Fig. 1.

The major steps of correlated cryo light and electron microscopy using two independent correlation markers. The process begins with sample preparation (step 1a) and vitrification by rapid plunge-freezing (step 1b). The grids are subsequently imaged by light and fluorescence cryo microscopy (cryoFM) (step 2a) in different channels. Each set of FM images is merged according to the accurate positions of TetraSpeck microspheres (step 2b). The correlation with cryoEM data starts with a rough alignment (step 3a). Then, blue FluoSpheres are used as reference points to assign new coordinates to the EM images (step 3b). Finally, the location of the feature of interest is calculated and tomograms are acquired.