Roles of steroid receptor coactivator (SRC)-1 and transcriptional intermediary factor (TIF) 2 in androgen receptor activity in mice.
Genetic disruption of the steroid receptor coactivator (SRC)-1 and transcriptional intermediary factor (TIF)2/SRC-2 in mouse resulted in distinctive mutant phenotypes. To quantify their roles in the function of androgen receptor (AR) transcriptional activity in vivo, we generated a unique transgenic AR-reporter mouse and analyzed the cell-specific contributions of SRC-1 and TIF2 to the activity of AR in mouse testis. Transgenic AR-luciferase and transgenic AR-lacZ mice harbor a recombinant mouse AR gene, AR(GAL4DBD), which is functionally coupled with a upstream activation sequence-mediated reporter gene (AR activity indicator). After characterization of these mice in terms of AR function, we further derived bigenic mice by crossing AR activity indicator mice with the SRC-1-/- or TIF2+/- mutant mice. Analyses of the resultant bigenic mice by in vivo imaging and luciferase assays showed that testicular AR activity was decreased significantly in those with the TIF2+/- mutation but not in the SRC-1+/- background, suggesting that TIF2 serves as the preferential coactivator for AR in testis. Immunohistological analysis confirmed that AR and TIF2 coexist in mouse testicular Sertoli cell nuclei under normal conditions. Although SRC-1 concentrates in Sertoli cell nuclei in the absence of TIF2, nuclear SRC-1 is not able to rescue AR activity in the TIF2 mutant background. Interestingly, SRC-1 appears to negatively influence AR activity, thereby counterbalancing the TIF2-stimulated AR activity. Our results provide unique in vivo insights to the multidimensional cell-type-specific interactions between AR and coregulators.
Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
Xiangcang
X
Ye
Sang Jun
SJ
Han
Sophia Y
SY
Tsai
Francesco J
FJ
DeMayo
Jianming
J
Xu
Ming-Jer
MJ
Tsai
Bert W
BW
O'Malley
D000818:Animals; D015153:Blotting, Western; D003433:Crosses, Genetic; D017931:DNA Primers; D051548:Histone Acetyltransferases; D007150:Immunohistochemistry; D007763:Lac Operon / Q000235:genetics; D008156:Luciferases / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D056920:Nuclear Receptor Coactivator 1; D010641:Phenotype; D011944:Receptors, Androgen / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013737:Testis / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D017931:DNA Primers; D009687:Nuclear Proteins; D011944:Receptors, Androgen; D014157:Transcription Factors; C093517:transcriptional intermediary factor 1; D008156:Luciferases; D051548:Histone Acetyltransferases; C538861:Ncoa1 protein, mouse; D056920:Nuclear Receptor Coactivator 1