Isolation and characterization of stable nuclear matrix preparations and associated DNA from avian erythroblasts

A novel procedure for isolation of nuclear matrices from chicken erythroblast cells was elaborated. The influence of variations in the isolation procedure on structural integrity and morphology of nuclear matrices as well as on properties of the nuclear matrix-associated DNA fractions was investigated. The incubation of isolated nuclei in the presence of Cu2+ ions provided significant stabilization of the nuclear matrix. Copper treatment of nuclei did not affect the properties of the nuclear skeleton-associated DNA fraction. In both copper-stabilized as well as unstabilized nuclei, nuclear matrix-attached DNA was digested to the same extent with nucleolytic enzymes, and could be totally removed from nuclear matrices by 2 M NaCl-2 M urea treatment. The fine morphology of the nuclear matrix did not change after extraction of nuclear skeleton-associated DNA fragments. In the presence or absence of copper ions, matrix DNA was found to be qualitatively different compared with total DNA, in particular with respect to the representation of specific repetitive sequences of the chicken beta globin gene domain.