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Task D, Lin CC, Vulpe A, Afify A, Ballou S, Brbic M, Schlegel P, Raji J, Jefferis GSXE, Li H, Menuz K, Potter CJ. Chemoreceptor co-expression in Drosophila melanogaster olfactory neurons. eLife 2022; 11:e72599. [PMID: 35442190 PMCID: PMC9020824 DOI: 10.7554/elife.72599] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 03/07/2022] [Indexed: 12/20/2022] Open
Abstract
Drosophila melanogaster olfactory neurons have long been thought to express only one chemosensory receptor gene family. There are two main olfactory receptor gene families in Drosophila, the odorant receptors (ORs) and the ionotropic receptors (IRs). The dozens of odorant-binding receptors in each family require at least one co-receptor gene in order to function: Orco for ORs, and Ir25a, Ir8a, and Ir76b for IRs. Using a new genetic knock-in strategy, we targeted the four co-receptors representing the main chemosensory families in D. melanogaster (Orco, Ir8a, Ir76b, Ir25a). Co-receptor knock-in expression patterns were verified as accurate representations of endogenous expression. We find extensive overlap in expression among the different co-receptors. As defined by innervation into antennal lobe glomeruli, Ir25a is broadly expressed in 88% of all olfactory sensory neuron classes and is co-expressed in 82% of Orco+ neuron classes, including all neuron classes in the maxillary palp. Orco, Ir8a, and Ir76b expression patterns are also more expansive than previously assumed. Single sensillum recordings from Orco-expressing Ir25a mutant antennal and palpal neurons identify changes in olfactory responses. We also find co-expression of Orco and Ir25a in Drosophila sechellia and Anopheles coluzzii olfactory neurons. These results suggest that co-expression of chemosensory receptors is common in insect olfactory neurons. Together, our data present the first comprehensive map of chemosensory co-receptor expression and reveal their unexpected widespread co-expression in the fly olfactory system.
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Affiliation(s)
- Darya Task
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Chun-Chieh Lin
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of MedicineBaltimoreUnited States
- Mortimer B. Zuckermann Mind Brain Behavior Institute, Columbia UniversityNew YorkUnited States
| | - Alina Vulpe
- Physiology & Neurobiology Department, University of ConnecticutMansfieldUnited States
| | - Ali Afify
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Sydney Ballou
- Physiology & Neurobiology Department, University of ConnecticutMansfieldUnited States
| | - Maria Brbic
- Department of Computer Science, Stanford UniversityStanfordUnited States
| | - Philipp Schlegel
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Joshua Raji
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Gregory SXE Jefferis
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Hongjie Li
- Department of Biology, Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Karen Menuz
- Physiology & Neurobiology Department, University of ConnecticutMansfieldUnited States
| | - Christopher J Potter
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of MedicineBaltimoreUnited States
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2
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Arcanjo C, Trémolet G, Giusti-Petrucciani N, Duflot A, Forget-Leray J, Boulangé-Lecomte C. Susceptibility of the Non-Targeted Crustacean Eurytemora affinis to the Endocrine Disruptor Tebufenozide: A Transcriptomic Approach. Genes (Basel) 2021; 12:genes12101484. [PMID: 34680879 PMCID: PMC8536038 DOI: 10.3390/genes12101484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/19/2021] [Accepted: 09/20/2021] [Indexed: 12/13/2022] Open
Abstract
Copepods are zooplanktonic crustaceans ubiquitously widespread in aquatic systems. Although they are not the target, copepods are exposed to a wide variety of pollutants such as insect growth regulators (IGRs). The aim of this study was to investigate the molecular response of a non-targeted organism, the copepod Eurytemora affinis, to an IGR. Adult males and females were exposed to two sub-lethal concentrations of tebufenozide (TEB). Our results indicate a sex-specific response with a higher sensitivity in males, potentially due to a differential activation of stress response pathways. In both sexes, exposure to TEB triggered similar pathways to those found in targeted species by modulating the transcription of early and late ecdysone responsive genes. Among them were genes involved in cuticle metabolism, muscle contraction, neurotransmission, and gametogenesis, whose mis-regulation could lead to moult, locomotor, and reproductive impairments. Furthermore, genes involved in epigenetic processes were found in both sexes, which highlights the potential impact of exposure to TEB on future generations. This work allows identification of (i) potential biomarkers of ecdysone agonists and (ii) further assessment of putative physiological responses to characterize the effects of TEB at higher biological levels. The present study reinforces the suitability of using E. affinis as an ecotoxicological model.
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Puñal VM, Ahmed M, Thornton-Kolbe EM, Clowney EJ. Untangling the wires: development of sparse, distributed connectivity in the mushroom body calyx. Cell Tissue Res 2021; 383:91-112. [PMID: 33404837 PMCID: PMC9835099 DOI: 10.1007/s00441-020-03386-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/07/2020] [Indexed: 01/16/2023]
Abstract
Appropriate perception and representation of sensory stimuli pose an everyday challenge to the brain. In order to represent the wide and unpredictable array of environmental stimuli, principle neurons of associative learning regions receive sparse, combinatorial sensory inputs. Despite the broad role of such networks in sensory neural circuits, the developmental mechanisms underlying their emergence are not well understood. As mammalian sensory coding regions are numerically complex and lack the accessibility of simpler invertebrate systems, we chose to focus this review on the numerically simpler, yet functionally similar, Drosophila mushroom body calyx. We bring together current knowledge about the cellular and molecular mechanisms orchestrating calyx development, in addition to drawing insights from literature regarding construction of sparse wiring in the mammalian cerebellum. From this, we formulate hypotheses to guide our future understanding of the development of this critical perceptual center.
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Affiliation(s)
- Vanessa M. Puñal
- Department of Molecular, Cellular & Developmental Biology, The University of Michigan, Ann Arbor, MI 48109, USA,Department of Molecular & Integrative Physiology, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Maria Ahmed
- Department of Molecular, Cellular & Developmental Biology, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Emma M. Thornton-Kolbe
- Department of Molecular, Cellular & Developmental Biology, The University of Michigan, Ann Arbor, MI 48109, USA,Neuroscience Graduate Program, The University of Michigan, Ann Arbor, MI 48109, USA
| | - E. Josephine Clowney
- Department of Molecular, Cellular & Developmental Biology, The University of Michigan, Ann Arbor, MI 48109, USA
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4
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Ågren JA, Munasinghe M, Clark AG. Mitochondrial-Y chromosome epistasis in Drosophila melanogaster. Proc Biol Sci 2020; 287:20200469. [PMID: 33081607 DOI: 10.1098/rspb.2020.0469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The coordination between mitochondrial and nuclear genes is crucial to eukaryotic organisms. Predicting the nature of these epistatic interactions can be difficult because of the transmission asymmetry of the genes involved. While autosomes and X-linked genes are transmitted through both sexes, genes on the Y chromosome and in the mitochondrial genome are uniparentally transmitted through males and females, respectively. Here, we generate 36 otherwise isogenic Drosophila melanogaster strains differing only in the geographical origin of their mitochondrial genome and Y chromosome, to experimentally examine the effects of the uniparentally inherited parts of the genome, as well as their interaction, in males. We assay longevity and gene expression through RNA-sequencing. We detect an important role for both mitochondrial and Y-linked genes, as well as extensive mitochondrial-Y chromosome epistasis. In particular, genes involved in male reproduction appear to be especially sensitive to such interactions, and variation on the Y chromosome is associated with differences in longevity. Despite these interactions, we find no evidence that the mitochondrial genome and Y chromosome are co-adapted within a geographical region. Overall, our study demonstrates a key role for the uniparentally inherited parts of the genome for male biology, but also that mito-nuclear interactions are complex and not easily predicted from simple transmission asymmetries.
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Affiliation(s)
- J Arvid Ågren
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Manisha Munasinghe
- Department of Computational Biology, Cornell University, Ithaca, NY, USA
| | - Andrew G Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.,Department of Computational Biology, Cornell University, Ithaca, NY, USA
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5
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Gupta A, Stocker H. FoxO suppresses endoplasmic reticulum stress to inhibit growth of Tsc1-deficient tissues under nutrient restriction. eLife 2020; 9:53159. [PMID: 32525804 PMCID: PMC7289595 DOI: 10.7554/elife.53159] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 05/22/2020] [Indexed: 12/27/2022] Open
Abstract
The transcription factor FoxO has been shown to block proliferation and progression in mTORC1-driven tumorigenesis but the picture of the relevant FoxO target genes remains incomplete. Here, we employed RNA-seq profiling on single clones isolated using laser capture microdissection from Drosophila larval eye imaginal discs to identify FoxO targets that restrict the proliferation of Tsc1-deficient cells under nutrient restriction (NR). Transcriptomics analysis revealed downregulation of endoplasmic reticulum-associated protein degradation pathway components upon foxo knockdown. Induction of ER stress pharmacologically or by suppression of other ER stress response pathway components led to an enhanced overgrowth of Tsc1 knockdown tissue. Increase of ER stress in Tsc1 loss-of-function cells upon foxo knockdown was also confirmed by elevated expression levels of known ER stress markers. These results highlight the role of FoxO in limiting ER stress to regulate Tsc1 mutant overgrowth.
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Affiliation(s)
- Avantika Gupta
- Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
| | - Hugo Stocker
- Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
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Jones KA, Luo Y, Dukes-Rimsky L, Srivastava DP, Koul-Tewari R, Russell TA, Shapiro LP, Srivastava AK, Penzes P. Neurodevelopmental disorder-associated ZBTB20 gene variants affect dendritic and synaptic structure. PLoS One 2018; 13:e0203760. [PMID: 30281617 PMCID: PMC6169859 DOI: 10.1371/journal.pone.0203760] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 08/27/2018] [Indexed: 11/18/2022] Open
Abstract
Dendritic spine morphology and dendritic arborization are key determinants of neuronal connectivity and play critical roles in learning, memory and behavior function. Recently, defects of ZBTB20, a BTB and zinc finger domain containing transcriptional repressor, have been implicated in a wide range of neurodevelopmental disorders, including intellectual disability and autism. Here we show distinct effects of expression of two major isoforms, long and short, of ZBTB20, and its neurodevelopmental disorder-linked variants, on dendritic architecture of cultured rat cortical pyramidal neurons. The N-terminal of ZBTB20 showed a role in regulating dendritic spine morphology. Two ZBTB20 single nucleotide variants, located at the N-terminal and central regions of the protein and potentially conferring autism risk, altered dendritic spine morphology. In contrast, a single nucleotide variant identified in patients with intellectual disability and located at the C-terminus of ZBTB20 affected dendritic arborization and dendritic length but had no effect on dendritic spine morphology. Furthermore, truncation of the extreme C-terminus of ZBTB20 caused spine and dendritic morphological changes that were similar but distinct from those caused by the C-terminal variant. Taken together, our study suggests ZBTB20's role in dendritic and synaptic structure and provide possible mechanisms of its effect in neurodevelopmental disorders.
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Affiliation(s)
- Kelly A. Jones
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Yue Luo
- J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, South Carolina, United States of America
| | - Lynn Dukes-Rimsky
- J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, South Carolina, United States of America
| | - Deepak P. Srivastava
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Richa Koul-Tewari
- J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, South Carolina, United States of America
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
| | - Theron A. Russell
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Lauren P. Shapiro
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Anand K. Srivastava
- J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, South Carolina, United States of America
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
- * E-mail: (PP); (AKS)
| | - Peter Penzes
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
- * E-mail: (PP); (AKS)
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7
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Monitoring food preference in Drosophila by oligonucleotide tagging. Proc Natl Acad Sci U S A 2018; 115:9020-9025. [PMID: 30127010 DOI: 10.1073/pnas.1716880115] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Drosophila melanogaster is a powerful model organism for dissecting the neurogenetic basis of appetitive and aversive behaviors. However, some methods used to assay food preference require or cause starvation. This can be problematic for fly ethanol research because it can be difficult to dissociate caloric preference for ethanol from pharmacological preference for the drug. We designed BARCODE, a starvation-independent assay that uses trace levels of oligonucleotide tags to differentially mark food types. In BARCODE, flies feed ad libitum, and relative food preference is monitored by qPCR of the oligonucleotides. Persistence of the ingested oligomers within the fly records the feeding history of the fly over several days. Using BARCODE, we identified a sexually dimorphic preference for ethanol. Females are attracted to ethanol-laden foods, whereas males avoid consuming it. Furthermore, genetically feminizing male mushroom body lobes induces preference for ethanol. In addition, we demonstrate that BARCODE can be used for multiplex diet measurements when animals are presented with more than two food choices.
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8
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Dinges N, Morin V, Kreim N, Southall TD, Roignant JY. Comprehensive Characterization of the Complex lola Locus Reveals a Novel Role in the Octopaminergic Pathway via Tyramine Beta-Hydroxylase Regulation. Cell Rep 2018; 21:2911-2925. [PMID: 29212035 DOI: 10.1016/j.celrep.2017.11.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 09/12/2017] [Accepted: 11/02/2017] [Indexed: 10/18/2022] Open
Abstract
Longitudinals lacking (lola) is one of the most complex genes in Drosophila melanogaster, encoding up to 20 protein isoforms that include key transcription factors involved in axonal pathfinding and neural reprogramming. Most previous studies have employed loss-of-function alleles that disrupt lola common exons, making it difficult to delineate isoform-specific functions. To overcome this issue, we have generated isoform-specific mutants for all isoforms using CRISPR/Cas9. This enabled us to study specific isoforms with respect to previously characterized roles for Lola and to demonstrate a specific function for one variant in axon guidance via activation of the microtubule-associated factor Futsch. Importantly, we also reveal a role for a second variant in preventing neurodegeneration via the positive regulation of a key enzyme of the octopaminergic pathway. Thus, our comprehensive study expands the functional repertoire of Lola functions, and it adds insights into the regulatory control of neurotransmitter expression in vivo.
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Affiliation(s)
- Nadja Dinges
- Laboratory of RNA Epigenetics, Institute of Molecular Biology (IMB), 55128 Mainz, Germany
| | - Violeta Morin
- Laboratory of RNA Epigenetics, Institute of Molecular Biology (IMB), 55128 Mainz, Germany
| | - Nastasja Kreim
- Bioinformatics Core Facility, Institute of Molecular Biology (IMB), 55128 Mainz, Germany
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London SW7 2AZ, UK
| | - Jean-Yves Roignant
- Laboratory of RNA Epigenetics, Institute of Molecular Biology (IMB), 55128 Mainz, Germany.
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9
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cGMP-Dependent Protein Kinase Encoded by foraging Regulates Motor Axon Guidance in Drosophila by Suppressing Lola Function. J Neurosci 2016; 36:4635-46. [PMID: 27098704 DOI: 10.1523/jneurosci.3726-15.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 03/21/2016] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED Correct pathfinding and target recognition of a developing axon are exquisitely regulated processes that require multiple guidance factors. Among these factors, the second messengers, cAMP and cGMP, are known to be involved in establishing the guidance cues for axon growth through different intracellular signaling pathways. However, whether and how cGMP-dependent protein kinase (PKG) regulates axon guidance remains poorly understood. Here, we show that the motor axons of intersegmental nerve b (ISNb) in the Drosophila embryo display targeting defects during axon development in the absence of foraging(for), a gene encoding PKG.In vivo tag expression revealed PKG to be present in the ventral nerve code at late embryonic stages, supporting its function in embryonic axon guidance. Mechanistic studies showed that the transcription factor longitudinal lacking(lola) genetically interacts with for.PKG physically associates with the LolaT isoform via the C-terminal zinc-finger-containing domain. Overexpression of PKG leads to the cytoplasmic retention of LolaT in S2 cells, suggesting a role for PKG in mediating the nucleocytoplasmic trafficking of Lola. Together, these findings reveal a novel function of PKG in regulating the establishment of neuronal connectivity by sequestering Lola in the cytoplasm. SIGNIFICANCE STATEMENT Axon pathfinding and target recognition are important processes in the formation of specific neuronal connectivity, which rely upon precise coordinated deployment of multiple guidance factors. This paper reveals the role of cGMP-dependent protein kinase (PKG) in regulating the pathfinding and targeting of the developing axons in Drosophila Moreover, our study indicates that PKG regulates the cytoplasmic-nuclear trafficking of the transcription factor LolaT, suggesting a mechanism of PKG in directing motor axon guidance. These findings highlight a new function of PKG in axon guidance by suppressing a transcription factor.
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10
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Chaharbakhshi E, Jemc JC. Broad-complex, tramtrack, and bric-à-brac (BTB) proteins: Critical regulators of development. Genesis 2016; 54:505-518. [DOI: 10.1002/dvg.22964] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/08/2016] [Accepted: 08/11/2016] [Indexed: 01/21/2023]
Affiliation(s)
- Edwin Chaharbakhshi
- Department of Biology; Loyola University Chicago; Chicago IL
- Stritch School of Medicine; Loyola University Chicago; Maywood IL
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11
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Legrand E, Forget-Leray J, Duflot A, Olivier S, Thomé JP, Danger JM, Boulangé-Lecomte C. Transcriptome analysis of the copepod Eurytemora affinis upon exposure to endocrine disruptor pesticides: Focus on reproduction and development. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 176:64-75. [PMID: 27111276 DOI: 10.1016/j.aquatox.2016.04.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Revised: 03/19/2016] [Accepted: 04/12/2016] [Indexed: 06/05/2023]
Abstract
Copepods-which include freshwater and marine species-represent the most abundant group of aquatic invertebrates. Among them, the calanoid copepod Eurytemora affinis is widely represented in the northern hemisphere estuaries and has become a species of interest in ecotoxicology. Like other non-target organisms, E. affinis may be exposed to a wide range of chemicals such as endocrine disruptors (EDs). This study investigated the gene expression variation in E. affinis after exposure to ED pesticides-chosen as model EDs-in order to (i) improve the knowledge on their effects in crustaceans, and (ii) highlight relevant transcripts for further development of potential biomarkers of ED exposure/effect. The study focused on the reproduction function in response to ED. Copepods were exposed to sublethal concentrations of pyriproxyfen (PXF) and chlordecone (CLD) separately. After 48h, males and females (400 individuals each) were sorted for RNA extraction. Their transcriptome was pyrosequenced using the Illumina(®) technology. Contigs were blasted and functionally annotated using Blast2GO(®). The differential expression analysis between ED- and acetone-exposed organisms was performed according to sexes and contaminants. Half of the 19,721 contigs provided by pyrosequencing were annotated, mostly (80%) from arthropod sequences. Overall, 2,566 different genes were differentially expressed after ED exposures in comparison with controls. As many genes were differentially expressed after PXF exposure as after CLD exposure. In contrast, more genes were differentially expressed in males than in females after both exposures. Ninety-seven genes overlapped in all conditions. Finally, 31 transcripts involved in reproduction, growth and development, and changed in both chemical exposures were selected as potential candidates for future development of biomarkers.
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Affiliation(s)
- Eléna Legrand
- Normandy University, ULH, UMR-I 02 INERIS, Environmental Stresses and Biomonitoring of Aquatic Ecosystems (SEBIO)-SFR SCALE 4116, F-76600 Le Havre, France.
| | - Joëlle Forget-Leray
- Normandy University, ULH, UMR-I 02 INERIS, Environmental Stresses and Biomonitoring of Aquatic Ecosystems (SEBIO)-SFR SCALE 4116, F-76600 Le Havre, France.
| | - Aurélie Duflot
- Normandy University, ULH, UMR-I 02 INERIS, Environmental Stresses and Biomonitoring of Aquatic Ecosystems (SEBIO)-SFR SCALE 4116, F-76600 Le Havre, France.
| | - Stéphanie Olivier
- Normandy University, ULH, UMR-I 02 INERIS, Environmental Stresses and Biomonitoring of Aquatic Ecosystems (SEBIO)-SFR SCALE 4116, F-76600 Le Havre, France.
| | - Jean-Pierre Thomé
- University of Liège, Laboratory of Animal Ecology and Ecotoxicology (LEAE), Centre for Analytical Research and Technology (CART), 4000 SART-Tilman, Belgium.
| | - Jean-Michel Danger
- Normandy University, ULH, UMR-I 02 INERIS, Environmental Stresses and Biomonitoring of Aquatic Ecosystems (SEBIO)-SFR SCALE 4116, F-76600 Le Havre, France.
| | - Céline Boulangé-Lecomte
- Normandy University, ULH, UMR-I 02 INERIS, Environmental Stresses and Biomonitoring of Aquatic Ecosystems (SEBIO)-SFR SCALE 4116, F-76600 Le Havre, France.
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12
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Salvemini M, Arunkumar KP, Nagaraju J, Sanges R, Petrella V, Tomar A, Zhang H, Zheng W, Saccone G. De novo assembly and transcriptome analysis of the Mediterranean fruit fly Ceratitis capitata early embryos. PLoS One 2014; 9:e114191. [PMID: 25474564 PMCID: PMC4256415 DOI: 10.1371/journal.pone.0114191] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 11/05/2014] [Indexed: 01/04/2023] Open
Abstract
The agricultural pest Ceratitis capitata, also known as the Mediterranean fruit fly or Medfly, belongs to the Tephritidae family, which includes a large number of other damaging pest species. The Medfly has been the first non-drosophilid fly species which has been genetically transformed paving the way for designing genetic-based pest control strategies. Furthermore, it is an experimentally tractable model, in which transient and transgene-mediated RNAi have been successfully used. We applied Illumina sequencing to total RNA preparations of 8–10 hours old embryos of C. capitata, This developmental window corresponds to the blastoderm cellularization stage. In summary, we assembled 42,614 transcripts which cluster in 26,319 unique transcripts of which 11,045 correspond to protein coding genes; we identified several hundreds of long ncRNAs; we found an enrichment of transcripts encoding RNA binding proteins among the highly expressed transcripts, such as CcTRA-2, known to be necessary to establish and, most likely, to maintain female sex of C. capitata. Our study is the first de novo assembly performed for Ceratitis capitata based on Illumina NGS technology during embryogenesis and it adds novel data to the previously published C. capitata EST databases. We expect that it will be useful for a variety of applications such as gene cloning and phylogenetic analyses, as well as to advance genetic research and biotechnological applications in the Medfly and other related Tephritidae.
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Affiliation(s)
- Marco Salvemini
- Department of Biology, University of Naples Federico II, Naples, Italy
| | | | | | - Remo Sanges
- Stazione Zoologica "Anton Dohrn", Naples, Italy
| | - Valeria Petrella
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Archana Tomar
- Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Hongyu Zhang
- State Key Laboratory of Agricultural Microbiology and Institute of Urban and Horticultural Pests, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Weiwei Zheng
- State Key Laboratory of Agricultural Microbiology and Institute of Urban and Horticultural Pests, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Giuseppe Saccone
- Department of Biology, University of Naples Federico II, Naples, Italy
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Abstract
Precise connections established between pre- and postsynaptic partners during development are essential for the proper function of the nervous system. The olfactory system detects a wide variety of odorants and processes the information in a precisely connected neural circuit. A common feature of the olfactory systems from insects to mammals is that the olfactory receptor neurons (ORNs) expressing the same odorant receptor make one-to-one connections with a single class of second-order olfactory projection neurons (PNs). This represents one of the most striking examples of targeting specificity in developmental neurobiology. Recent studies have uncovered central roles of transmembrane and secreted proteins in organizing this one-to-one connection specificity in the olfactory system. Here, we review recent advances in the understanding of how this wiring specificity is genetically controlled and focus on the mechanisms by which transmembrane and secreted proteins regulate different stages of the Drosophila olfactory circuit assembly in a coordinated manner. We also discuss how combinatorial coding, redundancy, and error-correcting ability could contribute to constructing a complex neural circuit in general.
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14
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Sen S, Biagini S, Reichert H, VijayRaghavan K. Orthodenticle is required for the development of olfactory projection neurons and local interneurons in Drosophila. Biol Open 2014; 3:711-7. [PMID: 24996925 PMCID: PMC4133724 DOI: 10.1242/bio.20148524] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The accurate wiring of nervous systems involves precise control over cellular processes like cell division, cell fate specification, and targeting of neurons. The nervous system of Drosophila melanogaster is an excellent model to understand these processes. Drosophila neurons are generated by stem cell like precursors called neuroblasts that are formed and specified in a highly stereotypical manner along the neuroectoderm. This stereotypy has been attributed, in part, to the expression and function of transcription factors that act as intrinsic cell fate determinants in the neuroblasts and their progeny during embryogenesis. Here we focus on the lateral neuroblast lineage, ALl1, of the antennal lobe and show that the transcription factor-encoding cephalic gap gene orthodenticle is required in this lineage during postembryonic brain development. We use immunolabelling to demonstrate that Otd is expressed in the neuroblast of this lineage during postembryonic larval stages. Subsequently, we use MARCM clonal mutational methods to show that the majority of the postembryonic neuronal progeny in the ALl1 lineage undergoes apoptosis in the absence of orthodenticle. Moreover, we demonstrate that the neurons that survive in the orthodenticle loss-of-function condition display severe targeting defects in both the proximal (dendritic) and distal (axonal) neurites. These findings indicate that the cephalic gap gene orthodenticle acts as an important intrinsic determinant in the ALl1 neuroblast lineage and, hence, could be a member of a putative combinatorial code involved in specifying the fate and identity of cells in this lineage.
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Affiliation(s)
- Sonia Sen
- National Centre for Biological Sciences - Tata Institute of Fundamental Research, UAS-GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Silvia Biagini
- National Centre for Biological Sciences - Tata Institute of Fundamental Research, UAS-GKVK Campus, Bellary Road, Bangalore 560065, India Present address: FIRC Institute of Molecular Oncology, Via Adamello, 16-20139 Milan, Italy
| | - Heinrich Reichert
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - K VijayRaghavan
- National Centre for Biological Sciences - Tata Institute of Fundamental Research, UAS-GKVK Campus, Bellary Road, Bangalore 560065, India
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15
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Levy P, Larsen C. Odd-skipped labels a group of distinct neurons associated with the mushroom body and optic lobe in the adult Drosophila brain. J Comp Neurol 2014; 521:3716-40. [PMID: 23749685 PMCID: PMC3957007 DOI: 10.1002/cne.23375] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 01/22/2013] [Accepted: 05/23/2013] [Indexed: 01/22/2023]
Abstract
Olfactory processing has been intensively studied in Drosophila melanogaster. However, we still know little about the descending neural pathways from the higher order processing centers and how these connect with other neural circuits. Here we describe, in detail, the adult projections patterns that arise from a cluster of 78 neurons, defined by the expression of the Odd-skipped transcription factor. We term these neurons Odd neurons. By using expression of genetically encoded axonal and dendritic markers, we show that a subset of the Odd neurons projects dendrites into the calyx of the mushroom body (MB) and axons into the inferior protocerebrum. We exclude the possibility that the Odd neurons are part of the well-known Kenyon cells whose projections form the MB and conclude that the Odd neurons belong to a previously not described class of extrinsic MB neurons. In addition, three of the Odd neurons project into the lobula plate of the optic lobe, and two of these cells extend axons ipsi- and contralaterally in the brain. Anatomically, these cells do not resemble any previously described lobula plate tangential cells (LPTCs) in Drosophila. We show that the Odd neurons are predominantly cholinergic but also include a small number of γ-aminobutyric acid (GABA)ergic neurons. Finally, we provide evidence that the Odd neurons are a hemilineage, suggesting they are born from a defined set of neuroblasts. Our anatomical analysis hints at the possibility that subgroups of Odd neurons could be involved in olfactory and visual processing.
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Affiliation(s)
- Peter Levy
- Medical Research Council Centre for Developmental Neurobiology, King's College London, London, United Kingdom
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16
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Tripathy R, Kunwar PS, Sano H, Renault AD. Transcriptional regulation of Drosophila gonad formation. Dev Biol 2014; 392:193-208. [PMID: 24927896 DOI: 10.1016/j.ydbio.2014.05.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 05/22/2014] [Accepted: 05/26/2014] [Indexed: 01/08/2023]
Abstract
The formation of the Drosophila embryonic gonad, involving the fusion of clusters of somatic gonadal precursor cells (SGPs) and their ensheathment of germ cells, provides a simple and genetically tractable model for the interplay between cells during organ formation. In a screen for mutants affecting gonad formation we identified a SGP cell autonomous role for Midline (Mid) and Longitudinals lacking (Lola). These transcriptional factors are required for multiple aspects of SGP behaviour including SGP cluster fusion, germ cell ensheathment and gonad compaction. The lola locus encodes more than 25 differentially spliced isoforms and we have identified an isoform specific requirement for lola in the gonad which is distinct from that in nervous system development. Mid and Lola work in parallel in gonad formation and surprisingly Mid overexpression in a lola background leads to additional SGPs at the expense of fat body cells. Our findings support the idea that although the transcription factors required by SGPs can ostensibly be assigned to those being required for either SGP specification or behaviour, they can also interact to impinge on both processes.
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Affiliation(s)
- Ratna Tripathy
- Max Planck Institute for Developmental Biology, Spemannstr. 35, 72074 Tübingen, Germany
| | - Prabhat S Kunwar
- Division of Biology, California Institute of Technology, Pasadena, CA, USA
| | - Hiroko Sano
- Department of Molecular Genetics, Institute of Life Sciences, Kurume University, Kurume, Fukuoka, Japan
| | - Andrew D Renault
- Max Planck Institute for Developmental Biology, Spemannstr. 35, 72074 Tübingen, Germany.
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17
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Ferreira T, Ou Y, Li S, Giniger E, van Meyel DJ. Dendrite architecture organized by transcriptional control of the F-actin nucleator Spire. Development 2014; 141:650-60. [PMID: 24449841 DOI: 10.1242/dev.099655] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The architectures of dendritic trees are crucial for the wiring and function of neuronal circuits because they determine coverage of receptive territories, as well as the nature and strength of sensory or synaptic inputs. Here, we describe a cell-intrinsic pathway sculpting dendritic arborization (da) neurons in Drosophila that requires Longitudinals Lacking (Lola), a BTB/POZ transcription factor, and its control of the F-actin cytoskeleton through Spire (Spir), an actin nucleation protein. Loss of Lola from da neurons reduced the overall length of dendritic arbors, increased the expression of Spir, and produced inappropriate F-actin-rich dendrites at positions too near the cell soma. Selective removal of Lola from only class IV da neurons decreased the evasive responses of larvae to nociception. The increased Spir expression contributed to the abnormal F-actin-rich dendrites and the decreased nocifensive responses because both were suppressed by reduced dose of Spir. Thus, an important role of Lola is to limit expression of Spir to appropriate levels within da neurons. We found Spir to be expressed in dendritic arbors and to be important for their development. Removal of Spir from class IV da neurons reduced F-actin levels and total branch number, shifted the position of greatest branch density away from the cell soma, and compromised nocifensive behavior. We conclude that the Lola-Spir pathway is crucial for the spatial arrangement of branches within dendritic trees and for neural circuit function because it provides balanced control of the F-actin cytoskeleton.
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Affiliation(s)
- Tiago Ferreira
- McGill Centre for Research in Neuroscience, McGill University Health Centre, 1650 Cedar Avenue, Montreal, QC H3G 1A4, Canada
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18
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Insight into insulin secretion from transcriptome and genetic analysis of insulin-producing cells of Drosophila. Genetics 2014; 197:175-92. [PMID: 24558258 PMCID: PMC4012477 DOI: 10.1534/genetics.113.160663] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Insulin-producing cells (IPCs) in the Drosophila brain produce and release insulin-like peptides (ILPs) to the hemolymph. ILPs are crucial for growth and regulation of metabolic activity in flies, functions analogous to those of mammalian insulin and insulin-like growth factors (IGFs). To identify components functioning in IPCs to control ILP production, we employed genomic and candidate gene approaches. We used laser microdissection and messenger RNA sequencing to characterize the transcriptome of larval IPCs. IPCs highly express many genes homologous to genes active in insulin-producing β-cells of the mammalian pancreas. The genes in common encode ILPs and proteins that control insulin metabolism, storage, secretion, β-cell proliferation, and some not previously linked to insulin production or β-cell function. Among these novelties is unc-104, a kinesin 3 family gene, which is more highly expressed in IPCs compared to most other neurons. Knockdown of unc-104 in IPCs impaired ILP secretion and reduced peripheral insulin signaling. Unc-104 appears to transport ILPs along axons. As a complementary approach, we tested dominant-negative Rab genes to find Rab proteins required in IPCs for ILP production or secretion. Rab1 was identified as crucial for ILP trafficking in IPCs. Inhibition of Rab1 in IPCs increased circulating sugar levels, delayed development, and lowered weight and body size. Immunofluorescence labeling of Rab1 showed its tight association with ILP2 in the Golgi of IPCs. Unc-104 and Rab1 join other proteins required for ILP transport in IPCs.
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19
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Abstract
The proper formation and morphogenesis of dendrites is fundamental to the establishment of neural circuits in the brain. Following cell cycle exit and migration, neurons undergo organized stages of dendrite morphogenesis, which include dendritic arbor growth and elaboration followed by retraction and pruning. Although these developmental stages were characterized over a century ago, molecular regulators of dendrite morphogenesis have only recently been defined. In particular, studies in Drosophila and mammalian neurons have identified numerous cell-intrinsic drivers of dendrite morphogenesis that include transcriptional regulators, cytoskeletal and motor proteins, secretory and endocytic pathways, cell cycle-regulated ubiquitin ligases, and components of other signaling cascades. Here, we review cell-intrinsic drivers of dendrite patterning and discuss how the characterization of such crucial regulators advances our understanding of normal brain development and pathogenesis of diverse cognitive disorders.
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Affiliation(s)
- Sidharth V Puram
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
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20
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Niki Y, Sato T, Yamaguchi T, Saisho A, Uetake H, Watanabe H. Drosophila germline stem cells for in vitro analyses of PIWI-mediated RNAi. Methods Mol Biol 2014; 1093:13-23. [PMID: 24178553 DOI: 10.1007/978-1-62703-694-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The Drosophila piwi gene has multiple functions in soma and germ cells. An in vitro system provides a powerful tool for elucidating PIWI function in each cell type using stable cell lines originating from germline stem cells (GSCs) and ovarian soma of adult ovaries. We have described methods for the maintenance and expansion of GSCs in an established cell line (fGS/OSS) and an in situ hybridization method for analyzing piwi.
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Affiliation(s)
- Yuzo Niki
- Department of Biology, Faculty of Science, Ibaraki University, Mito, Ibaraki, Japan
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21
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Hattori Y, Usui T, Satoh D, Moriyama S, Shimono K, Itoh T, Shirahige K, Uemura T. Sensory-neuron subtype-specific transcriptional programs controlling dendrite morphogenesis: genome-wide analysis of Abrupt and Knot/Collier. Dev Cell 2013; 27:530-44. [PMID: 24290980 DOI: 10.1016/j.devcel.2013.10.024] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 08/08/2013] [Accepted: 10/31/2013] [Indexed: 11/18/2022]
Abstract
The transcription factors Abrupt (Ab) and Knot (Kn) act as selectors of distinct dendritic arbor morphologies in two classes of Drosophila sensory neurons, termed class I and class IV, respectively. We performed binding-site mapping and transcriptional profiling of these isolated neurons. Their profiles were similarly enriched in cell-type-specific enhancers of genes implicated in neural development. We identified a total of 429 target genes, of which 56 were common to Ab and Kn; these targets included genes necessary to shape dendritic arbors in either or both of the two sensory subtypes. Furthermore, a common target gene, encoding the cell adhesion molecule Ten-m, was expressed more strongly in class I than class IV, and this differential was critical to the class-selective directional control of dendritic branch sprouting or extension. Our analyses illustrate how differentiating neurons employ distinct and shared repertoires of gene expression to produce class-selective morphological traits.
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Affiliation(s)
- Yukako Hattori
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Tadao Usui
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Daisuke Satoh
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Sanefumi Moriyama
- Kobayashi-Maskawa Institute, Nagoya University, Aichi 464-8602, Japan; Graduate School of Mathematics, Nagoya University, Aichi 464-8602, Japan
| | - Kohei Shimono
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Takehiko Itoh
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Kanagawa 226-8501, Japan
| | - Katsuhiko Shirahige
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo 113-0032, Japan
| | - Tadashi Uemura
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan.
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22
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Nair IS, Rodrigues V, Reichert H, VijayRaghavan K. The zinc finger transcription factor Jing is required for dendrite/axonal targeting in Drosophila antennal lobe development. Dev Biol 2013; 381:17-27. [PMID: 23810656 DOI: 10.1016/j.ydbio.2013.06.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 06/11/2013] [Accepted: 06/13/2013] [Indexed: 12/22/2022]
Abstract
An important role in olfactory system development is played by transcription factors which act in sensory neurons or in their interneuron targets as cell autonomous regulators of downstream effectors such as cell surface molecules and signalling systems that control neuronal identity and process guidance. Some of these transcriptional regulators have been characterized in detail in the development of the neural elements that innervate the antennal lobe in the olfactory system of Drosophila. Here we identify the zinc finger transcription factor Jing as a cell autonomously acting transcriptional regulator that is required both for dendrite targeting of projection neurons and local interneurons as well as for axonal targeting of olfactory sensory neurons in Drosophila olfactory system development. Immunocytochemical analysis shows that Jing is widely expressed in the neural cells during postembryonic development. MARCM-based clonal analysis of projection neuron and local interneuron lineages reveals a requirement for Jing in dendrite targeting; Jing loss-of-function results in loss of innervation in specific glomeruli, ectopic innervation of inappropriate glomeruli, aberrant profuse dendrite arborisation throughout the antennal lobe, as well as mistargeting to other parts of the CNS. ey-FLP-based MARCM analysis of olfactory sensory neurons reveals an additional requirement for Jing in axonal targeting; mutational inactivation of Jing causes specific mistargeting of some olfactory sensory neuron axons to the DA1 glomerulus, reduction of targeting to other glomeruli, as well as aberrant stalling of axons in the antennal lobe. Taken together, these findings indicate that Jing acts as a key transcriptional control element in wiring of the circuitry in the developing olfactory sensory system in Drosophila.
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Affiliation(s)
- Indu S Nair
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
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23
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Brown EB, Layne JE, Zhu C, Jegga AG, Rollmann SM. Genome-wide association mapping of natural variation in odour-guided behaviour inDrosophila. GENES BRAIN AND BEHAVIOR 2013; 12:503-15. [DOI: 10.1111/gbb.12048] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 05/01/2013] [Accepted: 05/11/2013] [Indexed: 11/26/2022]
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24
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Sekine SU, Haraguchi S, Chao K, Kato T, Luo L, Miura M, Chihara T. Meigo governs dendrite targeting specificity by modulating ephrin level and N-glycosylation. Nat Neurosci 2013; 16:683-91. [PMID: 23624514 DOI: 10.1038/nn.3389] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 04/01/2013] [Indexed: 11/09/2022]
Abstract
Neural circuit assembly requires precise dendrite and axon targeting. We identified an evolutionarily conserved endoplasmic reticulum (ER) protein, Meigo, from a mosaic genetic screen in Drosophila melanogaster. Meigo was cell-autonomously required in olfactory receptor neurons and projection neurons to target their axons and dendrites to the lateral antennal lobe and to refine projection neuron dendrites into individual glomeruli. Loss of Meigo induced an unfolded protein response and reduced the amount of neuronal cell surface proteins, including Ephrin. Ephrin overexpression specifically suppressed the projection neuron dendrite refinement defect present in meigo mutant flies, and ephrin knockdown caused a similar projection neuron dendrite refinement defect. Meigo positively regulated the level of Ephrin N-glycosylation, which was required for its optimal function in vivo. Thus, Meigo, an ER-resident protein, governs neuronal targeting specificity by regulating ER folding capacity and protein N-glycosylation. Furthermore, Ephrin appears to be an important substrate that mediates Meigo's function in refinement of glomerular targeting.
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Affiliation(s)
- Sayaka U Sekine
- Department of Genetics, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
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25
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Veverytsa L, Allan DW. Subtype-specific neuronal remodeling during Drosophila metamorphosis. Fly (Austin) 2013; 7:78-86. [PMID: 23579264 DOI: 10.4161/fly.23969] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
During metamorphosis in holometabolous insects, the nervous system undergoes dramatic remodeling as it transitions from its larval to its adult form. Many neurons are generated through post-embryonic neurogenesis to have adult-specific roles, but perhaps more striking is the dramatic remodeling that occurs to transition neurons from functioning in the larval to the adult nervous system. These neurons exhibit a remarkable degree of plasticity during this transition; many subsets undergo programmed cell death, others remodel their axonal and dendritic arbors extensively, whereas others undergo trans-differentiation to alter their terminal differentiation gene expression profiles. Yet other neurons appear to be developmentally frozen in an immature state throughout larval life, to be awakened at metamorphosis by a process we term temporally-tuned differentiation. These multiple forms of remodeling arise from subtype-specific responses to a single metamorphic trigger, ecdysone. Here, we discuss recent progress in Drosophila melanogaster that is shedding light on how subtype-specific programs of neuronal remodeling are generated during metamorphosis.
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Affiliation(s)
- Lyubov Veverytsa
- Department of Cellular and Physiological Sciences, Life Sciences Centre, Health Sciences Mall, University of British Columbia, Vancouver, BC Canada
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26
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Davies EL, Lim JGY, Joo WJ, Tam CH, Fuller MT. The transcriptional regulator lola is required for stem cell maintenance and germ cell differentiation in the Drosophila testis. Dev Biol 2012; 373:310-21. [PMID: 23159836 DOI: 10.1016/j.ydbio.2012.11.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 10/28/2012] [Accepted: 11/05/2012] [Indexed: 01/28/2023]
Abstract
Stem cell behavior is regulated by extrinsic signals from specialized microenvironments, or niches, and intrinsic factors required for execution of context-appropriate responses to niche signals. Here we show that function of the transcriptional regulator longitudinals lacking (lola) is required cell autonomously for germline stem cell and somatic cyst stem cell maintenance in the Drosophila testis. In addition, lola is also required for proper execution of key developmental transitions during male germ cell differentiation, including the switch from transit amplifying progenitor to spermatocyte growth and differentiation, as well as meiotic cell cycle progression and spermiogenesis. Different lola isoforms, each having unique C-termini and zinc finger domains, may control different aspects of proliferation and differentiation in the male germline and somatic cyst stem cell lineages.
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Affiliation(s)
- Erin L Davies
- Department of Developmental Biology, Stanford University School of Medicine, 279 Campus Drive, Beckman Center B300, Stanford, CA 94305-5329, USA
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27
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The SUMO protease Verloren regulates dendrite and axon targeting in olfactory projection neurons. J Neurosci 2012; 32:8331-40. [PMID: 22699913 DOI: 10.1523/jneurosci.6574-10.2012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Sumoylation is a post-translational modification regulating numerous biological processes. Small ubiquitin-like modifier (SUMO) proteases are required for the maturation and deconjugation of SUMO proteins, thereby either promoting or reverting sumoylation to modify protein function. Here, we show a novel role for a predicted SUMO protease, Verloren (Velo), during projection neuron (PN) target selection in the Drosophila olfactory system. PNs target their dendrites to specific glomeruli within the antennal lobe (AL) and their axons stereotypically into higher brain centers. We uncovered mutations in velo that disrupt PN targeting specificity. PN dendrites that normally target to a particular dorsolateral glomerulus instead mistarget to incorrect glomeruli within the AL or to brain regions outside the AL. velo mutant axons also display defects in arborization. These phenotypes are rescued by postmitotic expression of Velo in PNs but not by a catalytic domain mutant of Velo. Two other SUMO proteases, DmUlp1 and CG12717, can partially compensate for the function of Velo in PN dendrite targeting. Additionally, mutations in SUMO and lesswright (which encodes a SUMO conjugating enzyme) similarly disrupt PN targeting, confirming that sumoylation is required for neuronal target selection. Finally, genetic interaction studies suggest that Velo acts in SUMO deconjugation rather than in maturation. Our study provides the first in vivo evidence for a specific role of a SUMO protease during neuronal target selection that can be dissociated from its functions in neuronal proliferation and survival.
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28
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Thum AS, Leisibach B, Gendre N, Selcho M, Stocker RF. Diversity, variability, and suboesophageal connectivity of antennal lobe neurons in D. melanogaster larvae. J Comp Neurol 2012; 519:3415-32. [PMID: 21800296 DOI: 10.1002/cne.22713] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Whereas the "vertical" elements of the insect olfactory pathway, the olfactory receptor neurons and the projection neurons, have been studied in great detail, local interneurons providing "horizontal" connections in the antennal lobe were ignored for a long time. Recent studies in adult Drosophila demonstrate diverse roles for these neurons in the integration of odor information, consistent with the identification of a large variety of anatomical and neurochemical subtypes. Here we focus on the larval olfactory circuit of Drosophila, which is much reduced in terms of cell numbers. We show that the horizontal connectivity in the larval antennal lobe differs largely from its adult counterpart. Only one of the five anatomical types of neurons we describe is restricted to the antennal lobe and therefore fits the definition of a local interneuron. Interestingly, the four remaining subtypes innervate both the antennal lobe and the suboesophageal ganglion. In the latter, they may overlap with primary gustatory terminals and with arborizations of hugin cells, which are involved in feeding control. This circuitry suggests special links between smell and taste, which may reflect the chemosensory constraints of a crawling and burrowing lifestyle. We also demonstrate that many of the neurons we describe exhibit highly variable trajectories and arborizations, especially in the suboesophageal ganglion. Together with reports from adult Drosophila, these data suggest that wiring variability may be another principle of insect brain organization, in parallel with stereotypy.
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Affiliation(s)
- A S Thum
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland.
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29
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Fukui A, Inaki M, Tonoe G, Hamatani H, Homma M, Morimoto T, Aburatani H, Nose A. Lola regulates glutamate receptor expression at the Drosophila neuromuscular junction. Biol Open 2012; 1:362-75. [PMID: 23213426 PMCID: PMC3509458 DOI: 10.1242/bio.2012448] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Communication between pre- and post-synaptic cells is a key process in the development and modulation of synapses. Reciprocal induction between pre- and postsynaptic cells involves regulation of gene transcription, yet the underlying genetic program remains largely unknown. To investigate how innervation-dependent gene expression in postsynaptic cells supports synaptic differentiation, we performed comparative microarray analysis of Drosophila muscles before and after innervation, and of prospero mutants, which show a delay in motor axon outgrowth. We identified 84 candidate genes that are potentially up- or downregulated in response to innervation. By systematic functional analysis, we found that one of the downregulated genes, longitudinals lacking (lola), which encodes a BTB-Zn-finger transcription factor, is required for proper expression of glutamate receptors. When the function of lola was knocked down in muscles by RNAi, the abundance of glutamate receptors (GluRs), GluRIIA, GluRIIB and GluRIII, as well as that of p-21 activated kinase (PAK), was greatly reduced at the neuromuscular junctions (NMJs). Recordings of the synaptic response revealed a decrease in postsynaptic quantal size, consistent with the reduction in GluR levels. Lola appears to regulate the expression of GluRs and PAK at the level of transcription, because the amount of mRNAs encoding these molecules was also reduced in the mutants. The transcriptional level of lola, in turn, is downregulated by increased neural activity. We propose that Lola coordinates expression of multiple postsynaptic components by transcriptional regulation.
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Affiliation(s)
- Ai Fukui
- Department of Physics, Graduate School of Science, University of Tokyo , Hongo, Bunkyo-ku, Tokyo 113-0033 , Japan
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30
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Scott JA, Williams DW, Truman JW. The BTB/POZ zinc finger protein Broad-Z3 promotes dendritic outgrowth during metamorphic remodeling of the peripheral stretch receptor dbd. Neural Dev 2011; 6:39. [PMID: 22152995 PMCID: PMC3275534 DOI: 10.1186/1749-8104-6-39] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 12/12/2011] [Indexed: 11/14/2022] Open
Abstract
Background Various members of the family of BTB/POZ zinc-finger transcription factors influence patterns of dendritic branching. One such member, Broad, is notable because its BrZ3 isoform is widely expressed in Drosophila in immature neurons around the time of arbor outgrowth. We used the metamorphic remodeling of an identified sensory neuron, the dorsal bipolar dendrite sensory neuron (dbd), to examine the effects of BrZ3 expression on the extent and pattern of dendrite growth during metamorphosis. Results Using live imaging of dbd in Drosophila pupae, we followed its normal development during metamorphosis and the effect of ectopic expression of BrZ3 on this development. After migration of its cell body, dbd extends a growth-cone that grows between two muscle bands followed by branching and turning back on itself to form a compact dendritic bundle. The ectopic expression of the BrZ3 isoform, using the GAL4/UAS system, caused dbd's dendritic tree to transform from its normal, compact, fasciculated form into a comb-like arbor that spread over on the body wall. Time-lapse analysis revealed that the expression of BrZ3 caused the premature extension of the primary dendrite onto immature myoblasts, ectopic growth past the muscle target region, and subsequent elaboration onto the epidermis. To control the timing of expression of BrZ3, we used a temperature-sensitive GAL80 mutant. When BrZ3 expression was delayed until after the extension of the primary dendrite, then a normal arbor was formed. By contrast, when BrZ3 expression was confined to only the early outgrowth phase, then ectopic arbors were subsequently formed and maintained on the epidermis despite the subsequent absence of BrZ3. Conclusions The adult arbor of dbd is a highly branched arbor whose branches self-fasciculate to form a compact dendritic bundle. The ectopic expression of BrZ3 in this cell causes a premature extension of its growth-cone, resulting in dendrites that extend beyond their normal muscle substrate and onto the epidermis, where they form a comb-shaped, ectopic arbor. Our quantitative data suggest that new ectopic arbor represents an 'unpacking' of the normally fasciculated arbor onto the epidermis. These data suggest that the nature of their local environment can change dendrite behavior from self-adhesion to self-avoidance.
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Affiliation(s)
- Janet A Scott
- Department of Biology, Box 351800, University of Washington, Seattle, WA 98195, USA
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Gates MA, Kannan R, Giniger E. A genome-wide analysis reveals that the Drosophila transcription factor Lola promotes axon growth in part by suppressing expression of the actin nucleation factor Spire. Neural Dev 2011; 6:37. [PMID: 22129300 PMCID: PMC3262752 DOI: 10.1186/1749-8104-6-37] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 11/30/2011] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND The phylogenetically conserved transcription factor Lola is essential for many aspects of axon growth and guidance, synapse formation and neural circuit development in Drosophila. To date it has been difficult, however, to obtain an overall view of Lola functions and mechanisms. RESULTS We use expression microarrays to identify the lola-dependent transcriptome in the Drosophila embryo. We find that lola regulates the expression of a large selection of genes that are known to affect each of several lola-dependent developmental processes. Among other loci, we find lola to be a negative regulator of spire, an actin nucleation factor that has been studied for its essential role in oogenesis. We show that spire is expressed in the nervous system and is required for a known lola-dependent axon guidance decision, growth of ISNb motor axons. We further show that reducing spire gene dosage suppresses this aspect of the lola phenotype, verifying that derepression of spire is an important contributor to the axon stalling phenotype of embryonic motor axons in lola mutants. CONCLUSIONS These data shed new light on the molecular mechanisms of many lola-dependent processes, and also identify several developmental processes not previously linked to lola that are apt to be regulated by this transcription factor. These data further demonstrate that excessive expression of the actin nucleation factor Spire is as deleterious for axon growth in vivo as is the loss of Spire, thus highlighting the need for a balance in the elementary steps of actin dynamics to achieve effective neuronal morphogenesis.
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Affiliation(s)
- Michael A Gates
- Basic Neuroscience Program, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892 USA
- Fred Hutchinson Cancer Research Center, Seattle, WA, 98109 USA
- Graduate Program in Molecular and Cellular Biology, University of Washington and Fred Hutchinson Cancer Research Center, Seattle, WA, 98109 USA
| | - Ramakrishnan Kannan
- Basic Neuroscience Program, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892 USA
| | - Edward Giniger
- Basic Neuroscience Program, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892 USA
- Fred Hutchinson Cancer Research Center, Seattle, WA, 98109 USA
- Graduate Program in Molecular and Cellular Biology, University of Washington and Fred Hutchinson Cancer Research Center, Seattle, WA, 98109 USA
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Behura SK, Haugen M, Flannery E, Sarro J, Tessier CR, Severson DW, Duman-Scheel M. Comparative genomic analysis of Drosophila melanogaster and vector mosquito developmental genes. PLoS One 2011; 6:e21504. [PMID: 21754989 PMCID: PMC3130749 DOI: 10.1371/journal.pone.0021504] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 05/30/2011] [Indexed: 11/18/2022] Open
Abstract
Genome sequencing projects have presented the opportunity for analysis of developmental genes in three vector mosquito species: Aedes aegypti, Culex quinquefasciatus, and Anopheles gambiae. A comparative genomic analysis of developmental genes in Drosophila melanogaster and these three important vectors of human disease was performed in this investigation. While the study was comprehensive, special emphasis centered on genes that 1) are components of developmental signaling pathways, 2) regulate fundamental developmental processes, 3) are critical for the development of tissues of vector importance, 4) function in developmental processes known to have diverged within insects, and 5) encode microRNAs (miRNAs) that regulate developmental transcripts in Drosophila. While most fruit fly developmental genes are conserved in the three vector mosquito species, several genes known to be critical for Drosophila development were not identified in one or more mosquito genomes. In other cases, mosquito lineage-specific gene gains with respect to D. melanogaster were noted. Sequence analyses also revealed that numerous repetitive sequences are a common structural feature of Drosophila and mosquito developmental genes. Finally, analysis of predicted miRNA binding sites in fruit fly and mosquito developmental genes suggests that the repertoire of developmental genes targeted by miRNAs is species-specific. The results of this study provide insight into the evolution of developmental genes and processes in dipterans and other arthropods, serve as a resource for those pursuing analysis of mosquito development, and will promote the design and refinement of functional analysis experiments.
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Affiliation(s)
- Susanta K. Behura
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Morgan Haugen
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, Indiana, United States of America
| | - Ellen Flannery
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Joseph Sarro
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Charles R. Tessier
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, Indiana, United States of America
| | - David W. Severson
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, Indiana, United States of America
| | - Molly Duman-Scheel
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, Indiana, United States of America
- * E-mail:
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Tea JS, Luo L. The chromatin remodeling factor Bap55 functions through the TIP60 complex to regulate olfactory projection neuron dendrite targeting. Neural Dev 2011; 6:5. [PMID: 21284845 PMCID: PMC3038883 DOI: 10.1186/1749-8104-6-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2010] [Accepted: 02/01/2011] [Indexed: 02/08/2023] Open
Abstract
Background The Drosophila olfactory system exhibits very precise and stereotyped wiring that is specified predominantly by genetic programming. Dendrites of olfactory projection neurons (PNs) pattern the developing antennal lobe before olfactory receptor neuron axon arrival, indicating an intrinsic wiring mechanism for PN dendrites. These wiring decisions are likely determined through a transcriptional program. Results We find that loss of Brahma associated protein 55 kD (Bap55) results in a highly specific PN mistargeting phenotype. In Bap55 mutants, PNs that normally target to the DL1 glomerulus mistarget to the DA4l glomerulus with 100% penetrance. Loss of Bap55 also causes derepression of a GAL4 whose expression is normally restricted to a small subset of PNs. Bap55 is a member of both the Brahma (BRM) and the Tat interactive protein 60 kD (TIP60) ATP-dependent chromatin remodeling complexes. The Bap55 mutant phenotype is partially recapitulated by Domino and Enhancer of Polycomb mutants, members of the TIP60 complex. However, distinct phenotypes are seen in Brahma and Snf5-related 1 mutants, members of the BRM complex. The Bap55 mutant phenotype can be rescued by postmitotic expression of Bap55, or its human homologs BAF53a and BAF53b. Conclusions Our results suggest that Bap55 functions through the TIP60 chromatin remodeling complex to regulate dendrite wiring specificity in PNs. The specificity of the mutant phenotypes suggests a position for the TIP60 complex at the top of a regulatory hierarchy that orchestrates dendrite targeting decisions.
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Affiliation(s)
- Joy S Tea
- Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, CA 94305, USA
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Brochtrup A, Hummel T. Olfactory map formation in the Drosophila brain: genetic specificity and neuronal variability. Curr Opin Neurobiol 2010; 21:85-92. [PMID: 21112768 DOI: 10.1016/j.conb.2010.11.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 11/02/2010] [Indexed: 11/17/2022]
Abstract
The development of the Drosophila olfactory system is a striking example of how genetic programs specify a large number of different neuron types and assemble them into functional circuits. To ensure precise odorant perception, each sensory neuron has to not only select a single olfactory receptor (OR) type out of a large genomic repertoire but also segregate its synaptic connections in the brain according to the OR class identity. Specification and patterning of second-order interneurons in the olfactory brain center occur largely independent of sensory input, followed by a precise point-to-point matching of sensory and relay neurons. Here we describe recent progress in the understanding of how cell-intrinsic differentiation programs and context-dependent cellular interactions generate a stereotyped sensory map in the Drosophila brain. Recent findings revealed an astonishing morphological diversity among members of the same interneuron class, suggesting an unexpected variability in local microcircuits involved in insect sensory processing.
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Affiliation(s)
- Anna Brochtrup
- Institut für Neurobiologie, Universität Münster, Badestr. 9, D-48149 Münster, Germany
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Histone deacetylase Rpd3 regulates olfactory projection neuron dendrite targeting via the transcription factor Prospero. J Neurosci 2010; 30:9939-46. [PMID: 20660276 DOI: 10.1523/jneurosci.1643-10.2010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Compared to the mechanisms of axon guidance, relatively little is known about the transcriptional control of dendrite guidance. The Drosophila olfactory system with its stereotyped organization provides an excellent model to study the transcriptional control of dendrite wiring specificity. Each projection neuron (PN) targets its dendrites to a specific glomerulus in the antennal lobe and its axon stereotypically to higher brain centers. Using a forward genetic screen, we identified a mutation in Rpd3 that disrupts PN targeting specificity. Rpd3 encodes a class I histone deacetylase (HDAC) homologous to mammalian HDAC1 and HDAC2. Rpd3(-/-) PN dendrites that normally target to a dorsolateral glomerulus mistarget to medial glomeruli in the antennal lobe, and axons exhibit a severe overbranching phenotype. These phenotypes can be rescued by postmitotic expression of Rpd3 but not HDAC3, the only other class I HDAC in Drosophila. Furthermore, disruption of the atypical homeodomain transcription factor Prospero (Pros) yields similar phenotypes, which can be rescued by Pros expression in postmitotic neurons. Strikingly, overexpression of Pros can suppress Rpd3(-/-) phenotypes. Our study suggests a specific function for the general chromatin remodeling factor Rpd3 in regulating dendrite targeting in neurons, largely through the postmitotic action of the Pros transcription factor.
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Imai T, Sakano H, Vosshall LB. Topographic mapping--the olfactory system. Cold Spring Harb Perspect Biol 2010; 2:a001776. [PMID: 20554703 DOI: 10.1101/cshperspect.a001776] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Sensory systems must map accurate representations of the external world in the brain. Although the physical senses of touch and vision build topographic representations of the spatial coordinates of the body and the field of view, the chemical sense of olfaction maps discontinuous features of chemical space, comprising an extremely large number of possible odor stimuli. In both mammals and insects, olfactory circuits are wired according to the convergence of axons from sensory neurons expressing the same odorant receptor. Synapses are organized into distinctive spherical neuropils--the olfactory glomeruli--that connect sensory input with output neurons and local modulatory interneurons. Although there is a strong conservation of form in the olfactory maps of mammals and insects, they arise using divergent mechanisms. Olfactory glomeruli provide a unique solution to the problem of mapping discontinuous chemical space onto the brain.
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Affiliation(s)
- Takeshi Imai
- The University of Tokyo, Graduate School of Science, Department of Biophysics and Biochemistry, Yayoi 2-11-16, Bunkyo-ku, Tokyo 113-0032, Japan
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Abstract
The dendritic arborization (da) neurons of the Drosophila peripheral nervous system (PNS) provide an excellent model system in which to investigate the molecular mechanisms underlying class-specific dendrite morphogenesis. To facilitate molecular analyses of class-specific da neuron development, it is vital to obtain these cells in a pure population. Although a range of different cell, and tissue-specific RNA isolation techniques exist for Drosophila cells, including magnetic bead based cell purification, Fluorescent Activated Cell Sorting (FACS), and RNA binding protein based strategies, none of these methods can be readily utilized for isolating single or multiple class-specific Drosophila da neurons with a high degree of spatial precision. Laser Capture Microdissection (LCM) has emerged as an extremely powerful tool that can be used to isolate specific cell types from tissue sections with a high degree of spatial resolution and accuracy. RNA obtained from isolated cells can then be used for analyses including qRT-PCR and microarray expression profiling within a given cell type. To date, LCM has not been widely applied in the analysis of Drosophila tissues and cells, including da neurons at the third instar larval stage of development. Here we present our optimized protocol for isolation of Drosophila da neurons using the infrared (IR) class of LCM. This method allows for the capture of single, class-specific or multiple da neurons with high specificity and spatial resolution. Age-matched third instar larvae expressing a UAS-mCD8::GFP transgene under the control of either the class IV da neuron specific ppk-GAL4 driver or the pan-da neuron specific 21-7-GAL4 driver were used for these experiments. RNA obtained from the isolated da neurons is of very high quality and can be directly used for downstream applications, including qRT-PCR or microarray analyses. Furthermore, this LCM protocol can be readily adapted to capture other Drosophila cell types a various stages of development dependent upon the cell type specific, GAL4-driven expression pattern of GFP.
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The Drosophila neural lineages: a model system to study brain development and circuitry. Dev Genes Evol 2010; 220:1-10. [PMID: 20306203 PMCID: PMC2886914 DOI: 10.1007/s00427-010-0323-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2009] [Accepted: 02/02/2010] [Indexed: 11/03/2022]
Abstract
In Drosophila, neurons of the central nervous system are grouped into units called lineages. Each lineage contains cells derived from a single neuroblast. Due to its clonal nature, the Drosophila brain is a valuable model system to study neuron development and circuit formation. To better understand the mechanisms underlying brain development, genetic manipulation tools can be utilized within lineages to visualize, knock down, or over-express proteins. Here, we will introduce the formation and development of lineages, discuss how one can utilize this model system, offer a comprehensive list of known lineages and their respective markers, and then briefly review studies that have utilized Drosophila neural lineages with a look at how this model system can benefit future endeavors.
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Hong W, Zhu H, Potter CJ, Barsh G, Kurusu M, Zinn K, Luo L. Leucine-rich repeat transmembrane proteins instruct discrete dendrite targeting in an olfactory map. Nat Neurosci 2009; 12:1542-50. [PMID: 19915565 PMCID: PMC2826190 DOI: 10.1038/nn.2442] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 10/01/2009] [Indexed: 11/09/2022]
Abstract
Olfactory systems utilize discrete neural pathways to process and integrate odorant information. In Drosophila, axons of first-order olfactory receptor neurons (ORNs) and dendrites of second-order projection neurons (PNs) form class-specific synaptic connections at approximately 50 glomeruli. The mechanisms underlying PN dendrite targeting to distinct glomeruli in a three-dimensional discrete neural map are unclear. We found that the leucine-rich repeat (LRR) transmembrane protein Capricious (Caps) was differentially expressed in different classes of PNs. Loss-of-function and gain-of-function studies indicated that Caps instructs the segregation of Caps-positive and Caps-negative PN dendrites to discrete glomerular targets. Moreover, Caps-mediated PN dendrite targeting was independent of presynaptic ORNs and did not involve homophilic interactions. The closely related protein Tartan was partially redundant with Caps. These LRR proteins are probably part of a combinatorial cell-surface code that instructs discrete olfactory map formation.
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Affiliation(s)
- Weizhe Hong
- Howard Hughes Medical Institute and Department of Biology, Stanford University, Stanford, California, USA
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Corty MM, Matthews BJ, Grueber WB. Molecules and mechanisms of dendrite development in Drosophila. Development 2009; 136:1049-61. [PMID: 19270170 DOI: 10.1242/dev.014423] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Neurons are one of the most morphologically diverse cell types, in large part owing to their intricate dendrite branching patterns. Dendrites are structures that are specialized to receive and process inputs in neurons, thus their specific morphologies reflect neural connectivity and influence information flow through circuits. Recent studies in Drosophila on the molecular basis of dendrite diversity, dendritic guidance, the cell biology of dendritic branch patterning and territory formation have identified numerous intrinsic and extrinsic cues that shape diverse features of dendrites. As we discuss in this review, many of the mechanisms that are being elucidated show conservation in diverse systems.
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Affiliation(s)
- Megan M Corty
- Center for Neurobiology and Behavior, Columbia University Medical Center, New York, NY 10032, USA.
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Das A, Sen S, Lichtneckert R, Okada R, Ito K, Rodrigues V, Reichert H. Drosophila olfactory local interneurons and projection neurons derive from a common neuroblast lineage specified by the empty spiracles gene. Neural Dev 2008; 3:33. [PMID: 19055770 PMCID: PMC2647541 DOI: 10.1186/1749-8104-3-33] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Accepted: 12/03/2008] [Indexed: 11/26/2022] Open
Abstract
Background Encoding of olfactory information in insects occurs in the antennal lobe where the olfactory receptor neurons interact with projection neurons and local interneurons in a complex sensory processing circuitry. While several studies have addressed the developmental mechanisms involved in specification and connectivity of olfactory receptor neurons and projection neurons in Drosophila, the local interneurons are far less well understood. Results In this study, we use genetic marking techniques combined with antibody labelling and neuroblast ablation to analyse lineage specific aspects of local interneuron development. We find that a large set of local interneurons labelled by the GAL4-LN1 (NP1227) and GAL4-LN2 (NP2426) lines arise from the lateral neuroblast, which has also been shown to generate uniglomerular projection neurons. Moreover, we find that a remarkable diversity of local interneuron cell types with different glomerular innervation patterns and neurotransmitter expression derives from this lineage. We analyse the birth order of these two distinct neuronal types by generating MARCM (mosaic analysis with a repressible cell marker) clones at different times during larval life. This analysis shows that local interneurons arise throughout the proliferative cycle of the lateral neuroblast beginning in the embryo, while uniglomerular projection neurons arise later during the second larval instar. The lateral neuroblast requires the function of the cephalic gap gene empty spiracles for the development of olfactory interneurons. In empty spiracles null mutant clones, most of the local interneurons and lateral projection neurons are lacking. These findings reveal similarities in the development of local interneurons and projection neurons in the olfactory system of Drosophila. Conclusion We find that the lateral neuroblast of the deutocerebrum gives rise to a large and remarkably diverse set of local interneurons as well as to projection neurons in the antennal lobe. Moreover, we show that specific combinations of these two neuron types are produced in specific time windows in this neuroblast lineage. The development of both these cell types in this lineage requires the function of the empty spiracles gene.
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Affiliation(s)
- Abhijit Das
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.
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MicroRNA processing pathway regulates olfactory neuron morphogenesis. Curr Biol 2008; 18:1754-9. [PMID: 19013069 DOI: 10.1016/j.cub.2008.09.045] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Revised: 09/13/2008] [Accepted: 09/17/2008] [Indexed: 12/19/2022]
Abstract
The microRNA (miRNA) processing pathway produces miRNAs as posttranscriptional regulators of gene expression. The nuclear RNase III Drosha catalyzes the first processing step together with the dsRNA binding protein DGCR8/Pasha generating pre-miRNAs [1, 2]. The next cleavage employs the cytoplasmic RNase III Dicer producing miRNA duplexes [3, 4]. Finally, Argonautes are recruited with miRNAs into an RNA-induced silencing complex for mRNA recognition (Figure 1A). Here, we identify two members of the miRNA pathway, Pasha and Dicer-1, in a forward genetic screen for mutations that disrupt wiring specificity of Drosophila olfactory projection neurons (PNs). The olfactory system is built as discrete map of highly stereotyped neuronal connections [5, 6]. Each PN targets dendrites to a specific glomerulus in the antennal lobe and projects axons stereotypically into higher brain centers [7-9]. In selected PN classes, pasha and Dicer-1 mutants cause specific PN dendrite mistargeting in the antennal lobe and altered axonal terminations in higher brain centers. Furthermore, Pasha and Dicer-1 act cell autonomously in postmitotic neurons to regulate dendrite and axon targeting during development. However, Argonaute-1 and Argonaute-2 are dispensable for PN morphogenesis. Our findings suggest a role for the miRNA processing pathway in establishing wiring specificity in the nervous system.
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Genomic analysis of Drosophila neuronal remodeling: a role for the RNA-binding protein Boule as a negative regulator of axon pruning. J Neurosci 2008; 28:6092-103. [PMID: 18550751 DOI: 10.1523/jneurosci.0677-08.2008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Drosophila mushroom body (MB) gamma neurons undergo axon pruning during metamorphosis through a process of localized degeneration of specific axon branches. Developmental axon degeneration is initiated by the steroid hormone ecdysone, acting through a nuclear receptor complex composed of USP (ultraspiracle) and EcRB1 (ecdysone receptor B1) to regulate gene expression in MB gamma neurons. To identify ecdysone-dependent gene expression changes in MB gamma neurons at the onset of axon pruning, we use laser capture microdissection to isolate wild-type and mutant MB neurons in which EcR (ecdysone receptor) activity is genetically blocked, and analyze expression changes by microarray. We identify several molecular pathways that are regulated in MB neurons by ecdysone. The most striking observation is the upregulation of genes involved in the UPS (ubiquitin-proteasome system), which is cell autonomously required for gamma neuron pruning. In addition, we characterize the function of Boule, an evolutionarily conserved RNA-binding protein previously implicated in spermatogenesis in flies and vertebrates. boule expression is downregulated by ecdysone in MB neurons at the onset of pruning, and forced expression of Boule in MB gamma neurons is sufficient to inhibit axon pruning. This activity is dependent on the RNA-binding domain of Boule and a conserved DAZ (deleted in azoospermia) domain implicated in interactions with other RNA-binding proteins. However, loss of Boule does not result in obvious defects in axon pruning or morphogenesis of MB neurons, suggesting that it acts redundantly with other ecdyonse-regulated genes. We propose a novel function for Boule in the CNS as a negative regulator of developmental axon pruning.
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Lichtneckert R, Nobs L, Reichert H. Empty spiracles is required for the development of olfactory projection neuron circuitry in Drosophila. Development 2008; 135:2415-24. [PMID: 18550709 DOI: 10.1242/dev.022210] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In both insects and mammals, second-order olfactory neurons receive input from olfactory receptor neurons and relay olfactory input to higher brain centers. In Drosophila, the wiring specificity of these olfactory projection neurons (PNs) is predetermined by their lineage identity and birth order. However, the genetic programs that control this wiring specificity are not well understood. The cephalic gap gene empty spiracles (ems) encodes a homeodomain transcription factor required for embryonic development of the antennal brain neuromere. Here we show that ems is expressed postembryonically in the progenitors of the two major olfactory PN lineages. Moreover, we show that ems has cell lineage-specific functions in postembryonic PN development. Thus, in the lateral PN lineage, transient ems expression is essential for development of the correct number of PNs; in ems mutants, the number of PNs in the lineage is dramatically reduced by apoptosis. By contrast, in the anterodorsal PN lineage, transient ems expression is necessary for precise targeting of PN dendrites to appropriate glomeruli; in ems mutants, these PNs fail to innervate correct glomeruli, innervate inappropriate glomeruli, or mistarget dendrites to other brain regions. Furthermore, in the anterodorsal PN lineage, ems controls the expression of the POU-domain transcription factor Acj6 in approximately half of the cells and, in at least one glomerulus, ems function in dendritic targeting is mediated through Acj6. The finding that Drosophila ems, like its murine homologs Emx1/2, is required for the formation of olfactory circuitry implies that conserved genetic programs control olfactory system development in insects and mammals.
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Spurgeon SL, Jones RC, Ramakrishnan R. High throughput gene expression measurement with real time PCR in a microfluidic dynamic array. PLoS One 2008; 3:e1662. [PMID: 18301740 PMCID: PMC2244704 DOI: 10.1371/journal.pone.0001662] [Citation(s) in RCA: 312] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Accepted: 01/29/2008] [Indexed: 01/09/2023] Open
Abstract
We describe a high throughput gene expression platform based on microfluidic dynamic arrays. This system allows 2,304 simultaneous real time PCR gene expression measurements in a single chip, while requiring less pipetting than is required to set up a 96 well plate. We show that one can measure the expression of 45 different genes in 18 tissues with replicates in a single chip. The data have excellent concordance with conventional real time PCR and the microfluidic dynamic arrays show better reproducibility than commercial DNA microarrays.
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Affiliation(s)
- Sandra L. Spurgeon
- Fluidigm Corporation, South San Francisco, California, United States of America
| | - Robert C. Jones
- Fluidigm Corporation, South San Francisco, California, United States of America
| | - Ramesh Ramakrishnan
- Fluidigm Corporation, South San Francisco, California, United States of America
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Schuldiner O, Berdnik D, Levy JM, Wu JS, Luginbuhl D, Gontang AC, Luo L. piggyBac-based mosaic screen identifies a postmitotic function for cohesin in regulating developmental axon pruning. Dev Cell 2008; 14:227-38. [PMID: 18267091 PMCID: PMC2268086 DOI: 10.1016/j.devcel.2007.11.001] [Citation(s) in RCA: 183] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Revised: 10/24/2007] [Accepted: 11/02/2007] [Indexed: 12/25/2022]
Abstract
Developmental axon pruning is widely used to refine neural circuits. We performed a mosaic screen to identify mutations affecting axon pruning of Drosophila mushroom body gamma neurons. We constructed a modified piggyBac vector with improved mutagenicity and generated insertions in >2000 genes. We identified two cohesin subunits (SMC1 and SA) as being essential for axon pruning. The cohesin complex maintains sister-chromatid cohesion during cell division in eukaryotes. However, we show that the pruning phenotype in SMC1(-/-) clones is rescued by expressing SMC1 in neurons, revealing a postmitotic function. SMC1(-/-) clones exhibit reduced levels of the ecdysone receptor EcR-B1, a key regulator of axon pruning. The pruning phenotype is significantly suppressed by overexpressing EcR-B1 and is enhanced by a reduced dose of EcR, supporting a causal relationship. We also demonstrate a postmitotic role for SMC1 in dendrite targeting of olfactory projection neurons. We suggest that cohesin regulates diverse aspects of neuronal morphogenesis.
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Affiliation(s)
- Oren Schuldiner
- Howard Hughes Medical Institute, Department of Biological Sciences and Neurosciences Program, Stanford University, Stanford, CA 94305, USA
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