Cryoelectron microscopy of vitreous sections: a step further towards the native state

Nuclear architecture has been investigated intensively by various electron microscopy (EM) methods. Most of these require chemical fixation of the sample, although cryofixation has also been used in combination with cryosubstitution and resin embedding. This approach allowed one to considerably increase the knowledge about the structural features of different nuclear domains and their involvement in nuclear functions. Cryoelectron microscopy of vitreous sections (CEMOVIS) has added a new dimension to the ultrastructural analysis of the cell nucleus, especially thanks to the possibility of observing the specimen in its hydrated state. In this way one can analyse, at high resolution, cellular structures as close as possible to their native state. In this chapter we describe in detail the different steps of the CEMOVIS method, which should allow an electron microscopist to perform cryosectioning and cryoelectron microscopy of vitrified biological material.