Electron microscopy snapshots of single particles from single cells

Area of Science:

• Structural biology
• Cell biology
• Biophysics

Background:

• Cryo-electron microscopy (cryo-EM) is vital for macromolecular structure determination.
• Existing methods like single-particle analysis and tomography have limitations regarding sample purity and resolution.
• Characterizing protein complexes in native cellular environments remains challenging.

Purpose of the Study:

• To develop a novel method for high-resolution structural analysis of protein complexes from individual cells.
• To apply this method to study ribosomes in Caenorhabditis elegans embryos.
• To investigate developmental changes in protein complex abundance and structure.

Main Methods:

• Integration of microfluidic single-cell extraction with single-particle analysis by cryo-electron microscopy.
• Application to purified samples from individual Caenorhabditis elegans embryos.
• 3D reconstruction of protein complexes and quantitative analysis.

Main Results:

• Successfully obtained 3D structures of ribosomes directly from single embryo extracts.
• Quantified ribosome numbers per polysome during different developmental stages.
• Demonstrated the feasibility of analyzing protein complexes at the single-cell level.

Conclusions:

• The combined microfluidic and cryo-EM approach enables detailed structural and quantitative analysis of protein complexes in single cells.
• This method provides insights into protein complex dynamics during development.
• The technique has broad potential for studying protein architectures and abundance in various biological contexts.