[Interaction of chromatin non-histone proteins with homologous and heterologous DNA].

The interaction of different preparations of chromatin non-histone proteins (NHP) isolated from rat liver and thymus with homologous and heterologous DNA was studied by a membrane filter technique. All the NHP preparations studied form complexes with DNA in 0.02 tris-HCl (pH 7.5)--3 mM MgCl2. Denatured DNA binds NHP more effectively than native NDA. The largest part of NHP which interacts with DNA is bound to the latter non-specifically. A small part of NHP interacts specifically with homologous native DNA in 5 M urea. Specific binding of NHP to denaturate DNA is shown both in the presence of urea and in its absence. The data obtained are discussed in the light of a possible role of NHP in the specific regulation of transcription process.