Abstract
[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.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
