Correlative Microscopy for Localization of Proteins In Situ: Pre-embedding Immuno-Electron Microscopy Using...

Area of Science:

• Cell Biology
• Microscopy Techniques
• Protein Localization

Background:

• Immuno-electron microscopy (immuno-EM) is crucial for determining the subcellular localization of proteins.
• Existing immuno-EM methods include pre-embedding, post-embedding, and cryosectioning (Tokuyasu style).

Purpose of the Study:

• To describe a pre-embedding immuno-EM technique for in situ protein labeling.
• To demonstrate the retention of fluorescence signal in plastic for electron microscopy (EM) localization.
• To enable protein localization within a specific cellular context at the EM level.

Main Methods:

• A pre-embedding immuno-EM approach was developed and optimized.
• Optimization involved fixation protocols to preserve cellular morphology.
• Screening of compatible antibodies was essential for successful labeling.

Main Results:

• The described method allows for in situ labeling of target proteins.
• Fluorescence signal is retained within the plastic embedding medium.
• Successful localization of proteins at the EM level within the cellular context was achieved.

Conclusions:

• The developed pre-embedding immuno-EM technique is a powerful tool for protein localization.
• While technically challenging and labor-intensive, the method provides high-resolution subcellular localization data.
• Careful optimization of fixation and antibody screening is critical for success.