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Specification of functional identity and sensory plasticity of the Drosophila larval eye

English title Specification of functional identity and sensory plasticity of the Drosophila larval eye
Applicant Sprecher Simon
Number 123339
Funding scheme SNSF Professorships
Research institution Département de Biologie Faculté des Sciences Université de Fribourg
Institution of higher education University of Fribourg - FR
Main discipline Zoology
Start/End 01.10.2009 - 30.09.2013
Approved amount 930'292.00
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All Disciplines (4)

Discipline
Zoology
Cellular Biology, Cytology
Genetics
Embryology, Developmental Biology

Keywords (6)

sensory organs; visual system; Drosophila melanogaster; photoreceptor; neuronal development; neuron specification

Lay Summary (German)

Lead
Lay summary
Wie entsteht das Gehirn (als neuronales Netzwerk), wie erkennt und verarbeitet es sensorische Informationen aus der Umwelt und wie wird diese Information im Verhalten widerspiegelt? Die Komplexität und die Grösse des menschlichen Gehirns machen eine hochauflösende Antwort unmöglich. Deshalb bearbeiten wir die Fragen mit dem genetischen Modellsystemder Fruchtfliege Drosophila melanogaster. Diese besitzt ein einfacheres Nervensystem, benutzt jedoch hochspezielle sensorische Organe für verschiedene Verhalten.Dabei haben fast alle genetischen Prozesse, welche bei der Fruchtfliege entdeckt wurden auch für den Menschen Gültigkeit. Mein Interesse liegt vor allem im recht einfachen visuellen System der Fruchtfliegenlarve. Welches genetische Programm gibt den Lichtsinneszellen ihre Identität (um die richtige Farbe zu sehen), wie wird Information kodiert und im neuronalen Netzwerk verarbeitet?
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
In vitro imaging of primary neural cell culture from Drosophila
Egger Boris, Moraru Manuela, van Giesen Lena, Sprecher Simon (2013), In vitro imaging of primary neural cell culture from Drosophila, in Nature Protocols, 8(5), 958-965.
Analysis of cell identity, morphology, apoptosis and mitotic activity in a primary neural cell culture system in Drosophila
Moraru Manuela, Egger Boris, Diarra Bao, Sprecher Simon (2012), Analysis of cell identity, morphology, apoptosis and mitotic activity in a primary neural cell culture system in Drosophila, in Neural Development, 7(14), 1-10.
Drosophila Neural Development
Simon Sprecher (2012), Drosophila Neural Development, in Encyclopedia of Life Sciences, 1(1), 1-10.
Genetic and developmental mechanisms underlying the formation of the Drosophila compound eye
Tsachaki M, Sprecher SG (2012), Genetic and developmental mechanisms underlying the formation of the Drosophila compound eye, in DEVELOPMENTAL DYNAMICS, 241(1), 40-56.
Seeing the light: photobehavior in fruit fly larvae
Keene AC, Sprecher SG (2012), Seeing the light: photobehavior in fruit fly larvae, in TRENDS IN NEUROSCIENCES, 35(2), 104-110.
Capacity of Visual Classical Conditioning in Drosophila Larvae
von Essen AMHJ, Pauls D, Thum AS, Sprecher SG (2011), Capacity of Visual Classical Conditioning in Drosophila Larvae, in BEHAVIORAL NEUROSCIENCE, 125(6), 921-929.
Distinct Visual Pathways Mediate Drosophila Larval Light Avoidance and Circadian Clock Entrainment
Keene AC, Mazzoni EO, Zhen J, Younger MA, Yamaguchi S, Blau J, Desplan C, Sprecher SG (2011), Distinct Visual Pathways Mediate Drosophila Larval Light Avoidance and Circadian Clock Entrainment, in JOURNAL OF NEUROSCIENCE, 31(17), 6527-6534.
Feedback from rhodopsin controls rhodopsin exclusion in Drosophila photoreceptors
Vasiliauskas D, Mazzoni EO, Sprecher SG, Brodetskiy K, Johnston RJ, Lidder P, Vogt N, Celik A, Desplan C (2011), Feedback from rhodopsin controls rhodopsin exclusion in Drosophila photoreceptors, in NATURE, 479(7371), 108-108.
Photoreceptors: Unconventional Ways of Seeing
Diaz NN, Sprecher SG (2011), Photoreceptors: Unconventional Ways of Seeing, in CURRENT BIOLOGY, 21(1), 25-27.
The Drosophila larval visual system: High-resolution analysis of a simple visual neuropil
Sprecher SG, Cardona A, Hartenstein V (2011), The Drosophila larval visual system: High-resolution analysis of a simple visual neuropil, in DEVELOPMENTAL BIOLOGY, 358(1), 33-43.

Collaboration

Group / person Country
Types of collaboration
Harvard Physics Department United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
- Exchange of personnel
Universität Konstanz Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
UCLA United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
Universität Regensburg Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Exchange of personnel

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
HHMI Janelia Farm Conference: Vision in flies, Washington Talk given at a conference vision in Drosophila larvae 14.03.2011 Ashburn, Virginia, USA, United States of America Sprecher Simon;
Neurogenetics of Drosophila Larvae Talk given at a conference Development of the visual system 12.07.2010 Bangalore, Indien, India Sprecher Simon;
HHMI Janelia Farm workshop "larval Olympiad project" Talk given at a conference vision in Drosophila larvae 08.06.2010 Ashburn, Virginia, USA, United States of America Sprecher Simon;


Associated projects

Number Title Start Funding scheme
149499 Characterizing the genetic network mediating the binary cell fate decision in the Drosophila larval eye 01.10.2013 Project funding (Div. I-III)

Abstract

The visual system performs multiple tasks by transforming light-dependent information such as light intensity or color information represented by the wavelength of light. The expression of a sensory receptor gene defines the specificity of a sensory neuron, in the case of photoreceptors (PRs) rhodopsin/opsin genes. The larval eye of Drosophila represents a highly simplified visual system. It is composed of two types of PRs: four express the blue-sensitive rhodopsin5 (rh5), while the remaining eight express the green-sensitive rhodopsin6 (rh6). We have identified three transcription factors Orthodenticle (Otd), Spalt (Sal) and Seven-up (Svp) acting as key players orchestrating larval PR-subtype specification. The genetic program specifying larval green- and blue-sensitive PRs is surprisingly different from the program that controls expression of the same genes in the adult retina (Sprecher et al., 2007).We have also recently described an exciting phenomenon during metamorphosis, when the larval eye is transformed into the adult “eyelet”, a small light-sensory organ involved in circadian clock entrainment. During this process, larval Rh5-PRs switch their spectral sensitivity from Rh5 (blue) to Rh6 (green), a novel unexpected form of plasticity of fully differentiated and functioning sensory neurons. The green-sensitive larval Rh6-PRs undergo apoptotic cell death. The steroid hormone Ecdysone acts to control both processes, switch of rhodopsins in the Rh5-subtype and apoptosis in the Rh6-subtype. Moreover we have identified the transcription factor Senseless (Sens) as the factor that determines the very different responses to Ecdysone, acting as a survival factor in Rh5-PRs (Sprecher and Desplan, 2008). In the following aims, I propose to combine molecular and genetic techniques to study the mechanisms underlying this new form of plasticity. The main focus will be on the downstream events of Ecdysone hormonal signaling that regulate rhodopsins during the switch. This will also include the study of other forms of plasticity of these PRs, such as the reorganization of neuronal connectivity and appearance of an additional neurotransmitter. We will use two parallel approaches to identify the genes acting during the transformation. First, we will use microarray experiments to identify genes differentially regulated in response to EcR. Second, we will study the regulatory sequences of rh5 and rh6 during the switch, which will provide an understanding of the regulatory logic underlying sensory plasticity. These experimental approaches will at the same time provide deeper insight into the development of the larval eye. We will therefore continue our investigations of the mechanisms that specify larval PR-subtypes and thus obtain a global comparison between the distinct genetic programs acting in larval PRs, in the adult eyelet and retina to control rh5 and rh6.
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