The first insights into the site and mechanisms of RNA process- ing to functional mRNA in eukaryotic cells came from the group of Georgiev (Lukanidin et al. 1972) who demonstrated the association of rapidly labelled, heterogeneous nuclear RNA (hnRNA) with a limited number of specific proteins in the cell nucleus. These "informofers," i. e. packaged precursors of mRNA (pre-mRNA or hnRNA), are in a form presumably amenable to the action of nucleases. With the availability of better analytical techniques, the considerable heterogeneity of hnRNA associated proteins was revealed (Niessing and...

Since antibodies tagged with markers have been developed, immunocytochemistry has become the method of choice for identifying tissue substances or for the localisation of nucleic acid in tissue by in situ hybridisation. Resin-embedded tissue is routinely used and new techniques are constantly introduced. Thus, the novice entering these fields has a breathtaking variety of methods open to him. This labmanual covers the embedding of tissue using epoxy resin methods to the more sensitive procedures employing the acrylics. The possibilities and results are discussed so that an understanding of...