期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1978
卷号：75
期号：12
页码：6039-6043
DOI：10.1073/pnas.75.12.6039
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：[3H]Ponasterone A (PNA) of high specific activity has been used to identify and begin characterization of ecdysteroid (formerly called ecdysone) receptors in cytoplasmic and nuclear fractions of imaginal discs of Drosophila melanogaster. The equilibrium Kd of the observed macromolecular binding, 3--4 X 10(-9) M PNA, is in good agreement with the minimal concentration required for induction of complete morphogenesis in vitro, 4.2 X 10(-9) M PNA. Binding is analog specific and has kinetics consistent with a role in hormone response. On gentle homogenization, less than 5% of the binding capacity of the cell is released as soluble receptor; the other 95% remains with the nuclear fraction. This nuclear fraction specifically binds [3H]PNA in vitro. Greater than 95% of nuclear PNA receptors are released by extraction with 0.3 M KCl. The binding properties of the nuclear receptors are indistinguishable from those of the cytosol fraction or of the whole cell.
