DNA-nuclear matrix interactions analyzed by cross-linking reactions in intact nuclei from avian liver

To detect the interactions of DNA with the nuclear matrix proteins, DNA-protein cross-linkages were induced in intact nuclei from chicken liver by the use of cis-diammine dichloroplatinum. Methods have been devised for fast purification both of the proteins and of the DNA fragments involved in the cross-linked complexes. By Southern-Western blotting a number of matrix proteins isolated from the complexes have been shown to recognize specifically DNA sequences present in the cross-linked DNA fragments. This experimental approach not only allows to identify the nuclear matrix-DNA interactions existing in the nucleus before its disruption, but also provides a preparation of matrix proteins enriched in those species which are involved in such interactions and which can therefore be detected with high sensitivity.