Marker-free method for accurate alignment between correlated light, cryo-light, and electron cryo-microscopy data...

Area of Science:

• Cellular and Molecular Imaging
• Biophysics
• Microscopy Techniques

Background:

• Correlative light and electron microscopy (CLEM) integrates structural and functional information.
• Accurate alignment is crucial for combining data from disparate imaging modalities like fluorescence microscopy and cryo-electron tomography.
• Existing alignment methods often rely on fiducial markers, which can obscure cellular structures.

Purpose of the Study:

• To develop a marker-free alignment method for correlating fluorescence microscopy and electron cryo-microscopy data.
• To enable precise spatial localization of macromolecular assemblies within the cellular environment.
• To improve the integration and scaling between light and electron imaging modalities.

Main Methods:

• Utilized sample support features, specifically the holes in the carbon film, as natural fiducials.
• Developed a marker-free image alignment procedure for light/cryo-light fluorescence microscopy and electron cryo-microscopy.
• Assessed alignment accuracy by measuring prediction errors of hole center coordinates.

Main Results:

• Achieved accurate alignment between fluorescence and electron cryo-microscopy datasets without external markers.
• Demonstrated that the method leverages intrinsic sample support features for alignment.
• Quantified alignment accuracy, with prediction errors for hole center coordinates better than 100 nm.

Conclusions:

• The developed marker-free method provides a robust and accurate approach for correlating fluorescence and electron cryo-microscopy.
• This technique facilitates precise spatial localization and scale integration of cellular structures.
• The method enhances the utility of correlative imaging for studying macromolecular assemblies in their native cellular context.