General method for isolation of DNA sequences that interact with specific nuclear proteins in chromosomes: binding of the high mobility group protein HMG-T to a subset of the protamine gene family.

A general method is described for the isolation of the DNA with which specific nuclear proteins interact in chromosomes. This method is based on the covalent photo-cross-linking of nuclear proteins to the DNA sequences, to which they normally bind, by means of irradiation with UV light and the selective retrieval of specific subsets of protein-DNA adducts by using specific antibodies. The application of this procedure to isolate the DNA sequences with which the trout high mobility group protein (HMG-T) interacts has shown that in trout liver this protein associates specifically with DNA sequences in proximity to a subset of the family of protamine genes but not with the histone or vitellogenin genes. From these observations, it appears that the HMG-T protein may be associated with inactive gene sequences.