Abstract
Chicken erythrocyte nuclei prepared by isolation in isotonic KCl and Nonidet P-40 detergent contained numerous attached filaments with a mean diameter of 11.0 nm. In polypeptide content and solubility properties they resembled the vimentin type of intermediate filament found in cells of mesenchymal origin. Examination of their association with the nucleus suggests that more than a simple membrane attachment is involved.