Related Experiment Video
Updated: Jul 16, 2026
Dissection and Immunofluorescent Staining of Mushroom Body and Photoreceptor Neurons in Adult Drosophila melanogaster Brains
Published on: November 6, 2017
Precise control of fasciclin II expression is required for adult mushroom body development in Drosophila
Kazuma Fushima1, Hidenobu Tsujimura
1Developmental Biology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan.
Abstract:
Fasciclin II (FASII) is a cell adhesion molecule that participates in axonal pathfinding, fasciculation and divergence in the Drosophila nervous system. Here, we examined spatio-temporal control of fasII expression during the development of adult mushroom body (MB) and found that suppression of fasII in alpha'/beta' neurons is essential for the formation of adult alpha'/beta' and alpha/beta lobes. Of gamma, alpha'/beta' and alpha/beta neurons, which are derived sequentially from the same four MB neuroblasts, only gamma and alpha/beta neurons expressed fasII. When fasII was misexpressed in developing MB neurons, defects resulted, including loss or misdirection of adult alpha'/beta' lobes and concurrent misdirection of alpha/beta lobes. Although no gross anatomical defects were apparent in the larval MB lobes, alpha'/beta' lobes collapsed at the pupal stage when the larval lobe of gamma neurons degenerated. In addition, alpha/beta lobes, which developed at this time, were misdirected in close relationship with the collapse of alpha'/beta' lobes. These defects did not occur when fasII was overexpressed in only gamma and alpha/beta neurons, indicating that ectopic expression of fasII in alpha'/beta' neurons is required for the defects. Our findings also suggest that the alpha'/beta' lobe play a role in guiding the pathfinding by alpha/beta axons.
Insights
Suppression of Fasciclin II (FASII) in specific Drosophila mushroom body neurons is crucial for proper lobe formation. Misexpression of FASII disrupts axonal pathfinding and lobe development in adult brains.
Area of Science:
- Neuroscience
- Developmental Biology
- Molecular Biology
Background:
- Fasciclin II (FASII) is a cell adhesion molecule vital for neural development.
- Axonal pathfinding, fasciculation, and divergence are key processes in nervous system formation.
Purpose of the Study:
- To investigate the spatio-temporal regulation of Fasciclin II (FASII) expression during Drosophila mushroom body development.
- To determine the role of FASII in the formation of adult mushroom body lobes.
Main Methods:
- Analysis of fasII gene expression patterns in developing Drosophila mushroom body neurons.
- Experimental manipulation of fasII expression in specific neuronal subtypes (gamma, alpha'/beta', alpha/beta).
- Observation of adult mushroom body morphology and axonal guidance defects.
Main Results:
- FASII is normally expressed in gamma and alpha/beta neurons, but suppressed in alpha'/beta' neurons.
- Misexpression of FASII in alpha'/beta' neurons leads to defects in adult alpha'/beta' and alpha/beta lobe formation and guidance.
- Ectopic FASII expression in alpha'/beta' neurons, not gamma or alpha/beta neurons, causes these developmental defects.
Conclusions:
- Suppression of FASII in alpha'/beta' neurons is essential for correct adult mushroom body lobe development.
- The alpha'/beta' lobe plays a critical role in guiding the pathfinding of alpha/beta axons.
- FASII acts through distinct neuronal populations to regulate complex axonal targeting during development.
