Activation function-1 domain of androgen receptor contributes to the interaction between subnuclear splicing factor compartment and nuclear receptor compartment. Identification of the p102 U5 small nuclear ribonucleoprotein particle-binding protein as a coactivator for the receptor.
In the androgen receptor (AR), most of its transactivation activity is mediated via the activation function-1 (AF-1). By employing yeast two-hybrid assay, we isolated a cDNA sequence encoding a protein binding to AR-AF-1. This protein, named ANT-1 (AR N-terminal domain transactivating protein-1), enhanced the ligand-independent autonomous AF-1 transactivation function of AR or glucocorticoid receptor but did not enhance that of estrogen receptor alpha. In contrast, the ANT-1 did not enhance any ligand-dependent AF-2 activities. Furthermore, the ligand-independent interaction between AR-AF-1 and ANT-1 was confirmed in vivo and in vitro. The ANT-1 sequence was identical to that of a protein that binds to U5 small nuclear ribonucleoprotein particle, a human homologue of yeast splicing factor Prp6p, involved in spliceosome. ANT-1 was compartmentalized into 20-40 coarse splicing factor compartment speckles against the background of the diffuse reticular distribution. AR colocalized with ANT-1 only in the diffusely distributed area, whereas the ANT-1 speckles were spatially distinct from but surrounded by the AR compartments. The active gene transcription has been shown to couple simultaneously with pre-mRNA processing at the periphery of the splicing factor compartment. The molecular interaction between two spatially distinct subnuclear compartments mediated by ANT-1 may therefore recruit AR into the transcription-splicing-coupling machinery.
Zhao
Yue
Y
Department of Medicine and Bioregulatory Science (3rd Department of Internal Medicine), Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan.
Goto
Kiminobu
K
Saitoh
Masayuki
M
Yanase
Toshihiko
T
Nomura
Masatoshi
M
Okabe
Taijiro
T
Takayanagi
Ryoichi
R
Nawata
Hajime
H
D000818:Animals; D002451:Cell Compartmentation; D002460:Cell Line; D003001:Cloning, Molecular; D018076:DNA, Complementary; D006801:Humans; D011233:Precipitin Tests; D012326:RNA Splicing; D011944:Receptors, Androgen / Q000737:chemistry / Q000378:metabolism*; D017415:Ribonucleoprotein, U5 Small Nuclear / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D018076:DNA, Complementary; D011944:Receptors, Androgen; D017415:Ribonucleoprotein, U5 Small Nuclear