PRESENCE OF RIBOSOMAL RNA IN THE HEAVY BODIES OF SEA-URCHIN PARACENTROTUS-LIVIDUS EGGS AN IN-SITU HYBRIDIZATION STUDY WITH THE ELECTRON MICROSCOPE

Experimental conditions were found in which the presence of rRNA can be demonstrated by in situ hybridization at the EM level in the heavy bodies of sea urchin eggs. The specificity of the hybridization was controlled by RNase digestion and by competition experiments with unlabeled rRNA.