STRUCTURE AND RNA-CONTENT OF THE PROSOMES

Duck erythroblasts prosomes were analysed by small angle neutron scattering (SANS), dynamic light scattering and (cryo-)electron microscopy. A molecular weight of approximately 720,000 +/- 50,000, a radius of gyration of 64 +/- 2 angstrom and a hydrodynamic radius of approximately 86 angstrom were obtained. Electron micrographs show a hollow cylinder-like particle with a diameter of 120 angstrom, a height of 170 angstrom and a diameter of 40 angstrom for the cavity, built of four discs, the two outer ones being more pronounced than those in the center. Results from SANS indicate less then 5% of RNA in the purified prosomes, but nuclease protection assays confirm its presence.