The role of nonhistone chromosomal proteins in the interaction of prostate chromatin with androgen.receptor complex.

Rat prostate nonhistone chromatin proteins were fractionated by sequential extraction with 0.35 M NaCl and 2.0 M NaCl into 0.35 M NaCl-soluble, 2 M NaCl-soluble and -insoluble (residual) fractions. Interactions of [3H]dihydrotestosterone.receptor complex with reconstituted chromatin lacking one of these fractions and with reconstituted hybrid chromatin using spleen fractions indicate that binding of chromatin to androgen.receptor is largely determined by the residual fraction. The residual fraction of prostate also interacts directly with [3H]dihydrotestosterone.receptor complex target tissue-specifically similar to prostate chromatin. The DNA in the residual fraction is mostly bound by nonhistone proteins and the template activity of te residual DNA in transcription is severely restricted. These characteristics are discussed in relation to the acceptor role in the residual fraction in androgen action.