Evidence for an anti-parallel orientation of the ligand-activated human androgen receptor dimer.
Domain interactions of the human androgen receptor (AR) dimer were investigated using a protein-protein interaction assay in which the NH2- and carboxyl-terminal regions of human AR were fused to the Saccharomyces cerevisiae GAL4 DNA-binding domain and herpes simplex virus VP16 transactivation domain to produce chimeric proteins. Transcriptional activation of a GAL4 luciferase reporter vector up to 100-fold was greater than Fos/Jun leucine zipper binding, indicating stable AR interaction between AR NH2-terminal residues 1-503 and steroid-binding domain residues 624-919 that was specific for and dependent on androgen binding to the steroid-binding domain and was inhibited by anti-androgen binding. Deletion mutagenesis within the NH2-terminal region indicated transactivation domain residues 142-337 were not required for dimerization, whereas deletions near the NH2 terminus (delta 14-150) or NH2-terminal to the DNA-binding domain (delta 339-499) reduced or eliminated the AR interaction, respectively. An NH2-/NH2-terminal interaction was also observed, but no interaction was detected between ligand-free or bound steroid-binding domains. The results indicate that high affinity androgen binding promotes interactions between the NH2-terminal and steroid-binding domains of human AR, raising the possibility of an androgen-induced anti-parallel AR dimer.
Laboratory for Reproductive Biology, University of North Carolina, Chapel Hill 27599, USA.
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Langley
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Zhou
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Wilson
D000818:Animals; D016466:CHO Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D006224:Cricetinae; D004268:DNA-Binding Proteins; D004790:Enzyme Induction; D005656:Fungal Proteins / Q000096:biosynthesis; D006801:Humans; D007668:Kidney; D008024:Ligands; D008156:Luciferases / Q000096:biosynthesis / Q000378:metabolism; D011944:Receptors, Androgen / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D018139:Simplexvirus / Q000235:genetics; D014157:Transcription Factors; D015533:Transcriptional Activation; D014162:Transfection
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D008024:Ligands; D011944:Receptors, Androgen; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D008156:Luciferases