Complementary volume electron microscopy-based approaches reveal ultrastructural changes in germline intercellular...

Area of Science:

• Developmental Biology
• Cell Biology
• Microscopy

Background:

• The Drosophila melanogaster egg chamber is a key model for studying germline intercellular bridges, known as ring canals.
• Electron microscopy (EM) is crucial for visualizing ring canals, but traditional methods face technical challenges in capturing their structure.

Purpose of the Study:

• To apply advanced volume EM techniques to visualize ultrastructural changes in Drosophila germline ring canals.
• To gain new insights into ring canal structure, formation, and 3D organization.

Main Methods:

• Utilized a combination of array tomography and focused ion beam scanning electron microscopy (FIB-SEM).
• Reconstructed multiple egg chambers to understand the 3D orientation of cell-cell contacts.
• Quantified ring canal size and thickness within and between germline cell clusters.

Main Results:

• Visualized previously unappreciated aspects of ring canal ultrastructure.
• Observed membrane interdigitations near ring canals forming earlier than previously reported.
• Identified a novel membrane structure lining the ring canal lumen.
• Provided 3D orientation of extensive cell-cell contacts.

Conclusions:

• Advanced volume EM offers a powerful framework for studying challenging ultrastructural details in biological samples.
• This approach provides novel insights into ring canal development and organization in Drosophila.
• The imaging framework is applicable to other tissues with similar technical imaging challenges.