Published: Vol 7, Iss 17, Sep 5, 2017 DOI: 10.21769/BioProtoc.2523 Views: 8457
Reviewed by: Pengpeng LiAnonymous reviewer(s)
Protocol Collections
Comprehensive collections of detailed, peer-reviewed protocols focusing on specific topics
Related protocols
Isolation of In Vitro Osteoblastic-Derived Matrix Vesicles by Ultracentrifugation and Cell-Free Mineralization Assay
Irshad A. Sheikh [...] Fayez K. Ghishan
Apr 5, 2025 624 Views
Live Cell Imaging to Monitor Axonal Pruning in Drosophila Motor Neurons
Keyao Long [...] Menglong Rui
Jul 5, 2025 1267 Views
A Step-By-Step Protocol for Correlative Light and Electron Microscopy Imaging of Proteinaceous Deposits in Cultured Cells and Human Brain Tissues
Peizhou Jiang and Dennis W. Dickson
Aug 5, 2025 1277 Views
Abstract
We developed a protocol for photoconversion of endocytic marker FM1-43 followed by electron microscopy analysis of synaptic boutons at the Drosophila neuromuscular junction. This protocol allows detection of stained synaptic vesicle even when release rates are very low, such as during the spontaneous release mode. The preparations are loaded with the FM1-43 dye, pre-fixed, treated and illuminated to photoconvert the dye, and then processed for conventional electron microscopy. This procedure enables clear identification of stained synaptic vesicles at electron micrographs.
Keywords: Electron microscopyBackground
Neuronal transmitters are released via the fusion of synaptic vesicles with the neuronal plasma membrane. Vesicles can fuse spontaneously or in response to an action potential. Subsequently, vesicles become retrieved via endocytosis and recycled. Molecular mechanisms of synaptic vesicle recycling were investigated extensively with the tools of molecular biology, electrophysiology and microscopy (Slepnev and De Camilli, 2000; Sudhof, 2004; Rizzoli and Betz, 2005; Kavalali, 2006). Loading the endocytic marker FM1-43 coupled with the dye photoconversion followed by electron microscopy analysis is a powerful technique that allows the investigation and measurement of the recycling vesicle pools (Harata et al., 2001; Schikorski and Stevens, 2001; Rizzoli and Betz, 2004). Drosophila neuromuscular junction (NMJ) is an advantageous preparation with clearly defined synaptic boutons, which enables rapid generation of lines with mutated synaptic proteins and rigorous evaluation of vesicle recycling pools (Akbergenova and Bykhovskaia, 2009; Denker et al., 2009). A fundamental question in the field of synaptic transmission is whether the evoked and spontaneous transmission utilizes the same recycling pool. To address this question, the recycling pool utilized in the absence of stimulation needs to be measured. This is a challenging problem due to low rates of spontaneous release and recycling. We have developed a protocol for FM1-43 loading followed by the dye photoconversion and EM analysis, which enables rigorous evaluation of recycling pools utilized during spontaneous and evoked transmission at the Drosophila NMJ (Sabeva et al., 2017).
Materials and Reagents
Equipment
Software
Procedure
Data analysis
Notes
Recipes
Acknowledgments
This work was supported by National Institutes of Health Grant R01 MH099557 and NIH NINDS SNRP Grant 5U54NS083924.
References
Article Information
Copyright
© 2017 The Authors; exclusive licensee Bio-protocol LLC.
How to cite
Readers should cite both the Bio-protocol article and the original research article where this protocol was used:
Category
Neuroscience > Development > Neuron
Cell Biology > Cell imaging > Electron microscopy
Do you have any questions about this protocol?
Post your question to gather feedback from the community. We will also invite the authors of this article to respond.
Tips for asking effective questions
+ Description
Write a detailed description. Include all information that will help others answer your question including experimental processes, conditions, and relevant images.
Share
Bluesky
X
Copy link