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Barr J, Walz A, Restaino AC, Amit M, Barclay SM, Vichaya EG, Spanos WC, Dantzer R, Talbot S, Vermeer PD. Tumor-infiltrating nerves functionally alter brain circuits and modulate behavior in a male mouse model of head-and-neck cancer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.18.562990. [PMID: 37905135 PMCID: PMC10614955 DOI: 10.1101/2023.10.18.562990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Cancer patients often experience changes in mental health, prompting an exploration into whether nerves infiltrating tumors contribute to these alterations by impacting brain functions. Using a male mouse model for head and neck cancer, we utilized neuronal tracing techniques and show that tumor-infiltrating nerves indeed connect to distinct brain areas via the ipsilateral trigeminal ganglion. The activation of this neuronal circuitry led to behavioral alterations represented by decreased nest-building, increased latency to eat a cookie, and reduced wheel running. Tumor-infiltrating nociceptor neurons exhibited heightened activity, as indicated by increased calcium mobilization. Correspondingly, the specific brain regions receiving these neural projections showed elevated cFos and delta FosB expression in tumor-bearing mice, alongside markedly intensified calcium responses compared to non-tumor-bearing counterparts. The genetic elimination of nociceptor neurons in tumor-bearing mice led to decreased brain Fos expression and mitigated the behavioral alterations induced by the presence of the tumor. While analgesic treatment successfully restored behaviors involving oral movements to normalcy in tumor-bearing mice, it did not have a similar therapeutic effect on voluntary wheel running. This discrepancy points towards an intricate relationship, where pain is not the exclusive driver of such behavioral shifts. Unraveling the interaction between the tumor, infiltrating nerves, and the brain is pivotal to developing targeted interventions to alleviate the mental health burdens associated with cancer.
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Melkani Y, Pant A, Guo Y, Melkani GC. Automated assessment of cardiac dynamics in aging and dilated cardiomyopathy Drosophila models using machine learning. Commun Biol 2024; 7:702. [PMID: 38849449 PMCID: PMC11161577 DOI: 10.1038/s42003-024-06371-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 05/22/2024] [Indexed: 06/09/2024] Open
Abstract
The Drosophila model is pivotal in deciphering the pathophysiological underpinnings of various human ailments, notably aging and cardiovascular diseases. Cutting-edge imaging techniques and physiology yield vast high-resolution videos, demanding advanced analysis methods. Our platform leverages deep learning to segment optical microscopy images of Drosophila hearts, enabling the quantification of cardiac parameters in aging and dilated cardiomyopathy (DCM). Validation using experimental datasets confirms the efficacy of our aging model. We employ two innovative approaches deep-learning video classification and machine-learning based on cardiac parameters to predict fly aging, achieving accuracies of 83.3% (AUC 0.90) and 79.1%, (AUC 0.87) respectively. Moreover, we extend our deep-learning methodology to assess cardiac dysfunction associated with the knock-down of oxoglutarate dehydrogenase (OGDH), revealing its potential in studying DCM. This versatile approach promises accelerated cardiac assays for modeling various human diseases in Drosophila and holds promise for application in animal and human cardiac physiology under diverse conditions.
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Affiliation(s)
- Yash Melkani
- Department of Pathology, Division of Molecular and Cellular Pathology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
- Engineering Physics Department, College of Engineering, University of California, Berkeley, CA, USA
| | - Aniket Pant
- Department of Pathology, Division of Molecular and Cellular Pathology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Yiming Guo
- Department of Pathology, Division of Molecular and Cellular Pathology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Girish C Melkani
- Department of Pathology, Division of Molecular and Cellular Pathology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
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3
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Understanding cellular glycan surfaces in the central nervous system. Biochem Soc Trans 2018; 47:89-100. [PMID: 30559272 DOI: 10.1042/bst20180330] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/21/2018] [Accepted: 11/06/2018] [Indexed: 02/06/2023]
Abstract
Glycosylation, the enzymatic process by which glycans are attached to proteins and lipids, is the most abundant and functionally important type of post-translational modification associated with brain development, neurodegenerative disorders, psychopathologies and brain cancers. Glycan structures are diverse and complex; however, they have been detected and targeted in the central nervous system (CNS) by various immunohistochemical detection methods using glycan-binding proteins such as anti-glycan antibodies or lectins and/or characterized with analytical techniques such as chromatography and mass spectrometry. The glycan structures on glycoproteins and glycolipids expressed in neural stem cells play key roles in neural development, biological processes and CNS maintenance, such as cell adhesion, signal transduction, molecular trafficking and differentiation. This brief review will highlight some of the important findings on differential glycan expression across stages of CNS cell differentiation and in pathological disorders and diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, amyotrophic lateral sclerosis, schizophrenia and brain cancer.
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Gasparini SJ, Llonch S, Borsch O, Ader M. Transplantation of photoreceptors into the degenerative retina: Current state and future perspectives. Prog Retin Eye Res 2018; 69:1-37. [PMID: 30445193 DOI: 10.1016/j.preteyeres.2018.11.001] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 10/29/2018] [Accepted: 11/06/2018] [Indexed: 12/12/2022]
Abstract
The mammalian retina displays no intrinsic regenerative capacities, therefore retinal degenerative diseases such as age-related macular degeneration (AMD) or retinitis pigmentosa (RP) result in a permanent loss of the light-sensing photoreceptor cells. The degeneration of photoreceptors leads to vision impairment and, in later stages, complete blindness. Several therapeutic strategies have been developed to slow down or prevent further retinal degeneration, however a definitive cure i.e. replacement of the lost photoreceptors, has not yet been established. Cell-based treatment approaches, by means of photoreceptor transplantation, have been studied in pre-clinical animal models over the last three decades. The introduction of pluripotent stem cell-derived retinal organoids represents, in principle, an unlimited source for the generation of transplantable human photoreceptors. However, safety, immunological and reproducibility-related issues regarding the use of such cells still need to be solved. Moreover, the recent finding of cytoplasmic material transfer between donor and host photoreceptors demands reinterpretation of several former transplantation studies. At the same time, material transfer between healthy donor and dysfunctional patient photoreceptors also offers a potential alternative strategy for therapeutic intervention. In this review we discuss the history and current state of photoreceptor transplantation, the techniques used to assess rescue of visual function, the prerequisites for effective transplantation as well as the main roadblocks, including safety and immune response to the graft, that need to be overcome for successful clinical translation of photoreceptor transplantation approaches.
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Affiliation(s)
- Sylvia J Gasparini
- CRTD/Center for Regenerative Therapies Dresden, Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Fetscherstraße 105, 01307, Dresden, Germany
| | - Sílvia Llonch
- CRTD/Center for Regenerative Therapies Dresden, Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Fetscherstraße 105, 01307, Dresden, Germany
| | - Oliver Borsch
- CRTD/Center for Regenerative Therapies Dresden, Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Fetscherstraße 105, 01307, Dresden, Germany
| | - Marius Ader
- CRTD/Center for Regenerative Therapies Dresden, Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Fetscherstraße 105, 01307, Dresden, Germany.
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Mysore K, Li P, Duman-Scheel M. Identification of Aedes aegypti cis-regulatory elements that promote gene expression in olfactory receptor neurons of distantly related dipteran insects. Parasit Vectors 2018; 11:406. [PMID: 29996889 PMCID: PMC6042464 DOI: 10.1186/s13071-018-2982-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/27/2018] [Indexed: 12/25/2022] Open
Abstract
Background Sophisticated tools for manipulation of gene expression in select neurons, including neurons that regulate sexually dimorphic behaviors, are increasingly available for analysis of genetic model organisms. However, we lack comparable genetic tools for analysis of non-model organisms, including Aedes aegypti, a vector mosquito which displays sexually dimorphic behaviors that contribute to pathogen transmission. Formaldehyde-assisted isolation of regulatory elements followed by sequencing (FAIRE-seq) recently facilitated genome-wide discovery of putative A. aegypti cis-regulatory elements (CREs), many of which could be used to manipulate gene expression in mosquito neurons and other tissues. The goal of this investigation was to identify FAIRE DNA elements that promote gene expression in the olfactory system, a tissue of vector importance. Results Eight A. aegypti CREs that promote gene expression in antennal olfactory receptor neurons (ORNs) were identified in a Drosophila melanogaster transgenic reporter screen. Four CREs identified in the screen were cloned upstream of GAL4 in a transgenic construct that is compatible with transformation of a variety of insect species. These constructs, which contained FAIRE DNA elements associated with the A. aegypti odorant coreceptor (orco), odorant receptor 1 (Or1), odorant receptor 8 (Or8) and fruitless (fru) genes, were used for transformation of A. aegypti. Six A. aegypti strains, including strains displaying transgene expression in all ORNs, subsets of these neurons, or in a sex-specific fashion, were isolated. The CREs drove transgene expression in A. aegypti that corresponded to endogenous gene expression patterns of the orco, Or1, Or8 and fru genes in the mosquito antenna. CRE activity in A. aegypti was found to be comparable to that observed in D. melanogaster reporter assays. Conclusions These results provide further evidence that FAIRE-seq, which can be paired with D. melanogaster reporter screening to test FAIRE DNA element activity in select tissues, is a useful method for identification of mosquito cis-regulatory elements. These findings expand the genetic toolkit available for the study of Aedes neurobiology. Moreover, given that the CREs drive comparable olfactory neural expression in both A. aegypti and D. melanogaster, it is likely that they may function similarly in multiple dipteran insects, including other disease vector mosquito species.
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Affiliation(s)
- Keshava Mysore
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, 1234 Notre Dame Avenue, Raclin-Carmichael Hall, South Bend, IN, 46617, USA.,The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, 46556, USA
| | - Ping Li
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, 1234 Notre Dame Avenue, Raclin-Carmichael Hall, South Bend, IN, 46617, USA.,The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, 46556, USA
| | - Molly Duman-Scheel
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, 1234 Notre Dame Avenue, Raclin-Carmichael Hall, South Bend, IN, 46617, USA. .,The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, 46556, USA. .,Department of Biological Sciences, The University of Notre Dame, Notre Dame, IN, 46556, USA.
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Hellier V, Brock O, Candlish M, Desroziers E, Aoki M, Mayer C, Piet R, Herbison A, Colledge WH, Prévot V, Boehm U, Bakker J. Female sexual behavior in mice is controlled by kisspeptin neurons. Nat Commun 2018; 9:400. [PMID: 29374161 PMCID: PMC5786055 DOI: 10.1038/s41467-017-02797-2] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 12/29/2017] [Indexed: 12/17/2022] Open
Abstract
Sexual behavior is essential for the survival of many species. In female rodents, mate preference and copulatory behavior depend on pheromones and are synchronized with ovulation to ensure reproductive success. The neural circuits driving this orchestration in the brain have, however, remained elusive. Here, we demonstrate that neurons controlling ovulation in the mammalian brain are at the core of a branching neural circuit governing both mate preference and copulatory behavior. We show that male odors detected in the vomeronasal organ activate kisspeptin neurons in female mice. Classical kisspeptin/Kiss1R signaling subsequently triggers olfactory-driven mate preference. In contrast, copulatory behavior is elicited by kisspeptin neurons in a parallel circuit independent of Kiss1R involving nitric oxide signaling. Consistent with this, we find that kisspeptin neurons impinge onto nitric oxide-synthesizing neurons in the ventromedial hypothalamus. Our data establish kisspeptin neurons as a central regulatory hub orchestrating sexual behavior in the female mouse brain. Mate preference and copulatory behavior in female rodents are coordinated with the ovulation cycles of the animal. This study shows that hypothalamic kisspeptin neurons control both mate choice and copulation, and therefore, that sexual behavior and ovulation may be synchronized by the same neuropeptide.
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Affiliation(s)
- Vincent Hellier
- GIGA Neurosciences, Neuroendocrinology, University of Liege, 4000, Liege, Belgium
| | - Olivier Brock
- GIGA Neurosciences, Neuroendocrinology, University of Liege, 4000, Liege, Belgium.,Netherlands Institute for Neuroscience, 1105 BA, Amsterdam, The Netherlands
| | - Michael Candlish
- Experimental Pharmacology, Center for Molecular Signaling (PZMS), Saarland University School of Medicine, 66421, Homburg, Germany
| | - Elodie Desroziers
- GIGA Neurosciences, Neuroendocrinology, University of Liege, 4000, Liege, Belgium
| | - Mari Aoki
- Experimental Pharmacology, Center for Molecular Signaling (PZMS), Saarland University School of Medicine, 66421, Homburg, Germany
| | | | - Richard Piet
- Center for Neuroendocrinology and Department of Physiology, University of Otago, Dunedin, 9054, New Zealand
| | - Allan Herbison
- Center for Neuroendocrinology and Department of Physiology, University of Otago, Dunedin, 9054, New Zealand
| | - William Henry Colledge
- Reproductive Physiology Group, Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Vincent Prévot
- Laboratory of Development and Plasticity of the Neuroendocrine Brain, Jean-Pierre Aubert Research Center, Inserm U1172, F- 59000, Lille Cedex, France
| | - Ulrich Boehm
- Experimental Pharmacology, Center for Molecular Signaling (PZMS), Saarland University School of Medicine, 66421, Homburg, Germany.
| | - Julie Bakker
- GIGA Neurosciences, Neuroendocrinology, University of Liege, 4000, Liege, Belgium. .,Netherlands Institute for Neuroscience, 1105 BA, Amsterdam, The Netherlands.
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Koseki N, Mori S, Suzuki S, Tonooka Y, Kosugi S, Miyakawa H, Morimoto T. Individual differences in sensory responses influence decision making by Drosophila melanogaster larvae on exposure to contradictory cues. J Neurogenet 2016; 30:288-296. [PMID: 27309770 DOI: 10.1080/01677063.2016.1202949] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Animals make decisions on behavioral choice by evaluating internal and external signals. Individuals often make decisions in different ways, but the underlying neural mechanisms are not well understood. Here, we describe a system for observing the behavior of individual Drosophila melanogaster larvae simultaneously presented with contradictory signals, in this case attractive (yeast paste) and aversive (NaCl) signals. Olfaction was used to detect the yeast paste, whereas the ENaC/Pickpocket channel was important for NaCl detection. We found that wild-type (Canton-S) larvae fall into two decision making groups: one group decided to approach the yeast paste by overcoming the aversive signal, whereas the other group decided to forgo the yeast paste because of the aversive signal. Our findings indicate that different endogenous sensitivities to NaCl contribute to make differences between two groups and that diverse decision making steps occur in individual animals.
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Affiliation(s)
- Nozomi Koseki
- a Laboratory of Cellular Neurobiology, School of Life Sciences , Tokyo University of Pharmacy and Life Sciences , Hachioji , Tokyo , Japan
| | - Satoshi Mori
- a Laboratory of Cellular Neurobiology, School of Life Sciences , Tokyo University of Pharmacy and Life Sciences , Hachioji , Tokyo , Japan
| | - Shoki Suzuki
- a Laboratory of Cellular Neurobiology, School of Life Sciences , Tokyo University of Pharmacy and Life Sciences , Hachioji , Tokyo , Japan
| | - Yuta Tonooka
- a Laboratory of Cellular Neurobiology, School of Life Sciences , Tokyo University of Pharmacy and Life Sciences , Hachioji , Tokyo , Japan
| | - Sakiko Kosugi
- a Laboratory of Cellular Neurobiology, School of Life Sciences , Tokyo University of Pharmacy and Life Sciences , Hachioji , Tokyo , Japan
| | - Hiroyoshi Miyakawa
- a Laboratory of Cellular Neurobiology, School of Life Sciences , Tokyo University of Pharmacy and Life Sciences , Hachioji , Tokyo , Japan
| | - Takako Morimoto
- a Laboratory of Cellular Neurobiology, School of Life Sciences , Tokyo University of Pharmacy and Life Sciences , Hachioji , Tokyo , Japan
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Mecklenburg KL, Freed SA, Raval M, Quintero OA, Yengo CM, O'Tousa JE. Invertebrate and vertebrate class III myosins interact with MORN repeat-containing adaptor proteins. PLoS One 2015; 10:e0122502. [PMID: 25822849 PMCID: PMC4379085 DOI: 10.1371/journal.pone.0122502] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 02/18/2015] [Indexed: 12/22/2022] Open
Abstract
In Drosophila photoreceptors, the NINAC-encoded myosin III is found in a complex with a small, MORN-repeat containing, protein Retinophilin (RTP). Expression of these two proteins in other cell types showed NINAC myosin III behavior is altered by RTP. NINAC deletion constructs were used to map the RTP binding site within the proximal tail domain of NINAC. In vertebrates, the RTP ortholog is MORN4. Co-precipitation experiments demonstrated that human MORN4 binds to human myosin IIIA (MYO3A). In COS7 cells, MORN4 and MYO3A, but not MORN4 and MYO3B, co-localize to actin rich filopodia extensions. Deletion analysis mapped the MORN4 binding to the proximal region of the MYO3A tail domain. MYO3A dependent MORN4 tip localization suggests that MYO3A functions as a motor that transports MORN4 to the filopodia tips and MORN4 may enhance MYO3A tip localization by tethering it to the plasma membrane at the protrusion tips. These results establish conserved features of the RTP/MORN4 family: they bind within the tail domain of myosin IIIs to control their behavior.
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Affiliation(s)
- Kirk L. Mecklenburg
- Department of Biology, Indiana University South Bend, South Bend, Indiana, United States of America
| | - Stephanie A. Freed
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Manmeet Raval
- Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, United States of America
| | - Omar A. Quintero
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
| | - Christopher M. Yengo
- Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, United States of America
- * E-mail: (CY); (JO)
| | - Joseph. E. O'Tousa
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- * E-mail: (CY); (JO)
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Negative regulation of the novel norpA(P24) suppressor, diehard4, in the endo-lysosomal trafficking underlies photoreceptor cell degeneration. PLoS Genet 2013; 9:e1003559. [PMID: 23754968 PMCID: PMC3674991 DOI: 10.1371/journal.pgen.1003559] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Accepted: 04/24/2013] [Indexed: 12/16/2022] Open
Abstract
Rhodopsin has been used as a prototype system to investigate G protein-coupled receptor (GPCR) internalization and endocytic sorting mechanisms. Failure of rhodopsin recycling upon light activation results in various degenerative retinal diseases. Accumulation of internalized rhodopsin in late endosomes and the impairment of its lysosomal degradation are associated with unregulated cell death that occurs in dystrophies. However, the molecular basis of rhodopsin accumulation remains elusive. We found that the novel norpAP24 suppressor, diehard4, is responsible for the inability of endo-lysosomal rhodopsin trafficking and retinal degeneration in Drosophila models of retinal dystrophies. We found that diehard4 encodes Osiris 21. Loss of its function suppresses retinal degeneration in norpAP24, rdgC306, and trp1, but not in rdgB2, suggesting a common cause of photoreceptor death. In addition, the loss of Osiris 21 function shifts the membrane balance between late endosomes and lysosomes as evidenced by smaller late endosomes and the proliferation of lysosomal compartments, thus facilitating the degradation of endocytosed rhodopsin. Our results demonstrate the existence of negative regulation in vesicular traffic between endosomes and lysosomes. We anticipate that the identification of additional components and an in-depth description of this specific molecular machinery will aid in therapeutic interventions of various retinal dystrophies and GPCR-related human diseases. Malfunctioning of phototransduction is the major cause of human blindness. Without functional phototransduction, rhodopsin-1, the major visual pigment, is rapidly endocytosed and accumulated in late endosomes. Impaired lysosomal delivery of endocytosed rhodopsin and its degradation has been reported to trigger progressive and light-dependent retinal degeneration in Drosophila models. It is intriguing why endocytosed rhodopsin accumulates in late endosomes instead of being delivered to lysosomes for degradation. Is this attributable to a saturation of rhodopsin endocytosis, which impedes the delivery capacity of the cell? To investigate the underlying mechanisms of rhodopsin accumulation in late endosomes, we used a suppressor of phototransduction mutants, which was identified previously from our unbiased genetic screen. This suppressor, called diehard4, shifts the membrane balance between late endosomes and lysosomes, resulting in the facilitated degradation of endocytosed rhodopsin. Our results clearly demonstrate that a previously unknown mechanism of negative regulation is actively engaged in vesicular traffic between endosomes and lysosomes in fly photoreceptors. We showed that eliminating such blockage alone was enough to rescue retinal degeneration in phototransduction mutants. From these results, we anticipate that the identification of additional components and an in-depth description of this molecular machinery will aid in therapeutic interventions of various retinal dystrophies and neurodegenerative disorders.
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Hibbard KL, O’Tousa JE. A role for the cytoplasmic DEAD box helicase Dbp21E2 in rhodopsin maturation and photoreceptor viability. J Neurogenet 2012; 26:177-88. [PMID: 22794106 PMCID: PMC3680124 DOI: 10.3109/01677063.2012.692412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The Dbp21E2 (DEAD box protein 21E2) is a member of a family of DEAD box helicases active in RNA processing and stability. The authors used genetic mosaics to identify mutants in Dbp21E2 that affect rhodopsin biogenesis and the maintenance of photoreceptor structure. Analysis of a green fluorescent protein (GFP)-tagged Rh1 rhodopsin construct placed under control of a heat shock promoter showed that Dbp21E21 fails to efficiently transport Rh1 from the photoreceptor cell body to the rhabdomere. Retinal degeneration is not dependent on the Rh1 transport defects. The authors also showed that GFP- and red fluorescent protein (RFP)-tagged Dbp21E2 proteins are localized to discrete cytoplasmic structures that are not associated with organelles known to be active in rhodopsin transport. The molecular genetic analysis described here reveals an unexpected role for the Dbp21E2 helicase and provides an experimental system to further characterize its function.
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Affiliation(s)
- Karen L. Hibbard
- Dept. of Biological Sciences, Univ. of Notre Dame, Notre Dame, IN, USA
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11
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Nakashiba T, Cushman JD, Pelkey KA, Renaudineau S, Buhl DL, McHugh TJ, Rodriguez Barrera V, Chittajallu R, Iwamoto KS, McBain CJ, Fanselow MS, Tonegawa S. Young dentate granule cells mediate pattern separation, whereas old granule cells facilitate pattern completion. Cell 2012; 149:188-201. [PMID: 22365813 DOI: 10.1016/j.cell.2012.01.046] [Citation(s) in RCA: 614] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 12/05/2011] [Accepted: 01/12/2012] [Indexed: 10/28/2022]
Abstract
Adult-born granule cells (GCs), a minor population of cells in the hippocampal dentate gyrus, are highly active during the first few weeks after functional integration into the neuronal network, distinguishing them from less active, older adult-born GCs and the major population of dentate GCs generated developmentally. To ascertain whether young and old GCs perform distinct memory functions, we created a transgenic mouse in which output of old GCs was specifically inhibited while leaving a substantial portion of young GCs intact. These mice exhibited enhanced or normal pattern separation between similar contexts, which was reduced following ablation of young GCs. Furthermore, these mutant mice exhibited deficits in rapid pattern completion. Therefore, pattern separation requires adult-born young GCs but not old GCs, and older GCs contribute to the rapid recall by pattern completion. Our data suggest that as adult-born GCs age, their function switches from pattern separation to rapid pattern completion.
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Affiliation(s)
- Toshiaki Nakashiba
- Department of Biology, RIKEN-MIT Center for Neural Circuit Genetics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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12
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Lee J, Lee J, Ju BG. Drosophila arf72A acts as an essential regulator of endoplasmic reticulum quality control and suppresses autosomal-dominant retinopathy. Int J Biochem Cell Biol 2011; 43:1392-401. [PMID: 21693198 DOI: 10.1016/j.biocel.2011.06.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 05/25/2011] [Accepted: 06/06/2011] [Indexed: 11/27/2022]
Abstract
The eukaryotic endoplasmic reticulum operates multiple quality control mechanisms to ensure that only properly folded proteins are exported to their final destinations via the secretory pathway and those that are not are destroyed via the degradation pathway. However, molecular mechanisms underlying such regulated exportation to these distinct routes are unknown. In this article, we report the role of Drosophila arf72A--the fly homologue of the mammalian Arl1 - in the quality checks of proteins and in the autosomal-dominant retinopathy. ARF72A localizes to the Golgi membranes of Drosophila photoreceptor cells, consistent with mammalian Arl1 localization in cell culture systems. A loss of arf72A function changes the membrane character of the endoplasmic reticulum and shifts the membrane balance between the endoplasmic reticulum and the Golgi complex toward the Golgi complex, resulting in over-proliferated Golgi complexes and accelerated protein secretion. Interestingly, our study indicated that more ARF72A localized on the endoplasmic reticulum in the ninaE(D1) photoreceptor cell, a Drosophila model of autosomal-dominant retinitis pigmentosa, compared to that in the wild-type. In addition, arf72A loss was shown to rescue the ninaE(D1)-related membrane accumulation and the rhodopsin maturation defect, and suppress ninaE(D1)-triggered retinal degeneration, indicating that rhodopsin accumulated in the endoplasmic reticulum bypasses the quality checks. While previous studies of ARF small GTPases have focused on their roles in vesicular budding and transport between the specific organelles, our findings establish an additional function of arf72A in the quality check machinery of the endoplasmic reticulum distinguishing the cargoes for secretion from those for degradation.
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Affiliation(s)
- Jongwoo Lee
- Department of Biological Science, University of Notre Dame, Notre Dame, IN 46556, USA.
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13
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Ohashi Y, Tsubota T, Sato A, Koyano KW, Tamura K, Miyashita Y. A bicistronic lentiviral vector-based method for differential transsynaptic tracing of neural circuits. Mol Cell Neurosci 2010; 46:136-47. [PMID: 20816792 DOI: 10.1016/j.mcn.2010.08.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 08/21/2010] [Accepted: 08/25/2010] [Indexed: 12/18/2022] Open
Abstract
We developed a bicistronic HIV1-derived lentiviral vector system co-expressing green fluorescent protein (AcGFP1) and wheat germ agglutinin (WGA) mediated by picornaviral 2A peptide. This system was first applied to the analysis of the rat cerebellar efferent pathways. When the lentiviral vector was injected into a specific lobule, the local Purkinje cell population (first-order neurons) was efficiently infected and co-expressed both AcGFP1 and WGA protein. In the second-order neurons in the cerebellar and vestibular nuclei, WGA but not AcGFP1 protein was differentially detected, demonstrating that the presence of AcGFP1 protein enables discrimination of first-order neurons from second-order neurons. Furthermore, WGA protein was detected in the contralateral ventrolateral thalamic nucleus (third-order nucleus). This system also successfully labeled rat cortical pathways from the primary somatosensory cortex and monkey cerebellar efferent pathways. Thus, this bicistronic lentiviral vector system is a useful tool for differential transsynaptic tracing of neural pathways originating from local brain regions.
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Affiliation(s)
- Yohei Ohashi
- Department of Physiology, The University of Tokyo School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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14
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Huh Y, Oh MS, Leblanc P, Kim KS. Gene transfer in the nervous system and implications for transsynaptic neuronal tracing. Expert Opin Biol Ther 2010; 10:763-72. [PMID: 20367126 DOI: 10.1517/14712591003796538] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
IMPORTANCE OF THE FIELD Neuronal circuitries are determined by specific synaptic connections and they provide the cellular basis of cognitive processes and behavioral functions. To investigate neuronal circuitries, tracers are typically used to identify the original neurons and their projection targets. AREAS COVERED IN THIS REVIEW Traditional tracing methods using chemical tracers have major limitations such as non-specificity. In this review, we highlight novel genetic tracing approaches that enable visualization of specific neuronal pathways by introducing cDNA encoding a transsynaptic tracer. In contrast to conventional tracing methods, these genetic approaches use cell-type-specific promoters to express transsynaptic tracers such as wheat germ agglutinin and C-terminal fragment of tetanus toxin, which allows labeling of either the input or output populations and connections of specific neuronal type. WHAT THE READER WILL GAIN Specific neuronal circuit information by these genetic approaches will allow more precise, comprehensive and novel information about individual neural circuits and their function in normal and diseased brains. TAKE HOME MESSAGE Using tracer gene transfer, neuronal circuit plasticity after traumatic injury or neurodegenerative diseases can be visualized. Also, this can provide a good marker for evaluation of therapeutic effects of neuroprotective or neurotrophic agents.
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Affiliation(s)
- Youngbuhm Huh
- Department of Anatomy and Neurobiology, Kyung Hee University, Seoul, Republic of Korea
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15
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Jones WD. The expanding reach of the GAL4/UAS system into the behavioral neurobiology of Drosophila. BMB Rep 2009; 42:705-12. [PMID: 19944010 DOI: 10.5483/bmbrep.2009.42.11.705] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Our understanding of the relationships between genes, brains, and behaviors has changed a lot since the first behavioral mutants were isolated in the fly bottles of the Benzer lab at Caltech (1), but Drosophila is still an excellent model system for studying the neurobiology of behavior. Recent advances provide an unprecedented level of control over fly neural circuits. Efforts are underway to add to existing GAL4-driver lines that permit exogenous expression of genetic tools in small populations of neurons. Combining these driver lines with a variety of inducible UAS lines permits the visualization of neuronal morphology, connectivity, and activity. These driver lines also make it possible to specifically ablate, inhibit, or activate subsets of neurons and assess their roles in the generation of behavioral responses. Here, I will briefly review the extensive arsenal now available to drosophilists for investigating the neuronal control of behavior.
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Affiliation(s)
- Walton D Jones
- Department of Biological Sciences, KAIST, Daejeon, Korea.
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16
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Koganezawa M, Matsuo T, Kimura KI, Yamamoto D. Shaping of Drosophila male courtship posture by a gustatory pheromone. Ann N Y Acad Sci 2009; 1170:497-501. [PMID: 19686184 DOI: 10.1111/j.1749-6632.2009.03889.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Drosophila melanogaster males display stereotypical courtship ritual in courting potential mates. The fruitless (fru) gene plays a pivotal role in the generation of male-typical courtship behavior by instructing the formation of the central circuitry underlying this behavior during development. The fru gene expression can be monitored by a reporter, fruNP21, that labels approximately 800 neurons in the adult male brain. Among these fru-expressing neurons, a male-specific neural cluster called P1 initiated male-typical courtship behavior; when the P1 cluster was ectopically produced in the female brain, many such females displayed male-typical courtship behavior toward a target female. To further elucidate the central circuitry for courtship behavior, we examined central projections of sensory neurons that appear to perceive sex pheromones sensed in the foreleg gustatory receptors. The central terminals of these sensory neurons are located near dendrites of the fru-expressing interneurons named mAL. These results suggest that different subsets of fru-expressing neurons are involved in both the sensory integration of sexual cues and the activation of motor centers that generate motor outputs for courtship behavior in the Drosophila brain.
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Affiliation(s)
- Masayuki Koganezawa
- Division of Neurogenetics, Department of Developmental Biology and Neurosciences, Tohoku University Graduate School of Life Science, Sendai, Japan
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17
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Richard M, Muschalik N, Grawe F, Ozüyaman S, Knust E. A role for the extracellular domain of Crumbs in morphogenesis of Drosophila photoreceptor cells. Eur J Cell Biol 2009; 88:765-77. [PMID: 19717208 DOI: 10.1016/j.ejcb.2009.07.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 07/30/2009] [Accepted: 07/30/2009] [Indexed: 12/01/2022] Open
Abstract
Morphogenesis of Drosophila photoreceptor cells includes the subdivision of the apical membrane into the photosensitive rhabdomere and the associated stalk membrane, as well as a considerable elongation of the cell. Drosophila Crumbs (Crb), an evolutionarily conserved transmembrane protein, organizes an apical protein scaffold, which is required for elongation of the photoreceptor cell and extension of the stalk membrane. To further elucidate the role played by different Crb domains during eye morphogenesis, we performed a structure-function analysis in the eye. The analysis showed that the three variants tested, namely full-length Crb, the membrane-bound intracellular domain and the extracellular domain were able to rescue the elongation defects of crb mutant rhabdomeres. However, only full-length Crb and the membrane-bound intracellular domain could partially restore the length of the stalk membrane, while the extracellular domain failed to do so. This failure was associated with the inability of the extracellular domain to recruit beta(Heavy)-spectrin to the stalk membrane. These results highlight the functional importance of the extracellular domain of Crb in the Drosophila eye. They are in line with previous observations, which showed that mutations in the extracellular domain of human CRB1 are associated with retinitis pigmentosa 12 and Leber congenital amaurosis, two severe forms of retinal dystrophy.
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Affiliation(s)
- Mélisande Richard
- Institut für Genetik, Heinrich Heine Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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18
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Ohmoto M, Matsumoto I, Yasuoka A, Yoshihara Y, Abe K. Genetic tracing of the gustatory and trigeminal neural pathways originating from T1R3-expressing taste receptor cells and solitary chemoreceptor cells. Mol Cell Neurosci 2008; 38:505-17. [PMID: 18539481 DOI: 10.1016/j.mcn.2008.04.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Revised: 04/21/2008] [Accepted: 04/24/2008] [Indexed: 10/22/2022] Open
Abstract
We established transgenic mouse lines expressing a transneuronal tracer, wheat germ agglutinin (WGA), under the control of mouse T1R3 gene promoter/enhancer. In the taste buds, WGA transgene was faithfully expressed in T1R3-positive sweet/umami taste receptor cells. WGA protein was transferred not laterally to the synapse-bearing, sour-responsive type III cells in the taste buds but directly to a subset of neurons in the geniculate and nodose/petrosal ganglia, and further conveyed to a rostro-central region of the nucleus of solitary tract. In addition, WGA was expressed in solitary chemoreceptor cells in the nasal epithelium and transferred along the trigeminal sensory pathway to the brainstem neurons. The solitary chemoreceptor cells endogenously expressed T1R3 together with bitter taste receptors T2Rs. This result shows an exceptional signature of receptor expression. Thus, the t1r3-WGA transgenic mice revealed the sweet/umami gustatory pathways from taste receptor cells and the trigeminal neural pathway from solitary chemoreceptor cells.
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Affiliation(s)
- Makoto Ohmoto
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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19
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Rister J, Heisenberg M. Distinct functions of neuronal synaptobrevin in developing and mature fly photoreceptors. ACTA ACUST UNITED AC 2006; 66:1271-84. [PMID: 16967508 DOI: 10.1002/neu.20284] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Neuronal synaptobrevin (n-Syb, alias VAMP2), a synaptic vesicle membrane protein with a central role in neurotransmission, is specifically cleaved by the light chain of tetanus neurotoxin (TNT) that is known to reliably block neuroexocytosis. Here, we study fly photoreceptors transmitting continuous, graded signals to first order interneurons in the lamina, and report consequences of targeted expression of TNT in these cells using the UAS/GAL4 driver/effector system. Expressing the toxin throughout photoreceptor development causes developmental, electrophysiological, and behavioral defects. These can be differentiated by confining toxin expression to shorter developmental periods. Applying a method for controlled temporal and spatial TNT expression, we found that in the early pupa it impaired the development of the retina; in the midpupa, during synapse formation TNT caused a severe hypoplasia of the lamina that persisted into adulthood and left the photoreceptor-interneuron synapses of the lamina without function. Finally, during adulthood TNT neither blocks synaptic transmission in photoreceptors nor depletes the cells of n-Syb. Our study suggests a novel, cell type-specific function of n-Syb in synaptogenesis and it distinguishes between two synapse types: TNT resistant and TNT sensitive ones. These results need to be taken into account if TNT is used for neural circuit analysis.
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Affiliation(s)
- Jens Rister
- Lehrstuhl für Genetik und Neurobiologie der Universität Würzburg, Biozentrum Am Hubland, D-97074 Würzburg, Germany
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20
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Fritz KI, Zubrow A, Mishra OP, Delivoria-Papadopoulos M. Hypercapnia-induced modifications of neuronal function in the cerebral cortex of newborn piglets. Pediatr Res 2005; 57:299-304. [PMID: 15585683 DOI: 10.1203/01.pdr.0000148718.47137.9b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
There is significant controversy over the effects of hypercapnia on the human newborn brain. Previous studies have shown that 1 h of an arterial CO2 pressure (Paco2) of 80 mm Hg alters brain cell membrane Na+K+-ATPase enzyme activity in the cerebral cortex of newborn piglets. The present study tests the hypothesis that hypercapnia (either a Paco2 of 65 or 80 mm Hg) results in decreased energy metabolism and alters neuronal nuclear enzyme activity and protein expression, specifically Ca++/calmodulin-dependent kinase (CaMK) IV activity, phosphorylation of cAMP response element binding protein (CREB), and expression of apoptotic proteins in cortical neuronal nuclei of newborn piglets. Studies were performed in 20 anesthetized normoxic piglets ventilated at either a Paco2 of 65 mm Hg, 80 mm Hg, or 40 mm Hg for 6 h. Energy metabolism was documented by ATP and phosphocreatine (PCr) levels. Results show ATP and PCr levels were significantly lower in the hypercapnic groups than the normocapnic. CaMK IV activity, phosphorylated CREB density, and Bax protein expression were all significantly higher in the hypercapnic groups than the normocapnic group. Bcl-2 protein was similar in all three groups, making the ratio of Bax/Bcl-2 significantly higher in the hypercapnic groups than in the normocapnic group. We conclude that hypercapnia alters neuronal energy metabolism, increases phosphorylation of transcription factors, and increases the expression of apoptotic proteins in the cerebral cortex of newborn piglets and therefore may be deleterious to the newborn brain.
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Affiliation(s)
- Karen I Fritz
- Department of Pediatrics, Drexel University College of Medicine and St. Christopher's Hospital for Children, Division of Neonatology, Front and Erie Sts., Ste. 2212, Philadelphia, PA 19134, USA.
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21
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Morante J, Desplan C. Building a projection map for photoreceptor neurons in the Drosophila optic lobes. Semin Cell Dev Biol 2004; 15:137-43. [PMID: 15036216 DOI: 10.1016/j.semcdb.2003.09.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The sensory tasks performed by the eye are diverse and complex. In Drosophila, the eye performs motion detection for navigation as well as detection of the quality of light (color and polarized light). Both types of inputs are processed separately, as different photoreceptors are specialized in these tasks and contact different target cell layers in the optic lobe. However, their respective outputs are likely to be integrated in higher brain centers. Here, we discuss the cell diversity and potential role of the several ganglia that form the fly optic lobe. We also discuss the power of modern genetic tools to provide the potential to trace the visual neural networks.
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Affiliation(s)
- Javier Morante
- Department of Biology, New York University, 1009 Silver Building, 100 Washington Square East, New York, NY 10003, USA
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22
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Gu G, Yang J, Mitchell KA, O'Tousa JE. Drosophila ninaB and ninaD act outside of retina to produce rhodopsin chromophore. J Biol Chem 2004; 279:18608-13. [PMID: 14982930 DOI: 10.1074/jbc.m400323200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Drosophila ninaB gene encodes a beta,beta-carotene-15,15'-oxygenase responsible for the centric cleavage of beta-carotene that produces the retinal chromophore of rhodopsin. The ninaD gene encodes a membrane receptor required for efficient use of beta-carotene. Despite their importance to the synthesis of visual pigment, we show that these genes are not active in the retina. Mosaic analysis shows that ninaB and ninaD are not required in the retina, and exclusive retinal expression of either gene, or both genes simultaneously, does not support rhodopsin biogenesis. In contrast, neuron-specific expression of ninaB and ninaD allows for rhodopsin biogenesis. Additional directed expression studies failed to identify other tissues supporting ninaB activity in rhodopsin biogenesis. These results show that nonretinal sites of NinaB beta,beta-carotene-15,15'-oxygenase activity, likely neurons of the central nervous system, are essential for production of the visual chromophore. Retinal or another C(20) retinoid, not members of the beta-carotene family of C(40) carotenoids, are supplied to photoreceptors for rhodopsin biogenesis.
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Affiliation(s)
- Guie Gu
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
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23
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von Bartheld CS. Axonal transport and neuronal transcytosis of trophic factors, tracers, and pathogens. ACTA ACUST UNITED AC 2003; 58:295-314. [PMID: 14704960 DOI: 10.1002/neu.10315] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Neurons can specifically internalize macromolecules, such as trophic factors, lectins, toxins, and other pathogens. Upon internalization in terminals, proteins can move retrogradely along axons, or, upon internalization at somatodendritic domains, they can move into an anterograde axonal transport pathway. Release of internalized proteins from neurons after either retrograde or anterograde axonal transport results in transcytosis and trafficking of proteins across multiple synapses. Recent studies of binding properties of several such proteins suggest that pathogens and lectins may utilize existing transport machineries designed for trafficking of trophic factors. Specific pathways may protect trophic factors, pathogens, and toxins from degradation after internalization and may target the trophic or pathogenic cargo for transcytosis after either retrograde or anterograde transport along axons. Elucidating the molecular mechanisms of sorting steps and transport pathways will further our understanding of trophic signaling and could be relevant for an understanding and possible treatment of neurological diseases such as rabies, Alzheimer's disease, and prion encephalopathies. At present, our knowledge is remarkably sparse about the types of receptors used by pathogens for trafficking, the signals that sort trophins or pathogens into recycling or degradation pathways, and the mechanisms that regulate their release from somatodendritic domains or axon terminals. This review intends to draw attention to potential convergences and parallels in trafficking of trophic and pathogenic proteins. It discusses axonal transport/trafficking mechanisms that may help to understand and eventually treat neurological diseases by targeted drug delivery.
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Affiliation(s)
- Christopher S von Bartheld
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada 89557, USA.
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24
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Yoshihara Y. Visualizing selective neural pathways with WGA transgene: combination of neuroanatomy with gene technology. Neurosci Res 2002; 44:133-40. [PMID: 12354628 DOI: 10.1016/s0168-0102(02)00130-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Functional logic employed by the nervous system for information processing resides mainly in the wiring patterns among specific types of neurons. Therefore, detailed knowledge on neuronal networks is essential for understanding a wide range of brain functions. A powerful and long-awaited method for analyzing the neuronal connectivity patterns would be to deliver tracers selectively to specific types of neurons and at the same time to label transsynaptically their axonal target neurons. For this purpose, we took advantage of a unique property of plant lectin, wheat germ agglutinin (WGA), which has been used as a transsynaptic tracer in classical neuroanatomical studies. We developed a novel genetic strategy that employs WGA cDNA as a transgene, for the visualization of selective and functional neural pathways in the nervous system. In this article, I will introduce several examples of neural pathways visualized with the WGA transgene and discuss about its further refinement and applications.
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Affiliation(s)
- Yoshihiro Yoshihara
- Laboratory for Neurobiology of Synapse, RIKEN Brain Science Institute, Hirosawa 2-1, Wako, Saitama 351-0198, Japan.
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25
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Pace KE, Lebestky T, Hummel T, Arnoux P, Kwan K, Baum LG. Characterization of a novel Drosophila melanogaster galectin. Expression in developing immune, neural, and muscle tissues. J Biol Chem 2002; 277:13091-8. [PMID: 11809773 DOI: 10.1074/jbc.m112105200] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have cloned and characterized the first galectin to be identified in Drosophila melanogaster. The amino acid sequence of Drosophila galectin showed striking sequence similarity to invertebrate and vertebrate galectins and contained amino acids that are crucial for binding beta-galactoside sugars. Confirming its identity as a galectin family member, the Drosophila galectin bound beta-galactoside sugars. Structurally, the Drosophila galectin was a tandem repeat galectin containing two carbohydrate recognition domains connected by a unique peptide link. This divalent structure suggests that like mammalian galectins, Drosophila galectin may mediate cell-cell communication or facilitate cross-linking of receptors to trigger signal transduction events. The Drosophila galectin was very abundant in embryonic, larval, and adult Drosophila. During embryogenesis, Drosophila galectin had a unique and specific tissue distribution. Drosophila galectin expression was concentrated in somatic and visceral musculature and in the central nervous system. Similar to other insect lectins, Drosophila galectin may function in both embryogenesis and in host defense. Drosophila galectin was expressed by hemocytes, circulating phagocytic cells, suggesting a role for Drosophila galectin in the innate immune system.
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Affiliation(s)
- Karen E Pace
- Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, California 90095, USA
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26
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Pellikka M, Tanentzapf G, Pinto M, Smith C, McGlade CJ, Ready DF, Tepass U. Crumbs, the Drosophila homologue of human CRB1/RP12, is essential for photoreceptor morphogenesis. Nature 2002; 416:143-9. [PMID: 11850625 DOI: 10.1038/nature721] [Citation(s) in RCA: 356] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The apical transmembrane protein Crumbs is a central regulator of epithelial apical-basal polarity in Drosophila. Loss-of-function mutations in the human homologue of Crumbs, CRB1 (RP12), cause recessive retinal dystrophies, including retinitis pigmentosa. Here we show that Crumbs and CRB1 localize to corresponding subdomains of the photoreceptor apical plasma membrane: the stalk of the Drosophila photoreceptor and the inner segment of mammalian photoreceptors. These subdomains support the morphogenesis and orientation of the photosensitive membrane organelles: rhabdomeres and outer segments, respectively. Drosophila Crumbs is required to maintain zonula adherens integrity during the rapid apical membrane expansion that builds the rhabdomere. Crumbs also regulates stalk development by stabilizing the membrane-associated spectrin cytoskeleton, a function mechanistically distinct from its role in epithelial apical-basal polarity. We propose that Crumbs is a central component of a molecular scaffold that controls zonula adherens assembly and defines the stalk as an apical membrane subdomain. Defects in such scaffolds may contribute to human CRB1-related retinal dystrophies.
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Affiliation(s)
- Milena Pellikka
- Department of Zoology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
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27
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Iwai Y, Hirota Y, Ozaki K, Okano H, Takeichi M, Uemura T. DN-cadherin is required for spatial arrangement of nerve terminals and ultrastructural organization of synapses. Mol Cell Neurosci 2002; 19:375-88. [PMID: 11906210 DOI: 10.1006/mcne.2001.1081] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We studied roles of DN-cadherin, the Drosophila major neuronal cadherin, in neuronal connections in the visual system. In DN-cadherin mutants, axon terminals of a large subset of photoreceptor cells reached and associated with their target interneurons, but their characteristic spatial arrangement was disrupted as synaptogenesis proceeded. Although synapses were formed at contact sites between the axon terminals and target neurons, underlying cytoplasmic structures were not fully specialized at both pre- and postsynaptic terminals and synaptic vesicles appeared to accumulate at the presynapses. These results suggest that the cadherin adhesion system is required for interaction between pre- and postsynaptic terminals and for generation of the mature synaptic structures.
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Affiliation(s)
- Youichi Iwai
- Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
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28
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White B, Osterwalder T, Keshishian H. Molecular genetic approaches to the targeted suppression of neuronal activity. Curr Biol 2001; 11:R1041-53. [PMID: 11747845 DOI: 10.1016/s0960-9822(01)00621-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Understanding how the diverse cells of the nervous system generate sensations, memories and behaviors is a profound challenge. This is because the activity of most neurons cannot easily be monitored or individually manipulated in vivo. As a result, it has been difficult to determine how different neurons contribute to nervous system function, even in simple organisms like Drosophila. Recent advances promise to change this situation by supplying molecular genetic tools for modulating neuronal activity that can be deployed in a spatially and temporally restricted fashion. In some cases, targeted groups of neurons can be 'switched off' and back 'on' at will in living, behaving animals.
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Affiliation(s)
- B White
- Molecular, Cellular, and Developmental Biology Department, Yale University, New Haven, Connecticut 06520, USA.
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