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Posnien N, Hunnekuhl VS, Bucher G. Gene expression mapping of the neuroectoderm across phyla - conservation and divergence of early brain anlagen between insects and vertebrates. eLife 2023; 12:e92242. [PMID: 37750868 PMCID: PMC10522337 DOI: 10.7554/elife.92242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 09/18/2023] [Indexed: 09/27/2023] Open
Abstract
Gene expression has been employed for homologizing body regions across bilateria. The molecular comparison of vertebrate and fly brains has led to a number of disputed homology hypotheses. Data from the fly Drosophila melanogaster have recently been complemented by extensive data from the red flour beetle Tribolium castaneum with its more insect-typical development. In this review, we revisit the molecular mapping of the neuroectoderm of insects and vertebrates to reconsider homology hypotheses. We claim that the protocerebrum is non-segmental and homologous to the vertebrate fore- and midbrain. The boundary between antennal and ocular regions correspond to the vertebrate mid-hindbrain boundary while the deutocerebrum represents the anterior-most ganglion with serial homology to the trunk. The insect head placode is shares common embryonic origin with the vertebrate adenohypophyseal placode. Intriguingly, vertebrate eyes develop from a different region compared to the insect compound eyes calling organ homology into question. Finally, we suggest a molecular re-definition of the classic concepts of archi- and prosocerebrum.
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Affiliation(s)
- Nico Posnien
- Department of Developmental Biology, Johann-Friedrich-Blumenbach Institute, University GoettingenGöttingenGermany
| | - Vera S Hunnekuhl
- Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, University of GöttingenGöttingenGermany
| | - Gregor Bucher
- Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, University of GöttingenGöttingenGermany
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2
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Al Sayed Y, Howard SR. Panel testing for the molecular genetic diagnosis of congenital hypogonadotropic hypogonadism – a clinical perspective. Eur J Hum Genet 2022; 31:387-394. [PMID: 36517585 PMCID: PMC10133250 DOI: 10.1038/s41431-022-01261-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/21/2022] [Accepted: 11/28/2022] [Indexed: 12/16/2022] Open
Abstract
AbstractCongenital hypogonadotropic hypogonadism (CHH) is a rare endocrine disorder that results in reproductive hormone deficiency and reduced potential for fertility in adult life. Discoveries of the genetic aetiology of CHH have advanced dramatically in the past 30 years, with currently over 40 genes recognised to cause or contribute to the development of this condition. The genetic complexity of CHH is further increased by the observation of di- and oligogenic, as well as classic monogenic, inheritance and incomplete penetrance. Very recently in the UK, a panel of 14 genes has been curated for the genetic diagnosis of CHH within the NHS Genomic Medicine Service programme. The aim of this review is to appraise the advantages and potential pitfalls of the use of a CHH panel in clinical endocrine diagnostics, and to consider the future avenues for developing this panel including the potential of whole exome or whole genome sequencing data analysis in this condition.
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3
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Drosophila Homeodomain-Interacting Protein Kinase (Hipk) Phosphorylates the Homeodomain Proteins Homeobrain, Empty Spiracles, and Muscle Segment Homeobox. Int J Mol Sci 2019; 20:ijms20081931. [PMID: 31010135 PMCID: PMC6515119 DOI: 10.3390/ijms20081931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/16/2019] [Accepted: 04/17/2019] [Indexed: 11/30/2022] Open
Abstract
The Drosophila homeodomain-interacting protein kinase (Hipk) is the fly representative of the well-conserved group of HIPKs in vertebrates. It was initially found through its characteristic interactions with homeodomain proteins. Hipk is involved in a variety of important developmental processes, such as the development of the eye or the nervous system. In the present study, we set Hipk and the Drosophila homeodomain proteins Homeobrain (Hbn), Empty spiracles (Ems), and Muscle segment homeobox (Msh) in an enzyme-substrate relationship. These homeoproteins are transcription factors that function during Drosophila neurogenesis and are, at least in part, conserved in vertebrates. We reveal a physical interaction between Hipk and the three homeodomain proteins in vivo using bimolecular fluorescence complementation (BiFC). In the course of in vitro phosphorylation analysis and subsequent mutational analysis we mapped several Hipk phosphorylation sites of Hbn, Ems, and Msh. The phosphorylation of Hbn, Ems, and Msh may provide further insight into the function of Hipk during development of the Drosophila nervous system.
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4
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Kim YJ, Osborn DP, Lee JY, Araki M, Araki K, Mohun T, Känsäkoski J, Brandstack N, Kim HT, Miralles F, Kim CH, Brown NA, Kim HG, Martinez-Barbera JP, Ataliotis P, Raivio T, Layman LC, Kim SH. WDR11-mediated Hedgehog signalling defects underlie a new ciliopathy related to Kallmann syndrome. EMBO Rep 2018; 19:269-289. [PMID: 29263200 PMCID: PMC5797970 DOI: 10.15252/embr.201744632] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 11/14/2017] [Accepted: 11/17/2017] [Indexed: 12/27/2022] Open
Abstract
WDR11 has been implicated in congenital hypogonadotropic hypogonadism (CHH) and Kallmann syndrome (KS), human developmental genetic disorders defined by delayed puberty and infertility. However, WDR11's role in development is poorly understood. Here, we report that WDR11 modulates the Hedgehog (Hh) signalling pathway and is essential for ciliogenesis. Disruption of WDR11 expression in mouse and zebrafish results in phenotypic characteristics associated with defective Hh signalling, accompanied by dysgenesis of ciliated tissues. Wdr11-null mice also exhibit early-onset obesity. We find that WDR11 shuttles from the cilium to the nucleus in response to Hh signalling. WDR11 regulates the proteolytic processing of GLI3 and cooperates with the transcription factor EMX1 in the induction of downstream Hh pathway gene expression and gonadotrophin-releasing hormone production. The CHH/KS-associated human mutations result in loss of function of WDR11. Treatment with the Hh agonist purmorphamine partially rescues the WDR11 haploinsufficiency phenotypes. Our study reveals a novel class of ciliopathy caused by WDR11 mutations and suggests that CHH/KS may be a part of the human ciliopathy spectrum.
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Affiliation(s)
- Yeon-Joo Kim
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK
| | - Daniel Ps Osborn
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK
| | - Ji-Young Lee
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK
| | - Masatake Araki
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Kimi Araki
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | | | | | | | - Hyun-Taek Kim
- Department of Biology, Chungnam National University, Daejeon, Korea
| | - Francesc Miralles
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK
| | - Cheol-Hee Kim
- Department of Biology, Chungnam National University, Daejeon, Korea
| | - Nigel A Brown
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK
| | - Hyung-Goo Kim
- Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Juan Pedro Martinez-Barbera
- Developmental Biology and Cancer Programme, Birth Defects Research Centre, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Paris Ataliotis
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK
| | - Taneli Raivio
- Helsinki University Central Hospital, Helsinki, Finland
| | | | - Soo-Hyun Kim
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK
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5
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Wei L, Murphy BL, Wu G, Parker M, Easton J, Gilbertson RJ, Zhang J, Roussel MF. Exome sequencing analysis of murine medulloblastoma models identifies WDR11 as a potential tumor suppressor in Group 3 tumors. Oncotarget 2017; 8:64685-64697. [PMID: 29029386 PMCID: PMC5630286 DOI: 10.18632/oncotarget.19642] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 07/09/2017] [Indexed: 01/11/2023] Open
Abstract
Mouse models of human cancers are widely used in cancer research, yet questions frequently arise regarding their faithfulness in recapitulating their human counterparts. To compare the somatic mutations of murine models with human medulloblastoma (MB), we performed whole-exome sequencing on 12 tumors representing three distinct medulloblastoma subgroups: Wnt, Sonic Hedgehog (Shh) and Group 3 (G3). In total, 64 somatic mutations were identified and validated, including 40 predicted to cause amino acid changes. After filtering and cross-species analysis with 366 human MBs from four independent studies, human orthologs for 16 of the 40 mouse genes were found to harbor non-silent mutations in human MB. Loss-of-function Kmt2d mutations detected in one mouse tumor was previously reported in 30 of 366 human MBs. In mice bearing G3 MB, one mouse succumbed to tumor burden at least 15 days earlier than other mice, raising the possibility that somatic mutations may have accelerated the tumorigenesis process. In this mouse tumor, four novel candidate genes harbored non-silent somatic mutations, Lrfn2, Smyd1, Ubn2 and Wdr11. Extended survival was found in mice harboring mouse G3 overexpressing WDR11 but not the other three genes. Genes in the KEGG WNT signaling pathway, including Ccnd1/2/3, Myc and Tcf7l1, were down-regulated in the transcriptome of G3 MB tumorspheres overexpressing WDR11, consistent with reduced tumor progression. In conclusion, we demonstrated that common spontaneous mutations were shared between human and murine models of MB suggesting similar molecular mechanisms of tumorigenesis, and identified WDR11 as a protein with tumor suppressive activity in G3 MB.
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Affiliation(s)
- Lei Wei
- Department of Computational Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
- Biostatistics and Bioinformatics, Roswell Park Cancer Institute, Buffalo, NY, USA
| | - Brian L. Murphy
- Department of Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
- Department of Molecular Oncology, Moffitt Cancer Center, Tampa, FL, USA
| | - Gang Wu
- Department of Computational Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Matthew Parker
- Department of Computational Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
- Genomics England, Queen Mary University of London, London, UK
| | - John Easton
- Pediatric Cancer Genome Project, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Richard J. Gilbertson
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Jinghui Zhang
- Department of Computational Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Martine F. Roussel
- Department of Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
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6
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Yang CP, Fu CC, Sugino K, Liu Z, Ren Q, Liu LY, Yao X, Lee LP, Lee T. Transcriptomes of lineage-specific Drosophila neuroblasts profiled by genetic targeting and robotic sorting. Development 2015; 143:411-21. [PMID: 26700685 DOI: 10.1242/dev.129163] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 12/11/2015] [Indexed: 12/21/2022]
Abstract
A brain consists of numerous distinct neurons arising from a limited number of progenitors, called neuroblasts in Drosophila. Each neuroblast produces a specific neuronal lineage. To unravel the transcriptional networks that underlie the development of distinct neuroblast lineages, we marked and isolated lineage-specific neuroblasts for RNA sequencing. We labeled particular neuroblasts throughout neurogenesis by activating a conditional neuroblast driver in specific lineages using various intersection strategies. The targeted neuroblasts were efficiently recovered using a custom-built device for robotic single-cell picking. Transcriptome analysis of mushroom body, antennal lobe and type II neuroblasts compared with non-selective neuroblasts, neurons and glia revealed a rich repertoire of transcription factors expressed among neuroblasts in diverse patterns. Besides transcription factors that are likely to be pan-neuroblast, many transcription factors exist that are selectively enriched or repressed in certain neuroblasts. The unique combinations of transcription factors present in different neuroblasts may govern the diverse lineage-specific neuron fates.
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Affiliation(s)
- Ching-Po Yang
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Chi-Cheng Fu
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA Departments of Bioengineering, Electrical Engineering and Computer Science, and Biophysics Graduate Program, University of California, Berkeley, CA 94720, USA
| | - Ken Sugino
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Zhiyong Liu
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Qingzhong Ren
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Ling-Yu Liu
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Xiaohao Yao
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Luke P Lee
- Departments of Bioengineering, Electrical Engineering and Computer Science, and Biophysics Graduate Program, University of California, Berkeley, CA 94720, USA
| | - Tzumin Lee
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
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7
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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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8
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Expression pattern of empty-spiracles, a conserved head-patterning gene, in honeybee (Apis mellifera) embryos. Gene Expr Patterns 2014; 15:142-8. [PMID: 24999162 DOI: 10.1016/j.gep.2014.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 06/19/2014] [Accepted: 06/20/2014] [Indexed: 11/21/2022]
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9
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Wong DC, Lovick JK, Ngo KT, Borisuthirattana W, Omoto JJ, Hartenstein V. Postembryonic lineages of the Drosophila brain: II. Identification of lineage projection patterns based on MARCM clones. Dev Biol 2013; 384:258-89. [PMID: 23872236 PMCID: PMC3928077 DOI: 10.1016/j.ydbio.2013.07.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 07/11/2013] [Accepted: 07/11/2013] [Indexed: 01/13/2023]
Abstract
The Drosophila central brain is largely composed of lineages, units of sibling neurons derived from a single progenitor cell or neuroblast. During the early embryonic period, neuroblasts generate the primary neurons that constitute the larval brain. Neuroblasts reactivate in the larva, adding to their lineages a large number of secondary neurons which, according to previous studies in which selected lineages were labeled by stably expressed markers, differentiate during metamorphosis, sending terminal axonal and dendritic branches into defined volumes of the brain neuropil. We call the overall projection pattern of neurons forming a given lineage the "projection envelope" of that lineage. By inducing MARCM clones at the early larval stage, we labeled the secondary progeny of each neuroblast. For the supraesophageal ganglion excluding mushroom body (the part of the brain investigated in the present work) we obtained 81 different types of clones. Based on the trajectory of their secondary axon tracts (described in the accompanying paper, Lovick et al., 2013), we assigned these clones to specific lineages defined in the larva. Since a labeled clone reveals all aspects (cell bodies, axon tracts, terminal arborization) of a lineage, we were able to describe projection envelopes for all secondary lineages of the supraesophageal ganglion. This work provides a framework by which the secondary neurons (forming the vast majority of adult brain neurons) can be assigned to genetically and developmentally defined groups. It also represents a step towards the goal to establish, for each lineage, the link between its mature anatomical and functional phenotype, and the genetic make-up of the neuroblast it descends from.
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Affiliation(s)
- Darren C. Wong
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jennifer K. Lovick
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Kathy T. Ngo
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Wichanee Borisuthirattana
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jaison J. Omoto
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Volker Hartenstein
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
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10
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Lovick JK, Ngo KT, Omoto JJ, Wong DC, Nguyen JD, Hartenstein V. Postembryonic lineages of the Drosophila brain: I. Development of the lineage-associated fiber tracts. Dev Biol 2013; 384:228-57. [PMID: 23880429 DOI: 10.1016/j.ydbio.2013.07.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 07/11/2013] [Accepted: 07/11/2013] [Indexed: 11/16/2022]
Abstract
Neurons of the Drosophila central brain fall into approximately 100 paired groups, termed lineages. Each lineage is derived from a single asymmetrically-dividing neuroblast. Embryonic neuroblasts produce 1,500 primary neurons (per hemisphere) that make up the larval CNS followed by a second mitotic period in the larva that generates approximately 10,000 secondary, adult-specific neurons. Clonal analyses based on previous works using lineage-specific Gal4 drivers have established that such lineages form highly invariant morphological units. All neurons of a lineage project as one or a few axon tracts (secondary axon tracts, SATs) with characteristic trajectories, thereby representing unique hallmarks. In the neuropil, SATs assemble into larger fiber bundles (fascicles) which interconnect different neuropil compartments. We have analyzed the SATs and fascicles formed by lineages during larval, pupal, and adult stages using antibodies against membrane molecules (Neurotactin/Neuroglian) and synaptic proteins (Bruchpilot/N-Cadherin). The use of these markers allows one to identify fiber bundles of the adult brain and associate them with SATs and fascicles of the larval brain. This work lays the foundation for assigning the lineage identity of GFP-labeled MARCM clones on the basis of their close association with specific SATs and neuropil fascicles, as described in the accompanying paper (Wong et al., 2013. Postembryonic lineages of the Drosophila brain: II. Identification of lineage projection patterns based on MARCM clones. Submitted.).
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Affiliation(s)
- Jennifer K Lovick
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, 610 Charles E. Young Drive, 5009 Terasaki Life Sciences Bldg, Los Angeles, CA 90095, USA
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11
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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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12
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Sen S, Reichert H, VijayRaghavan K. Conserved roles of ems/Emx and otd/Otx genes in olfactory and visual system development in Drosophila and mouse. Open Biol 2013; 3:120177. [PMID: 23635521 PMCID: PMC3866872 DOI: 10.1098/rsob.120177] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The regional specialization of brain function has been well documented in the mouse and fruitfly. The expression of regulatory factors in specific regions of the brain during development suggests that they function to establish or maintain this specialization. Here, we focus on two such factors—the Drosophila cephalic gap genes empty spiracles (ems) and orthodenticle (otd), and their vertebrate homologues Emx1/2 and Otx1/2—and review novel insight into their multiple crucial roles in the formation of complex sensory systems. While the early requirement of these genes in specification of the neuroectoderm has been discussed previously, here we consider more recent studies that elucidate the later functions of these genes in sensory system formation in vertebrates and invertebrates. These new studies show that the ems and Emx genes in both flies and mice are essential for the development of the peripheral and central neurons of their respective olfactory systems. Moreover, they demonstrate that the otd and Otx genes in both flies and mice are essential for the development of the peripheral and central neurons of their respective visual systems. Based on these recent experimental findings, we discuss the possibility that the olfactory and visual systems of flies and mice share a common evolutionary origin, in that the conserved visual and olfactory circuit elements derive from conserved domains of otd/Otx and ems/Emx action in the urbilaterian ancestor.
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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
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13
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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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14
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Lin S, Lee T. Generating neuronal diversity in the Drosophila central nervous system. Dev Dyn 2011; 241:57-68. [PMID: 21932323 DOI: 10.1002/dvdy.22739] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2011] [Indexed: 11/07/2022] Open
Abstract
Generating diverse neurons in the central nervous system involves three major steps. First, heterogeneous neural progenitors are specified by positional cues at early embryonic stages. Second, neural progenitors sequentially produce neurons or intermediate precursors that acquire different temporal identities based on their birth-order. Third, sister neurons produced during asymmetrical terminal mitoses are given distinct fates. Determining the molecular mechanisms underlying each of these three steps of cellular diversification will unravel brain development and evolution. Drosophila has a relatively simple and tractable CNS, and previous studies on Drosophila CNS development have greatly advanced our understanding of neuron fate specification. Here we review those studies and discuss how the lessons we have learned from fly teach us the process of neuronal diversification in general.
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Affiliation(s)
- Suewei Lin
- Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, Virginia 20147, USA
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Ando M, Totani Y, Walldorf U, Furukubo-Tokunaga K. TALE-class homeodomain transcription factors, homothorax and extradenticle, control dendritic and axonal targeting of olfactory projection neurons in the Drosophila brain. Dev Biol 2011; 358:122-36. [PMID: 21801717 DOI: 10.1016/j.ydbio.2011.07.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Revised: 07/06/2011] [Accepted: 07/13/2011] [Indexed: 12/31/2022]
Abstract
Precise neuronal connectivity in the nervous system depends on specific axonal and dendritic targeting of individual neurons. In the Drosophila brain, olfactory projection neurons convey odor information from the antennal lobe to higher order brain centers such as the mushroom body and the lateral horn. Here, we show that Homothorax (Hth), a TALE-class homeodomain transcription factor, is expressed in many of the antennal lobe neurons including projection neurons and local interneurons. In addition, HTH is expressed in the progenitors of the olfactory projection neurons, and the activity of hth is required for the generation of the lateral but not for the anterodorsal and ventral lineages. MARCM analyses show that the hth is essential for correct dendritic targeting of projection neurons in the antennal lobe. Moreover, the activity of hth is required for axonal fasciculation, correct routing and terminal branching of the projection neurons. We also show that another TALE-class homeodomain protein, Extradenticle (Exd), is required for the dendritic and axonal development of projection neurons. Mutation of exd causes projection neuron defects that are reminiscent of the phenotypes caused by the loss of the hth activity. Double immunostaining experiments show that Hth and Exd are coexpressed in olfactory projection neurons and their progenitors, and that the expressions of Hth and Exd require the activity of each other gene. These results thus demonstrate the functional importance of the TALE-class homeodomain proteins in cell-type specification and precise wiring of the Drosophila olfactory network.
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Affiliation(s)
- Mai Ando
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Japan
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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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Sen S, Hartmann B, Reichert H, Rodrigues V. Expression and function of the empty spiracles gene in olfactory sense organ development of Drosophila melanogaster. Development 2010; 137:3687-95. [PMID: 20940227 DOI: 10.1242/dev.052407] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In Drosophila, the cephalic gap gene empty spiracles plays key roles in embryonic patterning of the peripheral and central nervous system. During postembryonic development, it is involved in the development of central olfactory circuitry in the antennal lobe of the adult. However, its possible role in the postembryonic development of peripheral olfactory sense organs has not been investigated. Here, we show that empty spiracles acts in a subset of precursors that generate the olfactory sense organs of the adult antenna. All empty spiracles-expressing precursor cells co-express the proneural gene amos and the early patterning gene lozenge. Moreover, the expression of empty spiracles in these precursor cells is dependent on both amos and lozenge. Functional analysis reveals two distinct roles of empty spiracles in the development of olfactory sense organs. Genetic interaction studies in a lozenge-sensitized background uncover a requirement of empty spiracles in the formation of trichoid and basiconic olfactory sensilla. MARCM-based clonal mutant analysis reveals an additional role during axonal targeting of olfactory sensory neurons to glomeruli within the antennal lobe. Our findings on empty spiracles action in olfactory sense organ development complement previous studies that demonstrate its requirement in olfactory interneurons and, taken together with studies on the murine homologs of empty spiracles, suggest that conserved molecular genetic programs might be responsible for the formation of both peripheral and central olfactory circuitry in insects and mammals.
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Affiliation(s)
- Sonia Sen
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bellary Road, Bangalore 560065, India
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18
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Kim HG, Ahn JW, Kurth I, Ullmann R, Kim HT, Kulharya A, Ha KS, Itokawa Y, Meliciani I, Wenzel W, Lee D, Rosenberger G, Ozata M, Bick DP, Sherins RJ, Nagase T, Tekin M, Kim SH, Kim CH, Ropers HH, Gusella JF, Kalscheuer V, Choi CY, Layman LC. WDR11, a WD protein that interacts with transcription factor EMX1, is mutated in idiopathic hypogonadotropic hypogonadism and Kallmann syndrome. Am J Hum Genet 2010; 87:465-79. [PMID: 20887964 DOI: 10.1016/j.ajhg.2010.08.018] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 08/10/2010] [Accepted: 08/31/2010] [Indexed: 12/25/2022] Open
Abstract
By defining the chromosomal breakpoint of a balanced t(10;12) translocation from a subject with Kallmann syndrome and scanning genes in its vicinity in unrelated hypogonadal subjects, we have identified WDR11 as a gene involved in human puberty. We found six patients with a total of five different heterozygous WDR11 missense mutations, including three alterations (A435T, R448Q, and H690Q) in WD domains important for β propeller formation and protein-protein interaction. In addition, we discovered that WDR11 interacts with EMX1, a homeodomain transcription factor involved in the development of olfactory neurons, and that missense alterations reduce or abolish this interaction. Our findings suggest that impaired pubertal development in these patients results from a deficiency of productive WDR11 protein interaction.
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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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Kumar A, Fung S, Lichtneckert R, Reichert H, Hartenstein V. Arborization pattern of engrailed-positive neural lineages reveal neuromere boundaries in the Drosophila brain neuropil. J Comp Neurol 2009; 517:87-104. [PMID: 19711412 DOI: 10.1002/cne.22112] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The Drosophila brain is a highly complex structure composed of thousands of neurons that are interconnected in numerous exquisitely organized neuropil structures such as the mushroom bodies, central complex, antennal lobes, and other specialized neuropils. While the neurons of the insect brain are known to derive in a lineage-specific fashion from a stereotyped set of segmentally organized neuroblasts, the developmental origin and neuromeric organization of the neuropil formed by these neurons is still unclear. In this study we used genetic labeling techniques to characterize the neuropil innervation pattern of engrailed-expressing brain lineages of known neuromeric origin. We show that the neurons of these lineages project to and form most arborizations, in particular all of their proximal branches, in the same brain neuropil compartments in embryonic, larval and adult stages. Moreover, we show that engrailed-positive neurons of differing neuromeric origin respect boundaries between neuromere-specific compartments in the brain. This is confirmed by an analysis of the arborization pattern of empty spiracles-expressing lineages. These findings indicate that arborizations of lineages deriving from different brain neuromeres innervate a nonoverlapping set of neuropil compartments. This supports a model for neuromere-specific brain neuropil, in which a given lineage forms its proximal arborizations predominantly in the compartments that correspond to its neuromere of origin.
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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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Reichert H. Evolutionary conservation of mechanisms for neural regionalization, proliferation and interconnection in brain development. Biol Lett 2009; 5:112-6. [PMID: 18755655 PMCID: PMC2657731 DOI: 10.1098/rsbl.2008.0337] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 07/28/2008] [Accepted: 07/28/2008] [Indexed: 11/12/2022] Open
Abstract
Comparative studies of brain development in vertebrate and invertebrate model systems demonstrate remarkable similarities in expression and action of developmental control genes during embryonic patterning, neural proliferation and circuit formation in the brain. Thus, comparable sets of developmental control genes are involved in specifying the early brain primordium as well as in regionalized patterning along its anteroposterior and dorsoventral axes. Furthermore, similar cellular and molecular mechanisms underlie the formation and proliferation of neural stem cell-like progenitors that generate the neurons in the central nervous systems. Finally, neural identity and some complex circuit interconnections in specific brain domains appear to be comparable in vertebrates and invertebrates and may depend on similar developmental control genes.
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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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