[Isolation and comparative characteristics of the DNA attached to the axial structures of interphase nuclei and metaphase chromosomes].

DNA fractions enriched in sequences located closely to the sites of attachment of DNA loops to the axial protein structures of interphase nuclei ad metaphase chromosomes were isolated with the aid of two techniques. The method involving treatment with EcorI endonuclease has been described earlier. The new method is based on the mild treatment of the preparations with micrococcal nuclease.

[Isolation of DNA fraction bound to the axial structure of metaphase chromosomes and studies of renaturation].

Mitotic chromosomes of L cells (metaphase plates) were dehistonized by centrifugation through a layer of 2 M NaCl and then treated with restriction endonuclease EcoRI and HindIII. Alternatively, they were pretreated with EcoRI endonuclease. The DNA remaining attached to the axial structure of the chromosomes was isolated and investigated in renaturation experiments.