MAP2 and bone osteosarcoma: To demonstrate SR-cryoCLEM on mammalian cells, we cultured human bone osteosarcoma epithelial (U2OS) cells on top of EM grids and transfected the cells with plasmid encoding rsEGFP2 fused to microtubule-associated protein 2 (MAP2), prior to vitrification by plunge-freezing.