expression and kinase activity were later shown to play a key role in the division of labour in diverse social insect species as well. In particular, foraging appears to regulate worker transitions between behavioural tasks and specific behavioural traits associated with morphological castes. Although the specific neuroethological role of foraging in the insect brain remains mostly unknown, studies in genetically tractable insect species indicate that PKG signalling plays a conserved role in the neuronal plasticity of sensory, cognitive and motor functions, which underlie behaviours relevant to division of labour, including appetitive learning, aggression, stress response, phototaxis, and the response to pheromones.
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Affiliation(s)
- Christophe Lucas
- Institut de Recherche sur la Biologie de l'Insecte (UMR7261), CNRS - University of Tours, Tours, France
| | - Yehuda Ben-Shahar
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
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6
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Reiss AP, Rankin CH. Gaining an understanding of behavioral genetics through studies of foraging in Drosophila and learning in C. elegans. J Neurogenet 2021; 35:119-131. [PMID: 34151727 DOI: 10.1080/01677063.2021.1928113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The pursuit of understanding behavior has led to investigations of how genes, the environment, and the nervous system all work together to produce and influence behavior, giving rise to a field of research known as behavioral neurogenetics. This review focuses on the research journeys of two pioneers of aspects of behavioral neurogenetic research: Dr. Marla Sokolowski and Dr. Catharine Rankin as examples of how different approaches have been used to understand relationships between genes and behavior. Marla Sokolowski's research is centered around the discovery and analysis of foraging, a gene responsible for the natural behavioral polymorphism of Drosophila melanogaster larvae foraging behavior. Catharine Rankin's work began with demonstrating the ability to learn in Caenorhabditis elegans and then setting out to investigate the mechanisms underlying the "simplest" form of learning, habituation. Using these simple invertebrate organisms both investigators were able to perform in-depth dissections of behavior at genetic and molecular levels. By exploring their research and highlighting their findings we present ways their work has furthered our understanding of behavior and contributed to the field of behavioral neurogenetics.
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Affiliation(s)
- Aaron P Reiss
- Department of Psychology, University of British Columbia, Vancouver, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Catharine H Rankin
- Department of Psychology, University of British Columbia, Vancouver, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
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7
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Greenspan RJ. Learning about quantitative genetics from Marla Sokolowski. J Neurogenet 2021; 35:110-111. [PMID: 34128769 DOI: 10.1080/01677063.2021.1940167] [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: 10/21/2022]
Abstract
Marla Sokolowski is a true pioneer in behavioral genetics, having made the first molecular delineation of a naturally occurring behavioral polymorphism in her work on the foraging locus in Drosophila melanogaster. The gene was subsequently found to be responsible for behavioral variants and types in many other species, both invertebrate and mammal (human). The path to get there is a paradigmatic example of how to use the power of genetic analysis, including some rather esoteric techniques, to zero in on a gene and delineate its molecular identity and its pleiotropic roles.
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Affiliation(s)
- Ralph J Greenspan
- Kavli Institute for Brain and Mind, University of California San Diego, La Jolla, CA, USA
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8
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Alwash N, Allen AM, B Sokolowski M, Levine JD. The Drosophila melanogaster foraging gene affects social networks. J Neurogenet 2021; 35:249-261. [PMID: 34121597 DOI: 10.1080/01677063.2021.1936517] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Drosophila melanogaster displays social behaviors including courtship, mating, aggression, and group foraging. Recent studies employed social network analyses (SNAs) to show that D. melanogaster strains differ in their group behavior, suggesting that genes influence social network phenotypes. Aside from genes associated with sensory function, few studies address the genetic underpinnings of these networks. The foraging gene (for) is a well-established example of a pleiotropic gene that regulates multiple behavioral phenotypes and their plasticity. In D. melanogaster, there are two naturally occurring alleles of for called rover and sitter that differ in their larval and adult food-search behavior as well as other behavioral phenotypes. Here, we hypothesize that for affects behavioral elements required to form social networks and the social networks themselves. These effects are evident when we manipulate gene dosage. We found that flies of the rover and sitter strains exhibit differences in duration, frequency, and reciprocity of pairwise interactions, and they form social networks with differences in assortativity and global efficiency. Consistent with other adult phenotypes influenced by for, rover-sitter heterozygotes show intermediate patterns of dominance in many of these characteristics. Multiple generations of backcrossing a rover allele into a sitter strain showed that many but not all of these rover-sitter differences may be attributed to allelic variation at for. Our findings reveal the significant role that for plays in affecting social network properties and their behavioral elements in Drosophila melanogaster.
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Affiliation(s)
- Nawar Alwash
- Department of Biology, University of Toronto at Mississauga, Mississauga, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Aaron M Allen
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.,Centre for Neural Circuits and Behavior, University of Oxford, Oxford, UK
| | - Marla B Sokolowski
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), MaRS Centre, Toronto, Canada
| | - Joel D Levine
- Department of Biology, University of Toronto at Mississauga, Mississauga, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), MaRS Centre, Toronto, Canada
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9
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Oepen AS, Catalano JL, Azanchi R, Kaun KR. The foraging gene affects alcohol sensitivity, metabolism and memory in Drosophila. J Neurogenet 2021; 35:236-248. [PMID: 34092172 DOI: 10.1080/01677063.2021.1931178] [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: 10/21/2022]
Abstract
The genetic basis of alcohol use disorder (AUD) is complex. Understanding how natural genetic variation contributes to alcohol phenotypes can help us identify and understand the genetic basis of AUD. Recently, a single nucleotide polymorphism in the human foraging (for) gene ortholog, Protein Kinase cGMP-Dependent 1 (PRKG1), was found to be associated with stress-induced risk for alcohol abuse. However, the mechanistic role that PRKG1 plays in AUD is not well understood. We use natural variation in the Drosophila for gene to describe how variation of cGMP-dependent protein kinase (PKG) activity modifies ethanol-induced phenotypes. We found that variation in for affects ethanol-induced increases in locomotion and memory of the appetitive properties of ethanol intoxication. Further, these differences may stem from the ability to metabolize ethanol. Together, this data suggests that natural variation in PKG modulates cue reactivity for alcohol, and thus could influence alcohol cravings by differentially modulating metabolic and behavioral sensitivities to alcohol.
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Affiliation(s)
- Anne S Oepen
- Department of Neuroscience, Brown University, Providence, RI, USA.,Masters Program in Developmental, Neuronal and Behavioral Biology, Georg-August-University, Göttingen, Germany
| | - Jamie L Catalano
- Department of Neuroscience, Brown University, Providence, RI, USA.,Molecular Pharmacology and Physiology Graduate Program, Brown University, Providence, RI, USA
| | - Reza Azanchi
- Department of Neuroscience, Brown University, Providence, RI, USA
| | - Karla R Kaun
- Department of Neuroscience, Brown University, Providence, RI, USA
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10
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Dason JS, Sokolowski MB. A cGMP-dependent protein kinase, encoded by the Drosophila foraging gene, regulates neurotransmission through changes in synaptic structure and function. J Neurogenet 2021; 35:213-220. [PMID: 33998378 DOI: 10.1080/01677063.2021.1905639] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A cGMP-dependent protein kinase (PKG) encoded by the Drosophila foraging (for) gene regulates both synaptic structure (nerve terminal growth) and function (neurotransmission) through independent mechanisms at the Drosophila larval neuromuscular junction (nmj). Glial for is known to restrict nerve terminal growth, whereas presynaptic for inhibits synaptic vesicle (SV) exocytosis during low frequency stimulation. Presynaptic for also facilitates SV endocytosis during high frequency stimulation. for's effects on neurotransmission can occur independent of any changes in nerve terminal growth. However, it remains unclear if for's effects on neurotransmission affect nerve terminal growth. Furthermore, it's possible that for's effects on synaptic structure contribute to changes in neurotransmission. In the present study, we examined these questions using RNA interference to selectively knockdown for in presynaptic neurons or glia at the Drosophila larval nmj. Consistent with our previous findings, presynaptic knockdown of for impaired SV endocytosis, whereas knockdown of glial for had no effect on SV endocytosis. Surprisingly, we found that knockdown of either presynaptic or glial for increased neurotransmitter release in response to low frequency stimulation. Knockdown of presynaptic for did not affect nerve terminal growth, demonstrating that for's effects on neurotransmission does not alter nerve terminal growth. In contrast, knockdown of glial for enhanced nerve terminal growth. This enhanced nerve terminal growth was likely the cause of the enhanced neurotransmitter release seen following knockdown of glial for. Overall, we show that for can affect neurotransmitter release by regulating both synaptic structure and function.
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Affiliation(s)
- Jeffrey S Dason
- Department of Cell & Systems Biology, University of Toronto, Toronto, Canada.,Department of Biomedical Sciences, University of Windsor, Windsor, Canada
| | - Marla B Sokolowski
- Department of Cell & Systems Biology, University of Toronto, Toronto, Canada.,Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Canada.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Canada
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11
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McKinney RM, Valdez R, Ben-Shahar Y. The genetic architecture of larval aggregation behavior in Drosophila. J Neurogenet 2021; 35:274-284. [PMID: 33629904 DOI: 10.1080/01677063.2021.1887174] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Many insect species exhibit basal social behaviors such as aggregation, which play important roles in their feeding and mating ecologies. However, the evolutionary, genetic, and physiological mechanisms that regulate insect aggregation remain unknown for most species. Here, we used natural populations of Drosophila melanogaster to identify the genetic architecture that drives larval aggregation feeding behavior. By using quantitative and reverse genetic approaches, we have identified a complex neurogenetic network that plays a role in regulating the decision of larvae to feed in either solitude or as a group. Results from single gene, RNAi-knockdown experiments show that several of the identified genes represent key nodes in the genetic network that determines the level of aggregation while feeding. Furthermore, we show that a single non-coding variant in the gene CG14205, a putative acyltransferase, is associated with both decreased mRNA expression and increased aggregate formation, which suggests that it has a specific role in inhibiting aggregation behavior. Our results identify, for the first time, the genetic components which interact to regulate naturally occurring levels of aggregation in D. melanogaster larvae.
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Affiliation(s)
- Ross M McKinney
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
| | - Ryan Valdez
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
| | - Yehuda Ben-Shahar
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
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12
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Boto T, Stahl A, Tomchik SM. Cellular and circuit mechanisms of olfactory associative learning in Drosophila. J Neurogenet 2020; 34:36-46. [PMID: 32043414 DOI: 10.1080/01677063.2020.1715971] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Recent years have witnessed significant progress in understanding how memories are encoded, from the molecular to the cellular and the circuit/systems levels. With a good compromise between brain complexity and behavioral sophistication, the fruit fly Drosophila melanogaster is one of the preeminent animal models of learning and memory. Here we review how memories are encoded in Drosophila, with a focus on short-term memory and an eye toward future directions. Forward genetic screens have revealed a large number of genes and transcripts necessary for learning and memory, some acting cell-autonomously. Further, the relative numerical simplicity of the fly brain has enabled the reverse engineering of learning circuits with remarkable precision, in some cases ascribing behavioral phenotypes to single neurons. Functional imaging and physiological studies have localized and parsed the plasticity that occurs during learning at some of the major loci. Connectomics projects are significantly expanding anatomical knowledge of the nervous system, filling out the roadmap for ongoing functional/physiological and behavioral studies, which are being accelerated by simultaneous tool development. These developments have provided unprecedented insight into the fundamental neural principles of learning, and lay the groundwork for deep understanding in the near future.
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Affiliation(s)
- Tamara Boto
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, USA
| | - Aaron Stahl
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, USA
| | - Seth M Tomchik
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, USA
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13
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Abstract
The Drosophila melanogaster foraging (for) gene is a well-established example of a gene with major effects on behavior and natural variation. This gene is best known for underlying the behavioral strategies of rover and sitter foraging larvae, having been mapped and named for this phenotype. Nevertheless, in the last three decades an extensive array of studies describing for's role as a modifier of behavior in a wide range of phenotypes, in both Drosophila and other organisms, has emerged. Furthermore, recent work reveals new insights into the genetic and molecular underpinnings of how for affects these phenotypes. In this article, we discuss the history of the for gene and its role in natural variation in behavior, plasticity, and behavioral pleiotropy, with special attention to recent findings on the molecular structure and transcriptional regulation of this gene.
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Affiliation(s)
- Ina Anreiter
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S 3B2, Canada;
| | - Marla B Sokolowski
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S 3B2, Canada;
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14
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Merlino DJ, Barton JR, Charsar BA, Byrne MD, Rappaport JA, Smeyne RJ, Lepore AC, Snook AE, Waldman SA. Two distinct GUCY2C circuits with PMV (hypothalamic) and SN/VTA (midbrain) origin. Brain Struct Funct 2019; 224:2983-2999. [PMID: 31485718 DOI: 10.1007/s00429-019-01949-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 08/24/2019] [Indexed: 12/16/2022]
Abstract
Guanylyl cyclase C (GUCY2C) is the afferent central receptor in the gut-brain endocrine axis regulated by the anorexigenic intestinal hormone uroguanylin. GUCY2C mRNA and protein are produced in the hypothalamus, a major center regulating appetite and metabolic homeostasis. Further, GUCY2C mRNA and protein are expressed in the ventral midbrain, a principal structure regulating hedonic reward from behaviors including eating. While GUCY2C is expressed in hypothalamus and midbrain, its precise neuroanatomical organization and relationship with circuits regulating satiety remain unknown. Here, we reveal that hypothalamic GUCY2C mRNA is confined to the ventral premammillary nucleus (PMV), while in midbrain it is produced by neurons in the ventral tegmental area (VTA) and substantia nigra (SN). GUCY2C in the PMV is produced by 46% of neurons expressing anorexigenic leptin receptors, while in the VTA/SN it is produced in most tyrosine hydroxylase-immunoreactive neurons. In contrast to mRNA, GUCY2C protein is widely distributed throughout the brain in canonical sites of PMV and VTA/SN axonal projections. Selective stereotaxic ablation of PMV or VTA/SN neurons eliminated GUCY2C only in their respective canonical projection sites. Conversely, specific anterograde tracer analyses of PMV or VTA/SN neurons confirmed distinct GUCY2C-immunoreactive axons projecting to those canonical locations. Together, these findings reveal two discrete neuronal circuits expressing GUCY2C originating in the PMV in the hypothalamus and in the VTA/SN in midbrain, which separately project to other sites throughout the brain. They suggest a structural basis for a role for the GUCY2C-uroguanylin gut-brain endocrine axis in regulating homeostatic and behavioral components contributing to satiety.
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Affiliation(s)
- D J Merlino
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, 1020 Locust Street, 368 JAH, Philadelphia, PA, 19107, USA
| | - J R Barton
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, 1020 Locust Street, 368 JAH, Philadelphia, PA, 19107, USA
| | - B A Charsar
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, USA
| | - M D Byrne
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, USA
| | - J A Rappaport
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, 1020 Locust Street, 368 JAH, Philadelphia, PA, 19107, USA
| | - R J Smeyne
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, USA
| | - A C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, USA
| | - A E Snook
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, 1020 Locust Street, 368 JAH, Philadelphia, PA, 19107, USA
| | - S A Waldman
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, 1020 Locust Street, 368 JAH, Philadelphia, PA, 19107, USA.
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15
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Drosophila melanogaster foraging regulates a nociceptive-like escape behavior through a developmentally plastic sensory circuit. Proc Natl Acad Sci U S A 2019; 117:23286-23291. [PMID: 31213548 DOI: 10.1073/pnas.1820840116] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Painful or threatening experiences trigger escape responses that are guided by nociceptive neuronal circuitry. Although some components of this circuitry are known and conserved across animals, how this circuitry is regulated at the genetic and developmental levels is mostly unknown. To escape noxious stimuli, such as parasitoid wasp attacks, Drosophila melanogaster larvae generate a curling and rolling response. Rover and sitter allelic variants of the Drosophila foraging (for) gene differ in parasitoid wasp susceptibility, suggesting a link between for and nociception. By optogenetically activating cells associated with each of for's promoters (pr1-pr4), we show that pr1 cells regulate larval escape behavior. In accordance with rover and sitter differences in parasitoid wasp susceptibility, we found that rovers have higher pr1 expression and increased sensitivity to nociception relative to sitters. The for null mutants display impaired responses to thermal nociception, which are rescued by restoring for expression in pr1 cells. Conversely, knockdown of for in pr1 cells phenocopies the for null mutant. To gain insight into the circuitry underlying this response, we used an intersectional approach and activity-dependent GFP reconstitution across synaptic partners (GRASP) to show that pr1 cells in the ventral nerve cord (VNC) are required for the nociceptive response, and that multidendritic sensory nociceptive neurons synapse onto pr1 neurons in the VNC. Finally, we show that activation of the pr1 circuit during development suppresses the escape response. Our data demonstrate a role of for in larval nociceptive behavior. This function is specific to for pr1 neurons in the VNC, guiding a developmentally plastic escape response circuit.
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16
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Abstract
Foraging is a goal-directed behavior that balances the need to explore the environment for resources with the need to exploit those resources. In Drosophila melanogaster, distinct phenotypes have been observed in relation to the foraging gene (for), labeled the rover and sitter. Adult rovers explore their environs more extensively than do adult sitters. We explored whether this distinction would be conserved in humans. We made use of a distinction from regulatory mode theory between those who "get on with it," so-called locomotors, and those who prefer to ensure they "do the right thing," so-called assessors. In this logic, rovers and locomotors share similarities in goal pursuit, as do sitters and assessors. We showed that genetic variation in PRKG1, the human ortholog of for, is associated with preferential adoption of a specific regulatory mode. Next, participants performed a foraging task to see whether genetic differences associated with distinct regulatory modes would be associated with distinct goal pursuit patterns. Assessors tended to hug the boundary of the foraging environment, much like behaviors seen in Drosophila adult sitters. In a patchy foraging environment, assessors adopted more cautious search strategies maximizing exploitation. These results show that distinct patterns of goal pursuit are associated with particular genotypes of PRKG1, the human ortholog of for.
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17
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Page H, Sweeney A, Pilko A, Pinter-Wollman N. Underlying mechanisms and ecological context of variation in exploratory behavior of the Argentine ant, Linepithema humile. J Exp Biol 2018; 221:jeb188722. [PMID: 30385482 PMCID: PMC6307874 DOI: 10.1242/jeb.188722] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 10/29/2018] [Indexed: 01/30/2023]
Abstract
Uncovering how and why animals explore their environment is fundamental for understanding population dynamics, the spread of invasive species, species interactions, etc. In social animals, individuals within a group can vary in their exploratory behavior, and the behavioral composition of the group can determine its collective success. Workers of the invasive Argentine ant (Linepithema humile) exhibit individual variation in exploratory behavior, which affects the colony's collective nest selection behavior. Here, we examine the mechanisms underlying this behavioral variation in exploratory behavior and determine its implications for the ecology of this species. We first establish that individual variation in exploratory behavior is repeatable and consistent across situations. We then show a relationship between exploratory behavior and the expression of genes that have been previously linked with other behaviors in social insects. Specifically, we found a negative relationship between exploratory behavior and the expression of the foraging (Lhfor) gene. Finally, we determine how colonies allocate exploratory individuals in natural conditions. We found that ants from inside the nest are the least exploratory individuals, whereas workers on newly formed foraging trails are the most exploratory individuals. Furthermore, we found temporal differences throughout the year: in early-mid spring, when new resources emerge, workers are more exploratory than at the end of winter, potentially allowing the colony to find and exploit new resources. These findings reveal the importance of individual variation in behavior for the ecology of social animals.
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Affiliation(s)
- Hannah Page
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Andrew Sweeney
- Biocircuits Institute, University of California, San Diego, San Diego, CA 92093, USA
| | - Anna Pilko
- Institute of Quantitative and Computational Biosciences, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Noa Pinter-Wollman
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Institute of Quantitative and Computational Biosciences, University of California, Los Angeles, Los Angeles, CA 90095, USA
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18
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Risley MG, Kelly SP, Minnerly J, Jia K, Dawson-Scully K. egl-4 modulates electroconvulsive seizure duration in C. elegans. INVERTEBRATE NEUROSCIENCE 2018; 18:8. [PMID: 29845318 DOI: 10.1007/s10158-018-0211-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/30/2018] [Indexed: 12/16/2022]
Abstract
Increased neuronal excitability causes seizures with debilitating symptoms. Effective and noninvasive treatments are limited for easing symptoms, partially due to the complexity of the disorder and lack of knowledge of specific molecular faults. An unexplored, novel target for seizure therapeutics is the cGMP/protein kinase G (PKG) pathway, which targets downstream K+ channels, a mechanism similar to Retigabine, a recently FDA-approved antiepileptic drug. Our results demonstrate that increased PKG activity decreased seizure duration in C. elegans utilizing a recently developed electroconvulsive seizure assay. While the fly is a well-established seizure model, C. elegans are an ideal yet unexploited model which easily uptakes drugs and can be utilized for high-throughput screens. In this study, we show that treating the worms with either a potassium channel opener, Retigabine or published pharmaceuticals that increase PKG activity, significantly reduces seizure recovery times. Our results suggest that PKG signaling modulates downstream K+ channel conductance to control seizure recovery time in C. elegans. Hence, we provide powerful evidence, suggesting that pharmacological manipulation of the PKG signaling cascade may control seizure duration across phyla.
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Affiliation(s)
- Monica G Risley
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA.,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA
| | - Stephanie P Kelly
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA.,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA
| | - Justin Minnerly
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA.,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA
| | - Kailiang Jia
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA.,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA. .,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA.
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19
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Widmann A, Eichler K, Selcho M, Thum AS, Pauls D. Odor-taste learning in Drosophila larvae. JOURNAL OF INSECT PHYSIOLOGY 2018; 106:47-54. [PMID: 28823531 DOI: 10.1016/j.jinsphys.2017.08.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 08/07/2017] [Accepted: 08/16/2017] [Indexed: 06/07/2023]
Abstract
The Drosophila larva is an attractive model system to study fundamental questions in the field of neuroscience. Like the adult fly, the larva offers a seemingly unlimited genetic toolbox, which allows one to visualize, silence or activate neurons down to the single cell level. This, combined with its simplicity in terms of cell numbers, offers a useful system to study the neuronal correlates of complex processes including associative odor-taste learning and memory formation. Here, we summarize the current knowledge about odor-taste learning and memory at the behavioral level and integrate the recent progress on the larval connectome to shed light on the sub-circuits that allow Drosophila larvae to integrate present sensory input in the context of past experience and to elicit an appropriate behavioral response.
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Affiliation(s)
| | - Katharina Eichler
- Department of Biology, University of Konstanz, D-78464 Konstanz, Germany; HHMI Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Mareike Selcho
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, D-97074 Würzburg, Germany
| | - Andreas S Thum
- Department of Biology, University of Konstanz, D-78464 Konstanz, Germany; Department of Genetics, University of Leipzig, D-04103 Leipzig, Germany.
| | - Dennis Pauls
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, D-97074 Würzburg, Germany.
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20
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Anreiter I, Sokolowski MB. Deciphering pleiotropy: How complex genes regulate behavior. Commun Integr Biol 2018; 11:1-4. [PMID: 30083283 PMCID: PMC6067849 DOI: 10.1080/19420889.2018.1447743] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 02/28/2018] [Indexed: 11/10/2022] Open
Abstract
The genetic underpinnings of animal behavior are exceedingly complex. Behavioral phenotypes are commonly regulated by many genes, and the behavioral effects of a gene often dependent on environmental conditions and genetic background. To complicate the study of behavioral genetics further, many genes that regulate behavioral phenotypes are themselves very complex genes, with several gene products and functions. One example of such a complex gene is the foraging gene in D. melanogaster. foraging influences many behaviors in the fruit fly, and the key to its effects likely lies in its complex molecular structure. We've recently found that expression levels of a small subset of transcripts of the foraging gene underlie the behavioral differences seen in adult foraging patterns of the rover and sitter D. melanogaster strains. Here we comment on the larger implications of this and other findings on gene regulation and pleiotropy in behavior.
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Affiliation(s)
- Ina Anreiter
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), MaRS Centre, Toronto, Ontario, Canada
| | - Marla B Sokolowski
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), MaRS Centre, Toronto, Ontario, Canada
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21
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Foley BR, Marjoram P, Nuzhdin SV. Basic reversal-learning capacity in flies suggests rudiments of complex cognition. PLoS One 2017; 12:e0181749. [PMID: 28813432 PMCID: PMC5558953 DOI: 10.1371/journal.pone.0181749] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 07/06/2017] [Indexed: 11/19/2022] Open
Abstract
The most basic models of learning are reinforcement learning models (for instance, classical and operant conditioning) that posit a constant learning rate; however many animals change their learning rates with experience. This process is sometimes studied by reversing an existing association between cues and rewards, and measuring the rate of relearning. Augmented reversal-learning, where learning rates increase with practice, can be an important component of behavioral flexibility; and may provide insight into higher cognition. Previous studies of reversal-learning in Drosophila have not measured learning rates, but have tended to focus on measuring gross deficits in reversal-learning, as the ratio of two timepoints. These studies have uncovered a diversity of mechanisms underlying reversal-learning, but natural genetic variation in this trait has yet to be assessed. We conducted a reversal-learning regime on a diverse panel of Drosophila melanogaster genotypes. We found highly significant genetic variation in their baseline ability to learn. We also found that they have a consistent, and strong (1.3×), increase in their learning speed with reversal. We found no evidence, however, that there was genetic variation in their ability to increase their learning rates with experience. This may suggest that Drosophila have a hitherto unrecognized ability to integrate acquired information, and improve their decision making; but that their mechanisms for doing so are under strong constraints.
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Affiliation(s)
- Brad R. Foley
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
| | - Paul Marjoram
- Department of Preventative Medicine, Keck School of Medicine of USC, Los Angeles, California, United States of America
| | - Sergey V. Nuzhdin
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California, United States of America
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22
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McConnell MW, Fitzpatrick MJ. 'Foraging' for a place to lay eggs: A genetic link between foraging behaviour and oviposition preferences. PLoS One 2017; 12:e0179362. [PMID: 28622389 PMCID: PMC5473555 DOI: 10.1371/journal.pone.0179362] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 05/30/2017] [Indexed: 11/18/2022] Open
Abstract
Gravid female arthropods in search of egg-laying substrates embark on foraging-like forays: they survey the environment assessing multiple patches, tasting each with their tarsi and proboscis, and then, if interested, they deposit an egg (or eggs). In fruit flies, Drosophila melanogaster, allelic variation in the foraging gene (for) underlies the rover/sitter foraging behaviour polymorphism. Rover flies (forR) are more active foragers (both within and between food patches) compared to sitters (fors). In nematodes, Caenorhabditis elegans, a mutation in egl-4, the ortholog of for, leads to aberrations in egg laying. Given this and the notion that females may 'forage' for a place to oviposit, we hypothesized that for may underlie egg-laying decisions in the fruit fly. Indeed, when given a choice between patches of low- and high-nutrient availability, rovers lay significantly more eggs on the low-nutrient patches than sitters and also a sitter mutant (fors2). We confirm the role of for by inducing rover-like oviposition preferences in a sitter fly using the transgenic overexpression of for-mRNA in the nervous system.
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Affiliation(s)
- Murray W. McConnell
- Integrative Behaviour & Neuroscience Group, Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Mark J. Fitzpatrick
- Integrative Behaviour & Neuroscience Group, Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON, Canada
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
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23
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Sokolowski HM, Vasquez OE, Unternaehrer E, Sokolowski DJ, Biergans SD, Atkinson L, Gonzalez A, Silveira PP, Levitan R, O'Donnell KJ, Steiner M, Kennedy J, Meaney MJ, Fleming AS, Sokolowski MB. The Drosophila foraging gene human orthologue PRKG1 predicts individual differences in the effects of early adversity on maternal sensitivity. COGNITIVE DEVELOPMENT 2016; 42:62-73. [PMID: 28827895 DOI: 10.1016/j.cogdev.2016.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
There is variation in the extent to which childhood adverse experience affects adult individual differences in maternal behavior. Genetic variation in the animal foraging gene, which encodes a cGMP-dependent protein kinase, contributes to variation in the responses of adult fruit flies, Drosophila melanogaster, to early life adversity and is also known to play a role in maternal behavior in social insects. Here we investigate genetic variation in the human foraging gene (PRKG1) as a predictor of individual differences in the effects of early adversity on maternal behavior in two cohorts. We show that the PRKG1 genetic polymorphism rs2043556 associates with maternal sensitivity towards their infants. We also show that rs2043556 moderates the association between self-reported childhood adversity of the mother and her later maternal sensitivity. Mothers with the TT allele of rs2043556 appeared buffered from the effects of early adversity, whereas mothers with the presence of a C allele were not. Our study used the Toronto Longitudinal Cohort (N=288 mother-16 month old infant pairs) and the Maternal Adversity and Vulnerability and Neurodevelopment Cohort (N=281 mother-18 month old infant pairs). Our findings expand the literature on the contributions of both genetics and gene-environment interactions to maternal sensitivity, a salient feature of the early environment relevant for child neurodevelopment.
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Affiliation(s)
- H Moriah Sokolowski
- Department of Psychology, Brain and Mind Institute, The University of Western Ontario, Westminster Hall, Room 325, London, Ontario, Canada, N6A 3K7
| | - Oscar E Vasquez
- Department of Ecology and Evolutionary Biology, 25 Wilcocks St. University of Toronto, Toronto, Ontario, Canada, M5S 3B2
| | - Eva Unternaehrer
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, 6875, Boulevard LaSalle, Montréal, Québec, Canada H4H 1R3
| | - Dustin J Sokolowski
- Department of Biology, University of Western, Ontario, Toronto, Canada, N6A 3K7
| | - Stephanie D Biergans
- Department of Ecology and Evolutionary Biology, 25 Wilcocks St. University of Toronto, Toronto, Ontario, Canada, M5S 3B2
| | - Leslie Atkinson
- Department of Psychology, Ryerson University, Toronto, Ontario, Canada, M5B2K3
| | - Andrea Gonzalez
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Department of Psychiatry and Behavioural Neurosciences, Offord Centre for Child Studies, McMaster Innovation Park, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1
| | - Patricia P Silveira
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, 6875, Boulevard LaSalle, Montréal, Québec, Canada H4H 1R3
| | - Robert Levitan
- Women's Health Concerns Clinic, St. Joseph's Healthcare, 50 Charlton Avenue East, Hamilton, Ontario, Canada, L8G 5E4
| | - Kieran J O'Donnell
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, 6875, Boulevard LaSalle, Montréal, Québec, Canada H4H 1R3.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), 180 Dundas St West, Suite 1400, Toronto, Ontario Canada M5G 1Z8
| | - Meir Steiner
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Department of Psychiatry and Behavioural Neurosciences, Offord Centre for Child Studies, McMaster Innovation Park, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1.,Women's Health Concerns Clinic, St. Joseph's Healthcare, 50 Charlton Avenue East, Hamilton, Ontario, Canada, L8G 5E4
| | - James Kennedy
- Department of Psychiatry, University of Toronto and Centre for Addiction an Mental Health, 33 Russell St, Toronto, Ontario, M5S 3M1
| | - Michael J Meaney
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, 6875, Boulevard LaSalle, Montréal, Québec, Canada H4H 1R3.,Singapore Institute for Clinical Science, Brenner Centre for Molecular Medicine 30 Medical Drive, Singapore 117609.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), 180 Dundas St West, Suite 1400, Toronto, Ontario Canada M5G 1Z8
| | - Alison S Fleming
- Department of Psychology, 100 St. George Street, Sidney Smith Hall Toronto, Ontario, Canada M5S 3G3
| | - Marla B Sokolowski
- Department of Ecology and Evolutionary Biology, 25 Wilcocks St. University of Toronto, Toronto, Ontario, Canada, M5S 3B2.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), 180 Dundas St West, Suite 1400, Toronto, Ontario Canada M5G 1Z8
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24
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cGMP-Dependent Protein Kinase Encoded by foraging Regulates Motor Axon Guidance in Drosophila by Suppressing Lola Function. J Neurosci 2016; 36:4635-46. [PMID: 27098704 DOI: 10.1523/jneurosci.3726-15.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 03/21/2016] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED Correct pathfinding and target recognition of a developing axon are exquisitely regulated processes that require multiple guidance factors. Among these factors, the second messengers, cAMP and cGMP, are known to be involved in establishing the guidance cues for axon growth through different intracellular signaling pathways. However, whether and how cGMP-dependent protein kinase (PKG) regulates axon guidance remains poorly understood. Here, we show that the motor axons of intersegmental nerve b (ISNb) in the Drosophila embryo display targeting defects during axon development in the absence of foraging(for), a gene encoding PKG.In vivo tag expression revealed PKG to be present in the ventral nerve code at late embryonic stages, supporting its function in embryonic axon guidance. Mechanistic studies showed that the transcription factor longitudinal lacking(lola) genetically interacts with for.PKG physically associates with the LolaT isoform via the C-terminal zinc-finger-containing domain. Overexpression of PKG leads to the cytoplasmic retention of LolaT in S2 cells, suggesting a role for PKG in mediating the nucleocytoplasmic trafficking of Lola. Together, these findings reveal a novel function of PKG in regulating the establishment of neuronal connectivity by sequestering Lola in the cytoplasm. SIGNIFICANCE STATEMENT Axon pathfinding and target recognition are important processes in the formation of specific neuronal connectivity, which rely upon precise coordinated deployment of multiple guidance factors. This paper reveals the role of cGMP-dependent protein kinase (PKG) in regulating the pathfinding and targeting of the developing axons in Drosophila Moreover, our study indicates that PKG regulates the cytoplasmic-nuclear trafficking of the transcription factor LolaT, suggesting a mechanism of PKG in directing motor axon guidance. These findings highlight a new function of PKG in axon guidance by suppressing a transcription factor.
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25
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Smid HM, Vet LE. The complexity of learning, memory and neural processes in an evolutionary ecological context. CURRENT OPINION IN INSECT SCIENCE 2016; 15:61-69. [PMID: 27436733 DOI: 10.1016/j.cois.2016.03.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 03/18/2016] [Accepted: 03/22/2016] [Indexed: 06/06/2023]
Abstract
The ability to learn and form memories is widespread among insects, but there exists considerable natural variation between species and populations in these traits. Variation manifests itself in the way information is stored in different memory forms. This review focuses on ecological factors such as environmental information, spatial aspects of foraging behavior and resource distribution that drive the evolution of this natural variation and discusses the role of different genes and neural networks. We conclude that at the level of individual, population or species, insect learning and memory cannot be described as good or bad. Rather, we argue that insects evolve tailor-made learning and memory types; they gate learned information into memories with high or low persistence. This way, they are prepared to learn and form memory to optimally deal with the specific ecologies of their foraging environments.
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Affiliation(s)
- Hans M Smid
- Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands
| | - Louise Em Vet
- Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands; Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.
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26
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Mannai S, Bitri L, Thany SH. cGMP/cGMP-dependent protein kinase pathway modulates nicotine-induced currents through the activation of α-bungarotoxin-insensitive nicotinic acetylcholine receptors from insect neurosecretory cells. J Neurochem 2016; 137:931-8. [PMID: 27059649 DOI: 10.1111/jnc.13633] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/24/2016] [Accepted: 03/24/2016] [Indexed: 11/28/2022]
Abstract
Insect neurosecretory cells, called dorsal unpaired median neurons, are known to express two α-bungarotoxin-insensitive nicotinic acetylcholine receptor (nAChR) subtypes, nAChR1 and nAChR2. It was demonstrated that nAChR1 was sensitive to cAMP/cAMP-dependent protein kinase (PKA) regulation, resulting in a modulation of nicotine currents. In this study, we show that cyclic guanosine monophosphate (cGMP)/cGMP-dependent protein kinase (PKG) pathway modulates nicotine-induced currents, as increased cGMP affects the second compound of the biphasic current-voltage curve, corresponding to the nAChR2 receptors. Indeed, maintaining the guanosine triphosphate level with 100 μM guanosine triphosphate-γ-S increased nicotine currents through nAChR2. We also demonstrated that inhibition of PKG activity with 0.2 μM (8R,9S,11S)-(-)-9-methoxy-carbamyl-8-methyl-2,3,9,10-tetrahydro-8,11-epoxy-1H,8H,11H-2,7b,11a-trizadibenzo-(a,g)-cycloocta-(c,d,e)-trinden-1-one (KT5823), a PKG specific inhibitor, reduced nicotine-induced current amplitudes. KT5823 effect on nicotine currents is associated with calcium (Ca(2+) ) activity because inhibition of Ca(2+) concentration with cadmium chloride (CdCl2 ) abolished KT5823-induced inhibition mediated by nAChR2. However, specific inhibition of nitric oxide-guanylyl cyclase (GC) complex by 10 μM 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) significantly increased nicotine-induced current amplitudes on both nAChR1 and nAChR2. These results suggest that nicotine-induced currents mediated by both α-bungarotoxin-insensitive nAChR1 and nAChR2 are coupled to the cGMP/PKG pathway. We propose that nicotinic acetylcholine receptor activation induces an increase in intracellular calcium (Ca(2+) ) concentration. Elevation of intracellular Ca(2+) results in the formation of Ca(2+) -calmodulin (CaM) complex, which activates guanylyl cyclase (GC) and/or adenylyl cyclase (AC). Ca(2+) -CaM complex could activate Ca(2+) calmodulin kinase II which could directly or indirectly modulate the nicotinic response. The mechanisms by which cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) interact remain unclear. We demonstrate that nicotine-induced currents are coupled to the cGMP/PKG pathway.
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Affiliation(s)
- Safa Mannai
- Université d'Orléans, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), UPRES EA, Rue de Chartres, Orléans, France.,Université de Tunis El Manar, Faculté des Sciences, Campus Universitaire Farhat Hached, Rommana Tunis, Tunisie
| | - Lofti Bitri
- Université de Tunis El Manar, Faculté des Sciences, Campus Universitaire Farhat Hached, Rommana Tunis, Tunisie
| | - Steeve H Thany
- Université d'Orléans, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), UPRES EA, Rue de Chartres, Orléans, France
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27
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Rohwedder A, Selcho M, Chassot B, Thum AS. Neuropeptide F neurons modulate sugar reward during associative olfactory learning ofDrosophilalarvae. J Comp Neurol 2015; 523:2637-64. [DOI: 10.1002/cne.23873] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 07/19/2015] [Accepted: 07/28/2015] [Indexed: 01/29/2023]
Affiliation(s)
- Astrid Rohwedder
- Department of Biology; University of Fribourg; Fribourg Switzerland
| | - Mareike Selcho
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter; University of Würzburg; Würzburg Germany
| | - Bérénice Chassot
- Department of Biology; University of Fribourg; Fribourg Switzerland
| | - Andreas S. Thum
- Department of Biology; University of Fribourg; Fribourg Switzerland
- Department of Biology; University of Konstanz; Konstanz Germany
- Zukunftskolleg; University of Konstanz; Konstanz Germany
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28
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Urquhart-Cronish M, Sokolowski MB. Gene-environment interplay in Drosophila melanogaster: chronic nutritional deprivation in larval life affects adult fecal output. JOURNAL OF INSECT PHYSIOLOGY 2014; 69:95-100. [PMID: 24929224 DOI: 10.1016/j.jinsphys.2014.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 06/01/2014] [Accepted: 06/05/2014] [Indexed: 06/03/2023]
Abstract
Life history consequences of stress in early life are varied and known to have lasting impacts on the fitness of an organism. Gene-environment interactions play a large role in how phenotypic differences are mediated by stressful conditions during development. Here we use natural allelic 'rover/sitter' variants of the foraging (for) gene and chronic early life nutrient deprivation to investigate gene-environment interactions on excretion phenotypes. Excretion assay analysis and a fully factorial nutritional regimen encompassing the larval and adult life cycle of Drosophila melanogaster were used to assess the effects of larval and adult nutritional stress on adult excretion phenotypes. Natural allelic variants of for exhibited differences in the number of fecal spots when they were nutritionally deprived as larvae and well fed as adults. for mediates the excretion response to chronic early-life nutritional stress in mated female, virgin female, and male rovers and sitters. Transgenic manipulations of for in a sitter genetic background under larval but not adult food deprivation increases the number of fecal spots. Our study shows that food deprivation early in life affects adult excretion phenotypes and these excretion differences are mediated by for.
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Affiliation(s)
| | - Marla B Sokolowski
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada; Child and Brain Development Program, Canadian Institute for Advanced Research, Toronto, ON M5G 1ZB, Canada.
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29
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Kohn NR, Reaume CJ, Moreno C, Burns JG, Sokolowski MB, Mery F. Social environment influences performance in a cognitive task in natural variants of the foraging gene. PLoS One 2013; 8:e81272. [PMID: 24349049 PMCID: PMC3861308 DOI: 10.1371/journal.pone.0081272] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 10/10/2013] [Indexed: 11/19/2022] Open
Abstract
In Drosophila melanogaster, natural genetic variation in the foraging gene affects the foraging behaviour of larval and adult flies, larval reward learning, adult visual learning, and adult aversive training tasks. Sitters (for(s)) are more sedentary and aggregate within food patches whereas rovers (for(R)) have greater movement within and between food patches, suggesting that these natural variants are likely to experience different social environments. We hypothesized that social context would differentially influence rover and sitter behaviour in a cognitive task. We measured adult rover and sitter performance in a classical olfactory training test in groups and alone. All flies were reared in groups, but fly training and testing were done alone and in groups. Sitters trained and tested in a group had significantly higher learning performances compared to sitters trained and tested alone. Rovers performed similarly when trained and tested alone and in a group. In other words, rovers learning ability is independent of group training and testing. This suggests that sitters may be more sensitive to the social context than rovers. These differences in learning performance can be altered by pharmacological manipulations of PKG activity levels, the foraging (for) gene's gene product. Learning and memory is also affected by the type of social interaction (being in a group of the same strain or in a group of a different strain) in rovers, but not in sitters. These results suggest that for mediates social learning and memory in D. melanogaster.
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Affiliation(s)
- Nancy R. Kohn
- Laboratoire Evolution, Génome et Spéciation, CNRS, Gif sur Yvette, France
- Department of Biology, University of Missouri–Saint Louis, Saint Louis, Missouri, United States of America
| | - Christopher J. Reaume
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Celine Moreno
- Laboratoire Evolution, Génome et Spéciation, CNRS, Gif sur Yvette, France
| | - James G. Burns
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Marla B. Sokolowski
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Frederic Mery
- Laboratoire Evolution, Génome et Spéciation, CNRS, Gif sur Yvette, France
- * E-mail:
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Tobback J, Verlinden H, Vuerinckx K, Vleugels R, Vanden Broeck J, Huybrechts R. Developmental- and food-dependent foraging transcript levels in the desert locust. INSECT SCIENCE 2013; 20:679-688. [PMID: 23956060 DOI: 10.1111/1744-7917.12012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/12/2012] [Indexed: 06/02/2023]
Abstract
Drastic changes in the environment during a lifetime require developmental and physiological flexibility to ensure animal survival. Desert locusts, Schistocerca gregaria, live in an extremely changeable environment, which alternates between periods of rainfall and abundant food and periods of drought and starvation. In order to survive, locusts display an extreme form of phenotypic plasticity that allows them to rapidly cope with these changing conditions by converting from a cryptic solitarious phase to a swarming, voracious gregarious phase. To accomplish this, locusts possess different conserved mediators of phenotypic plasticity. Recently, attention has been drawn to the possible roles of protein kinases in this process. In addition to cyclic AMP-dependent protein kinase (PKA), also cyclic GMP-dependent protein kinase (PKG), which was shown to be involved in changes of food-related behavior in a variety of insects, has been associated with locust phenotypic plasticity. In this article, we study the transcript levels of the S. gregaria orthologue of the foraging gene that encodes a PKG in different food-related, developmental and crowding conditions. Transcript levels of the S. gregaria foraging orthologue are highest in different parts of the gut and differ between isolated and crowd-reared locusts. They change when the availability of food is altered, display a distinct pattern with higher levels after a moult and decrease with age during postembryonic development.
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Affiliation(s)
- Julie Tobback
- Department of Biology, K.U.Leuven, Naamsestraat 59, 3000, Leuven, Belgium
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31
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Durisko Z, Dukas R. Effects of Early-Life Experience on Learning Ability in Fruit Flies. Ethology 2013. [DOI: 10.1111/eth.12168] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zachary Durisko
- Animal Behaviour Group; Department of Psychology, Neuroscience & Behaviour; McMaster University; Hamilton Ontario Canada
| | - Reuven Dukas
- Animal Behaviour Group; Department of Psychology, Neuroscience & Behaviour; McMaster University; Hamilton Ontario Canada
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Diegelmann S, Klagges B, Michels B, Schleyer M, Gerber B. Maggot learning and Synapsin function. ACTA ACUST UNITED AC 2013; 216:939-51. [PMID: 23447663 DOI: 10.1242/jeb.076208] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Drosophila larvae are focused on feeding and have few neurons. Within these bounds, however, there still are behavioural degrees of freedom. This review is devoted to what these elements of flexibility are, and how they come about. Regarding odour-food associative learning, the emerging working hypothesis is that when a mushroom body neuron is activated as a part of an odour-specific set of mushroom body neurons, and coincidently receives a reinforcement signal carried by aminergic neurons, the AC-cAMP-PKA cascade is triggered. One substrate of this cascade is Synapsin, and therefore this review features a general and comparative discussion of Synapsin function. Phosphorylation of Synapsin ensures an alteration of synaptic strength between this mushroom body neuron and its target neuron(s). If the trained odour is encountered again, the pattern of mushroom body neurons coding this odour is activated, such that their modified output now allows conditioned behaviour. However, such an activated memory trace does not automatically cause conditioned behaviour. Rather, in a process that remains off-line from behaviour, the larvae compare the value of the testing situation (based on gustatory input) with the value of the odour-activated memory trace (based on mushroom body output). The circuit towards appetitive conditioned behaviour is closed only if the memory trace suggests that tracking down the learned odour will lead to a place better than the current one. It is this expectation of a positive outcome that is the immediate cause of appetitive conditioned behaviour. Such conditioned search for reward corresponds to a view of aversive conditioned behaviour as conditioned escape from punishment, which is enabled only if there is something to escape from - much in the same way as we only search for things that are not there, and run for the emergency exit only when there is an emergency. One may now ask whether beyond 'value' additional information about reinforcement is contained in the memory trace, such as information about the kind and intensity of the reinforcer used. The Drosophila larva may allow us to develop satisfyingly detailed accounts of such mnemonic richness - if it exists.
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Affiliation(s)
- Sören Diegelmann
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, Brenneckestrasse 6, 39118 Magdeburg, Germany
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33
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Li L, Sase A, Patil S, Sunyer B, Höger H, Smalla KH, Stork O, Lubec G. Distinct set of kinases induced after retrieval of spatial memory discriminate memory modulation processes in the mouse hippocampus. Hippocampus 2013; 23:672-83. [PMID: 23536525 DOI: 10.1002/hipo.22127] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2013] [Indexed: 12/15/2022]
Abstract
Protein phosphorylation and dephosphorylation events play a key role in memory formation and various protein kinases and phosphatases have been firmly associated with memory performance. Here, we determined expression changes of protein kinases and phosphatases following retrieval of spatial memory in CD1 mice in a Morris Water Maze task, using antibody microarrays and confirmatory Western blot. Comparing changes following single and consecutive retrieval, we identified stably and differentially expressed kinases, some of which have never been implicated before in memory functions. On the basis of these findings we define a small signaling network associated with spatial memory retrieval. Moreover, we describe differential regulation and correlation of expression levels with behavioral performance of polo-like kinase 1. Together with its recently observed genetic association to autism-spectrum disorders our data suggest a role of this kinase in balancing preservation and flexibility of learned behavior.
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Affiliation(s)
- Lin Li
- Department of Pediatrics, Medical University of Vienna, Vienna, Austria
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Nitric oxide synthesis and cGMP production is important for neurite growth and synapse remodeling after axotomy. J Neurosci 2013; 33:5626-37. [PMID: 23536077 DOI: 10.1523/jneurosci.3659-12.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nitric oxide (NO) is an important signaling molecule with a variety of functions in the CNS, including a potential role in modulating neuronal growth and synapse formation. In the present study, we used tractable, identified neurons in the CNS of the pond snail Lymnaea stagnalis to study the role of endogenous NO signaling in neuronal growth and synaptic remodeling after nerve injury. Axonal damage of L. stagnalis neurons B1 and B2 induces extensive central growth of neurites that is accompanied by changes in existing electrical connections, the transient formation of novel electrical connections, and the formation of a novel excitatory chemical synapse from B2 to B1 neurons. Partial chronic inhibition of endogenous NO synthesis reduces neurite growth in NO-synthase-expressing B2, but has only minor effects on NOS-negative B1 neurons. Chronic application of an NO donor while inhibiting endogenous NO synthesis rescues neurite extension in B2 neurons and boosts growth of B1 neurons. Blocking soluble guanylate cyclase activity completely suppresses neurite extension and synaptic remodeling after nerve crush, demonstrating the importance of cGMP in these processes. Interestingly, inhibition of cGMP-dependent protein kinase only suppresses chemical synapse formation without effects on neuronal growth and electrical synapse remodeling. We conclude that NO signaling via cGMP is an important modulator of both neurite growth and synaptic remodeling after nerve crush. However, differential effects of cGMP-dependent protein kinase inhibition on neurite growth and synaptic remodeling suggest that these effects are mediated by separate signaling pathways.
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Milton SL, Dawson-Scully K. Alleviating brain stress: what alternative animal models have revealed about therapeutic targets for hypoxia and anoxia. FUTURE NEUROLOGY 2013; 8:287-301. [PMID: 25264428 DOI: 10.2217/fnl.13.12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
While the mammalian brain is highly dependent on oxygen, and can withstand only a few minutes without air, there are both vertebrate and invertebrate examples of anoxia tolerance. One example is the freshwater turtle, which can withstand days without oxygen, thus providing a vertebrate model with which to examine the physiology of anoxia tolerance without the pathology seen in mammalian ischemia/reperfusion studies. Insect models such as Drosophila melanogaster have additional advantages, such as short lifespans, low cost and well-described genetics. These models of anoxia tolerance share two common themes that enable survival without oxygen: entrance into a state of deep hypometabolism, and the suppression of cellular injury during anoxia and upon restoration of oxygen. The study of such models of anoxia tolerance, adapted through millions of years of evolution, may thus suggest protective pathways that could serve as therapeutic targets for diseases characterized by oxygen deprivation and ischemic/reperfusion injuries.
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Affiliation(s)
- Sarah L Milton
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA
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Kuntz S, Poeck B, Sokolowski MB, Strauss R. The visual orientation memory of Drosophila requires Foraging (PKG) upstream of Ignorant (RSK2) in ring neurons of the central complex. Learn Mem 2012; 19:337-40. [PMID: 22815538 DOI: 10.1101/lm.026369.112] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Orientation and navigation in a complex environment requires path planning and recall to exert goal-driven behavior. Walking Drosophila flies possess a visual orientation memory for attractive targets which is localized in the central complex of the adult brain. Here we show that this type of working memory requires the cGMP-dependent protein kinase encoded by the foraging gene in just one type of ellipsoid-body ring neurons. Moreover, genetic and epistatic interaction studies provide evidence that Foraging functions upstream of the Ignorant Ribosomal-S6 Kinase 2, thus revealing a novel neuronal signaling pathway necessary for this type of memory in Drosophila.
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Affiliation(s)
- Sara Kuntz
- Institut für Zoologie III-Neurobiologie, Johannes-Gutenberg Universität Mainz, D-55099 Mainz, Germany
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37
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Eschbach C, Cano C, Haberkern H, Schraut K, Guan C, Triphan T, Gerber B. Associative learning between odorants and mechanosensory punishment in larval Drosophila. ACTA ACUST UNITED AC 2012; 214:3897-905. [PMID: 22071180 DOI: 10.1242/jeb.060533] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We tested whether Drosophila larvae can associate odours with a mechanosensory disturbance as a punishment, using substrate vibration conveyed by a loudspeaker (buzz:). One odour (A) was presented with the buzz, while another odour (B) was presented without the buzz (A/B training). Then, animals were offered the choice between A and B. After reciprocal training (A/B), a second experimental group was tested in the same way. We found that larvae show conditioned escape from the previously punished odour. We further report an increase of associative performance scores with the number of punishments, and an increase according to the number of training cycles. Within the range tested (between 50 and 200 Hz), however, the pitch of the buzz does not apparently impact associative success. Last, but not least, we characterized odour-buzz memories with regard to the conditions under which they are behaviourally expressed--or not. In accordance with what has previously been found for associative learning between odours and bad taste (such as high concentration salt or quinine), we report that conditioned escape after odour-buzz learning is disabled if escape is not warranted, i.e. if no punishment to escape from is present during testing. Together with the already established paradigms for the association of odour and bad taste, the present assay offers the prospect of analysing how a relatively simple brain orchestrates memory and behaviour with regard to different kinds of 'bad' events.
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Affiliation(s)
- Claire Eschbach
- Universität Würzburg, Biozentrum, Neurobiologie und Genetik, Würzburg, Germany
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38
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Critical role for protein kinase A in the acquisition of gregarious behavior in the desert locust. Proc Natl Acad Sci U S A 2011; 109:E381-7. [PMID: 22184243 DOI: 10.1073/pnas.1114990109] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The mechanisms that integrate genetic and environmental information to coordinate the expression of complex phenotypes are little understood. We investigated the role of two protein kinases (PKs) in the population density-dependent transition to gregarious behavior that underlies swarm formation in desert locusts: the foraging gene product, a cGMP-dependent PK (PKG) implicated in switching between alternative group-related behaviors in several animal species; and cAMP-dependent PK (PKA), a signal transduction protein with a preeminent role in different forms of learning. Solitarious locusts acquire key behavioral characters of the swarming gregarious phase within just 1 to 4 h of forced crowding. Injecting the PKA inhibitor KT5720 before crowding prevented this transition, whereas injecting KT5823, an inhibitor of PKG, did not. Neither drug altered the behavior of long-term gregarious locusts. RNAi against foraging effectively reduced its expression in the central nervous system, but this did not prevent gregarization upon crowding. By contrast, solitarious locusts with an RNAi-induced reduction in PKA catalytic subunit C1 expression behaved less gregariously after crowding, and RNAi against the inhibitory R1 subunit promoted more extensive gregarization following a brief crowding period. A central role of PKA is congruent with the recent discovery that serotonin mediates gregarization in locusts and with findings in vertebrates that similarly implicate PKA in the capacity to cope with adverse life events. Our results show that PKA has been coopted into effecting the wide-ranging transformation from solitarious to gregarious behavior, with PKA-mediated behavioral plasticity resulting in an environmentally driven reorganization of a complex phenotype.
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39
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Reaume CJ, Sokolowski MB. Conservation of gene function in behaviour. Philos Trans R Soc Lond B Biol Sci 2011; 366:2100-10. [PMID: 21690128 DOI: 10.1098/rstb.2011.0028] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Behaviour genetic research has shown that a given gene or gene pathway can influence categorically similar behaviours in different species. Questions about the conservation of gene function in behaviour are increasingly tractable. This is owing to the surge of DNA and 'omics data, bioinformatic tools, as well as advances in technologies for behavioural phenotyping. Here, we discuss how gene function, as a hierarchical biological phenomenon, can be used to examine behavioural homology across species. The question can be addressed independently using different levels of investigation including the DNA sequence, the gene's position in a genetic pathway, spatial-temporal tissue expression and neural circuitry. Selected examples from the literature are used to illustrate this point. We will also discuss how qualitative and quantitative comparisons of the behavioural phenotype, its function and the importance of environmental and social context should be used in cross-species comparisons. We conclude that (i) there are homologous behaviours, (ii) they are hard to define and (iii) neurogenetics and genomics investigations should help in this endeavour.
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Affiliation(s)
- Christopher J Reaume
- Department of Biology, University of Toronto, Mississauga, Ontario, Canada, L5L 1C6
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40
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van Swinderen B. An assay for visual learning in individual Drosophila larvae. Cold Spring Harb Protoc 2011; 2011:1200-2. [PMID: 21969627 DOI: 10.1101/pdb.prot065888] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Vision is a major sensory modality in Drosophila behavior, with more than one-half of the Drosophila brain devoted to visual processing. The mechanisms of vision in Drosophila can now be studied in individuals and in populations of flies by using various paradigms. Simple strategies for conducting visual perception and learning studies consist of individual studies performed on single flies on solid supports (larvae on agar or adults in a T-maze) using a light/dark association paradigm. These approaches are quite easy to implement but are fairly limited in their ability to address questions of visual perception. Nevertheless, the simpler approaches treating vision in one dimension (light, dark) do provide effective paradigms for genetic analysis. This article describes a protocol for larval visual learning. Larvae are transferred back and forth between well-lit or dark agarose plates that either do or do not contain fructose (which is appetitive) as the unconditioned stimulus (US). Such appetitive larval visual memory is tested by tallying the time spent in light or dark quadrants of a plate (without a US).
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41
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Chen A, Kramer EF, Purpura L, Krill JL, Zars T, Dawson-Scully K. The influence of natural variation at the foraging gene on thermotolerance in adult Drosophila in a narrow temperature range. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011; 197:1113-8. [PMID: 21861180 DOI: 10.1007/s00359-011-0672-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 07/08/2011] [Accepted: 07/30/2011] [Indexed: 11/26/2022]
Abstract
Poikilothermic organisms such as insects have mechanisms to protect neural function under high temperature stress. Natural variation at the foraging (for) locus of the fruit fly, Drosophila melanogaster, encoding a cGMP-dependent protein kinase (PKG), influences neural thermotolerance in Drosophila larvae. The current study re-examines thermotolerance of adult flies to account for inconsistencies in the documented role of for during hyperthermia. We found that adult for (R) (rover) flies with high PKG activity were incapacitated faster under hyperthermic conditions of 39°C compared to their lower PKG activity counterparts for (s) and for (s2) (sitters), but not at higher temperatures. This indicates that lowered PKG activity promotes tolerance to heat stress, and that the for gene influences thermotolerance for a narrow range of temperatures in adult flies.
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Affiliation(s)
- Adam Chen
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
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42
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Fussnecker BL, McKenzie AM, Grozinger CM. cGMP modulates responses to queen mandibular pheromone in worker honey bees. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011; 197:939-48. [PMID: 21626397 DOI: 10.1007/s00359-011-0654-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 05/11/2011] [Accepted: 05/14/2011] [Indexed: 11/26/2022]
Abstract
Responses to social cues, such as pheromones, can be modified by genotype, physiology, or environmental context. Honey bee queens produce a pheromone (queen mandibular pheromone; QMP) which regulates aspects of worker bee behavior and physiology. Forager bees are less responsive to QMP than young bees engaged in brood care, suggesting that physiological changes associated with behavioral maturation modulate response to this pheromone. Since 3',5'-cyclic guanosine monophosphate (cGMP) is a major regulator of behavioral maturation in workers, we examined its role in modulating worker responses to QMP. Treatment with a cGMP analog resulted in significant reductions in both behavioral and physiological responses to QMP in young caged workers. Treatment significantly reduced attraction to QMP and inhibited the QMP-mediated increase in vitellogenin RNA levels in the fat bodies of worker bees. Genome-wide analysis of brain gene expression patterns demonstrated that cGMP has a larger effect on expression levels than QMP, and that QMP has specific effects in the presence of cGMP, suggesting that some responses to QMP may be dependent on an individual bees' physiological state. Our data suggest that cGMP-mediated processes play a role in modulating responses to QMP in honey bees at the behavioral, physiological, and molecular levels.
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Affiliation(s)
- Brendon L Fussnecker
- Department of Genetics, North Carolina State University, Box 7614, Raleigh 27695, USA.
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43
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Tobback J, Mommaerts V, Vandersmissen HP, Smagghe G, Huybrechts R. Age- and task-dependent foraging gene expression in the bumblebee Bombus terrestris. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2011; 76:30-42. [PMID: 21136525 DOI: 10.1002/arch.20401] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In eusocial insects, the division of labor within a colony, based on either age or size, is correlated with a differential foraging (for) gene expression and PKG activity. This article presents in the first part a study on the for gene, encoding a cGMP-dependent protein kinase (PKG) in the bumblebee Bombus terrestris. Cloning of the open reading frame allowed phylogenetic tracing, which showed conservation of PKGs among social insects. Our results confirm the proposed role for PKGs in division of labor. Btfor gene expression is significantly higher in the larger foragers compared with the smaller sized nurses. More importantly, we discovered an age-related decrease in Btfor expression in both nursing and foraging bumblebees. We therefore speculate that the presence of BtFOR is required for correct adaptation to new external stimuli and rapid learning for foraging. In a second series of experiments, worker bumblebees of B. terrestris were treated with two insecticides imidacloprid and kinoprene, which have shown to cause impaired foraging behavior. Compared with controls, only the latter treatment resulted in a decreased Btfor expression, which concurs with a stimulation of ovarian growth and a shift in labor toward nest-related tasks. The data are discussed in relation to Btfor expression in the complex physiological event of foraging and side-effects by pesticides.
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44
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Ribeiro AS, Eales BA, Biddle FG. Learning of paw preference in mice is strain dependent, gradual and based on short-term memory of previous reaches. Anim Behav 2011. [DOI: 10.1016/j.anbehav.2010.10.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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45
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Dawson-Scully K, Bukvic D, Chakaborty-Chatterjee M, Ferreira R, Milton SL, Sokolowski MB. Controlling anoxic tolerance in adult Drosophila via the cGMP-PKG pathway. ACTA ACUST UNITED AC 2010; 213:2410-6. [PMID: 20581270 DOI: 10.1242/jeb.041319] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In this study we identify a cGMP-dependent protein kinase (PKG) cascade as a biochemical pathway critical for controlling low-oxygen tolerance in the adult fruit fly, Drosophila melanogaster. Even though adult Drosophila can survive in 0% oxygen (anoxia) environments for hours, air with less than 2% oxygen rapidly induces locomotory failure resulting in an anoxic coma. We use natural genetic variation and an induced mutation in the foraging (for) gene, which encodes a Drosophila PKG, to demonstrate that the onset of anoxic coma is correlated with PKG activity. Flies that have lower PKG activity demonstrate a significant increase in time to the onset of anoxic coma. Further, in vivo pharmacological manipulations reveal that reducing either PKG or protein phosphatase 2A (PP2A) activity increases tolerance of behavior to acute hypoxic conditions. Alternatively, PKG activation and phosphodiesterase (PDE5/6) inhibition significantly reduce the time to the onset of anoxic coma. By manipulating these targets in paired combinations, we characterized a specific PKG cascade, with upstream and downstream components. Further, using genetic variants of PKG expression/activity subjected to chronic anoxia over 6 h, approximately 50% of animals with higher PKG activity survive, while only approximately 25% of those with lower PKG activity survive after a 24 h recovery. Therefore, in this report we describe the PKG pathway and the differential protection of function vs survival in a critically low oxygen environment.
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Affiliation(s)
- K Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA.
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46
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Drosophila larvae establish appetitive olfactory memories via mushroom body neurons of embryonic origin. J Neurosci 2010; 30:10655-66. [PMID: 20702697 DOI: 10.1523/jneurosci.1281-10.2010] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Insect mushroom bodies are required for diverse behavioral functions, including odor learning and memory. Using the numerically simple olfactory pathway of the Drosophila melanogaster larva, we provide evidence that the formation of appetitive olfactory associations relies on embryonic-born intrinsic mushroom body neurons (Kenyon cells). The participation of larval-born Kenyon cells, i.e., neurons that become gradually integrated in the developing mushroom body during larval life, in this task is unlikely. These data provide important insights into how a small set of identified Kenyon cells can store and integrate olfactory information in a developing brain. To investigate possible functional subdivisions of the larval mushroom body, we anatomically disentangle its input and output neurons at the single-cell level. Based on this approach, we define 10 subdomains of the larval mushroom body that may be implicated in mediating specific interactions between the olfactory pathway, modulatory neurons, and neuronal output.
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47
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Lucas C, Kornfein R, Chakaborty-Chatterjee M, Schonfeld J, Geva N, Sokolowski MB, Ayali A. The locust foraging gene. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2010; 74:52-66. [PMID: 20422718 DOI: 10.1002/arch.20363] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Our knowledge of how genes act on the nervous system in response to the environment to generate behavioral plasticity is limited. A number of recent advancements in this area concern food-related behaviors and a specific gene family called foraging (for), which encodes a cGMP-dependent protein kinase (PKG). The desert locust (Schistocerca gregaria) is notorious for its destructive feeding and long-term migratory behavior. Locust phase polyphenism is an extreme example of environmentally induced behavioral plasticity. In response to changes in population density, locusts dramatically alter their behavior, from solitary and relatively sedentary behavior to active aggregation and swarming. Very little is known about the molecular and genetic basis of this striking behavioral phenomenon. Here we initiated studies into the locust for gene by identifying, cloning, and studying expression of the gene in the locust brain. We determined the phylogenetic relationships between the locust PKG and other known PKG proteins in insects. FOR expression was found to be confined to neurons of the anterior midline of the brain, the pars intercerebralis. Our results suggest that differences in PKG enzyme activity are correlated to well-established phase-related behavioral differences. These results lay the groundwork for functional studies of the locust for gene and its possible relations to locust phase polyphenism.
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Affiliation(s)
- C Lucas
- Department of Biology, University of Toronto, Mississauga, Ontario, Canada
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Zars T. Short-term memories in Drosophila are governed by general and specific genetic systems. Learn Mem 2010; 17:246-51. [PMID: 20418404 DOI: 10.1101/lm.1706110] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In a dynamic environment, there is an adaptive value in the ability of animals to acquire and express memories. That both simple and complex animals can learn is therefore not surprising. How animals have solved this problem genetically and anatomically probably lies somewhere in a range between a single molecular/anatomical mechanism that applies to all situations and a specialized mechanism for each learning situation. With an intermediate level of nervous system complexity, the fruit fly Drosophila has both general and specific resources to support different short-term memories. Some biochemical/cellular mechanisms are common between learning situations, indicating that flies do not have a dedicated system for each learning context. The opposite possible extreme does not apply to Drosophila either. Specialization in some biochemical and anatomical terms suggests that there is not a single learning mechanism that applies to all conditions. The distributed basis of learning in Drosophila implies that these systems were independently selected.
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Affiliation(s)
- Troy Zars
- Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211, USA.
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Abstract
Deciphering the genetic and neurobiological underpinnings of social behavior is a difficult task. Simple model organisms such as C. elegans, Drosophila, and social insects display a wealth of social behaviors similar to those in more complex animals, including social dominance, group decision making, learning from experienced individuals, and foraging in groups. Although the study of social interactions is still in its infancy, the ability to assess the contributions of gene expression, neural circuitry, and the environment in response to social context in these simple model organisms is unsurpassed. Here, I take a comparative approach, discussing selected examples of social behavior across species and highlighting the common themes that emerge.
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Lucas C, Hughson BN, Sokolowski MB. Job switching in ants: Role of a kinase. Commun Integr Biol 2010; 3:6-8. [PMID: 20539773 PMCID: PMC2881231 DOI: 10.4161/cib.3.1.9723] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Accepted: 08/03/2009] [Indexed: 11/19/2022] Open
Abstract
Reproductive division of labor is a defining characteristic of eusociality in insect societies. The task of reproduction is performed by the fertile males and queens of the colony, while the non-fertile female worker caste performs all other tasks related to colony upkeep, foraging and nest defence. Division of labor, or polyethism, within the worker caste is organized such that specific tasks are performed by discrete groups of individuals. Ordinarily, workers of one group will not participate in the tasks of other groups making the groups of workers behaviorally distinct. In some eusocial species, this has led to the evolution of a remarkable diversity of subcaste morphologies within the worker caste, and a division of labor amongst the subcastes. This caste polyethism is best represented in many species of ants where a smaller-bodied minor subcaste typically performs foraging duties while larger individuals of the major subcaste are tasked with nest defence. Recent work suggests that polyethism in the worker caste is influenced by an evolutionarily conserved, yet diversely regulated, gene called foraging (for), which encodes a cGMP-dependent protein kinase (PKG). Additionally, flexibility in the activity of this enzyme allows for workers from one task group to assist the workers of other task groups in times of need during the colony's life.In a recent article, Lucas and Sokolowski1 report that PKG mediates behavioral flexibility in the minor and major worker subcastes of the ant Pheidole pallidula. By changing the task-specific stimulus (a mealworm to induce foraging or alien intruders to induce defensive behavior) or pharmacologically manipulating PKG activity, they are able to alter the behavior of both subcastes. They also show differences in the spatial localization of the FOR protein in minor and major brains. Furthermore, manipulation of ppfor activity levels in the brain alters the behavior of both P. pallidula subcastes. The foraging gene is thus emerging as a major player in regulating the flexibility of responses to environmental change.
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Affiliation(s)
- Christophe Lucas
- Department of Ecology and Evolution; University of Lausanne; Lausanne Switzerland
| | - Bryon N Hughson
- Department of Biology; University of Toronto; Mississauga, ON Canada
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