Changes in template activity of rat ventral prostate chromatin after brief or prolonged in vivo exposure to androgen: Evidence for a succession of chromatin “conformers”

Abstract

The template activity of rat ventral prostate chromatin, estimated by incubation with E. coli RNA polymerase, was compared in preparations exposed to in vivo androgen for brief (4 hours) or protracted (72 hours) periods of time. After 72 hours, a “paradoxical” result (C>N or CT72) was observed. However, N and CT72 chromatin contained more non-histone protein. At 4 hours, CT4 chromatin template activity exceeded that of C by 60–80%, and this was associated with a massive (+30%) uptake of non-histone (acidic) proteins. Differences in the activities of nucleases and ribonucleoside triphosphatases did not appear to account for these results. Such findings may reflect conformational changes in prostate chromatin related to the androgen-dependent influx from the cytoplasm of non-histone “nuclear” proteins. Changes in template activity following a variety of experimental regimes can be viewed in terms of a succession of chromatin “conformers” brought about and sustained by their association with analogous non-histone proteins.