title: Interaction of calf uterine estrogen receptors with chicken target cell nuclei.
abstract: The calf uterine estrogen receptor (ER) was used to study the capacity and the characteristics of the acceptor sites in chicken target cell nuclei. The temperature-activated ER is bound at 0 degrees C with a high affinity to all chicken cell nuclei tested (Kd = 0.4-1.0 nM). The nuclear binding displayed tissue specificity: oviduct greater than liver, heart greater than spleen greater than erythrocytes and was salt-dependent. ER binding to liver nuclei measured in 0.15 M KCl varied between 3000 and 6000 acceptor sites per nucleus. Liver nuclei isolated from estrogen-treated cockerels showed a 2-fold lower binding capacity than nuclei from non-treated chickens. When nuclei were incubated with [3H]ER from embryo liver and increasing concentrations of uterine non-radioactive-ER a progressive inhibition of the binding of the liver ER was found. These experiments suggest that liver and uterine ER compete for a common acceptor site. Liver nuclei charged in vitro with calf uterine ER were digested at 0 degree C with DNAase I and micrococcal nuclease. Both enzymes excised the ER in the form of a chromatin-ER complex. A considerable portion was associated with nucleosomal subunits and a minor fraction was associated with a nuclease-sensitive, protein-poor fraction of the chromatin.
mesh_terms: D000818:Animals; D002417:Cattle; D002467:Cell Nucleus / Q000378:metabolism*; D002645:Chickens; D003850:Deoxyribonuclease I; D004706:Endodeoxyribonucleases / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D008099:Liver / Q000378:metabolism; D008836:Micrococcal Nuclease / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D010057:Oviducts / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism*; D013154:Spleen / Q000378:metabolism; D013696:Temperature; D014599:Uterus / Q000378:metabolism*
chemical_list: D011960:Receptors, Estrogen; D004706:Endodeoxyribonucleases; D003850:Deoxyribonuclease I; D008836:Micrococcal Nuclease