Immuno-correlative light and electron microscopy (iCLEM) using TEM v1
Immuno- correlative light and electron microscopy (iCLEM) combines ultrastructural information obtained from high resolution electron microscopy with the use of genetically encoded or cytochemical markers. Immuno-CLEM takes advantage of the antigenicity preserved by Tokuyasu sample preparation to identify, quantify and characterise heterogeneous cell populations in small organisms, organs and tissue of healthy and diseased states. iCLEM can be used in combination with scanning EM (SEM), scanning TEM (STEM), and transmission EM (TEM). These protocols are well-suited, for example, for investigating neural stem and progenitor cell populations of the vertebrate nerve system and are available as separate protocols on protocol.io. Here, a method for iCLEM-TEM is described using an adult zebrafish telencephalon brain as a model. This organ is small in size allowing the complete dorsal telencephalic niche to be visualised in sections, and has diverse cell profiles and regenerative potential of local neural stem and progenitor cells. iCLEM-TEM provides high resolution ultrastructural detail of cells, and consecutive ultrathin (62-70 nm) tissue sections can be examined using different labelling techniques involving the use of immunofluorescent and immunogold markers.