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A Behavioral Assay for Mechanosensation of MARCM-based Clones in Drosophila melanogaster
Published on: December 30, 2015
A Behavioral Assay for Mechanosensation of MARCM-based Clones in Drosophila melanogaster
Timothy P Murphy1, Dan D Luu2, Jessica A DeSimone3
1Department of Biology, College of the Holy Cross; School of Medicine, Georgetown University.
Abstract:
Because of the structural and functional homology to the hair cells of the mammalian inner ear, the neurons that innervate the Drosophila external sense organs provide an excellent model system for the study of mechanosensation. This protocol describes a simple touch behavior in fruit flies which can be used to identify mutations that interfere with mechanosensation. The tactile stimulation of a macrochaete bristle on the thorax of flies elicits a grooming reflex from either the first or third leg. Mutations that interfere with mechanotransduction (such as NOMPC), or with other aspects of the reflex arc, can inhibit the grooming response. A traditional screen of adult behaviors would have missed mutants that have essential roles during development. Instead, this protocol combines the touch screen with mosaic analysis with a repressible cell marker (MARCM) to allow for only limited regions of homozygous mutant cells to be generated and marked by the expression of green fluorescent protein (GFP). By testing MARCM clones for abnormal behavioral responses, it is possible to screen a collection of lethal p-element mutations to search for new genes involved in mechanosensation that would have been missed by more traditional methods.
Insights
Fruit flies exhibit a grooming reflex to touch, aiding mechanosensation research. This study identifies new genes involved in touch sensation using a novel screening method with fruit fly models.
Area of Science:
- Neuroscience
- Genetics
- Developmental Biology
Background:
- The neurons innervating Drosophila external sense organs are homologous to mammalian inner ear hair cells, making them a valuable model for mechanosensation studies.
- Mechanosensation, the biological response to touch, is crucial for survival and involves complex neural pathways.
Purpose of the Study:
- To develop and validate a protocol for identifying mutations affecting mechanosensation in Drosophila.
- To uncover novel genes essential for mechanosensation, including those with critical roles during development.
Main Methods:
- A simple touch behavior assay was established, where tactile stimulation of thoracic bristles elicits a grooming reflex in fruit flies.
- Mosaic Analysis with a Repressible Cell Marker (MARCM) was combined with the touch screen to generate and identify homozygous mutant cells expressing green fluorescent protein (GFP).
- This approach allowed for the screening of lethal p-element mutations that would be missed by traditional adult behavior screens.
Main Results:
- The study successfully demonstrated that mutations affecting mechanotransduction (e.g., NOMPC) or other parts of the reflex arc can inhibit the grooming response.
- The MARCM technique enabled the identification of previously undiscovered genes involved in mechanosensation by analyzing abnormal behavioral responses in mutant clones.
- This method effectively screened lethal mutations that are essential during development, overcoming limitations of traditional screens.
Conclusions:
- The developed touch screen protocol, combined with MARCM, is an effective method for identifying new genes involved in Drosophila mechanosensation.
- This approach is particularly valuable for discovering genes with essential developmental roles that are often missed by conventional screening techniques.
- The study provides a robust platform for future research into the genetic and molecular mechanisms of touch sensation.
