In recent years correlative microscopy, combining the power and advantages of light and electron microscopy, has become an important tool for biomedical research.
Light microscopy has the advantage of easily searching large areas, even volumes, for the cells of interest, e.g., a special cell type in tissue, astrocytes in brain2 or for cells that have been modified either by transfections or by RNAi in a large population of non-modified cells. Also on thin sections, the low magnification of light microscopy and therefore ease of searching large areas are very beneficial to speed-up the analysis of rare events3. The predominant disadvantage of this technique, however, is that only the fluorescently labelled structures can be imaged in relation to each other.
Electron microscopy reveals the cellular ultrastructure a high resolution and individual organelles, even large protein polymers like cytoskeletal filaments or ribosomes can unequivocally identified. Proteins of interest can be labelled with colloidal gold. Searching for a few gold particles within a few cells of a large tissue, however, is very cumbersome and can be extremely time consuming.
Seen the advantages of light and electron microscopy suggests that the optimal approach is to combine both techniques for cell biology research. Localisation of rare cellular events are followed and identified by (fluorescence) light microscopy, the high resolution data and fine localisation to cellular substructures are done by electron microscopy.
In this presentation we will describe the approach we have chosen to follow the cell(s) of interest from sampling the tissue until the analysis by electron microscopy4.
1Tsien, R.Y., Annu Rev Biochem 67 (1998). 509-544.
2Loussert Fonta, C., et al., J Struct Biol 189 (2015). 53-61.
3Schwarz, H. and B.M. Humbel, Methods Mol Biol 1117 (2014). 559-592.
4Loussert Fonta, C. and B.M. Humbel, Arch Biochem Biophys 581 (2015). 98-110.
