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Updated: Feb 14, 2026

Detecting the Ligand-binding Domain Dimerization Activity of Estrogen Receptor Alpha Using the Mammalian Two-Hybrid Assay
Published on: December 19, 2018
Iodination of the progesterone receptor from hen oviduct spares the DNA-binding domain
1Bioengineering Research Laboratory, SRI International, Menlo Park, California 94025.
Abstract:
The progesterone receptor from hen oviduct is isolated as a complex of two subunits, A and B. The A protein binds one molecule of progesterone and also binds to DNA with high affinity. The native A protein can be labeled with iodine with no loss of DNA-binding activity. Limited Staphylococcus aureus V8 protease digestion of the labeled preparation results in a number of DNA-binding and non-DNA-binding fragments of the receptor. The progesterone-binding domain contains iodine label. However, two low-molecular-weight DNA-binding fragments do not contain iodine label, indicating a lack of susceptible tyrosine residues near the DNA-binding site of the native receptor. The labeled receptor and its fragments will facilitate studies of the isolated DNA-binding and progesterone-binding domains of the hen A protein as well as of the activity of the native receptor in the presence and absence of hormone.
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