Cytochemical and immunocytochemical study of coiled bodies in different cultured cell lines

We analyzed by different cytochemical and immunocytochemical approaches the biochemical compositon of coiled bodies in three different cultured cell lines. Coiled bodies are stained by the AgNOR staining method and by the EDTA regressive staining method preferential for ribonucleoprotein (RNP). Using the in situ polyadenylate nucleotidyl transferase-immunogold technique or anti-RNA antibodies, we decisively demonstrated the presence of appreciable amounts of RNA in coiled bodies. Neither the in situ terminal deoxynucleotidyl transferase-immunogold technique nor anti-DNA antibodies revealed any DNA in coiled bodies. Coiled bodies thus appear as distinct regions of cell nuclei involved in some steps of RNA metabolism but not directly in RNA synthesis. Their relationships with the dense fibrillar component of the nucleolus and with interchromatin granule clusters are discussed.