Localization of Bovine Brain Filament Antibody on Intermediate (100 angstrom) Filaments in Guinea Pig Vascular Endothelial Cells and Chick Cardiac Muscle Cells

Guinea pig vascular endothelial cells contain naturally occurring rings of intermediate filaments that completely encircle the nucleus. Indirect immunofluorescence staining showed that these perinuclear rings bound antibody prepared against protein from bovine brain 9-nm filaments. In endothelial cells grown in the presence of 1 μ M demecolcine (Colcemid) the perinuclear ring ``coils'' into a juxtanuclear ``cap.'' Throughout this process we could demonstrate staining of the intermediate filaments. Chick cardiac muscle cells in culture stained diffusely with the antibody. After treatment for 24 hr with 1 μ M demecolcine the cardiac cells accumulated large bands of intermediate filaments. These bands stained intensely with the antibody. Our findings suggest that intermediate filaments in guinea pig endothelial cells and those induced in chick cardiac muscle cells are antigenically similar to bovine brain filaments. The staining of these filaments is not affected by treatment with demecolcine.