Visualization of anti-histone antibodies on SV40 minichromosomes by scanning transmission electron microscopy (STEM)

The unique capabilities of the scanning transmission electron microscope (STEM) have been used for a high resolution study of antibody binding to individual SV40 minichromosomes. A method of sample preparation has been developed which allows direct visualization of the antibody molecules in a clearly recognizable form. Using this technique, we have studied the binding of anti-H2B and anti-H3 immunoglobulins to SV40 minichromosomes. The results indicate that histones H2B and H3 are located only in the nucleosomes and are absent in the linker regions.