Yu Xiuping, Gupta Aparna, Wang Yongqing, Suzuki Kichiya, Mirosevich Janni, Orgebin-Crist Marie-Claire, Matusik Robert J
Department of Urologic Surgery, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
Ann N Y Acad Sci. 2005 Dec;1061:77-93. doi: 10.1196/annals.1336.009.
Previous studies from our group have shown that Foxa1 is expressed in the prostate and interacts with the androgen receptor (AR) to regulate prostate-specific genes such as prostate-specific antigen (PSA) and probasin (PB). We report here that Foxa2 but not Foxa1 is expressed in the epididymis. Further, Foxa2 interacts with the AR to regulate the mouse epididymal retinoic acid binding protein (mE-RABP) gene, an epididymis-specific gene. Binding of Foxa2 to the mE-RABP promoter was confirmed by gel-shift and chromatin immunoprecipitation (ChIP) assays. Overexpression of Foxa2 suppresses androgen activation of the mE-RABP promoter while overexpression of Foxa2 with prostate-specific promoters activates gene expression in an androgen-independent manner. GST pull-down assays determined that both Foxa1 and Foxa2 physically interact with the DNA binding domain of the AR. The interaction between Foxa proteins and AR was further confirmed by gel-shift assays where Foxa protein was recruited to AR binding oligomers even when Foxa binding sites were not present, and AR was recruited to Foxa binding oligomers even in the absence of an AR binding site. Given that Foxa1 and Foxa2 proteins are expressed differentially in the prostate and epididymis, these data suggest that the Foxa proteins have distinct effects on AR-regulated genes in different male reproductive accessory organs.
我们团队之前的研究表明，Foxa1在前列腺中表达，并与雄激素受体（AR）相互作用，以调节前列腺特异性基因，如前列腺特异性抗原（PSA）和前列腺素（PB）。我们在此报告，Foxa2而非Foxa1在附睾中表达。此外，Foxa2与AR相互作用，以调节小鼠附睾视黄酸结合蛋白（mE-RABP）基因，这是一种附睾特异性基因。通过凝胶迁移和染色质免疫沉淀（ChIP）试验证实了Foxa2与mE-RABP启动子的结合。Foxa2的过表达抑制了mE-RABP启动子的雄激素激活，而Foxa2与前列腺特异性启动子的过表达以雄激素非依赖的方式激活基因表达。GST下拉试验确定Foxa1和Foxa2均与AR的DNA结合结构域发生物理相互作用。凝胶迁移试验进一步证实了Foxa蛋白与AR之间的相互作用，即使不存在Foxa结合位点，Foxa蛋白也会被募集到AR结合寡聚体中，即使不存在AR结合位点，AR也会被募集到Foxa结合寡聚体中。鉴于Foxa1和Foxa2蛋白在前列腺和附睾中的表达存在差异，这些数据表明Foxa蛋白在不同的雄性生殖附属器官中对AR调节基因具有不同的作用。
