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Baker CA, Guan XJ, Choi M, Murthy M. The role of fruitless in specifying courtship behaviors across divergent Drosophila species. SCIENCE ADVANCES 2024; 10:eadk1273. [PMID: 38478605 PMCID: PMC10936877 DOI: 10.1126/sciadv.adk1273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 02/08/2024] [Indexed: 04/20/2024]
Abstract
Sex-specific behaviors are critical for reproduction and species survival. The sex-specifically spliced transcription factor fruitless (fru) helps establish male courtship behaviors in invertebrates. Forcing male-specific fru (fruM) splicing in Drosophila melanogaster females produces male-typical behaviors while disrupting female-specific behaviors. However, whether fru's joint role in specifying male and inhibiting female behaviors is conserved across species is unknown. We used CRISPR-Cas9 to force FruM expression in female Drosophila virilis, a species in which males and females produce sex-specific songs. In contrast to D. melanogaster, in which one fruM allele is sufficient to generate male behaviors in females, two alleles are needed in D. virilis females. D. virilis females expressing FruM maintain the ability to sing female-typical song as well as lay eggs, whereas D. melanogaster FruM females cannot lay eggs. These results reveal potential differences in fru function between divergent species and underscore the importance of studying diverse behaviors and species for understanding the genetic basis of sex differences.
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Affiliation(s)
| | - Xiao-Juan Guan
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
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2
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Kimura KI, Kumano R, Yamamoto D. Activin is a neural inducer of a male-specific muscle in Drosophila. Sci Rep 2024; 14:3740. [PMID: 38355873 PMCID: PMC10866940 DOI: 10.1038/s41598-024-54295-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 02/11/2024] [Indexed: 02/16/2024] Open
Abstract
Drosophila melanogaster has a pair of male-specific muscles called the muscle of Lawrence (MOL) in abdominal segment 5 (A5) of adult flies. The MOL is produced only when its innervating motoneuron expresses FruitlessM (FruM) neural masculinizing proteins. We show that MOL induction is hampered by: (1) silencing electrical activities in the motoneuron, (2) blocking vesicular release from the motoneuron, and (3) knocking down Activin ß (Actß) in the motoneuron or knocking down Actß signaling pathway components in the myoblasts. Our timelapse live imaging of the developing neuromuscular system reveals that, upon contact with the presumptive MOL, the motoneuronal axon retracts concomitant with the progression of MOL degeneration resulting from neural silencing. We conclude that MOL formation depends on the bidirectional trophic interactions between pre- and postsynaptic cells, with motoneuron-derived Actß playing an inducing role in MOL formation.
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Affiliation(s)
- Ken-Ichi Kimura
- Laboratory of Biology, Sapporo Campus, Hokkaido University of Education, Sapporo, 002-8502, Japan.
| | - Rimi Kumano
- Laboratory of Biology, Sapporo Campus, Hokkaido University of Education, Sapporo, 002-8502, Japan
| | - Daisuke Yamamoto
- Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe, 651-2492, Japan
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3
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Sun J, Liu WK, Ellsworth C, Sun Q, Pan Y, Huang YC, Deng WM. Integrating lipid metabolism, pheromone production and perception by Fruitless and Hepatocyte Nuclear Factor 4. SCIENCE ADVANCES 2023; 9:eadf6254. [PMID: 37390217 PMCID: PMC10313179 DOI: 10.1126/sciadv.adf6254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 05/30/2023] [Indexed: 07/02/2023]
Abstract
Sexual attraction and perception are crucial for mating and reproductive success. In Drosophila melanogaster, the male-specific isoform of Fruitless (Fru), FruM, is a known master neuro-regulator of innate courtship behavior to control the perception of sex pheromones in sensory neurons. Here, we show that the non-sex-specific Fru isoform (FruCOM) is necessary for pheromone biosynthesis in hepatocyte-like oenocytes for sexual attraction. Loss of FruCOM in oenocytes resulted in adults with reduced levels of cuticular hydrocarbons (CHCs), including sex pheromones, and show altered sexual attraction and reduced cuticular hydrophobicity. We further identify Hepatocyte nuclear factor 4 (Hnf4) as a key target of FruCOM in directing fatty acid conversion to hydrocarbons. Fru or Hnf4 depletion in oenocytes disrupts lipid homeostasis, resulting in a sex-dimorphic CHC profile that differs from doublesex- and transformer-dependent CHC dimorphism. Thus, Fru couples pheromone perception and production in separate organs to regulate chemosensory communications and ensure efficient mating behavior.
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Affiliation(s)
- Jie Sun
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Wen-Kan Liu
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Calder Ellsworth
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Qian Sun
- Department of Entomology, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Yufeng Pan
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Yi-Chun Huang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Wu-Min Deng
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
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4
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Rajan A, Anhezini L, Rives-Quinto N, Chhabra JY, Neville MC, Larson ED, Goodwin SF, Harrison MM, Lee CY. Low-level repressive histone marks fine-tune gene transcription in neural stem cells. eLife 2023; 12:e86127. [PMID: 37314324 PMCID: PMC10344426 DOI: 10.7554/elife.86127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 06/11/2023] [Indexed: 06/15/2023] Open
Abstract
Coordinated regulation of gene activity by transcriptional and translational mechanisms poise stem cells for a timely cell-state transition during differentiation. Although important for all stemness-to-differentiation transitions, mechanistic understanding of the fine-tuning of gene transcription is lacking due to the compensatory effect of translational control. We used intermediate neural progenitor (INP) identity commitment to define the mechanisms that fine-tune stemness gene transcription in fly neural stem cells (neuroblasts). We demonstrate that the transcription factor FruitlessC (FruC) binds cis-regulatory elements of most genes uniquely transcribed in neuroblasts. Loss of fruC function alone has no effect on INP commitment but drives INP dedifferentiation when translational control is reduced. FruC negatively regulates gene expression by promoting low-level enrichment of the repressive histone mark H3K27me3 in gene cis-regulatory regions. Identical to fruC loss-of-function, reducing Polycomb Repressive Complex 2 activity increases stemness gene activity. We propose low-level H3K27me3 enrichment fine-tunes gene transcription in stem cells, a mechanism likely conserved from flies to humans.
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Affiliation(s)
- Arjun Rajan
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
| | - Lucas Anhezini
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
| | - Noemi Rives-Quinto
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
| | - Jay Y Chhabra
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
| | - Megan C Neville
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Elizabeth D Larson
- Department of Biomolecular Chemistry, University of Wisconsin-MadisonMadisonUnited States
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin-MadisonMadisonUnited States
| | - Cheng-Yu Lee
- Life Sciences Institute, University of Michigan-Ann ArborAnn ArborUnited States
- Department of Cell and Developmental Biology, University of Michigan Medical SchoolAnn ArborUnited States
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan Medical SchoolAnn ArborUnited States
- Rogel Cancer Center, University of Michigan Medical SchoolAnn ArborUnited States
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Sun J, Liu WK, Ellsworth C, Sun Q, Pan YF, Huang YC, Deng WM. Integrating lipid metabolism, pheromone production and perception by Fruitless and Hepatocyte nuclear factor 4. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.23.529767. [PMID: 36865119 PMCID: PMC9980076 DOI: 10.1101/2023.02.23.529767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Sexual attraction and perception, governed by separate genetic circuits in different organs, are crucial for mating and reproductive success, yet the mechanisms of how these two aspects are integrated remain unclear. In Drosophila , the male-specific isoform of Fruitless (Fru), Fru M , is known as a master neuro-regulator of innate courtship behavior to control perception of sex pheromones in sensory neurons. Here we show that the non-sex specific Fru isoform (Fru COM ) is necessary for pheromone biosynthesis in hepatocyte-like oenocytes for sexual attraction. Loss of Fru COM in oenocytes resulted in adults with reduced levels of the cuticular hydrocarbons (CHCs), including sex pheromones, and show altered sexual attraction and reduced cuticular hydrophobicity. We further identify Hepatocyte nuclear factor 4 ( Hnf4 ) as a key target of Fru COM in directing fatty acid conversion to hydrocarbons in adult oenocytes. fru - and Hnf4 -depletion disrupts lipid homeostasis, resulting in a novel sex-dimorphic CHC profile, which differs from doublesex - and transformer -dependent sexual dimorphism of the CHC profile. Thus, Fru couples pheromone perception and production in separate organs for precise coordination of chemosensory communication that ensures efficient mating behavior. Teaser Fruitless and lipid metabolism regulator HNF4 integrate pheromone biosynthesis and perception to ensure robust courtship behavior.
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Affiliation(s)
- Jie Sun
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Wen-Kan Liu
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Calder Ellsworth
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Qian Sun
- Department of Entomology, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Yu-Feng Pan
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing 210096, China
| | - Yi-Chun Huang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Wu-Min Deng
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
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Palmateer CM, Artikis C, Brovero SG, Friedman B, Gresham A, Arbeitman MN. Single-cell transcriptome profiles of Drosophila fruitless-expressing neurons from both sexes. eLife 2023; 12:e78511. [PMID: 36724009 PMCID: PMC9891730 DOI: 10.7554/elife.78511] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 01/08/2023] [Indexed: 02/02/2023] Open
Abstract
Drosophila melanogaster reproductive behaviors are orchestrated by fruitless neurons. We performed single-cell RNA-sequencing on pupal neurons that produce sex-specifically spliced fru transcripts, the fru P1-expressing neurons. Uniform Manifold Approximation and Projection (UMAP) with clustering generates an atlas containing 113 clusters. While the male and female neurons overlap in UMAP space, more than half the clusters have sex differences in neuron number, and nearly all clusters display sex-differential expression. Based on an examination of enriched marker genes, we annotate clusters as circadian clock neurons, mushroom body Kenyon cell neurons, neurotransmitter- and/or neuropeptide-producing, and those that express doublesex. Marker gene analyses also show that genes that encode members of the immunoglobulin superfamily of cell adhesion molecules, transcription factors, neuropeptides, neuropeptide receptors, and Wnts have unique patterns of enriched expression across the clusters. In vivo spatial gene expression links to the clusters are examined. A functional analysis of fru P1 circadian neurons shows they have dimorphic roles in activity and period length. Given that most clusters are comprised of male and female neurons indicates that the sexes have fru P1 neurons with common gene expression programs. Sex-specific expression is overlaid on this program, to build the potential for vastly different sex-specific behaviors.
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Affiliation(s)
- Colleen M Palmateer
- Department of Biomedical Sciences, Florida State University, College of MedicineTallahasseeUnited States
| | - Catherina Artikis
- Department of Biomedical Sciences, Florida State University, College of MedicineTallahasseeUnited States
| | - Savannah G Brovero
- Department of Biomedical Sciences, Florida State University, College of MedicineTallahasseeUnited States
| | - Benjamin Friedman
- Department of Biomedical Sciences, Florida State University, College of MedicineTallahasseeUnited States
| | - Alexis Gresham
- Department of Biomedical Sciences, Florida State University, College of MedicineTallahasseeUnited States
| | - Michelle N Arbeitman
- Department of Biomedical Sciences, Florida State University, College of MedicineTallahasseeUnited States
- Program of Neuroscience, Florida State UniversityTallahasseeUnited States
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Zhu R, Guo J, Li G, Liu R, Yi T, Jin D. Identification of potential sex determination genes and functional analyses in Neoseiulus californicus under prey stress. PEST MANAGEMENT SCIENCE 2022; 78:5024-5040. [PMID: 36056789 DOI: 10.1002/ps.7128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 07/27/2022] [Accepted: 08/15/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Phytoseiid mites are important natural enemies of spider mites. Sex-determination mechanism are important basic scientific issues in the reproduction and evolution of predatory mites. Clarifying sex-determination mechanism may provide reference for exploring genetic approach to have the phytoseiid mites produce more female offspring, which could improve their effectiveness as a biological control agent. RESULTS We used transcriptome sequencing to identify and characterize 20 putative sex-determination genes in the phytoseiid mite Neoseiulus californicus, a species with uncommon pseudo-arrhenotoky, including doublesex-like (dsx1-like), transformer-2 (tra-2), intersex (ix), and fruitless-like (BTB2). A significant negative correlation was found between prey stress and offspring sex ratio. But the most genes identified showed no difference in expression between the groups with lowest and highest female offspring ratios. The hatching rate and sex ratio of female offspring were reduced when the ix gene was silenced, and the oviposition days and fecundity were reduced when the BTB2 gene was silenced. The fecundity was reduced when the tra2 gene was silenced and the snf gene is essential for oviposition in female. There was no effect on reproduction and female sex determination when silencing the dsx1-like and dsx2-like gene. CONCLUSION The genes BTB2, tra2 and snf are involved in oviposition, and ix may be involved in female sex determination and egg formation in Neoseiulus californicus. The results are conductive to further understanding molecular regulatory mechanism of sex determination in predatory mites and may provide a reference for better use of this predatory by producing more females. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Rui Zhu
- Institute of Entomology, Guizhou University, Guizhou Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, the Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affirs, the People's Republic of China, Guiyang, China
| | - Jianjun Guo
- Institute of Entomology, Guizhou University, Guizhou Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, the Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affirs, the People's Republic of China, Guiyang, China
| | - Gang Li
- Institute of Entomology, Guizhou University, Guizhou Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, the Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affirs, the People's Republic of China, Guiyang, China
| | - Rundong Liu
- Institute of Entomology, Guizhou University, Guizhou Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, the Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affirs, the People's Republic of China, Guiyang, China
| | - Tianci Yi
- Institute of Entomology, Guizhou University, Guizhou Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, the Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affirs, the People's Republic of China, Guiyang, China
| | - Daochao Jin
- Institute of Entomology, Guizhou University, Guizhou Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, the Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affirs, the People's Republic of China, Guiyang, China
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Casado-Navarro R, Serrano-Saiz E. DMRT Transcription Factors in the Control of Nervous System Sexual Differentiation. Front Neuroanat 2022; 16:937596. [PMID: 35958734 PMCID: PMC9361473 DOI: 10.3389/fnana.2022.937596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Sexual phenotypic differences in the nervous system are one of the most prevalent features across the animal kingdom. The molecular mechanisms responsible for sexual dimorphism throughout metazoan nervous systems are extremely diverse, ranging from intrinsic cell autonomous mechanisms to gonad-dependent endocrine control of sexual traits, or even extrinsic environmental cues. In recent years, the DMRT ancient family of transcription factors has emerged as being central in the development of sex-specific differentiation in all animals in which they have been studied. In this review, we provide an overview of the function of Dmrt genes in nervous system sexual regulation from an evolutionary perspective.
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Peng Q, Chen J, Pan Y. From fruitless to sex: On the generation and diversification of an innate behavior. GENES, BRAIN, AND BEHAVIOR 2021; 20:e12772. [PMID: 34672079 DOI: 10.1111/gbb.12772] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/10/2021] [Accepted: 09/10/2021] [Indexed: 11/28/2022]
Abstract
Male sexual behavior in Drosophila melanogaster, largely controlled by the fruitless (fru) gene encoding the male specific FruM protein, is among the best studied animal behaviors. Although substantial studies suggest that FruM specifies a neuronal circuitry governing all aspects of male sexual behaviors, recent findings show that FruM is not absolutely necessary for such behaviors. We propose that another regulatory gene doublesex encoding the male-specific DsxM protein builds a core neuronal circuitry that possesses the potential for courtship, which could be either induced through adult social experience or innately manifested during development by FruM expression in a broader neuronal circuitry. FruM expression levels and patterns determine the modes of courtship behavior from innate heterosexual, homosexual, bisexual, to learned courtship. We discuss how FruM expression is regulated by hormones and social experiences and tunes functional flexibility of the sex circuitry. We propose that regulatory genes hierarchically build the potential for innate and learned aspects of courtship behaviors, and expression changes of these regulatory genes among different individuals and species with different social experiences ultimately lead to behavioral diversification.
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Affiliation(s)
- Qionglin Peng
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing, China
| | - Jie Chen
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing, China
| | - Yufeng Pan
- The Key Laboratory of Developmental Genes and Human Disease, School of Life Science and Technology, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
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10
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Goodwin SF, Hobert O. Molecular Mechanisms of Sexually Dimorphic Nervous System Patterning in Flies and Worms. Annu Rev Cell Dev Biol 2021; 37:519-547. [PMID: 34613817 DOI: 10.1146/annurev-cellbio-120319-115237] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Male and female brains display anatomical and functional differences. Such differences are observed in species across the animal kingdom, including humans, but have been particularly well-studied in two classic animal model systems, the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans. Here we summarize recent advances in understanding how the worm and fly brain acquire sexually dimorphic features during development. We highlight the advantages of each system, illustrating how the precise anatomical delineation of sexual dimorphisms in worms has enabled recent analysis into how these dimorphisms become specified during development, and how focusing on sexually dimorphic neurons in the fly has enabled an increasingly detailed understanding of sex-specific behaviors.
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Affiliation(s)
- Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, United Kingdom;
| | - Oliver Hobert
- Department of Biological Sciences and Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA;
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11
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Mank JE, Rideout EJ. Developmental mechanisms of sex differences: from cells to organisms. Development 2021; 148:272484. [PMID: 34647574 DOI: 10.1242/dev.199750] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Male-female differences in many developmental mechanisms lead to the formation of two morphologically and physiologically distinct sexes. Although this is expected for traits with prominent differences between the sexes, such as the gonads, sex-specific processes also contribute to traits without obvious male-female differences, such as the intestine. Here, we review sex differences in developmental mechanisms that operate at several levels of biological complexity - molecular, cellular, organ and organismal - and discuss how these differences influence organ formation, function and whole-body physiology. Together, the examples we highlight show that one simple way to gain a more accurate and comprehensive understanding of animal development is to include both sexes.
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Affiliation(s)
- Judith E Mank
- Department of Zoology, Biodiversity Research Centre, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.,Biosciences, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK
| | - Elizabeth J Rideout
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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Mine S, Sumitani M, Aoki F, Hatakeyama M, Suzuki MG. Effects of Functional Depletion of Doublesex on Male Development in the Sawfly, Athalia rosae. INSECTS 2021; 12:insects12100849. [PMID: 34680618 PMCID: PMC8538284 DOI: 10.3390/insects12100849] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 09/18/2021] [Accepted: 09/20/2021] [Indexed: 01/04/2023]
Abstract
Simple Summary The sawfly, Athalia rosae, exploits a haplodiploid mode of reproduction, in which fertilized eggs develop into diploid females, whereas unfertilized eggs parthenogenetically develop into haploid males. The doublesex (dsx) gene is a well-conserved transcription factor that regulates sexual differentiation in insects. In the present study, we knocked down the A. rosae ortholog of dsx (Ardsx) during several developmental stages with repeated double-stranded RNA (dsRNA) injections. As a result, knockdown of Ardsx in haploid males caused almost complete male-to-female sex reversal, but the resulting eggs were infertile. The same knockdown approach using diploid males caused complete male-to-female sex reversal; they were able to produce fertile eggs and exhibited female behaviors. The same RNAi treatment did not affect female differentiation. These results demonstrated that dsx in the sawfly is essential for male development and its depletion caused complete male-to-female sex reversal. This is the first demonstration of functional depletion of dsx not causing intersexuality but inducing total sex reversal in males instead. Abstract The doublesex (dsx) gene, which encodes a transcription factor, regulates sexual differentiation in insects. Sex-specific splicing of dsx occurs to yield male- and female-specific isoforms, which promote male and female development, respectively. Thus, functional disruption of dsx leads to an intersexual phenotype in both sexes. We previously identified a dsx ortholog in the sawfly, Athalia rosae. Similar to dsx in other insects, dsx in the sawfly yields different isoforms in males and females as a result of alternative splicing. The sawfly exploits a haplodiploid mode of reproduction, in which fertilized eggs develop into diploid females, whereas unfertilized eggs parthenogenetically develop into haploid males. In the present study, we knocked down the A. rosae ortholog of dsx (Ardsx) during several developmental stages with repeated double-stranded RNA (dsRNA) injections. Knockdown of Ardsx via parental RNA interference (RNAi), which enables knockdown of genes in offspring embryos, led to a lack of internal and external genitalia in haploid male progeny. Additional injection of dsRNA targeting Ardsx in these animals caused almost complete male-to-female sex reversal, but the resulting eggs were infertile. Notably, the same knockdown approach using diploid males obtained by sib-crossing caused complete male-to-female sex reversal; they were morphologically and behaviorally females. The same RNAi treatment did not affect female differentiation. These results indicate that dsx in the sawfly is essential for male development and its depletion caused complete male-to-female sex reversal. This is the first demonstration of functional depletion of dsx not causing intersexuality but inducing total sex reversal in males instead.
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Affiliation(s)
- Shotaro Mine
- Department of Biosciences, Nihon University, 3-25-40 Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan;
| | - Megumi Sumitani
- Division of Biotechnology, Institute of Agrobiological Sciences, NARO, Owashi, Tsukuba 305-8634, Japan;
| | - Fugaku Aoki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8562, Japan;
| | - Masatsugu Hatakeyama
- Division of Applied Genetics, Institute of Agrobiological Sciences, NARO, Owashi, Tsukuba 305-8634, Japan;
| | - Masataka G. Suzuki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8562, Japan;
- Correspondence: ; Tel.: +81-4-7136-3694
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Neville MC, Eastwood A, Allen AM, de Haan A, Nojima T, Goodwin SF. Generation and characterization of fruitless P1 promoter mutant in Drosophila melanogaster. J Neurogenet 2021; 35:285-294. [PMID: 34338589 PMCID: PMC8477730 DOI: 10.1080/01677063.2021.1931179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The identification of mutations in the gene fruitless (fru) paved the way for understanding the genetic basis of male sexual behavior in the vinegar fly Drosophila melanogaster. D. melanogaster males perform an elaborate courtship display to the female, ultimately leading to copulation. Mutations in fru have been shown to disrupt most aspects of the male's behavioral display, rendering males behaviorally sterile. The fru genomic locus encodes for multiple transcription factor isoforms from several promoters; only those under the regulation of the most distal P1 promoter are under the control of the sex determination hierarchy and play a role in male-specific behaviors. In this study, we used CRISPR/Cas9-based targeted genome editing of the fru gene, to remove the P1 promoter region. We have shown that removal of the P1 promoter leads to a dramatic decrease in male courtship displays towards females and male-specific sterility. We have expanded the analysis of fru P1-dependent behaviors, examining male's response to courtship song and general activity levels during12-hour light: dark cycles. Our novel allele expands the mutant repertoire available for future studies of fru P1-derived function in D. melanogaster. Our fruΔP1 mutant will be useful for future studies of fru P1-derived function, as it can be homozygosed without disrupting additional downstream promoter function and can be utilized in heterozygous combinations with other extant fru alleles.
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Affiliation(s)
- Megan C. Neville
- University of Oxford, Centre for Neural Circuits & Behaviour, Oxford, UK,CONTACT Megan C. Neville University of Oxford, Centre for Neural Circuits & Behaviour, Oxford, UK
| | - Alexander Eastwood
- University of Oxford, Centre for Neural Circuits & Behaviour, Oxford, UK
| | - Aaron M. Allen
- University of Oxford, Centre for Neural Circuits & Behaviour, Oxford, UK
| | - Ammerins de Haan
- University of Oxford, Centre for Neural Circuits & Behaviour, Oxford, UK
| | - Tetsuya Nojima
- University of Oxford, Centre for Neural Circuits & Behaviour, Oxford, UK
| | - Stephen F. Goodwin
- University of Oxford, Centre for Neural Circuits & Behaviour, Oxford, UK
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14
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Mating increases Drosophila melanogaster females' choosiness by reducing olfactory sensitivity to a male pheromone. Nat Ecol Evol 2021; 5:1165-1173. [PMID: 34155384 PMCID: PMC9477091 DOI: 10.1038/s41559-021-01482-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/04/2021] [Indexed: 02/05/2023]
Abstract
Females that are highly selective when choosing a mate run the risk of remaining unmated or delaying commencing reproduction. Therefore, low female choosiness would be beneficial when males are rare but it would be maladaptive if males become more frequent. How can females resolve this issue? Polyandry would allow mating-status-dependent choosiness, with virgin females selecting their first mate with little selectivity and becoming choosier thereafter. This plasticity in choosiness would ensure timely acquisition of sperm and enable females to increase offspring quality during later mating. Here, we show that Drosophila melanogaster females display such mating-status-dependent choosiness by becoming more selective once mated and identify the underlying neurohormonal mechanism. Mating releases juvenile hormone, which desensitizes Or47b olfactory neurons to a pheromone produced by males, resulting in increased preference for pheromone-rich males. Besides providing a mechanism to a long-standing evolutionary prediction, these data suggest that intersexual selection in D. melanogaster, and possibly in all polyandrous, sperm-storing species, is mainly the domain of mated females since virgin females are less selective. Juvenile hormone influences behaviour by changing cue responsiveness across insects; the neurohormonal modulation of olfactory neurons uncovered in D. melanogaster provides an explicit mechanism for how this hormone modulates behavioural plasticity.
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15
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Evolution of a neuromuscular sexual dimorphism in the Drosophila montium species group. Sci Rep 2021; 11:15272. [PMID: 34315982 PMCID: PMC8316392 DOI: 10.1038/s41598-021-94722-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 06/24/2021] [Indexed: 12/04/2022] Open
Abstract
While epigamic traits likely evolve via sexual selection, the mechanism whereby internal sexual dimorphism arises remains less well understood. Seeking clues as to how the internal sexual dimorphism evolved, we compared the abdominal musculature of 41 Drosophila montium group species, to determine whether any of these species carry a male-specific muscle of Lawrence (MOL). Our quantitative analysis revealed that the size of a sexually dimorphic MOL analog found in 19 montium group species varied widely from species to species, suggesting the gradual evolution of this sexually dimorphic neuromuscular trait. We attempted the ancestral state reconstitution for the presence or absence of the neuromuscular sexual dimorphism in the A5 segment; the neuromuscular sexual dimorphism existed in an old ancestor of the montium group, which was lost in some of the most recent common ancestors of derived lineages, and subsequently some species regained it. This loss-and-gain history was not shared by evolutionary changes in the courtship song pattern, even though both traits were commonly regulated by the master regulator male-determinant protein FruM. It is envisaged that different sets of FruM target genes may serve for shaping the song and MOL characteristics, respectively, and, as a consequence, each phenotypic trait underwent a distinct evolutionary path.
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16
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Zatsepina OG, Nikitina EA, Shilova VY, Chuvakova LN, Sorokina S, Vorontsova JE, Tokmacheva EV, Funikov SY, Rezvykh AP, Evgen'ev MB. Hsp70 affects memory formation and behaviorally relevant gene expression in Drosophila melanogaster. Cell Stress Chaperones 2021; 26:575-594. [PMID: 33829398 PMCID: PMC8065088 DOI: 10.1007/s12192-021-01203-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 03/20/2021] [Accepted: 03/23/2021] [Indexed: 12/13/2022] Open
Abstract
Heat shock proteins, in particular Hsp70, play a central role in proteostasis in eukaryotic cells. Due to its chaperone properties, Hsp70 is involved in various processes after stress and under normal physiological conditions. In contrast to mammals and many Diptera species, inducible members of the Hsp70 family in Drosophila are constitutively synthesized at a low level and undergo dramatic induction after temperature elevation or other forms of stress. In the courtship suppression paradigm used in this study, Drosophila males that have been repeatedly rejected by mated females during courtship are less likely than naive males to court other females. Although numerous genes with known function were identified to play important roles in long-term memory, there is, to the best of our knowledge, no direct evidence implicating Hsp70 in this process. To elucidate a possible role of Hsp70 in memory formation, we used D. melanogaster strains containing different hsp70 copy numbers, including strains carrying a deletion of all six hsp70 genes. Our investigations exploring the memory of courtship rejection paradigm demonstrated that a low constitutive level of Hsp70 is apparently required for learning and the formation of short and long-term memories in males. The performed transcriptomic studies demonstrate that males with different hsp70 copy numbers differ significantly in the expression of a few definite groups of genes involved in mating, reproduction, and immunity in response to rejection. Specifically, our analysis reveals several major pathways that depend on the presence of hsp70 in the genome and participate in memory formation and consolidation, including the cAMP signaling cascade.
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Affiliation(s)
- O G Zatsepina
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, Russia
| | - E A Nikitina
- Department of Neurogenetics, Pavlov Institute of Physiology, Russian Academy of Sciences, St. Petersburg, Russia
- Department of Human and Animal Anatomy and Physiology, Herzen State Pedagogical University, St. Petersburg, Russia
| | - V Y Shilova
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, Russia
| | - L N Chuvakova
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, Russia
| | - S Sorokina
- Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Moscow, Russia
| | - J E Vorontsova
- Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Moscow, Russia
| | - E V Tokmacheva
- Department of Neurogenetics, Pavlov Institute of Physiology, Russian Academy of Sciences, St. Petersburg, Russia
| | - S Y Funikov
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, Russia
| | - A P Rezvykh
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, Russia
| | - M B Evgen'ev
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow, Russia.
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17
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Monyak RE, Golbari NM, Chan YB, Pranevicius A, Tang G, Fernández MP, Kravitz EA. Masculinized Drosophila females adapt their fighting strategies to their opponent. J Exp Biol 2021; 224:jeb.238006. [PMID: 33568440 DOI: 10.1242/jeb.238006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 02/02/2021] [Indexed: 11/20/2022]
Abstract
Many animal species show aggression to gain mating partners and to protect territories and other resources from competitors. Both male and female fruit flies of the species Drosophila melanogaster exhibit aggression in same-sex pairings, but the strategies used are sexually dimorphic. We have begun to explore the biological basis for the differing aggression strategies, and the cues promoting one form of aggression over the other. Here, we describe a line of genetically masculinized females that switch between male and female aggression patterns based on the sexual identity of their opponents. When these masculinized females are paired with more aggressive opponents, they increase the amount of male-like aggression they use, but do not alter the level of female aggression. This suggests that male aggression may be more highly responsive to behavioral cues than female aggression. Although the masculinized females of this line show opponent-dependent changes in aggression and courtship behavior, locomotor activity and sleep are unaffected. Thus, the driver line used may specifically masculinize neurons involved in social behavior. A discussion of possible different roles of male and female aggression in fruit flies is included here. These results can serve as precursors to future experiments aimed at elucidating the circuitry and triggering cues underlying sexually dimorphic aggressive behavior.
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Affiliation(s)
- Rachel E Monyak
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Nicole M Golbari
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Yick-Bun Chan
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Ausra Pranevicius
- Department of Neuroscience and Behavior, Barnard College of Columbia University, New York City, NY 10027, USA
| | - Grace Tang
- Department of Neuroscience and Behavior, Barnard College of Columbia University, New York City, NY 10027, USA
| | - Maria Paz Fernández
- Department of Neuroscience and Behavior, Barnard College of Columbia University, New York City, NY 10027, USA
| | - Edward A Kravitz
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
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18
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Nojima T, Rings A, Allen AM, Otto N, Verschut TA, Billeter JC, Neville MC, Goodwin SF. A sex-specific switch between visual and olfactory inputs underlies adaptive sex differences in behavior. Curr Biol 2021; 31:1175-1191.e6. [PMID: 33508219 PMCID: PMC7987718 DOI: 10.1016/j.cub.2020.12.047] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/15/2020] [Accepted: 12/24/2020] [Indexed: 01/05/2023]
Abstract
Although males and females largely share the same genome and nervous system, they differ profoundly in reproductive investments and require distinct behavioral, morphological, and physiological adaptations. How can the nervous system, while bound by both developmental and biophysical constraints, produce these sex differences in behavior? Here, we uncover a novel dimorphism in Drosophila melanogaster that allows deployment of completely different behavioral repertoires in males and females with minimum changes to circuit architecture. Sexual differentiation of only a small number of higher order neurons in the brain leads to a change in connectivity related to the primary reproductive needs of both sexes-courtship pursuit in males and communal oviposition in females. This study explains how an apparently similar brain generates distinct behavioral repertoires in the two sexes and presents a fundamental principle of neural circuit organization that may be extended to other species.
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Affiliation(s)
- Tetsuya Nojima
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Annika Rings
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Aaron M Allen
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Nils Otto
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Thomas A Verschut
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - Jean-Christophe Billeter
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - Megan C Neville
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK.
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK.
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19
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Brovkina MV, Duffié R, Burtis AEC, Clowney EJ. Fruitless decommissions regulatory elements to implement cell-type-specific neuronal masculinization. PLoS Genet 2021; 17:e1009338. [PMID: 33600447 PMCID: PMC7924761 DOI: 10.1371/journal.pgen.1009338] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 03/02/2021] [Accepted: 01/04/2021] [Indexed: 01/12/2023] Open
Abstract
In the fruit fly Drosophila melanogaster, male-specific splicing and translation of the Fruitless transcription factor (FruM) alters the presence, anatomy, and/or connectivity of >60 types of central brain neurons that interconnect to generate male-typical behaviors. While the indispensable function of FruM in sex-specific behavior has been understood for decades, the molecular mechanisms underlying its activity remain unknown. Here, we take a genome-wide, brain-wide approach to identifying regulatory elements whose activity depends on the presence of FruM. We identify 436 high-confidence genomic regions differentially accessible in male fruitless neurons, validate candidate regions as bona fide, differentially regulated enhancers, and describe the particular cell types in which these enhancers are active. We find that individual enhancers are not activated universally but are dedicated to specific fru+ cell types. Aside from fru itself, genes are not dedicated to or common across the fru circuit; rather, FruM appears to masculinize each cell type differently, by tweaking expression of the same effector genes used in other circuits. Finally, we find FruM motifs enriched among regulatory elements that are open in the female but closed in the male. Together, these results suggest that FruM acts cell-type-specifically to decommission regulatory elements in male fruitless neurons. Courtship behavior in male Drosophila melanogaster is controlled by a well-defined neural circuit that is labeled by the male-specific transcription factor Fruitless (FruM). While FruM is known to change the number, anatomy and connectivity of neurons which comprise the circuit and has been suggested to repress the expression of a few gene targets, the mechanism of how FruM regulates genes across many different kinds of neurons is unknown. Using an approach to identify gene regulatory elements based on their chromatin accessibility states (ATAC-seq), we identified a large set of chromatin accessibility changes downstream of Fruitless. By examining the activity of these regulatory elements in vivo, we found that their activity was 1) sexually dimorphic and 2) specific to a single class of FruM neurons, suggesting that FruM acts on different chromatin targets in different neuron classes comprising the courtship circuit. Further, we found a known FruM-regulated enhancer of the FruM-repressed gene Lgr3 to have closed chromatin specifically in FruM neurons. Combined with an enrichment of FruM motifs in regions which are closed in FruM neurons, we present a mechanism where FruM directs the decommissioning of sex-shared regulatory elements to masculinize neurons in a cell-type specific manner.
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Affiliation(s)
- Margarita V. Brovkina
- Graduate Program in Cellular and Molecular Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Rachel Duffié
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, United States of America
- Mortimer B. Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, New York, United States of America
| | - Abbigayl E. C. Burtis
- Department of Molecular, Cellular, and Developmental Biology, The University of Michigan, Ann Arbor, Michigan, United States of America
| | - E. Josephine Clowney
- Department of Molecular, Cellular, and Developmental Biology, The University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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20
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Zhang Y, Ng R, Neville MC, Goodwin SF, Su CY. Distinct Roles and Synergistic Function of Fru M Isoforms in Drosophila Olfactory Receptor Neurons. Cell Rep 2020; 33:108516. [PMID: 33326795 PMCID: PMC7845487 DOI: 10.1016/j.celrep.2020.108516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 10/27/2020] [Accepted: 11/20/2020] [Indexed: 12/16/2022] Open
Abstract
Sexual dimorphism in Drosophila courtship circuits requires the male-specific transcription factor fruM, which is alternatively spliced to encode the FruMA, FruMB, and FruMC isoforms. Most fruM-positive neurons express multiple variants; however, the functional significance of their co-expression remains undetermined. Do co-expressed isoforms each play unique roles to jointly regulate dimorphism? By focusing on fruM-positive olfactory receptor neurons (ORNs), here, we show that FruMB and FruMC are both required for males' age-dependent sensitization to aphrodisiac olfactory cues in a cell-autonomous manner. Interestingly, FruMB expression is upregulated with age in Or47b and Ir84a ORNs, and its overexpression mimics the effect of age in elevating olfactory responses. Mechanistically, FruMB and FruMC synergistically mediate response sensitization through cooperation of their respective downstream effectors, namely, PPK25 and PPK23, which are both required for forming a functional amplification channel in ORNs. Together, these results provide critical mechanistic insight into how co-expressed FruM isoforms jointly coordinate dimorphic neurophysiology.
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Affiliation(s)
- Ye Zhang
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Renny Ng
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Megan C Neville
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | - Chih-Ying Su
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA.
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21
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Bakshi A, Sipani R, Ghosh N, Joshi R. Sequential activation of Notch and Grainyhead gives apoptotic competence to Abdominal-B expressing larval neuroblasts in Drosophila Central nervous system. PLoS Genet 2020; 16:e1008976. [PMID: 32866141 PMCID: PMC7485976 DOI: 10.1371/journal.pgen.1008976] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 09/11/2020] [Accepted: 07/01/2020] [Indexed: 11/19/2022] Open
Abstract
Neural circuitry for mating and reproduction resides within the terminal segments of central nervous system (CNS) which express Hox paralogous group 9–13 (in vertebrates) or Abdominal-B (Abd-B) in Drosophila. Terminal neuroblasts (NBs) in A8-A10 segments of Drosophila larval CNS are subdivided into two groups based on expression of transcription factor Doublesex (Dsx). While the sex specific fate of Dsx-positive NBs is well investigated, the fate of Dsx-negative NBs is not known so far. Our studies with Dsx-negative NBs suggests that these cells, like their abdominal counterparts (in A3-A7 segments) use Hox, Grainyhead (Grh) and Notch to undergo cell death during larval development. This cell death also happens by transcriptionally activating RHG family of apoptotic genes through a common apoptotic enhancer in early to mid L3 stages. However, unlike abdominal NBs (in A3-A7 segments) which use increasing levels of resident Hox factor Abdominal-A (Abd-A) as an apoptosis trigger, Dsx-negative NBs (in A8-A10 segments) keep the levels of resident Hox factor Abd-B constant. These cells instead utilize increasing levels of the temporal transcription factor Grh and a rise in Notch activity to gain apoptotic competence. Biochemical and in vivo analysis suggest that Abdominal-A and Grh binding motifs in the common apoptotic enhancer also function as Abdominal-B and Grh binding motifs and maintains the enhancer activity in A8-A10 NBs. Finally, the deletion of this enhancer by the CRISPR-Cas9 method blocks the apoptosis of Dsx-negative NBs. These results highlight the fact that Hox dependent NB apoptosis in abdominal and terminal regions utilizes common molecular players (Hox, Grh and Notch), but seems to have evolved different molecular strategies to pattern CNS. Two major characteristic features of bilaterian organisms are the head to tail axis and a complex central nervous system. The Hox family of transcription factors, which are expressed segmentally along the head to tail axis, plays a critical role in determining both of these features. One of the ways by which Hox factors do this is by mediating differential programmed cell death of the neural stem cells along the head to tail axis of the developing central nervous system, thereby regulating the numerical diversity of the neurons generated along this axis. Our study with a subpopulation of neural stem cells in the most terminal region of the Drosophila larval central nervous system highlights that region-specific Hox-dependent cell death of neural stem cells in abdominal and terminal regions utilizes common molecular players (Hox, Grh and Notch), but seems to have evolved different molecular strategies to pattern the developing central nervous system.
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Affiliation(s)
- Asif Bakshi
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad, India
- Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Rashmi Sipani
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad, India
- Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Neha Ghosh
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad, India
- Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Rohit Joshi
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad, India
- * E-mail: ,
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22
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Allen AM, Neville MC, Birtles S, Croset V, Treiber CD, Waddell S, Goodwin SF. A single-cell transcriptomic atlas of the adult Drosophila ventral nerve cord. eLife 2020; 9:e54074. [PMID: 32314735 PMCID: PMC7173974 DOI: 10.7554/elife.54074] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 04/03/2020] [Indexed: 02/07/2023] Open
Abstract
The Drosophila ventral nerve cord (VNC) receives and processes descending signals from the brain to produce a variety of coordinated locomotor outputs. It also integrates sensory information from the periphery and sends ascending signals to the brain. We used single-cell transcriptomics to generate an unbiased classification of cellular diversity in the VNC of five-day old adult flies. We produced an atlas of 26,000 high-quality cells, representing more than 100 transcriptionally distinct cell types. The predominant gene signatures defining neuronal cell types reflect shared developmental histories based on the neuroblast from which cells were derived, as well as their birth order. The relative position of cells along the anterior-posterior axis could also be assigned using adult Hox gene expression. This single-cell transcriptional atlas of the adult fly VNC will be a valuable resource for future studies of neurodevelopment and behavior.
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Affiliation(s)
- Aaron M Allen
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Megan C Neville
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Sebastian Birtles
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Vincent Croset
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | | | - Scott Waddell
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
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23
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Wohl M, Ishii K, Asahina K. Layered roles of fruitless isoforms in specification and function of male aggression-promoting neurons in Drosophila. eLife 2020; 9:e52702. [PMID: 32314957 PMCID: PMC7173971 DOI: 10.7554/elife.52702] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 04/03/2020] [Indexed: 12/20/2022] Open
Abstract
Inter-male aggressive behavior is a prominent sexually dimorphic behavior. Neural circuits that underlie aggressive behavior are therefore likely under the control of sex-determining genes. However, the neurogenetic mechanism that generates sex-specific aggressive behavior remains largely unknown. Here, we found that a neuronal class specified by one of the Drosophila sex determining genes, fruitless (fru), belongs to the neural circuit that generates male-type aggressive behavior. This neuronal class can promote aggressive behavior independent of another sex determining gene, doublesex (dsx), although dsx is involved in ensuring that aggressive behavior is performed only toward males. We also found that three fru isoforms with different DNA binding domains show a division of labor on male aggressive behaviors. A dominant role of fru in specifying sex-specific aggressive behavior may underscore a genetic mechanism that allows male-type aggressive behavior to evolve at least partially independently from courtship behavior, which is under different selective pressures.
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Affiliation(s)
- Margot Wohl
- Molecular Neurobiology Laboratory, The Salk Institute for Biological StudiesLa JollaUnited States
- Neuroscience Graduate Program, University of CaliforniaSan DiegoUnited States
| | - Kenichi Ishii
- Molecular Neurobiology Laboratory, The Salk Institute for Biological StudiesLa JollaUnited States
- Neuroscience Graduate Program, University of CaliforniaSan DiegoUnited States
| | - Kenta Asahina
- Molecular Neurobiology Laboratory, The Salk Institute for Biological StudiesLa JollaUnited States
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24
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Wat LW, Chao C, Bartlett R, Buchanan JL, Millington JW, Chih HJ, Chowdhury ZS, Biswas P, Huang V, Shin LJ, Wang LC, Gauthier MPL, Barone MC, Montooth KL, Welte MA, Rideout EJ. A role for triglyceride lipase brummer in the regulation of sex differences in Drosophila fat storage and breakdown. PLoS Biol 2020; 18:e3000595. [PMID: 31961851 PMCID: PMC6994176 DOI: 10.1371/journal.pbio.3000595] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 01/31/2020] [Accepted: 01/03/2020] [Indexed: 01/26/2023] Open
Abstract
Triglycerides are the major form of stored fat in all animals. One important determinant of whole-body fat storage is whether an animal is male or female. Here, we use Drosophila, an established model for studies on triglyceride metabolism, to gain insight into the genes and physiological mechanisms that contribute to sex differences in fat storage. Our analysis of triglyceride storage and breakdown in both sexes identified a role for triglyceride lipase brummer (bmm) in the regulation of sex differences in triglyceride homeostasis. Normally, male flies have higher levels of bmm mRNA both under normal culture conditions and in response to starvation, a lipolytic stimulus. We find that loss of bmm largely eliminates the sex difference in triglyceride storage and abolishes the sex difference in triglyceride breakdown via strongly male-biased effects. Although we show that bmm function in the fat body affects whole-body triglyceride levels in both sexes, in males, we identify an additional role for bmm function in the somatic cells of the gonad and in neurons in the regulation of whole-body triglyceride homeostasis. Furthermore, we demonstrate that lipid droplets are normally present in both the somatic cells of the male gonad and in neurons, revealing a previously unrecognized role for bmm function, and possibly lipid droplets, in these cell types in the regulation of whole-body triglyceride homeostasis. Taken together, our data reveal a role for bmm function in the somatic cells of the gonad and in neurons in the regulation of male–female differences in fat storage and breakdown and identify bmm as a link between the regulation of triglyceride homeostasis and biological sex. An investigation of the genetic and physiological mechanisms underlying sex differences in fat storage and breakdown in the fruit fly Drosophila identifies previously unrecognized sex- and cell type-specific roles for the conserved triglyceride lipase brummer.
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Affiliation(s)
- Lianna W. Wat
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Charlotte Chao
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Rachael Bartlett
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Justin L. Buchanan
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Jason W. Millington
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Hui Ju Chih
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Zahid S. Chowdhury
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Puja Biswas
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Vivian Huang
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Leah J. Shin
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Lin Chuan Wang
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Marie-Pierre L. Gauthier
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Maria C. Barone
- Department of Biology, University of Rochester, Rochester, New York, United States of America
| | - Kristi L. Montooth
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Michael A. Welte
- Department of Biology, University of Rochester, Rochester, New York, United States of America
| | - Elizabeth J. Rideout
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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25
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Ghosh N, Bakshi A, Khandelwal R, Rajan SG, Joshi R. The Hox gene Abdominal-B uses Doublesex F as a cofactor to promote neuroblast apoptosis in the Drosophila central nervous system. Development 2019; 146:dev.175158. [PMID: 31371379 PMCID: PMC6737903 DOI: 10.1242/dev.175158] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 07/22/2019] [Indexed: 12/28/2022]
Abstract
Highly conserved DM domain-containing transcription factors (Doublesex/MAB-3/DMRT1) are responsible for generating sexually dimorphic features. In the Drosophila central nervous system, a set of Doublesex (Dsx)-expressing neuroblasts undergo apoptosis in females whereas their male counterparts proliferate and give rise to serotonergic neurons crucial for adult mating behaviour. Our study demonstrates that the female-specific isoform of Dsx collaborates with Hox gene Abdominal-B (Abd-B) to bring about this apoptosis. Biochemical results suggest that proteins AbdB and Dsx interact through their highly conserved homeodomain and DM domain, respectively. This interaction is translated into a cooperative binding of the two proteins on the apoptotic enhancer in the case of females but not in the case of males, resulting in female-specific activation of apoptotic genes. The capacity of AbdB to use the sex-specific isoform of Dsx as a cofactor underlines the possibility that these two classes of protein are capable of cooperating in selection and regulation of target genes in a tissue- and sex-specific manner. We propose that this interaction could be a common theme in generating sexual dimorphism in different tissues across different species.
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Affiliation(s)
- Neha Ghosh
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal 576104, India
| | - Asif Bakshi
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal 576104, India
| | - Risha Khandelwal
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal 576104, India
| | | | - Rohit Joshi
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad 500039, India
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26
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Asahina K. Sex differences in Drosophila behavior: Qualitative and Quantitative Dimorphism. CURRENT OPINION IN PHYSIOLOGY 2018; 6:35-45. [PMID: 30386833 PMCID: PMC6205217 DOI: 10.1016/j.cophys.2018.04.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The importance of sex as a biological variable is being recognized by more and more researchers, including those using Drosophila melanogaster as a model organism. Differences between the two sexes are not confined to well-known reproductive behaviors, but include other behaviors and physiological characteristics that are considered "common" to both sexes. It is possible to categorize sexual dimorphisms into "qualitative" and "quantitative" differences, and this review focuses on recent advances in elucidating genetic and neurophysiological basis of both qualitative and quantitative sex differences in Drosophila behavior. While sex-specific behaviors are often mediated by sexually dimorphic neural circuits, quantitative sexual dimorphism is caused by sex-specific modulation of a common neuronal substrate.
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Affiliation(s)
- Kenta Asahina
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, MNL-KA, La Jolla, California 92037, United States of America
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27
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Millington JW, Rideout EJ. Sex differences in Drosophila development and physiology. CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2018.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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28
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Molina-García L, Barrios A. Sex differences in learning — shared principles across taxa. CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2018.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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29
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Schenkel MA, Pen I, Beukeboom LW, Billeter J. Making sense of intralocus and interlocus sexual conflict. Ecol Evol 2018; 8:13035-13050. [PMID: 30619603 PMCID: PMC6309128 DOI: 10.1002/ece3.4629] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 09/17/2018] [Accepted: 09/18/2018] [Indexed: 01/13/2023] Open
Abstract
Sexual conflict occurs because males and females are exposed to different selection pressures. This can affect many aspects of female and male biology, such as physiology, behavior, genetics, and even population ecology. Its broad impact has caused widespread interest in sexual conflict. However, a key aspect of sexual conflict is often confused; it comprises two distinct forms: intralocus and interlocus sexual conflict (IASC and IRSC). Although both are caused by sex differences in selection, they operate via different proximate and ultimate mechanisms. Intralocus sexual conflict and IRSC are often not clearly defined as separate processes in the scientific literature, which impedes a proper understanding of each form as well as of their relative impact on sexual conflict. Furthermore, our current knowledge of the genetics of these phenomena is severely limited. This prevents us from empirically testing numerous theories regarding the role of these two forms of sexual conflict in evolution. Here, we clarify the distinction between IASC and IRSC, by discussing how male and female interests differ, how and when sex-specific adaptation occurs, and how this may lead to evolutionary change. We then describe a framework for their study, focusing on how future experiments may help identify the genetics underlying these phenomena. Through this, we hope to promote a more critical reflection on IASC and IRSC as well as underline the necessity of genetic and mechanistic studies of these two phenomena.
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Affiliation(s)
- Martijn A. Schenkel
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Ido Pen
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Leo W. Beukeboom
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Jean‐Christophe Billeter
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
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30
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Knoedler JR, Shah NM. Molecular mechanisms underlying sexual differentiation of the nervous system. Curr Opin Neurobiol 2018; 53:192-197. [PMID: 30316066 DOI: 10.1016/j.conb.2018.09.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 09/18/2018] [Indexed: 10/28/2022]
Abstract
A long-standing goal in developmental neuroscience is to understand the mechanisms by which steroid sex hormones pattern the mammalian central nervous system along male or female pathways to enable subsequent displays of sexually dimorphic behaviors. In this article, we review recent advances in understanding the epigenetic and transcriptional mechanisms mediating sexual differentiation of the brain in mammals, flies, and worms. These studies suggest a model of sexual differentiation wherein master regulators of sex determination initiate a cascade of sexually dimorphic gene expression that controls development of neural pathways and behavioral displays in a strikingly modular manner. With these advances in molecular genetics, it is now feasible to disassemble different components of sexually dimorphic social behaviors without disrupting other behavioral interactions. Such experimental tractability promises rapid advances in this exciting field.
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Affiliation(s)
- Joseph R Knoedler
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, United States
| | - Nirao M Shah
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, United States; Department of Neurobiology, Stanford University, Stanford, CA 94305, United States.
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31
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Zhang B, Sato K, Yamamoto D. Ecdysone signaling regulates specification of neurons with a male-specific neurite in Drosophila. Biol Open 2018; 7:7/2/bio029744. [PMID: 29463514 PMCID: PMC5861360 DOI: 10.1242/bio.029744] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Some mAL neurons in the male brain form the ipsilateral neurite (ILN[+]) in a manner dependent on FruBM, a male-specific transcription factor. FruBM represses robo1 transcription, allowing the ILN to form. We found that the proportion of ILN[+]-mALs in all observed single cell clones dropped from ∼90% to ∼30% by changing the heat-shock timing for clone induction from 4-5 days after egg laying (AEL) to 6-7 days AEL, suggesting that the ILN[+]-mALs are produced predominantly by young neuroblasts. Upon EcR-A knockdown, ILN[+]-mALs were produced at a high rate (∼60%), even when heat shocked at 6-7 days AEL, yet EcR-B1 knockdown reduced the proportion of ILN[+]-mALs to ∼30%. Immunoprecipitation assays in S2 cells demonstrated that EcR-A and EcR-B1 form a complex with FruBM. robo1 reporter transcription was repressed by FruBM and ecdysone counteracted FruBM. We suggest that ecdysone signaling modulates the FruBM action to produce an appropriate number of male-type neurons. Summary: The insect molting hormone ecdysone determines whether a single neuron develops a sex-specific structure, through crosstalk with signaling elements in a pathway dedicated to the sex-fate determination.
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Affiliation(s)
- Binglong Zhang
- Division of Neurogenetics, Tohoku University Graduate School of Life Sciences, Sendai, 980-8577, Japan
| | - Kosei Sato
- Division of Neurogenetics, Tohoku University Graduate School of Life Sciences, Sendai, 980-8577, Japan
| | - Daisuke Yamamoto
- Division of Neurogenetics, Tohoku University Graduate School of Life Sciences, Sendai, 980-8577, Japan
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32
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Garner SRC, Castellanos MC, Baillie KE, Lian T, Allan DW. Drosophila female-specific Ilp7 motoneurons are generated by Fruitless-dependent cell death in males and by a double-assurance survival role for Transformer in females. Development 2018; 145:dev.150821. [PMID: 29229771 DOI: 10.1242/dev.150821] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 11/13/2017] [Indexed: 01/03/2023]
Abstract
Female-specific Ilp7 neuropeptide-expressing motoneurons (FS-Ilp7 motoneurons) are required in Drosophila for oviduct function in egg laying. Here, we uncover cellular and genetic mechanisms underlying their female-specific generation. We demonstrate that programmed cell death (PCD) eliminates FS-Ilp7 motoneurons in males, and that this requires male-specific splicing of the sex-determination gene fruitless (fru) into the FruMC isoform. However, in females, fru alleles that only generate FruM isoforms failed to kill FS-Ilp7 motoneurons. This blockade of FruM-dependent PCD was not attributable to doublesex gene function but to a non-canonical role for transformer (tra), a gene encoding the RNA splicing activator that regulates female-specific splicing of fru and dsx transcripts. In both sexes, we show that Tra prevents PCD even when the FruM isoform is expressed. In addition, we found that FruMC eliminated FS-Ilp7 motoneurons in both sexes, but only when Tra was absent. Thus, FruMC-dependent PCD eliminates female-specific neurons in males, and Tra plays a double-assurance function in females to establish and reinforce the decision to generate female-specific neurons.
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Affiliation(s)
- Sarah Rose C Garner
- Department of Cellular and Physiological Sciences, University of British Columbia, 2420 Life Sciences Institute, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Monica C Castellanos
- Department of Cellular and Physiological Sciences, University of British Columbia, 2420 Life Sciences Institute, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Katherine E Baillie
- Department of Cellular and Physiological Sciences, University of British Columbia, 2420 Life Sciences Institute, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Tianshun Lian
- Department of Cellular and Physiological Sciences, University of British Columbia, 2420 Life Sciences Institute, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Douglas W Allan
- Department of Cellular and Physiological Sciences, University of British Columbia, 2420 Life Sciences Institute, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
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33
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Chowdhury ZS, Sato K, Yamamoto D. The core-promoter factor TRF2 mediates a Fruitless action to masculinize neurobehavioral traits in Drosophila. Nat Commun 2017; 8:1480. [PMID: 29133872 PMCID: PMC5684138 DOI: 10.1038/s41467-017-01623-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 10/02/2017] [Indexed: 11/29/2022] Open
Abstract
In fruit flies, the male-specific fruitless (fru) gene product FruBM plays a central role in establishing the neural circuitry for male courtship behavior by orchestrating the transcription of genes required for the male-type specification of individual neurons. We herein identify the core promoter recognition factor gene Trf2 as a dominant modifier of fru actions. Trf2 knockdown in the sexually dimorphic mAL neurons leads to the loss of a male-specific neurite and a reduction in male courtship vigor. TRF2 forms a repressor complex with FruBM, strongly enhancing the repressor activity of FruBM at the promoter region of the robo1 gene, whose function is required for inhibiting the male-specific neurite formation. In females that lack FruBM, TRF2 stimulates robo1 transcription. Our results suggest that TRF2 switches its own role from an activator to a repressor of transcription upon binding to FruBM, thereby enabling the ipsilateral neurite formation only in males.
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Affiliation(s)
| | - Kosei Sato
- Tohoku University Graduate School of Life Sciences, Sendai, 9808577, Japan
| | - Daisuke Yamamoto
- Tohoku University Graduate School of Life Sciences, Sendai, 9808577, Japan.
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34
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Pavlou HJ, Lin AC, Neville MC, Nojima T, Diao F, Chen BE, White BH, Goodwin SF. Neural circuitry coordinating male copulation. eLife 2016; 5:e20713. [PMID: 27855059 PMCID: PMC5114013 DOI: 10.7554/elife.20713] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 09/28/2016] [Indexed: 11/13/2022] Open
Abstract
Copulation is the goal of the courtship process, crucial to reproductive success and evolutionary fitness. Identifying the circuitry underlying copulation is a necessary step towards understanding universal principles of circuit operation, and how circuit elements are recruited into the production of ordered action sequences. Here, we identify key sex-specific neurons that mediate copulation in Drosophila, and define a sexually dimorphic motor circuit in the male abdominal ganglion that mediates the action sequence of initiating and terminating copulation. This sexually dimorphic circuit composed of three neuronal classes - motor neurons, interneurons and mechanosensory neurons - controls the mechanics of copulation. By correlating the connectivity, function and activity of these neurons we have determined the logic for how this circuitry is coordinated to generate this male-specific behavior, and sets the stage for a circuit-level dissection of active sensing and modulation of copulatory behavior.
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Affiliation(s)
- Hania J Pavlou
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
| | - Andrew C Lin
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Megan C Neville
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
| | - Tetsuya Nojima
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
| | - Fengqiu Diao
- Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, United States
| | - Brian E Chen
- Department of Medicine, McGill University, Montréal, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, Canada
| | - Benjamin H White
- Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, United States
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
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35
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Ito H, Sato K, Kondo S, Ueda R, Yamamoto D. Fruitless Represses robo1 Transcription to Shape Male-Specific Neural Morphology and Behavior in Drosophila. Curr Biol 2016; 26:1532-1542. [PMID: 27265393 DOI: 10.1016/j.cub.2016.04.067] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 04/21/2016] [Accepted: 04/27/2016] [Indexed: 11/17/2022]
Abstract
The Drosophila fruitless (fru) gene is regarded as a master regulator of the formation of male courtship circuitry, yet little is known about its molecular basis of action. We show that roundabout 1 (robo1) knockdown in females promotes formation of the male-specific neurite in sexually dimorphic mAL interneurons and that overexpression of the male-specific Fru(BM) diminishes the expression of Robo1 in the fly brain. Our electrophoretic mobility shift and reporter assays identify the 42-bp segment encompassing the palindrome sequence T T C G C T G C G C C G T G A A in the 5' UTR of robo1 exon1 as the Fru(BM)-responsive element. We find that ∼10-bp deletions in the palindrome sequence induce a loss of the male-specific neurite and disrupt male courtship patterns. This study paves the way for a thorough understanding of the mechanism whereby Fru proteins orchestrate transcription for the formation of courtship circuitry.
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Affiliation(s)
- Hiroki Ito
- Division of Neurogenetics, Tohoku University Graduate School of Life Sciences, Sendai 980-8577, Japan
| | - Kosei Sato
- Division of Neurogenetics, Tohoku University Graduate School of Life Sciences, Sendai 980-8577, Japan
| | - Shu Kondo
- National Institute of Genetics, Mishima 411-8540, Japan
| | - Ryu Ueda
- National Institute of Genetics, Mishima 411-8540, Japan
| | - Daisuke Yamamoto
- Division of Neurogenetics, Tohoku University Graduate School of Life Sciences, Sendai 980-8577, Japan.
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36
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Auer TO, Benton R. Sexual circuitry in Drosophila. Curr Opin Neurobiol 2016; 38:18-26. [PMID: 26851712 DOI: 10.1016/j.conb.2016.01.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 01/05/2016] [Indexed: 11/15/2022]
Abstract
The sexual behavior of Drosophila melanogaster is an outstanding paradigm to understand the molecular and neuronal basis of sophisticated animal actions. We discuss recent advances in our knowledge of the genetic hardwiring of the underlying neuronal circuitry, and how pertinent sensory cues are differentially detected and integrated in the male and female brain. We also consider how experience influences these circuits over short timescales, and the evolution of these pathways over longer timescales to endow species-specific sexual displays and responses.
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Affiliation(s)
- Thomas O Auer
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland.
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37
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Abstract
The development of sexually dimorphic morphology and the potential for sexually dimorphic behavior in Drosophila are regulated by the Fruitless (Fru) and Doublesex (Dsx) transcription factors. Several direct targets of Dsx have been identified, but direct Fru targets have not been definitively identified. We show that Drosophila leucine-rich repeat G protein-coupled receptor 3 (Lgr3) is regulated by Fru and Dsx in separate populations of neurons. Lgr3 is a member of the relaxin-receptor family and a receptor for Dilp8, necessary for control of organ growth. Lgr3 expression in the anterior central brain of males is inhibited by the B isoform of Fru, whose DNA binding domain interacts with a short region of an Lgr3 intron. Fru A and C isoform mutants had no observed effect on Lgr3 expression. The female form of Dsx (Dsx(F)) separately up- and down-regulates Lgr3 expression in distinct neurons in the abdominal ganglion through female- and male-specific Lgr3 enhancers. Excitation of neural activity in the Dsx(F)-up-regulated abdominal ganglion neurons inhibits female receptivity, indicating the importance of these neurons for sexual behavior. Coordinated regulation of Lgr3 by Fru and Dsx marks a point of convergence of the two branches of the sex-determination hierarchy.
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38
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Chen CJ, Shikina S, Chen WJ, Chung YJ, Chiu YL, Bertrand JAM, Lee YH, Chang CF. A Novel Female-Specific and Sexual Reproduction-Associated Dmrt Gene Discovered in the Stony Coral, Euphyllia ancora. Biol Reprod 2016; 94:40. [PMID: 26740592 DOI: 10.1095/biolreprod.115.133173] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 12/28/2015] [Indexed: 11/01/2022] Open
Abstract
Transcription factors encoded by the Dmrt gene family regulate multiple aspects of animal reproduction. Most studies investigating the Dmrt gene family were conducted in model organisms from bilateral species, with a particular emphasis on gene function in male sex determination. It is still unclear whether the E. ancora Dmrt (EaDmrt) genes found in basal metazoans such as cnidarians share similar characteristics with orthologs in other metazoans. In this study, seven full Dmrt gene transcript sequences for a gonochoric coral, Euphyllia ancora (phylum: Cnidaria; class: Anthozoa), were obtained through transcriptome data mining, RT-PCR analysis, rapid amplification of cDNA ends, and sequencing. These EaDmrts were subjected to quantitative assays measuring temporal and tissue-specific expression. Results demonstrated a unique gene expression pattern for EaDmrtE, which is enriched in female germ cells during the spawning season. Based on the phylogenetic analyses performed across the homologous Dmrt genes in metazoans, we found that the female-specific EaDmrtE gene is not related to the DM1 gene of Acropora spp. coral nor to Dmrt1 of vertebrates, which are involved in sexual reproduction, especially in sex determination (vertebrate Dmrt1). Additionally, high levels of EaDmrtE transcripts detected in unfertilized mature eggs are retained in newly formed zygotes but decrease during embryonic development. We suggest that the newly discovered gene may play a role in oogenesis and early embryogenesis as a maternal factor in corals. Therefore, the sexual reproduction-associated Dmrt gene(s) should have arisen in cnidarians and might have evolved multiple times in metazoans.
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Affiliation(s)
- Chieh-Jhen Chen
- Institute of Oceanography, National Taiwan University, Taipei, Taiwan Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan
| | - Shinya Shikina
- Institute of Marine Environment and Ecology, National Taiwan Ocean University, Keelung, Taiwan Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan
| | - Wei-Jen Chen
- Institute of Oceanography, National Taiwan University, Taipei, Taiwan
| | - Yi-Jou Chung
- Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan
| | - Yi-Ling Chiu
- Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan
| | | | - Yan-Horn Lee
- Tungkang Biotechnology Research Center, Fisheries Research Institute, Tungkang, Taiwan
| | - Ching-Fong Chang
- Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan
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39
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Nojima T, Neville MC, Goodwin SF. Fruitless isoforms and target genes specify the sexually dimorphic nervous system underlying Drosophila reproductive behavior. Fly (Austin) 2015; 8:95-100. [PMID: 25483248 PMCID: PMC4197022 DOI: 10.4161/fly.29132] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Courtship is pivotal to successful reproduction throughout the animal kingdom. Sexual differences in the nervous system are thought to underlie courtship behavior. Male courtship behavior in Drosophila is in large part regulated by the gene fruitless (fru). fru has been reported to encode at least three putative BTB-zinc-finger transcription factors predicted to have different DNA-binding specificities. Although a large number of previous studies have demonstrated that fru plays essential roles in male courtship behavior, we know little about the function of Fru isoforms at the molecular level. Our recent study revealed that male-specific Fru isoforms are expressed in highly overlapping subsets of neurons in the male brain and ventral nerve cord. Fru isoforms play both distinct and redundant roles in male courtship behavior. Importantly, we have identified for the first time, by means of the DamID technique, direct Fru transcriptional target genes. Fru target genes overwhelmingly represent genes previously reported to be involved in the nervous system development, such as CadN, lola and pdm2. Our study provides important insight into how the sexually dimorphic neural circuits underlying reproductive behavior are established.
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Affiliation(s)
- Tetsuya Nojima
- a Department of Physiology, Anatomy and Genetics; University of Oxford; Oxford, UK
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40
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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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Zhou C, Pan Y, Robinett C, Meissner G, Baker B. Central Brain Neurons Expressing doublesex Regulate Female Receptivity in Drosophila. Neuron 2014; 83:149-63. [DOI: 10.1016/j.neuron.2014.05.038] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2014] [Indexed: 10/25/2022]
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Guo Y, Feng Y, Li Z, Lin X. Drosophila heparan sulfate 3-O sulfotransferase B null mutant is viable and exhibits no defects in Notch signaling. J Genet Genomics 2014; 41:369-78. [PMID: 25064676 DOI: 10.1016/j.jgg.2014.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 04/18/2014] [Accepted: 04/24/2014] [Indexed: 11/26/2022]
Abstract
Heparan sulfate proteoglycans (HSPGs) are critically involved in a variety of biological events. The functions of HSPGs are determined by the nature of the core proteins and modifications of heparan sulfate (HS) glycosaminoglycan (GAG) chains. The distinct O-sulfotransferases are important for nonrandom modifications at specific positions. Two HS 3-O sulfotransferase (Hs3st) genes, Hs3st-A and Hs3st-B, were identified in Drosophila. Previous experiments using RNA interference (RNAi) suggested that Hs3st-B was required for Notch signaling. Here, we generated a null mutant of Hs3st-B via ends-out gene targeting and examined its role(s) in development. We found that homozygous Hs3st-B mutants have no neurogenic defects or alterations in the expression of Notch signaling target gene. Thus, our results strongly argue against an essential role for Hs3st-B in Notch signaling. Moreover, we have generated two independent Hs3st-A RNAi lines which worked to deplete Hs3st-A. Importantly, Hs3st-A RNAi combined with Hs3st-B mutant flies did not alter the expression of Notch signaling components, arguing that both Hs3st-A and Hs3st-B were not essential for Notch signaling. The establishment of Hs3st-B mutant and effective Hs3st-A RNAi lines provides essential tools for further studies of the physiological roles of Hs3st-A and Hs3st-B in development and homeostasis.
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Affiliation(s)
- Yueqin Guo
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ying Feng
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou 325000, China; State Key Laboratory of Stress Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361005, China
| | - Zhouhua Li
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; School of Life Sciences, Capital Normal University, Beijing 100048, China.
| | - Xinhua Lin
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
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Genetic identification and separation of innate and experience-dependent courtship behaviors in Drosophila. Cell 2014; 156:236-48. [PMID: 24439379 PMCID: PMC4677784 DOI: 10.1016/j.cell.2013.11.041] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 09/26/2013] [Accepted: 11/13/2013] [Indexed: 12/23/2022]
Abstract
Wild-type D. melanogaster males innately possess the ability to perform a multistep courtship ritual to conspecific females. The potential for this behavior is specified by the male-specific products of the fruitless (fru(M)) gene; males without fru(M) do not court females when held in isolation. We show that such fru(M) null males acquire the potential for courtship when grouped with other flies; they apparently learn to court flies with which they were grouped, irrespective of sex or species and retain this behavior for at least a week. The male-specific product of the doublesex gene (dsx(M)) is necessary and sufficient for the acquisition of the potential for such experience-dependent courtship. These results reveal a process that builds, via dsx(M) and social experience, the potential for a more flexible sexual behavior, which could be evolutionarily conserved as dsx-related genes that function in sexual development are found throughout the animal kingdom.
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Genome wide identification of fruitless targets suggests a role in upregulating genes important for neural circuit formation. Sci Rep 2014; 4:4412. [PMID: 24642956 PMCID: PMC3958720 DOI: 10.1038/srep04412] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 02/28/2014] [Indexed: 11/09/2022] Open
Abstract
The fruitless gene (fru) encodes a set of transcription factors (Fru) that display sexually dimorphic gene expression in the brain of the fruit-fly; Drosophila melanogaster. Behavioural studies have demonstrated that fru is essential for courtship behaviour in the male fly and is thought to act by directing the development of sex-specific neural circuitry that encodes this innate behavioural response. This study reports the identification of direct regulatory targets of the sexually dimorphic isoforms of the Fru protein using an in vitro model system. Genome wide binding sites were identified for each of the isoforms using Chromatin Immunoprecipitation coupled to deep sequencing (ChIP-Seq). Putative target genes were found to be involved in processes such as neurotransmission, ion-channel signalling and neuron development. All isoforms showed a significant bias towards genes located on the X-chromosome, which may reflect a specific role for Fru in regulating x-linked genes. Taken together with expression analysis carried out in Fru positive neurons specifically isolated from the male fly brain, it appears that the Fru protein acts as a transcriptional activator. Understanding the regulatory cascades induced by Fru will help to shed light on the molecular mechanisms that are important for specification of neural circuitry underlying complex behaviour.
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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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Neville MC, Nojima T, Ashley E, Parker DJ, Walker J, Southall T, Van de Sande B, Marques AC, Fischer B, Brand AH, Russell S, Ritchie MG, Aerts S, Goodwin SF. Male-specific fruitless isoforms target neurodevelopmental genes to specify a sexually dimorphic nervous system. Curr Biol 2014; 24:229-41. [PMID: 24440396 PMCID: PMC3969260 DOI: 10.1016/j.cub.2013.11.035] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 11/18/2013] [Accepted: 11/19/2013] [Indexed: 02/06/2023]
Abstract
Background In Drosophila, male courtship behavior is regulated in large part by the gene fruitless (fru). fru encodes a set of putative transcription factors that promote male sexual behavior by controlling the development of sexually dimorphic neuronal circuitry. Little is known about how Fru proteins function at the level of transcriptional regulation or the role that isoform diversity plays in the formation of a male-specific nervous system. Results To characterize the roles of sex-specific Fru isoforms in specifying male behavior, we generated novel isoform-specific mutants and used a genomic approach to identify direct Fru isoform targets during development. We demonstrate that all Fru isoforms directly target genes involved in the development of the nervous system, with individual isoforms exhibiting unique binding specificities. We observe that fru behavioral phenotypes are specified by either a single isoform or a combination of isoforms. Finally, we illustrate the utility of these data for the identification of novel sexually dimorphic genomic enhancers and novel downstream regulators of male sexual behavior. Conclusions These findings suggest that Fru isoform diversity facilitates both redundancy and specificity in gene expression, and that the regulation of neuronal developmental genes may be the most ancient and conserved role of fru in the specification of a male-specific nervous system. Isoform-specific fru mutants reveal both functional redundancy and specificity Fru isoform-specific genomic occupancy is characterized in the Drosophila nervous system All Fru isoforms directly target neuronal morphogenesis genes Isoform-specific motifs are associated with specific Fru isoform occupancy
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Affiliation(s)
- Megan C Neville
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford OX1 3PT, UK.
| | - Tetsuya Nojima
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford OX1 3PT, UK
| | - Elizabeth Ashley
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford OX1 3PT, UK
| | - Darren J Parker
- Centre for Biological Diversity, University of St Andrews, St Andrews, KY16 9TH, UK
| | - John Walker
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford OX1 3PT, UK
| | - Tony Southall
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Bram Van de Sande
- Laboratory of Computational Biology, Department of Human Genetics, University of Leuven, 3000 Leuven, Belgium
| | - Ana C Marques
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford OX1 3PT, UK
| | - Bettina Fischer
- Cambridge Systems Biology Centre, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK; Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
| | - Andrea H Brand
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Steven Russell
- Cambridge Systems Biology Centre, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK; Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
| | - Michael G Ritchie
- Centre for Biological Diversity, University of St Andrews, St Andrews, KY16 9TH, UK
| | - Stein Aerts
- Laboratory of Computational Biology, Department of Human Genetics, University of Leuven, 3000 Leuven, Belgium
| | - Stephen F Goodwin
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford OX1 3PT, UK.
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von Philipsborn AC, Jörchel S, Tirian L, Demir E, Morita T, Stern DL, Dickson BJ. Cellular and behavioral functions of fruitless isoforms in Drosophila courtship. Curr Biol 2014; 24:242-51. [PMID: 24440391 PMCID: PMC3969150 DOI: 10.1016/j.cub.2013.12.015] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 12/09/2013] [Accepted: 12/09/2013] [Indexed: 12/04/2022]
Abstract
Background Male-specific products of the fruitless (fru) gene control the development and function of neuronal circuits that underlie male-specific behaviors in Drosophila, including courtship. Alternative splicing generates at least three distinct Fru isoforms, each containing a different zinc-finger domain. Here, we examine the expression and function of each of these isoforms. Results We show that most fru+ cells express all three isoforms, yet each isoform has a distinct function in the elaboration of sexually dimorphic circuitry and behavior. The strongest impairment in courtship behavior is observed in fruC mutants, which fail to copulate, lack sine song, and do not generate courtship song in the absence of visual stimuli. Cellular dimorphisms in the fru circuit are dependent on FruC rather than other single Fru isoforms. Removal of FruC from the neuronal classes vAB3 or aSP4 leads to cell-autonomous feminization of arborizations and loss of courtship in the dark. Conclusions These data map specific aspects of courtship behavior to the level of single fru isoforms and fru+ cell types—an important step toward elucidating the chain of causality from gene to circuit to behavior. fru A, B, and C isoforms have largely overlapping expression in the male fly CNS All three fru isoforms contribute to male courtship, with fruC being the most critical FruC specifies sexual dimorphisms in neuron number and arborizations FruC is required in defined neuronal classes for male-specific anatomy and behavior
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Affiliation(s)
- Anne C von Philipsborn
- Research Institute of Molecular Pathology (IMP), Dr. Bohr-Gasse 7, 1030 Vienna, Austria.
| | - Sabrina Jörchel
- Research Institute of Molecular Pathology (IMP), Dr. Bohr-Gasse 7, 1030 Vienna, Austria
| | - Laszlo Tirian
- Research Institute of Molecular Pathology (IMP), Dr. Bohr-Gasse 7, 1030 Vienna, Austria
| | - Ebru Demir
- Research Institute of Molecular Pathology (IMP), Dr. Bohr-Gasse 7, 1030 Vienna, Austria
| | - Tomoko Morita
- Janelia Farm Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - David L Stern
- Janelia Farm Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Barry J Dickson
- Research Institute of Molecular Pathology (IMP), Dr. Bohr-Gasse 7, 1030 Vienna, Austria; Janelia Farm Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA.
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48
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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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49
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Laturney M, Billeter JC. Neurogenetics of female reproductive behaviors in Drosophila melanogaster. ADVANCES IN GENETICS 2014; 85:1-108. [PMID: 24880733 DOI: 10.1016/b978-0-12-800271-1.00001-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
We follow an adult Drosophila melanogaster female through the major reproductive decisions she makes during her lifetime, including habitat selection, precopulatory mate choice, postcopulatory physiological changes, polyandry, and egg-laying site selection. In the process, we review the molecular and neuronal mechanisms allowing females to integrate signals from both environmental and social sources to produce those behavioral outputs. We pay attention to how an understanding of D. melanogaster female reproductive behaviors contributes to a wider understanding of evolutionary processes such as pre- and postcopulatory sexual selection as well as sexual conflict. Within each section, we attempt to connect the theories that pertain to the evolution of female reproductive behaviors with the molecular and neurobiological data that support these theories. We draw attention to the fact that the evolutionary and mechanistic basis of female reproductive behaviors, even in a species as extensively studied as D. melanogaster, remains poorly understood.
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Affiliation(s)
- Meghan Laturney
- Behavioural Biology, Centre for Behaviour and Neurosciences, University of Groningen, Groningen, The Netherlands
| | - Jean-Christophe Billeter
- Behavioural Biology, Centre for Behaviour and Neurosciences, University of Groningen, Groningen, The Netherlands
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50
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Kohl J, Ostrovsky AD, Frechter S, Jefferis GSXE. A bidirectional circuit switch reroutes pheromone signals in male and female brains. Cell 2013; 155:1610-23. [PMID: 24360281 PMCID: PMC3898676 DOI: 10.1016/j.cell.2013.11.025] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 10/02/2013] [Accepted: 11/08/2013] [Indexed: 02/06/2023]
Abstract
The Drosophila sex pheromone cVA elicits different behaviors in males and females. First- and second-order olfactory neurons show identical pheromone responses, suggesting that sex genes differentially wire circuits deeper in the brain. Using in vivo whole-cell electrophysiology, we now show that two clusters of third-order olfactory neurons have dimorphic pheromone responses. One cluster responds in females; the other responds in males. These clusters are present in both sexes and share a common input pathway, but sex-specific wiring reroutes pheromone information. Regulating dendritic position, the fruitless transcription factor both connects the male-responsive cluster and disconnects the female-responsive cluster from pheromone input. Selective masculinization of third-order neurons transforms their morphology and pheromone responses, demonstrating that circuits can be functionally rewired by the cell-autonomous action of a switch gene. This bidirectional switch, analogous to an electrical changeover switch, provides a simple circuit logic to activate different behaviors in males and females.
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Affiliation(s)
- Johannes Kohl
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Aaron D Ostrovsky
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Shahar Frechter
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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