Steroid requirement for androgen receptor dimerization and DNA binding. Modulation by intramolecular interactions between the NH2-terminal and steroid-binding domains.
Infection of Spodoptera frugiperda Sf9 insect cells with recombinant human androgen receptor (AR) baculovirus results in expression of a 118-kDa phosphoprotein that displays high affinity androgen binding and androgen-dependent targeting to the nucleus. Using the DNA mobility shift assay, specific in vitro binding of full-length AR to androgen response element DNA (ARE) requires intracellular hormone exposure. The ability of a variety of steroids to induce ARE binding paralleled their transcriptional potential. Certain antihormones, cyproterone acetate and RU486, promote ARE binding, but a pure antiandrogen, hydroxyflutamide, inhibits AR binding to ARE DNA. AR dimerization requires incubation of recombinant baculovirus-infected insect cells with androgen, but only when one or both components of the dimer contain the NH2-terminal domain. Based on the intensities of ARE binding and lack of binding to an ARE half-site, it appears that, unlike the glucocorticoid receptor, AR binds DNA primarily as a dimer. Thus, full-length baculovirus-expressed AR requires intracellular hormone exposure for dimerization and ARE binding to overcome inhibition imposed by the AR NH2-terminal domain. Antihormones with agonist activity promote dimerization and ARE binding, while a pure antiandrogen blocks AR DNA binding. It is concluded that intramolecular interactions between the NH2-terminal and steroid-binding domains are regulated by the specificity of hormone binding and modulate receptor dimerization and DNA binding.
Wong
C I
CI
Laboratories for Reproductive Biology, University of North Carolina, Chapel Hill 27599.
Zhou
Z X
ZX
Sar
M
M
Wilson
E M
EM
D000728:Androgens / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D017373:Cyproterone Acetate / Q000494:pharmacology; D004247:DNA / Q000378:metabolism*; D005485:Flutamide / Q000031:analogs & derivatives / Q000494:pharmacology; D005822:Genetic Vectors; D006801:Humans; D046911:Macromolecular Substances; D015735:Mifepristone / Q000494:pharmacology; D008969:Molecular Sequence Data; D009036:Moths; D011944:Receptors, Androgen / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014162:Transfection
D000728:Androgens; D046911:Macromolecular Substances; D011944:Receptors, Androgen; D011994:Recombinant Proteins; C014290:hydroxyflutamide; D015735:Mifepristone; D017373:Cyproterone Acetate; D005485:Flutamide; D004247:DNA