Detection of ribosomal RNA during the cell cycle in Ehrlich tumour cells by electron microscope in situ hybridization.

The fine spatial distribution of rRNA within Ehrlich tumour cells has been investigated during the cell cycle by in situ hybridization with a biotinylated probe. In interphase cells, rRNA was essentially detected in the ribosome-rich cytoplasmic regions and in the three main nucleolar components. In mitotic cells, besides the presence, as expected, of rRNA in the ribosome-rich spaces, evident label was observed over material situated around and between the chromosomes during anaphase and telophase as well as over the reforming nucleoli during telophase.