Characterization of androgen receptor structure and nucleocytoplasmic shuttling of the rice field eel.
Androgen receptor (AR) plays a critical role in prostate cancer and male sexual differentiation. We have identified AR from a primitive vertebrate with a sex reversal characteristic, the rice field eel. AR of this species (eAR) is distinct from human AR, especially in the ligand binding domain (LBD), and its expression in gonads shows an increasing tendency during gonadal transformation from ovary via ovotestis to testis. eAR has a restricted androgen-dependent transactivation function after a nuclear translocation upon dihydrotestosterone exposure. A functional nuclear localization signal was further identified in the DNA binding domain and hinge region. Although nuclear export is CRM1-independent, eAR has a novel nuclear export signal, which is negatively charged, indicating that a nuclear export pathway may be mediated by electrostatic interaction. Further, our studies have identified critical sequences for ligand binding in the C terminus. A structure of three α-helices in the LBD has been conserved from eels to humans during vertebrate evolution, despite a distinct amino acid sequence. Mutation analysis confirmed that the LBD is essential for dihydrotestosterone-induced nuclear import of eAR and following transactivation function in the nucleus. In addition, eAR interacts with both Sox9a1 and Sox9a2, and their interaction regulates transactivation of eAR. Our data suggest that the primitive species conserves and especially acquires key novel domains, the nuclear export signal and LBD, for the eAR function in spite of a rapid sequence evolution.
Zhou
Fang
F
Department of Genetics and Center for Developmental Biology, College of Life Science, Wuhan University, Wuhan 430072, China.
Zhao
Wei
W
Zuo
Zhixiang
Z
Sheng
Yue
Y
Zhou
Xiang
X
Hou
Yu
Y
Cheng
Hanhua
H
Zhou
Rongjia
R
D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D000728:Androgens / Q000494:pharmacology; D000818:Animals; D015152:Blotting, Northern; D019556:COS Cells; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D002522:Chlorocebus aethiops; D013196:Dihydrotestosterone / Q000494:pharmacology; D004524:Eels / Q000235:genetics*; D017403:In Situ Hybridization; D028884:Karyopherins / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019913:Nuclear Localization Signals; D010802:Phylogeny; D011487:Protein Conformation; D011944:Receptors, Androgen / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D055758:SOX9 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions; D015533:Transcriptional Activation; D000097606:Exportin 1 Protein
D000728:Androgens; D013196:Dihydrotestosterone; D028884:Karyopherins; D019913:Nuclear Localization Signals; D011944:Receptors, Androgen; D018160:Receptors, Cytoplasmic and Nuclear; D055758:SOX9 Transcription Factor; D000097606:Exportin 1 Protein