Angiotensin II receptors in chromatin fragments generated by micrococcal nuclease

Rat liver nuclei were digested with micrococcal nuclease following incubation with 125 I-angiotensin II (AII) or with 125 I-AII and excess unlabeled hormone. Chromatin enriched in 125 I was solubilized after 3 min and was applied to a BIO-GEL A-5 M column. Labeled hormone was 40 – 60% displaceable by unlabeled hormone, in nucleoprotein eluting with a V/Vo near 1.9, indicating that these solubilized chromatin fragments contained specific receptors for AII. Furthermore, a discrete AII binding nucleoprotein particle was resolved on DNP gel electrophoresis. Additionally, binding to specific AII nuclear receptors appeared to bring about changes in chromatin structure consistent with the induction of transcriptional activity.