Electron microscopical observation of RNA on the surface of Ehrlich ascites tumor cells

The structure of RNA on the surface of Ehrlich ascites tumor cells was studied under an electron microscope using both plasma polymerization replica films and ultrathin sections of the cells. Necklace-like structures were found on the cell surface where anti-RNA antibody was bound in replica film, and particles which resemble cytoplasmic ribosomes in size and density were found distributed sparsely on the cell surface in ultrathin sections. These particles were found to gather at one pole of the cell surface after the cell was incubated at 4 degrees C with anti-RNA antibody and then incubated at 37 degrees C for 10 min in antibody-free medium. On the other hand, L1210 cells which do not bind with anti-RNA antibody showed hardly any such structures on the cell surface. These results suggest that RNA on the surface of Ehrlich ascites tumor cells is present in the form of particles.