OBJECTIVETo investigate the mechanisms of androgen/androgen receptor (AR) regulating the expression of Caveolin-1 in the mouse epididymis.

METHODSThe AR binding sites associated with the Caveolin-1 gene were identified by searching the database of genomewide AR binding sites in mouse epididymides obtained from chromatin immunoprecipitation-sequencing (ChIP-seq). Total RNA was extracted from the epididymal tissues of normal and castrated mice and those castrated but supplemented with testosterone propionate, and the expression of Caveolin-1 mRNA was detected by RT-PCR and RT-qPCR. ChIP was performed with AR antibodies, and ChIP-PCR and ChIP-qPCR were used to determine the in vivo AR occupancies on the two sites associated with Caveolin-1.

RESULTSTwo AR binding sites associated with Caveolin-1 were found in the database, both located in the second intron region. After castration, the expression of Caveolin-1 was significantly increased, 1.8 +/- 0.17 times that of the control group (P < 0.05), and the fold enrichments of the two AR binding sites were dramatically reduced from 13.5 +/- 1.47 and 10.5 +/- 1.03 to 1.05 +/- 0.17 and 1.4 +/- 0.14, respectively (P < 0.01). After androgen supplement, however, the expression of Caveolin-1 was decreased to normal (P < 0.05), and the fold enrichments of the two AR binding sites significantly increased to 16.4 +/- 2.6 and 10 +/- 0.92, respectively (P < 0.01).

CONCLUSIONCaveolin-1 is a bona fide AR direct target gene in the mouse epididymis, and its expression is negatively regulated by androgen. These findings have provided a new insight into the androgen/AR regulatory network in mouse epididymides.