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Scott D. INHIBITION OF FEMALE DROSOPHILA MELANOGASTER REMATING BY A SEMINAL FLUID PROTEIN (ESTERASE 6). Evolution 2017; 40:1084-1091. [PMID: 28556223 DOI: 10.1111/j.1558-5646.1986.tb00575.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/1985] [Accepted: 06/02/1986] [Indexed: 11/29/2022]
Abstract
Recent experiments have indicated that EST 6 transferred to D. melanogaster females during copulation mediates a large decrease in their attractiveness within the first six hours after mating. This decrease in attractiveness could increase the male's fitness if it were associated with less frequent remating by their mates, because a large proportion of the first male's sperm is lost if a female remates within one day. Here, I confirm a strong EST 6 influence on the receptivity of mated females; females with EST 6+ first mates remate significantly less frequently between 6 and 18 hours after mating than females that have not received EST 6 in the ejaculate. However, the previously observed effect of EST 6 on the attractiveness of mated females could not be substantiated. Transfer of EST 6 did not lead to a significant difference in attractiveness between EST 6°-and EST 6+ -mated females at any time within the first 10 hours after mating for females from either of two strains.
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Affiliation(s)
- David Scott
- Biology Department, Indiana University, Bloomington, IN, 47405
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2
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I Believe I Can Fly!: Use of Drosophila as a Model Organism in Neuropsychopharmacology Research. Neuropsychopharmacology 2016; 41:1439-46. [PMID: 26576740 PMCID: PMC4832023 DOI: 10.1038/npp.2015.322] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 10/14/2015] [Accepted: 10/16/2015] [Indexed: 01/03/2023]
Abstract
Neuropsychiatric disorders are of complex etiology, often including a large genetic component. In order to help identify and study the molecular and physiological mechanisms that such genes participate in, numerous animal models have been established in a variety of species. Over the past decade, this has increasingly included the vinegar fly, Drosophila melanogaster. Here, we outline why we study an invertebrate organism in the context of neuropsychiatric disorders, and we discuss how we can gain insight from studies in Drosophila. We focus on a few disorders and findings to make the larger point that modeling these diseases in flies can have both mechanistic and predictive validity. Highlighting some translational examples, we underline the fact that their brains works more like ours than one would have anticipated.
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Abstract
Post-transcriptional pre-mRNA splicing has emerged as a critical step in the gene expression cascade greatly influencing diversification and spatiotemporal control of the proteome in many developmental processes. The percentage of genes targeted by alternative splicing (AS) is shown to be over 95% in humans and 60% in Drosophila. Therefore, it is evident that deregulation of this process underlies many genetic diseases. Among all tissues, the brain shows the highest transcriptome diversity, which is not surprising in view of the complex inter- and intracellular networks underlying the development of this organ. Reports of isoforms known to function at different steps during Drosophila nervous system development are rapidly increasing as well as knowledge on their regulation and function, highlighting the role of AS during neuronal development in Drosophila.
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Affiliation(s)
- Carmen Mohr
- Institute of Human Genetics, University Medical Center Freiburg , Freiburg , Germany
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Neuroethology of male courtship in Drosophila: from the gene to behavior. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:251-64. [PMID: 24567257 DOI: 10.1007/s00359-014-0891-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 08/29/2013] [Accepted: 02/11/2014] [Indexed: 01/01/2023]
Abstract
Neurogenetic analyses in the fruit fly Drosophila melanogaster revealed that gendered behaviors, including courtship, are underpinned by sexually dimorphic neural circuitries, whose development is directed in a sex-specific manner by transcription factor genes, fruitless (fru) and doublesex (dsx), two core members composing the sex-determination cascade. Via chromatin modification the Fru proteins translated specifically in the male nervous system lead the fru-expressing neurons to take on the male fate, as manifested by their male-specific survival or male-specific neurite formations. One such male-specific neuron group, P1, was shown to be activated when the male taps the female abdomen. Moreover, when artificially activated, P1 neurons are sufficient to induce the entire repertoire of the male courtship ritual. These studies provide a conceptual framework for understanding how the genetic code for innate behavior can be embodied in the neuronal substrate.
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An Epigenetic Switch of the Brain Sex as a Basis of Gendered Behavior in Drosophila. EPIGENETIC SHAPING OF SOCIOSEXUAL INTERACTIONS - FROM PLANTS TO HUMANS 2014; 86:45-63. [DOI: 10.1016/b978-0-12-800222-3.00003-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Abstract
In Drosophila melanogaster, the causal links among a complex behaviour, single neurons and single genes can be demonstrated through experimental manipulations. A key player in establishing the male courtship circuitry is the fruitless (fru) gene, the expression of which yields the FruM proteins in a subset of male but not female neurons. FruM probably regulates chromatin states, leading to single-neuron sex differences and, consequently, a sexually dimorphic circuitry. The mutual connections among fru-expressing neurons--including primary sensory afferents, central interneurons such as the P1 neuron cluster that triggers courtship, and courtship motor pattern generators--probably form the core portion of the male courtship circuitry.
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7
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Latham KL, Liu YS, Taylor BJ. A small cohort of FRU(M) and Engrailed-expressing neurons mediate successful copulation in Drosophila melanogaster. BMC Neurosci 2013; 14:57. [PMID: 23688386 PMCID: PMC3664081 DOI: 10.1186/1471-2202-14-57] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 05/14/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In Drosophila, male flies require the expression of the male-specific Fruitless protein (FRU(M)) within the developing pupal and adult nervous system in order to produce male courtship and copulation behaviors. Recent evidence has shown that specific subsets of FRU(M) neurons are necessary for particular steps of courtship and copulation. In these neurons, FRU(M) function has been shown to be important for determining sex-specific neuronal characteristics, such as neurotransmitter profile and morphology. RESULTS We identified a small cohort of FRU(M) interneurons in the brain and ventral nerve cord by their co-expression with the transcription factor Engrailed (En). We used an En-GAL4 driver to express a fru(M) RNAi construct in order to selectively deplete FRU(M) in these En/FRU(M) co-expressing neurons. In courtship and copulation tests, these males performed male courtship at wild-type levels but were frequently sterile. Sterility was a behavioral phenotype as these En-fru(M)RNAi males were less able to convert a copulation attempt into a stable copulation, or did not maintain copulation for long enough to transfer sperm and/or seminal fluid. CONCLUSIONS We have identified a population of interneurons necessary for successful copulation in Drosophila. These data confirm a model in which subsets of FRU(M) neurons participate in independent neuronal circuits necessary for individual steps of male behavior. In addition, we have determined that these neurons in wild-type males have homologues in females and fru mutants, with similar placement, projection patterns, and neurochemical profiles.
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Affiliation(s)
- Kristin L Latham
- Department of Zoology, Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR 97331-2914, USA.
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Chu Y, Yang E, Schinaman JM, Chahda JS, Sousa-Neves R. Genetic analysis of mate discrimination in Drosophila simulans. Evolution 2013; 67:2335-47. [PMID: 23888855 DOI: 10.1111/evo.12115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Accepted: 03/19/2013] [Indexed: 11/29/2022]
Abstract
Courtship is an elaborate behavior that conveys information about the identity of animal species and suitability of individual males as mates. In Drosophila, there is extensive evidence that females are capable of evaluating and comparing male courtships, and accepting or rejecting males as mates. These relatively simple responses minimize random sexual encounters involving subpar conspecific males and heterospecific males, and over generations can potentially select novel physical and behavioral traits. Despite its evolutionary and behavioral significance, little is still known about the genes involved in mating choice and how choices for novel males and females arise during evolution. Drosophila simulans and Drosophila sechellia are two recently diverged species of Drosophila in which females have a preference for conspecific males. Here we analyzed a total of 1748 F2 hybrid females between these two species and found a small number of dominant genes controlling the preference for D. simulans males. We also mapped two redundant X-linked loci of mating choice, Macho-XA and Macho-XB, and show that neither one is required for female attractiveness. Together, our results reveal part of the genetic architecture that allows D. simulans females to recognize, mate, and successfully generate progenies with D. simulans males.
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Affiliation(s)
- Y Chu
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, USA
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Ziegler AB, Berthelot-Grosjean M, Grosjean Y. The smell of love in Drosophila. Front Physiol 2013; 4:72. [PMID: 23576993 PMCID: PMC3617446 DOI: 10.3389/fphys.2013.00072] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Accepted: 03/21/2013] [Indexed: 01/16/2023] Open
Abstract
Odors are key sensory signals for social communication and food search in animals including insects. Drosophila melanogaster, is a powerful neurogenetic model commonly used to reveal molecular and cellular mechanisms involved in odorant detection. Males use olfaction together with other sensory modalities to find their mates. Here, we review known olfactory signals, their related olfactory receptors, and the corresponding neuronal architecture impacting courtship. OR67d receptor detects 11-cis-Vaccenyl Acetate (cVA), a male specific pheromone transferred to the female during copulation. Transferred cVA is able to reduce female attractiveness for other males after mating, and is also suspected to decrease male-male courtship. cVA can also serve as an aggregation signal, maybe through another OR. OR47b was shown to be activated by fly odors, and to enhance courtship depending on taste pheromones. IR84a detects phenylacetic acid (PAA) and phenylacetaldehyde (PA). These two odors are not pheromones produced by flies, but are present in various fly food sources. PAA enhances male courtship, acting as a food aphrodisiac. Drosophila males have thus developed complementary olfactory strategies to help them to select their mates.
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Affiliation(s)
- Anna B Ziegler
- CNRS, Centre des Sciences du Goût et de l'Alimentation, UMR-6265 Dijon, France ; INRA, Centre des Sciences du Goût et de l'Alimentation, UMR-1324 Dijon, France ; UMR, Centre des Sciences du Goût et de l'Alimentation, Université de Bourgogne Dijon, France
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Zanini D, Jallon JM, Rabinow L, Samson ML. Deletion of theDrosophilaneuronal genefound in neuronsdisrupts brain anatomy and male courtship. GENES BRAIN AND BEHAVIOR 2012; 11:819-27. [DOI: 10.1111/j.1601-183x.2012.00817.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/18/2012] [Accepted: 06/25/2012] [Indexed: 12/18/2022]
Affiliation(s)
- D. Zanini
- UMR 8195, Centre de Neurosciences Paris-Sud; Univ Paris-Sud; Orsay; F-91405; Cedex; France
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Meissner GW, Manoli DS, Chavez JF, Knapp JM, Lin TL, Stevens RJ, Mellert DJ, Tran DH, Baker BS. Functional dissection of the neural substrates for sexual behaviors in Drosophila melanogaster. Genetics 2011; 189:195-211. [PMID: 21705753 PMCID: PMC3176112 DOI: 10.1534/genetics.111.129940] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 06/13/2011] [Indexed: 11/18/2022] Open
Abstract
The male-specific Fruitless proteins (FruM) act to establish the potential for male courtship behavior in Drosophila melanogaster and are expressed in small groups of neurons throughout the nervous system. We screened ∼1000 GAL4 lines, using assays for general courtship, male-male interactions, and male fertility to determine the phenotypes resulting from the GAL4-driven inhibition of FruM expression in subsets of these neurons. A battery of secondary assays showed that the phenotypic classes of GAL4 lines could be divided into subgroups on the basis of additional neurobiological and behavioral criteria. For example, in some lines, restoration of FruM expression in cholinergic neurons restores fertility or reduces male-male courtship. Persistent chains of males courting each other in some lines results from males courting both sexes indiscriminately, whereas in other lines this phenotype results from apparent habituation deficits. Inhibition of ectopic FruM expression in females, in populations of neurons where FruM is necessary for male fertility, can rescue female infertility. To identify the neurons responsible for some of the observed behavioral alterations, we determined the overlap between the identified GAL4 lines and endogenous FruM expression in lines with fertility defects. The GAL4 lines causing fertility defects generally had widespread overlap with FruM expression in many regions of the nervous system, suggesting likely redundant FruM-expressing neuronal pathways capable of conferring male fertility. From associations between the screened behaviors, we propose a functional model for courtship initiation.
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Affiliation(s)
- Geoffrey W. Meissner
- Neurosciences Program, and
- Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, Virginia 20147
| | | | - Jose F. Chavez
- Department of Biology, Stanford University, Stanford, California 94305
| | - Jon-Michael Knapp
- Neurosciences Program, and
- Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, Virginia 20147
| | - Tasha L. Lin
- Department of Biology, Stanford University, Stanford, California 94305
| | - Robin J. Stevens
- Department of Biology, Stanford University, Stanford, California 94305
| | - David J. Mellert
- Department of Biology, Stanford University, Stanford, California 94305
- Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, Virginia 20147
| | - David H. Tran
- Department of Biology, Stanford University, Stanford, California 94305
| | - Bruce S. Baker
- Neurosciences Program, and
- Department of Biology, Stanford University, Stanford, California 94305
- Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, Virginia 20147
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Pan Y, Robinett CC, Baker BS. Turning males on: activation of male courtship behavior in Drosophila melanogaster. PLoS One 2011; 6:e21144. [PMID: 21731661 PMCID: PMC3120818 DOI: 10.1371/journal.pone.0021144] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 05/20/2011] [Indexed: 11/18/2022] Open
Abstract
The innate sexual behaviors of Drosophila melanogaster males are an attractive system for elucidating how complex behavior patterns are generated. The potential for male sexual behavior in D. melanogaster is specified by the fruitless (fru) and doublesex (dsx) sex regulatory genes. We used the temperature-sensitive activator dTRPA1 to probe the roles of fru(M)- and dsx-expressing neurons in male courtship behaviors. Almost all steps of courtship, from courtship song to ejaculation, can be induced at very high levels through activation of either all fru(M) or all dsx neurons in solitary males. Detailed characterizations reveal different roles for fru(M) and dsx in male courtship. Surprisingly, the system for mate discrimination still works well when all dsx neurons are activated, but is impaired when all fru(M) neurons are activated. Most strikingly, we provide evidence for a fru(M)-independent courtship pathway that is primarily vision dependent.
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Affiliation(s)
- Yufeng Pan
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Carmen C. Robinett
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Bruce S. Baker
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
- * E-mail:
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von Philipsborn AC, Liu T, Yu JY, Masser C, Bidaye SS, Dickson BJ. Neuronal control of Drosophila courtship song. Neuron 2011; 69:509-22. [PMID: 21315261 DOI: 10.1016/j.neuron.2011.01.011] [Citation(s) in RCA: 239] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2011] [Indexed: 10/18/2022]
Abstract
The courtship song of the Drosophila male serves as a genetically tractable model for the investigation of the neural mechanisms of decision-making, action selection, and motor pattern generation. Singing has been causally linked to the activity of the set of neurons that express the sex-specific fru transcripts, but the specific neurons involved have not been identified. Here we identify five distinct classes of fru neuron that trigger or compose the song. Our data suggest that P1 and pIP10 neurons in the brain mediate the decision to sing, and to act upon this decision, while the thoracic neurons dPR1, vPR6, and vMS11 are components of a central pattern generator that times and shapes the song's pulses. These neurons are potentially connected in a functional circuit, with the descending pIP10 neuron linking the brain and thoracic song centers. Sexual dimorphisms in each of these neurons may explain why only males sing.
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Rubinstein CD, Rivlin PK, Hoy RR. Genetic feminization of the thoracic nervous system disrupts courtship song in male Drosophila melanogaster. J Neurogenet 2010; 24:234-45. [PMID: 20919857 PMCID: PMC3056398 DOI: 10.3109/01677063.2010.519805] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Despite the growing research investigating the sex-specific organization of courtship behavior in Drosophila melanogaster, much remains to be understood about the sex-specific organization of the motor circuit that drives this behavior. To investigate the sex-specification of a tightly patterned component of courtship behavior, courtship song, the authors used the GAL4/UAS targeted gene expression system to feminize the ventral ganglia in male Drosophila and analyzed the acoustic properties of courtship song. More specifically, the authors used the thoracic-specifying teashirt promoter (tsh(GAL4)) to express feminizing transgenes specifically in the ventral ganglia. When tsh(GAL4) drove expression of transformer (tra), males were unable to produce prolonged wing extensions. Transgenic expression of an RNAi construct directed against male-specific fruitless (fru(M)) transcripts resulted in normal wing extension, but highly defective courtship song, with 58% of males failing to generate detectable courtship song. Of those that did sing, widths of individual pulses were significantly broader than controls, suggesting thoracic fru(M) function serves to mediate proprioceptive-dependent wing vibration damping during pulse song. However, the most critical signal in the song, the interpulse interval, remained intact. The inability to phenocopy this effect by reducing fru(M) expression in motor neurons and proprioceptive neurons suggests thoracic interneurons require fru(M) for proper pulse song execution and patterning of pulse structure, but not for pulse timing. This provides evidence that genes establishing sex-specific activation of complex behaviors may also be used in establishing pattern-generating motor networks underlying these sex-specific behaviors.
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Affiliation(s)
- C Dustin Rubinstein
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York 14850, USA.
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Rideout EJ, Dornan AJ, Neville MC, Eadie S, Goodwin SF. Control of sexual differentiation and behavior by the doublesex gene in Drosophila melanogaster. Nat Neurosci 2010; 13:458-66. [PMID: 20305646 PMCID: PMC3092424 DOI: 10.1038/nn.2515] [Citation(s) in RCA: 244] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 02/09/2010] [Indexed: 01/07/2023]
Abstract
Doublesex proteins, which are part of the structurally and functionally conserved Dmrt gene family, are important for sex determination throughout the animal kingdom. We inserted Gal4 into the doublesex (dsx) locus of Drosophila melanogaster, allowing us to visualize and manipulate cells expressing dsx in various tissues. In the nervous system, we detected differences between the sexes in dsx-positive neuronal numbers, axonal projections and synaptic density. We found that dsx was required for the development of male-specific neurons that coexpressed fruitless (fru), a regulator of male sexual behavior. We propose that dsx and fru act together to form the neuronal framework necessary for male sexual behavior. We found that disrupting dsx neuronal function had profound effects on male sexual behavior. Furthermore, our results suggest that dsx-positive neurons are involved in pre- to post-copulatory female reproductive behaviors.
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Affiliation(s)
- Elizabeth J Rideout
- Faculty of Biomedical and Life Sciences, Integrative and Systems Biology, University of Glasgow, Glasgow, UK
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Moran CN, Kyriacou CP. Functional neurogenomics of the courtship song of male Drosophila melanogaster. Cortex 2009; 45:18-34. [DOI: 10.1016/j.cortex.2008.05.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 01/17/2008] [Accepted: 05/25/2008] [Indexed: 11/27/2022]
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Abstract
Decisions about whom to mate with can sometimes be difficult, but making the right choice is critical for an animal's reproductive success. The ubiquitous fruit fly, Drosophila, is clearly very good at making these decisions. Upon encountering another fly, a male may or may not choose to court. He estimates his chances of success primarily on the basis of pheromone signals and previous courtship experience. The female decides whether to accept or reject the male, depending on her perception of his pheromone and acoustic signals, as well as her own readiness to mate. This simple and genetically tractable system provides an excellent model to explore the neurobiology of decision making.
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Affiliation(s)
- Barry J Dickson
- Research Institute of Molecular Pathology, Doktor Bohr-gasse 7, A-1030 Vienna, Austria.
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Abstract
The passing of Seymour Benzer has inspired various retrospectives on his scientific career, and much attention has been paid to his inauguration of single-gene mutant studies of behavior in the fruitfly Drosophila melanogaster. Studies of genes and behavior actually go back to the beginnings of genetics. The end of the era marked by Benzer's life offers a good opportunity to look back at the origins of the field he influenced so profoundly.
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Sanders LE, Arbeitman MN. Doublesex establishes sexual dimorphism in the Drosophila central nervous system in an isoform-dependent manner by directing cell number. Dev Biol 2008; 320:378-90. [PMID: 18599032 DOI: 10.1016/j.ydbio.2008.05.543] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 05/13/2008] [Accepted: 05/20/2008] [Indexed: 02/05/2023]
Abstract
doublesex (dsx) encodes sex-specific transcription factors (DSX(F) in females and DSX(M) in males) that act at the bottom of the Drosophila somatic sex determination hierarchy. dsx, which is conserved among diverse taxa, is responsible for directing all aspects of Drosophila somatic sexual differentiation outside the nervous system. The role of dsx in the nervous system remainsminimally understood. Here, the mechanisms by which DSX acts to establish dimorphism in the central nervous system were examined. This study shows that the number of DSX-expressing cells in the central nervous system is sexually dimorphic during both pupal and adult stages. Additionally, the number of DSX-expressing cells depends on both the amount of DSX and the isoform present. One cluster of DSX-expressing neurons in the ventral nerve cord undergoes female-specific cell death that is DSX(F)-dependent. Another DSX-expressing cluster in the posterior brain undergoes more cell divisions in males than in females. Additionally, early in development, DSX(M) is present in a portion of the neural circuitry in which the male-specific product of fruitless (fru) is produced, in a region that has been shown to be critical for sex-specific behaviors. This study demonstrates that DSX(M) and FRU(M) expression patterns are established independent of each other in the regions of the central nervous system examined. In addition to the known role of dsx in establishing sexual dimorphism outside the central nervous system, the results demonstrate that DSX establishes sex-specific differences in neural circuitry by regulating the number of neurons using distinct mechanisms.
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Affiliation(s)
- Laura E Sanders
- Sections of Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
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Sex-Specific Control and Tuning of the Pattern Generator for Courtship Song in Drosophila. Cell 2008; 133:354-63. [DOI: 10.1016/j.cell.2008.01.050] [Citation(s) in RCA: 237] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 12/05/2007] [Accepted: 01/29/2008] [Indexed: 11/23/2022]
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Abstract
The reproductive biology of Drosophila melanogaster is described and critically discussed, primarily with regard to genetic studies of sex-specific behavior and its neural underpinnings. The investigatory history of this system includes, in addition to a host of recent neurobiological analyses of reproductive phenotypes, studies of mating as well as the behaviors leading up to that event. Courtship and mating have been delved into mostly with regard to male-specific behavior and biology, although a small number of studies has also pointed to the neural substrates of female reproduction. Sensory influences on interactions between courting flies have long been studied, partly by application of mutants and partly by surgical experiments. More recently, molecular-genetic approaches to sensations passing between flies in reproductive contexts have aimed to "dissect" further the meaning of separate sensory modalities. Notable among these are olfactory and contact-chemosensory stimuli, which perhaps have received an inordinate amount of attention in terms of the possibility that they could comprise the key cues involved in triggering and sustaining courtship actions. But visual and auditory stimuli are heavily involved as well--appreciated mainly from older experiments, but analyzable further using elementary approaches (single-gene mutations mutants and surgeries), as well as by applying the molecularly defined factors alluded to above. Regarding regulation of reproductive behavior by components of Drosophila's central nervous system (CNS), once again significant invigoration of the relevant inquiries has been stimulated and propelled by identification and application of molecular-genetic materials. A distinct plurality of the tools applied involves transposons inserted in the fly's chromosomes, defining "enhancer-trap" strains that can be used to label various portions of the nervous system and, in parallel, disrupt their structure and function by "driving" companion transgenes predesigned for these experimental purposes. Thus, certain components of interneuronal routes, functioning along pathways whose starting points are sensory reception by the peripheral nervous system (PNS), have been manipulated to enhance appreciation of sexually important sensory modalities, as well as to promote understanding of where such inputs end up within the CNS: Where are reproductively related stimuli processed, such that different kinds of sensation would putatively be integrated to mediate sex-specific behavioral readouts? In line with generic sensory studies that have tended to concentrate on chemical stimuli, PNS-to-CNS pathways focused upon in reproductive experiments relying on genic enhancers have mostly involved smell and taste. Enhancer traps have also been applied to disrupt various regions within the CNS to ask about the various ganglia, and portions thereof, that contribute to male- or female-specific behavior. These manipulations have encompassed structural or functional disruptions of such regions as well as application of molecular-genetic tricks to feminize or masculinize a given component of the CNS. Results of such experiments have, indeed, identified certain discrete subsets of centrally located ganglia that, on the one hand, lead to courtship defects when disrupted or, on the other, must apparently maintain sex-specific identity if the requisite courtship actions are to be performed. As just implied, perturbations of certain neural tissues not based on manipulating "sex factors" might lead to reproductive behavioral abnormalities, even though changing the sexual identity of such structures would not necessarily have analogous consequences. It has been valuable to uncover these sexually significant subsets of the Drosophila nervous system, although it must be said that not all of the transgenically based dissection outcomes are in agreement. Thus, the good news is that not all of the CNS is devoted to courtship control, whereby any and all locales disrupted might have led to sex-specific deficits; but the bad news is that the enhancer-trap approach to these matters has not led to definitive homing-in on some tractable number of mutually agreed-upon "courtship centers" within the brain or within the ventral nerve cord (VNC). The latter neural region, which comprises about half of the fly's CNS, is underanalyzed as to its sex-specific significance: How, for example, are various kinds of sensory inputs to posteriorly located PNS structures processed, such that they eventually end up modulating brain functions underlying courtship? And how are sex-specific motor outputs mediated by discrete collections of neurons within VNC ganglia--so that, for instance, male-specific whole-animal motor actions and appendage usages are evoked? These behaviors can be thought of as fixed action patterns. But it is increasingly appreciated that elements of the fly's reproductive behavior can be modulated by previous experience. In this regard, the neural substrates of conditioned courtship are being more and more analyzed, principally by further usages of various transgenic types. Additionally, a set of molecular neurogenetic experiments devoted to experience-dependent courtship was based on manipulations of a salient "sex gene" in D. melanogaster. This well-defined factor is called fruitless (fru). The gene, its encoded products, along with their behavioral and neurobiological significance, have become objects of frenetic attention in recent years. How normal, mutated, and molecularly manipulated forms of fru seem to be generating a good deal of knowledge and insight about male-specific courtship and mating is worthy of much attention. This previews the fact that fruitless matters are woven throughout this chapter as well as having a conspicuous section allocated to them. Finally, an acknowledgment that the reader is being subjected to lengthy preview of an article about this subject is given. This matter is mentioned because--in conjunction with the contemporary broadening and deepening of this investigatory area--brief summaries of its findings are appearing with increasing frequency. This chapter will, from time to time, present our opinion that a fair fraction of the recent minireviews are replete with too many catch phrases about what is really known. This is one reason why the treatment that follows not only attempts to describe the pertinent primary reports in detail but also pauses often to discuss our views about current understandings of sex-specific behavior in Drosophila and its underlying biology.
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Ebbs ML, Amrein H. Taste and pheromone perception in the fruit fly Drosophila melanogaster. Pflugers Arch 2007; 454:735-47. [PMID: 17473934 DOI: 10.1007/s00424-007-0246-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Revised: 01/04/2007] [Accepted: 01/15/2007] [Indexed: 01/25/2023]
Abstract
Taste is an essential sense for detection of nutrient-rich food and avoidance of toxic substances. The Drosophila melanogaster gustatory system provides an excellent model to study taste perception and taste-elicited behaviors. "The fly" is unique in the animal kingdom with regard to available experimental tools, which include a wide repertoire of molecular-genetic analyses (i.e., efficient production of transgenics and gene knockouts), elegant behavioral assays, and the possibility to conduct electrophysiological investigations. In addition, fruit flies, like humans, recognize sugars as a food source, but avoid bitter tasting substances that are often toxic to insects and mammals alike. This paper will present recent research progress in the field of taste and contact pheromone perception in the fruit fly. First, we shall describe the anatomical properties of the Drosophila gustatory system and survey the family of taste receptors to provide an appropriate background. We shall then review taste and pheromone perception mainly from a molecular genetic perspective that includes behavioral, electrophysiological and imaging analyses of wild type flies and flies with genetically manipulated taste cells. Finally, we shall provide an outlook of taste research in this elegant model system for the next few years.
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Affiliation(s)
- Michelle L Ebbs
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, 252 CARL Bldg./Research Drive, Durham, NC 27710, USA
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Lazareva AA, Roman G, Mattox W, Hardin PE, Dauwalder B. A role for the adult fat body in Drosophila male courtship behavior. PLoS Genet 2007; 3:e16. [PMID: 17257054 PMCID: PMC1781494 DOI: 10.1371/journal.pgen.0030016] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Accepted: 12/12/2006] [Indexed: 11/19/2022] Open
Abstract
Mating behavior in Drosophila depends critically on the sexual identity of specific regions in the brain, but several studies have identified courtship genes that express products only outside the nervous system. Although these genes are each active in a variety of non-neuronal cell types, they are all prominently expressed in the adult fat body, suggesting an important role for this tissue in behavior. To test its role in male courtship, fat body was feminized using the highly specific Larval serum protein promoter. We report here that the specific feminization of this tissue strongly reduces the competence of males to perform courtship. This effect is limited to the fat body of sexually mature adults as the feminization of larval fat body that normally persists in young adults does not affect mating. We propose that feminization of fat body affects the synthesis of male-specific secreted circulating proteins that influence the central nervous system. In support of this idea, we demonstrate that Takeout, a protein known to influence mating, is present in the hemolymph of adult males but not females and acts as a secreted protein.
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Affiliation(s)
- Anna A Lazareva
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
| | - Gregg Roman
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
| | - William Mattox
- Department of Molecular Genetics, University of Texas, M. D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Paul E Hardin
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Brigitte Dauwalder
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
- * To whom correspondence should be addressed. E-mail:
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Billeter JC, Rideout EJ, Dornan AJ, Goodwin SF. Control of male sexual behavior in Drosophila by the sex determination pathway. Curr Biol 2006; 16:R766-76. [PMID: 16950103 DOI: 10.1016/j.cub.2006.08.025] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Understanding how genes influence behavior, including sexuality, is one of biology's greatest challenges. Much of the recent progress in understanding how single genes can influence behavior has come from the study of innate behaviors in the fruit fly Drosophila melanogaster. In particular, the elaborate courtship ritual performed by the male fly has provided remarkable insights into how the neural circuitry underlying sexual behavior--which is largely innate in flies--is built into the nervous system during development, and how this circuitry functions in the adult. In this review we will discuss how genes of the sex determination pathway in Drosophila orchestrate the developmental events necessary for sex-specific behaviors and physiology, and the broader lessons this can teach us about the mechanisms underlying the development of sex-specific neural circuitry.
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Villella A, Ferri SL, Krystal JD, Hall JC. Functional analysis of fruitless gene expression by transgenic manipulations of Drosophila courtship. Proc Natl Acad Sci U S A 2005; 102:16550-7. [PMID: 16179386 PMCID: PMC1225315 DOI: 10.1073/pnas.0507056102] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A gal4-containing enhancer-trap called C309 was previously shown to cause subnormal courtship of Drosophila males toward females and courtship among males when driving a conditional disrupter of synaptic transmission (shi(TS)). We extended these manipulations to analyze all features of male-specific behavior, including courtship song, which was almost eliminated by driving shi(TS) at high temperature. In the context of singing defects and homosexual courtship affected by mutations in the fru gene, a tra-regulated component of the sex-determination hierarchy, we found a C309/tra(F) combination also to induce high levels of courtship between pairs of males and "chaining" behavior in groups; however, these doubly transgenic males sang normally. Because production of male-specific FRU(M) protein is regulated by TRA, we hypothesized that a fru-derived transgene encoding the male (M) form of an Inhibitory RNA (fru(MIR)) would mimic the effects of tra(F); but C309/fru(MIR) males exhibited no courtship chaining, although they courted other males in single-pair tests. Double-labeling of neurons in which GFP was driven by C309 revealed that 10 of the 20 CNS clusters containing FRU(M) in wild-type males included coexpressing neurons. Histological analysis of the developing CNS could not rationalize the absence of tra(F) or fru(MIR) effects on courtship song, because we found C309 to be coexpressed with FRU(M) within the same 10 neuronal clusters in pupae. Thus, we hypothesize that elimination of singing behavior by the C309/shi(TS) combination involves neurons acting downstream of FRU(M) cells.
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Affiliation(s)
- Adriana Villella
- Department of Biology, Brandeis University, Waltham, MA 02454, USA.
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Lin H, Mann KJ, Starostina E, Kinser RD, Pikielny CW. A Drosophila DEG/ENaC channel subunit is required for male response to female pheromones. Proc Natl Acad Sci U S A 2005; 102:12831-6. [PMID: 16129837 PMCID: PMC1200314 DOI: 10.1073/pnas.0506420102] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Odorants and pheromones as well as sweet- and bitter-tasting small molecules are perceived through activation of G protein-coupled chemosensory receptors. In contrast, gustatory detection of salty and sour tastes may involve direct gating of sodium channels of the DEG/ENaC family by sodium and hydrogen ions, respectively. We have found that ppk25, a Drosophila melanogaster gene encoding a DEG/ENaC channel subunit, is expressed at highest levels in the male appendages responsible for gustatory and olfactory detection of female pheromones: the legs, wings, and antennae. Mutations in the ppk25 gene reduce or even abolish male courtship response to females in the dark, conditions under which detection of female pheromones is an essential courtship-activating sensory input. In contrast, the same mutations have no effect on other behaviors tested. Importantly, ppk25 mutant males that show no response to females in the dark execute all of the normal steps of courtship behavior in the presence of visible light, suggesting that ppk25 is required for activation of courtship behavior by chemosensory perception of female pheromones. Finally, a ppk25 mutant allele predicted to encode a truncated protein has dominant-negative properties, suggesting that the normal Ppk25 protein acts as part of a multiprotein complex. Together, these results indicate that ppk25 is necessary for response to female pheromones by D. melanogaster males, and suggest that members of the DEG/ENaC family of genes play a wider role in chemical senses than previously suspected.
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Affiliation(s)
- Heping Lin
- Department of Genetics, Dartmouth Medical School, Hanover, NH 03755, USA
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Popov AV, Peresleni AI, Savvateeva-Popova EV, Wolf R, Heisenberg M. The role of the mushroom bodies and of the central complex of Drosophila melanogaster brain in the organization of courtship behavior and communicative sound production. J EVOL BIOCHEM PHYS+ 2004. [DOI: 10.1007/s10893-005-0021-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Broughton SJ, Kitamoto T, Greenspan RJ. Excitatory and inhibitory switches for courtship in the brain of Drosophila melanogaster. Curr Biol 2004; 14:538-47. [PMID: 15062094 DOI: 10.1016/j.cub.2004.03.037] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2003] [Revised: 02/04/2004] [Accepted: 02/09/2004] [Indexed: 11/26/2022]
Abstract
BACKGROUND Courtship is the best-studied behavior in Drosophila melanogaster, and work on its anatomical basis has concentrated mainly on the functional identification of sexually dimorphic sites in the brain. Much less is known of the more expansive, nondimorphic, but nonetheless essential, neural elements subserving male courtship behavior. RESULTS Sites in the CNS mediating initiation and early steps of male courtship in Drosophila melanogaster were identified by analyzing the behavior of mosaic flies expressing transgenes designed either to suppress neurotransmission or enhance neuronal excitability. Suppression of neurotransmission was accomplished by means of the dominantly acting, temperature-sensitive dynamin mutation shibire(ts1), whereas enhanced neuronal excitability was produced by means of a novel, dominantly acting, truncated eag potassium channel. By using a new, landmark-based procedure for aligning diverse expression patterns among the various mosaic strains, a comparison of courtship performance and affected brain sites in strains expressing the transgenes identified a cluster of cells in the posterior lateral protocerebrum that exerts reciprocal effects on the initiation of courtship, suppressing it when they are inactivated and enhancing it when they are hyperactivated, indicative of cells that normally play an excitatory, triggering role. A separate group of nearby cells, slightly more anterior in the lateral protocerebrum, was found to inhibit courtship when its activity is enhanced, indicative of an inhibitory role in courtship. CONCLUSIONS A cluster of cells, some excitatory and some inhibitory, in the lateral protocerebrum regulates courtship initiation in Drosophila. These cells are likely to be an integration center for the multiple sensory inputs that trigger male courtship.
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The role of the mushroom bodies and of the central complex of Drosophila melanogaster brain in the organization of courtship behavior and communicative sound production. J EVOL BIOCHEM PHYS+ 2004. [DOI: 10.1007/s10893-004-0005-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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31
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Popov AV, Sitnik NA, Savvateeva-Popova EV, Wolf R, Heisenberg M. The role of central parts of the brain in the control of sound production during courtship in Drosophila melanogaster. NEUROSCIENCE AND BEHAVIORAL PHYSIOLOGY 2003; 33:53-65. [PMID: 12617304 DOI: 10.1023/a:1021179331583] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The question of the roles of the two main parts of the insect brain, the mushroom bodies and the central complex, in controlling motor coordination and triggering a variety of behavioral programs, including sound production, remains controversial. With the aim of improving our understanding of this question, we studied the parameters of songs used by five-day-old males during courtship for fertilized wild-type females (Canton-S, C-S) over 5-min periods at 25 degrees C; males were of two wild-type Drosophila melanogaster lines (Berlin and C-S). Berlin males lacking mushroom bodies because of treatment with hydroxyurea during development (chemical removal of the mushroom bodies) were used, along with two mutants with defects in the mushroom bodies (mbm1 and mud1), two mutants with defects in the central complex (ccbKS127 and cexKS181), and mutant cxbN71 with defects in both the mushroom bodies and the central complex. The experiments reported here showed that courtship songs in males lacking mushroom bodies were virtually identical to those of wild-type males. The main parameters of pulsatile song in mutants mbm1 and mud1 (interpulse interval and train duration) were insignificantly different from those of the songs of wild-type flies, though the stability of the pulse oscillator was the same. Flies of these lines were no different from wild-type flies in terms of courtship success (percentage of copulating pairs in 10-min tests). Conversely, the songs of mutants with defects in the central complex differed from those of wild-type males. Firstly, there was degradation of the stability of the pulse oscillator and interpulse intervals were very variable. In addition, pulses were often significantly longer and appeared multicyclic, as in the well-known cacophony mutant, while the mean train duration was significantly shorter. Males of the line cexKS181 usually courted very intensely, though abnormal sounds were generally emitted. Mutants cexKS181 and ccbKS127 were significantly less successful in courtship than wild-type flies. These data show that the central complex appears to play a very important role in controlling song, while the mushroom bodies are not related to this function.
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Affiliation(s)
- A V Popov
- I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 M. Torez Prospekt, 194223 St. Petersburg, Russia
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Martin JR, Keller A, Sweeney ST. Targeted expression of tetanus toxin: a new tool to study the neurobiology of behavior. ADVANCES IN GENETICS 2002; 47:1-47. [PMID: 12000095 DOI: 10.1016/s0065-2660(02)47001-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Over the past few decades, the explosion of molecular genetic knowledge, particularly in the fruit fly Drosophila melanogaster, has led to the identification of a large number of genes, which, when mutated, directly or indirectly affect fly behavior. Beyond the genetic and molecular characterization of genes and their associated molecular pathways, recent advances in molecular genetics also have allowed the development of new tools dedicated more directly to the dissection of the neural bases for various behaviors. In particular, the conjunction of the development of two techniques--the enhancer-trap detection system and the targeted gene expression system, based on the yeast GAL4 transcription factor--has led to the development of the binary enhancer-trap P[GAL4] expression system, which allows the selective activation of any cloned gene in a wide variety of tissue- and cell-specific patterns. Thus, this development, in addition to allowing the anatomical characterization of neuronal circuitry, also allows, via the expression of tetanus toxin light chain (known to specifically block synaptic transmission), an investigation of the role of specific neurons in certain behaviors. Using this system of "toxigenetics," several forms of behavior--from those mediated by sensory systems, such as olfaction, mechanoreception, and vision, to those mediated by higher brain function, such as learning, memory and locomotion--have been studied. These studies aim to map neuronal circuitry underlying specific behaviors and thereby unravel relevant neurophysiological mechanisms. The advantage of this approach is that it is noninvasive and permits the investigation of behavior in the free moving animal. We review a number of behavioral studies that have successfully employed this toxigenetic approach, and we hope to persuade the reader that transgenic tetanus toxin light chain is a useful and appropriate tool for the armory of neuroethologists.
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Affiliation(s)
- Jean-René Martin
- NAMC, CNRS, UMR-8620, Université Paris-Sud, Centre Scientifique d'Orsay, France
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33
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Kitamoto T. Conditional disruption of synaptic transmission induces male-male courtship behavior in Drosophila. Proc Natl Acad Sci U S A 2002; 99:13232-7. [PMID: 12239352 PMCID: PMC130616 DOI: 10.1073/pnas.202489099] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It is reported here that male-male courtship behavior is evoked instantaneously in the fruit fly Drosophila by conditional disruption of synaptic transmission. A temperature-sensitive allele of the Drosophila dynamin gene shibire (shi(ts1)) was expressed by using the GAL4/UAS system to disrupt synaptic transmission from GAL4-positive neurons in a temperature-dependent manner. An enhancer-trap GAL4 line C309 directing shi(ts1) expression in central and peripheral neurons (C309/UAS-shi(ts1)) initiated stereotypical precopulatory behavior toward other mature males immediately after a temperature shift from the permissive to restrictive temperature. At the restrictive temperature, C309/UAS-shi(ts1) males formed "courtship chains" and exhibited abnormally high levels of head-to-head interactions. The temperature-induced male-male courtship is attributable not to an increase in sexual attractiveness but to an increase in sexual activity of C309/UAS-shi(ts1) males. Interestingly, the temperature-induced increase in sexual activity is specific toward male partners, because C309/UAS-shi(ts1) males courted receptive virgin females less vigorously and copulated less efficiently after shifted to the restrictive temperature. Among the GAL4-positive neurons in C309, conditional disruption of certain cholinergic neurons but not the mushroom body intrinsic neurons plays a critical role in the induction of male-male courtship. These neurons may be involved in inhibitory systems that normally suppress aberrant male-male courtship. The presented strategy that can induce behavioral abnormalities by disrupting synaptic transmission in an acute and noninvasive manner will allow further exploration as to how distinct neuronal groups control sexual orientation and other aspects of reproductive behavior in Drosophila.
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Affiliation(s)
- Toshihiro Kitamoto
- Division of Neurosciences, Beckman Research Institute of the City of Hope, 1450 East Duarte Road, Duarte, CA 91010, USA.
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Abstract
Courtship is a complex behavior in Drosophila that recruits a wide range of genes for its realization, including those concerning sex determination, ion channels, and circadian rhythms. Results from different experimental approaches-behavioral and genetic comparisons between species, analysis of mutants and mosaics, and identification of specific sensory stimuli-sketch the outlines of a set of pleiotropic genes acting on a distributed system in the brain to produce the species-specific sequence of responses and actions.
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Affiliation(s)
- R J Greenspan
- The Neurosciences Institute, San Diego, California 92121, USA.
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An X, Armstrong JD, Kaiser K, O'Dell KM. The effects of ectopic white and transformer expression on Drosophila courtship behavior. J Neurogenet 2000; 14:227-43,271. [PMID: 11342383 DOI: 10.3109/01677060009084500] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The sex determining genes of Drosophila males and females function to establish the potential for sex-specific behaviors. Previous studies suggest that ectopic GAL4-directed misexpression of the female-specific isoform of the sex-determining gene transformer (tra) in specific sub-domains of an otherwise male brain can lead to bisexual courtship behavior, thus identifying brain domains that may mediate sex-specific behavior. However, expression of mini-white, the marker gene used in both P[GAL4] and P[UAS(G)] constructs, also induces males to court other males, questioning whether GAL4-mediated tra expression alone can induce bisexual behavior. Here we demonstrate the consequences of inducing mutations in the mini-white genes within P[GAL4] and P[UAS(G)] constructs to generate flies in which a white mutant phenotype is revealed. In these mini-white mutant strains, P[GAL4]-mediated transformer expression alone is both sufficient and necessary to generate bisexual behavior. In addition, using RT-PCR, we reveal the presence of female transcripts of doublesex and fruitless in the brains of otherwise male (XY) flies exhibiting P[GAL4]-directed tra-expression, demonstrating that P[GAL4]-directed tra is functional at the molecular level. We conclude that P[GAL4]-directed misexpression of tra is responsible for the bisexual behavior previously described and that this is mediated via sex-specific splicing of dsx and fru. Our results support the validity of such strategies for identifying regions of the fly brain that underlie sex-specific behaviors.
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Affiliation(s)
- X An
- IBLS Division of Molecular Genetics, University of Glasgow, 54 Dumbarton Road, Glasgow G11 6NU, UK
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Zhu L, Wilken J, Phillips NB, Narendra U, Chan G, Stratton SM, Kent SB, Weiss MA. Sexual dimorphism in diverse metazoans is regulated by a novel class of intertwined zinc fingers. Genes Dev 2000. [DOI: 10.1101/gad.14.14.1750] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Sex determination is regulated by diverse pathways. Although upstream signals vary, a cysteine-rich DNA-binding domain (the DM motif) is conserved within downstream transcription factors ofDrosophila melanogaster (Doublesex) and Caenorhabditis elegans (MAB-3). Vertebrate DM genes have likewise been identified and, remarkably, are associated with human sex reversal (46, XY gonadal dysgenesis). Here we demonstrate that the structure of the Doublesex domain contains a novel zinc module and disordered tail. The module consists of intertwined CCHC and HCCC Zn2+-binding sites; the tail functions as a nascent recognition α-helix. Mutations in either Zn2+-binding site or tail can lead to an intersex phenotype. The motif binds in the DNA minor groove without sharp DNA bending. These molecular features, unusual among zinc fingers and zinc modules, underlie the organization of a Drosophila enhancer that integrates sex- and tissue-specific signals. The structure provides a foundation for analysis of DM mutations affecting sexual dimorphism and courtship behavior.
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Gatti S, Ferveur JF, Martin JR. Genetic identification of neurons controlling a sexually dimorphic behaviour. Curr Biol 2000; 10:667-70. [PMID: 10837249 DOI: 10.1016/s0960-9822(00)00517-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In the fruit fly Drosophila melanogaster, locomotor activity is sexually dimorphic: female flies constantly modulate their activity pattern whereas males show a steadier, stereotyped walking pace [1]. Here, we mapped the area of the brain controlling this behavioural dimorphism. Adult male Drosophila expressing a dominant feminising transgene in a small cluster of neurons in the pars intercerebralis exhibited a female-like pattern of locomotor activity. Genetic ablation of these neurons prevented the feminisation of the locomotor activity of transgenic males. The results suggest that this cluster of neurons modulates sex-specific activity, but is not involved in initiating fly locomotion. Nor does it control male courtship behaviour, because feminisation of courtship was not correlated with the feminisation of locomotor activity.
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Affiliation(s)
- S Gatti
- UMR-8620, Bases Neurales du Mouvement chez la Drosophile, Université Paris-Sud, Orsay, F-91405, France
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Goodwin SF, Taylor BJ, Villella A, Foss M, Ryner LC, Baker BS, Hall JC. Aberrant splicing and altered spatial expression patterns in fruitless mutants of Drosophila melanogaster. Genetics 2000; 154:725-45. [PMID: 10655225 PMCID: PMC1460956 DOI: 10.1093/genetics/154.2.725] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The fruitless (fru) gene functions in Drosophila males to establish the potential for male sexual behaviors. fru encodes a complex set of sex-specific and sex-nonspecific mRNAs through the use of multiple promoters and alternative pre-mRNA processing. The male-specific transcripts produced from the distal (P1) fru promoter are believed to be responsible for its role in specifying sexual behavior and are only expressed in a small fraction of central nervous system (CNS) cells. To understand the molecular etiology of fruitless mutant phenotypes, we compared wild-type and mutant transcription patterns. These experiments revealed that the fru(2), fru(3), fru(4), and fru(sat) mutations, which are due to P-element inserts, alter the pattern of sex-specific and sex-nonspecific fru RNAs. These changes arise in part from the P-element insertions containing splice acceptor sites that create alternative processing pathways. In situ hybridization revealed no alterations in the locations of cells expressing the P1-fru-promoter-derived transcripts in fru(2), fru(3), fru(4), and fru(sat) pharate adults. For the fru(1) mutant (which is due to an inversion breakpoint near the P1 promoter), Northern analyses revealed no significant changes in fru transcript patterns. However, in situ hybridization revealed anomalies in the level and distribution of P1-derived transcripts: in fru(1) males, fewer P1-expressing neurons are found in regions of the dorsal lateral protocerebrum and abdominal ganglion compared to wild-type males. In other regions of the CNS, expression of these transcripts appears normal in fru(1) males. The loss of fruitless expression in these regions likely accounts for the striking courtship abnormalities exhibited by fru(1) males. Thus, we suggest that the mutant phenotypes in fru(2), fru(3), fru(4), and fru(sat) animals are due to a failure to appropriately splice P1 transcripts, whereas the mutant phenotype of fru(1) animals is due to the reduction or absence of P1 transcripts within specific regions of the CNS.
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Affiliation(s)
- S F Goodwin
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454, USA.
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Abstract
Sex and death. Two things that come once in a lifetime. Only after death you're not nauseous. - Woody Allen 'Sleeper'. The brain and nervous system functions that underlie sex-specific behaviour are of obvious importance to all animals, including humans. To understand behaviour related to sex, it is important to distinguish those aspects that are controlled genetically. Much of the recent progress in studies of the molecular neurogenetics of sexual differentiation and behaviour has come from the use of genetically tractable organisms (i.e. fruitflies and nematode worms) that exhibit a full range of sexually dimorphic phenotypes.
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Affiliation(s)
- S F Goodwin
- IBLS-Division of Molecular Genetics, University of Glasgow, Glasgow, G11 6NU, UK.
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40
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Abstract
Sites in the brain that show functional, sexual dimorphism in courtship behavior have been mapped at high resolution in male/female mosaics of Drosophila melanogaster. The sex mosaics were produced by enhancer-trap expression of GAL4 driving the female-spliced form of the transformer gene (tra), revealing sites in the dorsal brain, lateral protocerebrum, suboesophageal, thoracic and abdominal ganglia, and suggesting the importance of cross-talk between these regions in the implementation of the courtship sequence.
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Affiliation(s)
- J F Ferveur
- Department of Biology, New York University, NY 10003, USA
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41
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A female nervous system is necessary for normal sperm storage in Drosophila melanogaster: a masculinized nervous system is as good as none. Proc Biol Sci 1998; 265:1749-1753. [PMCID: PMC1689365 DOI: 10.1098/rspb.1998.0498] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023] Open
Abstract
A male Drosophila melanogaster deposits many more sperm in a female's bursa copulatrix than are stored in her ventral receptacle or paired spermathecae soon after copula has ended. The remaining sperm are expelled by the female. These observations suggest a sexual conflict over the processes involved in sperm storage. We used genetically manipulated flies to study the role of the central nervous system in sperm storage. Flies with female bodies but masculinized nervous systems, or isolated female abdomens, stored significantly fewer sperm than did control females. Furthermore, compared with control flies, there were relatively more sperm in the ventral receptacle and relatively fewer in the spermathecae. These results suggest that the female nervous input counteracts the male's attempts to force sperm into the ventral receptacle during copula and promotes active transport of sperm to the spermathecae during and after copula. The female is clearly a very active partner in influencing processes involved in sperm competition, especially as only stored sperm can be used later to fertilize eggs. To our knowledge, this is the first study to show directly the involvement of the female nervous system in sperm storage.
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42
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Voila, a new Drosophila courtship variant that affects the nervous system: behavioral, neural, and genetic characterization. J Neurosci 1998. [PMID: 9592110 DOI: 10.1523/jneurosci.18-11-04335.1998] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In Drosophila melanogaster, a specific PGAL4 transposon induces the Voila1 genetic variant and produces multiple phenotypes. Homozygous Voila1/1 flies rarely reach adulthood, whereas heterozygous Voila1/+ adult males show strong bisexual behavior. Males with a single copy of Voila1 driving the feminizing transgene UAS-transformer show very reduced sexual activity but no overall effect on their behavior. Voila1 is specifically expressed in the nervous system. In the CNS, it is expressed mainly in the mushroom bodies and, to a lesser extent, in the antennal lobes. In the peripheral nervous system, GAL4 expression is almost entirely restricted to the gustatory sensilla. Using chromosomal deficiencies, the behavioral alteration was genetically mapped to the same location as the PGAL4 element (86E1-2). The multiple behavioral effects of the Voila genetic variant are discussed in light of its expression in the nervous system and its genetic basis.
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43
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Kerr C, Ringo J, Dowse H, Johnson E. Icebox, a recessive X-linked mutation in Drosophila causing low sexual receptivity. J Neurogenet 1997; 11:213-29. [PMID: 10876654 DOI: 10.3109/01677069709115097] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The X-linked recessive mutation icebox (ibx; 1-23, 7F1) of Drosophila melanogaster lowers the sexual receptivity of females. The probability of mating with mature wild-type males is reduced in ibx homozygotes, and the frequency of rejection behavior (rate per minute) towards courting males is increased. ibx fails to complement In(1)RA35, which is a lethal allele of Neuroglian (Nrg, which encodes a transmembrane protein found in embryonic tissues including the nervous system) due to a breakpoint in that gene; however, both l(1)B4 and l(1)VA142, other lethal mutations of Nrg, do complement ibx. 12-h ibx embryos exhibit a normal pattern of staining for the Neuroglian-specific antibody, Mab BP104. Males and females mutant for ibx have normal egg-to-adult survival and appear normal in several "general" behavioral traits including olfaction, phototaxis, locomotor activity, and heartbeat. ibx males court normally, and are successful in mating. These characteristics suggest that ibx does not cause sensory or motor defects. Ovarian growth and sperm storage are wild-type in ibx/ibx females. Treatment with the JH analog methoprene increases the receptivity of ibx/ibx females.
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Affiliation(s)
- C Kerr
- Department of Zoology, University of Maine, Orono 04469-5751, USA
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44
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Balaban E. Changes in multiple brain regions underlie species differences in a complex, congenital behavior. Proc Natl Acad Sci U S A 1997; 94:2001-6. [PMID: 9050894 PMCID: PMC20032 DOI: 10.1073/pnas.94.5.2001] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The evolutionary brain modifications that produce any complex, congenital behavioral difference between two species have never been identified. Evolutionary processes may (i) alter a single, "higher" brain area that generates and/or coordinates the diverse motor components of a complex act; (ii) separately change independent, "lower" brain areas that modulate the fine motor control of the individual components; or (iii) modify both types of areas. This study explores the brain localization of a species difference in one such behavior, the crowing of chickens (Gallus gallus domesticus) and Japanese quail (Coturnix coturnix japonica). Two major subcomponents of the behavioral difference can be independently transferred with interspecies transplantation of separate brain regions, despite the fact that these components, sound and patterned head movement, occur together in a highly integrated fashion. To our knowledge, this is the first experimental demonstration that species differences in a complex behavior are built up from separate changes to distinct cell groups in different parts of the brain and that these cell groups have independent effects on individual behavioral components.
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Affiliation(s)
- E Balaban
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
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45
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Abstract
We have identified two genes, roX1 and roX2, whose expression in the adult fly is restricted to neurons of males. The two genes reside on the X chromosome, and each encodes an RNA with no apparent open reading frame. Both genes are physically linked to female-specific genes that encode proteins expressed in the ovary: opt1, a novel peptide transporter, and nod, a member of the kinesin family. The male-specific transcripts are positively regulated by the dosage compensation pathway in an all-or-none fashion. Our data suggest that the multimeric complex of dosage compensation proteins may operate in different ways on different sets of X-linked genes.
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Affiliation(s)
- H Amrein
- Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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46
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Finley KD, Taylor BJ, Milstein M, McKeown M. dissatisfaction, a gene involved in sex-specific behavior and neural development of Drosophila melanogaster. Proc Natl Acad Sci U S A 1997; 94:913-8. [PMID: 9023356 PMCID: PMC19613 DOI: 10.1073/pnas.94.3.913] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Few mutations link well defined behaviors with individual neurons and the activity of specific genes. In Drosophila, recent evidence indicates the presence of a doublesex-independent pathway controlling sexual behavior and neuronal differentiation. We have identified a gene, dissatisfaction (dsf), that affects sex-specific courtship behaviors and neural differentiation in both sexes without an associated general behavioral debilitation. Male and female mutant animals exhibit abnormalities in courtship behaviors, suggesting a requirement for dsf in the brain. Virgin dsf females resist males during courtship and copulation and fail to lay mature eggs. dsf males actively court and attempt copulation with both mature males and females but are slow to copulate because of maladroit abdominal curling. Structural abnormalities in specific neurons indicate a role for dsf in the differentiation of sex-specific abdominal neurons. The egg-laying defect in females correlates with the absence of motor neuronal innervation on uterine muscles, and the reduced abdominal curling in males correlates with alteration in motor neuronal innervation of male ventral abdominal muscles. Epistasis experiments show that dsf acts in a tra-dependent and dsx-independent manner, placing dsf in the dsx-independent portion of the sex determination cascade.
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Affiliation(s)
- K D Finley
- Molecular Biology and Virology Laboratory, The Salk Institute, San Diego, CA 92186, USA
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47
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Abstract
Silver-intensified cobalt preparations reveal sex-specific neurons in the optic lobes of flies. The most pronounced of these are found in the lobula neuropil and subserve projections from the dorsal and frontal retina specifically. Two main types of male neurons have been resolved. These are single unique elements, two in each lobula, and small groups of columnar neurons. The present account describes three main features of sex-specific neurons. These are, first their shapes and dispositions; secondly, their relations with visual nerve cells that are common to both sexes, and thirdly, their exact mapping within the retinotopic mosaic of the lobula. The possible functional significance of these arrangements are discussed with respect to sex-specific visual behaviour.
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48
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Coyne JA, Oyama R. Localization of pheromonal sexual dimorphism in Drosophila melanogaster and its effect on sexual isolation. Proc Natl Acad Sci U S A 1995; 92:9505-9. [PMID: 7568163 PMCID: PMC40830 DOI: 10.1073/pnas.92.21.9505] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Drosophila melanogaster is sexually dimorphic for cuticular hydrocarbons, with males and females having strikingly different profiles of the long-chain compounds that act as contact pheromones. Gas-chromatographic analysis of sexual mosaics reveals that the sex specificity of hydrocarbons is located in the abdomen. This explains previous observations that D. melanogaster males display the strongest courtship toward mosaics with female abdomens. We also show that males of the sibling species Drosophila simulans preferentially court D. melanogaster mosaics with male abdomens. Because the primary male hydrocarbon in D. melanogaster is also the primary female hydrocarbon in D. simulans, this supports the idea that interspecific differences in cuticular hydrocarbons contribute to sexual isolation.
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Affiliation(s)
- J A Coyne
- Department of Ecology and Evolution, University of Chicago, IL 60637, USA
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49
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O'Dell KM, Armstrong JD, Yang MY, Kaiser K. Functional dissection of the Drosophila mushroom bodies by selective feminization of genetically defined subcompartments. Neuron 1995; 15:55-61. [PMID: 7619530 DOI: 10.1016/0896-6273(95)90064-0] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Relatively little is known about the neural circuitry underlying sex-specific behaviors. We have expressed the feminizing gene transformer in genetically defined subregions of the brain of male Drosophila, and in particular within different domains of the mushroom bodies. Mushroom bodies are phylogenetically conserved insect brain centers implicated in associative learning and various other aspects of behavior. Expression of transformer in lines that mark certain subsets of mushroom body intrinsic neurons, and in a line that marks a component of the antennal lobe, causes males to exhibit nondiscriminatory sexual behavior: they court mature males in addition to females. Expression of transformer in other mushroom body domains, and in control lines, has no such effect. Our data support the view that genetically defined subsets of mushroom body intrinsic neurons perform different functional roles.
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Affiliation(s)
- K M O'Dell
- Laboratory of Genetics, University of Glasgow, Scotland
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50
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Ferveur JF, Störtkuhl KF, Stocker RF, Greenspan RJ. Genetic feminization of brain structures and changed sexual orientation in male Drosophila. Science 1995; 267:902-5. [PMID: 7846534 DOI: 10.1126/science.7846534] [Citation(s) in RCA: 170] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The neural basis of sexual orientation in Drosophila was studied by the production of males with regionally feminized brains. Such flies express the female form of the sex determination gene transformer in a limited number of neurons under the control of GAL4 enhancer trap inserts. This method facilitated the creation of lines with a stable pattern of feminization. In tests of sexual preferences, flies that were feminized in a portion of the antennal lobes or in a subset of the corpora pedunculata (mushroom bodies) courted both males and females. These two brain structures, both of which are involved in olfactory processing, may function in the recognition of sex-specific pheromones, in the control of sex-specific behaviors, or both.
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Affiliation(s)
- J F Ferveur
- Department of Biology, New York University, NY 10003
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