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Mishra AK, Sprecher SG. Eye Development in Drosophila : From Photoreceptor Specification to Terminal Differentiation. Neurogenetics 2023. [DOI: 10.1007/978-3-031-07793-7_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Schnaitmann C, Pagni M, Reiff DF. Color vision in insects: insights from Drosophila. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:183-198. [PMID: 32020291 PMCID: PMC7069916 DOI: 10.1007/s00359-019-01397-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 12/12/2019] [Accepted: 12/17/2019] [Indexed: 02/07/2023]
Abstract
Color vision is an important sensory capability that enhances the detection of contrast in retinal images. Monochromatic animals exclusively detect temporal and spatial changes in luminance, whereas two or more types of photoreceptors and neuronal circuitries for the comparison of their responses enable animals to differentiate spectral information independent of intensity. Much of what we know about the cellular and physiological mechanisms underlying color vision comes from research on vertebrates including primates. In insects, many important discoveries have been made, but direct insights into the physiology and circuit implementation of color vision are still limited. Recent advances in Drosophila systems neuroscience suggest that a complete insect color vision circuitry, from photoreceptors to behavior, including all elements and computations, can be revealed in future. Here, we review fundamental concepts in color vision alongside our current understanding of the neuronal basis of color vision in Drosophila, including side views to selected other insects.
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Affiliation(s)
- Christopher Schnaitmann
- Department for Animal Physiology and Neurobiology, Institute of Biology I, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
| | - Manuel Pagni
- Department for Animal Physiology and Neurobiology, Institute of Biology I, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
| | - Dierk F Reiff
- Department for Animal Physiology and Neurobiology, Institute of Biology I, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany.
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Lin TY, Luo J, Shinomiya K, Ting CY, Lu Z, Meinertzhagen IA, Lee CH. Mapping chromatic pathways in the Drosophila visual system. J Comp Neurol 2015; 524:213-27. [PMID: 26179639 DOI: 10.1002/cne.23857] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 07/13/2015] [Accepted: 07/13/2015] [Indexed: 11/06/2022]
Abstract
In Drosophila, color vision and wavelength-selective behaviors are mediated by the compound eye's narrow-spectrum photoreceptors R7 and R8 and their downstream medulla projection (Tm) neurons Tm5a, Tm5b, Tm5c, and Tm20 in the second optic neuropil or medulla. These chromatic Tm neurons project axons to a deeper optic neuropil, the lobula, which in insects has been implicated in processing and relaying color information to the central brain. The synaptic targets of the chromatic Tm neurons in the lobula are not known, however. Using a modified GFP reconstitution across synaptic partners (GRASP) method to probe connections between the chromatic Tm neurons and 28 known and novel types of lobula neurons, we identify anatomically the visual projection neurons LT11 and LC14 and the lobula intrinsic neurons Li3 and Li4 as synaptic targets of the chromatic Tm neurons. Single-cell GRASP analyses reveal that Li4 receives synaptic contacts from over 90% of all four types of chromatic Tm neurons, whereas LT11 is postsynaptic to the chromatic Tm neurons, with only modest selectivity and at a lower frequency and density. To visualize synaptic contacts at the ultrastructural level, we develop and apply a "two-tag" double-labeling method to label LT11's dendrites and the mitochondria in Tm5c's presynaptic terminals. Serial electron microscopic reconstruction confirms that LT11 receives direct contacts from Tm5c. This method would be generally applicable to map the connections of large complex neurons in Drosophila and other animals.
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Affiliation(s)
- Tzu-Yang Lin
- Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, 20892.,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, 114, Taiwan
| | - Jiangnan Luo
- Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, 20892
| | - Kazunori Shinomiya
- Depart of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Chun-Yuan Ting
- Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, 20892
| | - Zhiyuan Lu
- Depart of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Ian A Meinertzhagen
- Depart of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Chi-Hon Lee
- Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, 20892
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Karuppudurai T, Lin TY, Ting CY, Pursley R, Melnattur KV, Diao F, White BH, Macpherson LJ, Gallio M, Pohida T, Lee CH. A hard-wired glutamatergic circuit pools and relays UV signals to mediate spectral preference in Drosophila. Neuron 2014; 81:603-615. [PMID: 24507194 DOI: 10.1016/j.neuron.2013.12.010] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2013] [Indexed: 11/27/2022]
Abstract
UNLABELLED Many visual animals have innate preferences for particular wavelengths of light, which can be modified by learning. Drosophila's preference for UV over visible light requires UV-sensing R7 photoreceptors and specific wide-field amacrine neurons called Dm8. Here we identify three types of medulla projection neurons downstream of R7 and Dm8 and show that selectively inactivating one of them (Tm5c) abolishes UV preference. Using a modified GRASP method to probe synaptic connections at the single-cell level, we reveal that each Dm8 neuron forms multiple synaptic contacts with Tm5c in the center of Dm8's dendritic field but sparse connections in the periphery. By single-cell transcript profiling and RNAi-mediated knockdown, we determine that Tm5c uses the kainate receptor Clumsy to receive excitatory glutamate input from Dm8. We conclude that R7s→Dm8→Tm5c form a hard-wired glutamatergic circuit that mediates UV preference by pooling ∼16 R7 signals for transfer to the lobula, a higher visual center. VIDEO ABSTRACT
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Affiliation(s)
- Thangavel Karuppudurai
- Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tzu-Yang Lin
- Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chun-Yuan Ting
- Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Randall Pursley
- Signal Processing and Instrumentation Section, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, MD 20892, USA
| | - Krishna V Melnattur
- Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Fengqiu Diao
- Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Benjamin H White
- Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lindsey J Macpherson
- Howard Hughes Medical Institute and Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Marco Gallio
- Howard Hughes Medical Institute and Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Thomas Pohida
- Signal Processing and Instrumentation Section, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chi-Hon Lee
- Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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Gao S, Takemura SY, Ting CY, Huang S, Lu Z, Luan H, Rister J, Thum AS, Yang M, Hong ST, Wang JW, Odenwald WF, White BH, Meinertzhagen IA, Lee CH. The neural substrate of spectral preference in Drosophila. Neuron 2008; 60:328-42. [PMID: 18957224 DOI: 10.1016/j.neuron.2008.08.010] [Citation(s) in RCA: 213] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 07/22/2008] [Accepted: 08/15/2008] [Indexed: 11/19/2022]
Abstract
Drosophila vision is mediated by inputs from three types of photoreceptor neurons; R1-R6 mediate achromatic motion detection, while R7 and R8 constitute two chromatic channels. Neural circuits for processing chromatic information are not known. Here, we identified the first-order interneurons downstream of the chromatic channels. Serial EM revealed that small-field projection neurons Tm5 and Tm9 receive direct synaptic input from R7 and R8, respectively, and indirect input from R1-R6, qualifying them to function as color-opponent neurons. Wide-field Dm8 amacrine neurons receive input from 13-16 UV-sensing R7s and provide output to projection neurons. Using a combinatorial expression system to manipulate activity in different neuron subtypes, we determined that Dm8 neurons are necessary and sufficient for flies to exhibit phototaxis toward ultraviolet instead of green light. We propose that Dm8 sacrifices spatial resolution for sensitivity by relaying signals from multiple R7s to projection neurons, which then provide output to higher visual centers.
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Affiliation(s)
- Shuying Gao
- Unit on Neuronal Connectivity, Laboratory of Gene Regulation and Development, National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
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Sprecher SG, Pichaud F, Desplan C. Adult and larval photoreceptors use different mechanisms to specify the same Rhodopsin fates. Genes Dev 2007; 21:2182-95. [PMID: 17785526 PMCID: PMC1950857 DOI: 10.1101/gad.1565407] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Accepted: 07/16/2007] [Indexed: 11/25/2022]
Abstract
Although development of the adult Drosophila compound eye is very well understood, little is known about development of photoreceptors (PRs) in the simple larval eye. We show here that the larval eye is composed of 12 PRs, four of which express blue-sensitive rhodopsin5 (rh5) while the other eight contain green-sensitive rh6. This is similar to the 30:70 ratio of adult blue and green R8 cells. However, the stochastic choice of adult color PRs and the bistable loop of the warts and melted tumor suppressor genes that unambiguously specify rh5 and rh6 in R8 PRs are not involved in specification of larval PRs. Instead, primary PR precursors signal via EGFR to surrounding tissue to develop as secondary precursors, which will become Rh6-expressing PRs. EGFR signaling is required for the survival of the Rh6 subtype. Primary precursors give rise to the Rh5 subtype. Furthermore, the combinatorial action of the transcription factors Spalt, Seven-up, and Orthodenticle specifies the two PR subtypes. Therefore, even though the larval PRs and adult R8 PRs express the same rhodopsins (rh5 and rh6), they use very distinct mechanisms for their specification.
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Affiliation(s)
- Simon G. Sprecher
- Center for Developmental Genetics, Department of Biology, New York University, New York, New York 10003, USA
| | - Franck Pichaud
- Center for Developmental Genetics, Department of Biology, New York University, New York, New York 10003, USA
| | - Claude Desplan
- Center for Developmental Genetics, Department of Biology, New York University, New York, New York 10003, USA
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Bell ML, Earl JB, Britt SG. Two types of Drosophila R7 photoreceptor cells are arranged randomly: a model for stochastic cell-fate determination. J Comp Neurol 2007; 502:75-85. [PMID: 17335038 DOI: 10.1002/cne.21298] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The R7 photoreceptor cells of the Drosophila retina are ultraviolet sensitive and are thought to mediate color discrimination and polarized light detection. In addition, there is growing evidence that the color sensitivity of the R8 cell within an individual ommatidium is regulated by a genetic switch that depends on the type of R7 cell adjacent to it. Here we examine the organization of the two major types of R7 cells by three different rigorous statistical methods and present evidence that they are arranged randomly and independently. First, we performed L-function analyses to test whether the organization of R7 cells (and the relationship between them) is regular, clustered, or completely spatially random. Next, we used generalized linear mixed models to test whether the proportion of R7 cell neighbors differs from their prevalence within the eye as a whole. Finally, we conducted a series of simulations to test whether the proportion of R7 cell neighbors differs from that in a random simulation. In each case, we found evidence that the organization of the two types of R7 cells is random and independent, suggesting that R7 cells in neighboring ommatidia are unlikely to interact and influence each other's identity and may be determined stochastically in a cell-autonomous manner. Compared with traditional lineage or inductive mechanisms, this may represent a novel mechanism of cell fate determination based on noisy or stochastic gene expression in which the differentiation of an individual R7 cell is a random event but the proportions of R7 cell subtypes are regulated.
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Affiliation(s)
- Melanie L Bell
- Department of Preventive and Social Medicine, University of Otago, Dunedin 9001, New Zealand
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Mikeladze-Dvali T, Wernet MF, Pistillo D, Mazzoni EO, Teleman AA, Chen YW, Cohen S, Desplan C. The growth regulators warts/lats and melted interact in a bistable loop to specify opposite fates in Drosophila R8 photoreceptors. Cell 2005; 122:775-87. [PMID: 16143107 DOI: 10.1016/j.cell.2005.07.026] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Revised: 06/07/2005] [Accepted: 07/25/2005] [Indexed: 10/25/2022]
Abstract
Color vision in Drosophila relies on the comparison between two color-sensitive photoreceptors, R7 and R8. Two types of ommatidia in which R7 and R8 contain different rhodopsins are distributed stochastically in the retina and appear to discriminate short (p-subset) or long wavelengths (y-subset). The choice between p and y fates is made in R7, which then instructs R8 to follow the corresponding fate, thus leading to a tight coupling between rhodopsins expressed in R7 and R8. Here, we show that warts, encoding large tumor suppressor (Lats) and melted encoding a PH-domain protein, play opposite roles in defining the yR 8 or pR8 fates. By interacting antagonistically at the transcriptional level, they form a bistable loop that insures a robust commitment of R8 to a single fate, without allowing ambiguity. This represents an unexpected postmitotic role for genes controlling cell proliferation (warts and its partner hippo and salvador) and cell growth (melted).
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Affiliation(s)
- Tamara Mikeladze-Dvali
- Department of Biology, Center for Developmental Genetics, New York University, New York, New York 10003, USA
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