New Phenomenon Androgen receptor binding sites identified in mouse testis

Androgen/androgen receptor (AR) signaling plays decisive roles in testicular spermatogenesis [1]. However, the under-lying molecular mechanism of androgen and AR regulation (i.e. the genes that are regulated and their functions) remains largely undefined. Microarray analysis combined with an-drogen treatment or AR knockout animal models has iden-tified androgen-dependent genes in mouse testis [2,3]. However, this approach does not distinguish direct and indirect targets of androgen/AR. Until now, only a few AR-binding sites containing androgen responsive elements (AREs) located within the promoter regions of androgen re-sponsive genes in testis have been reported, implying that these genes are direct targets of AR. These genes include kallikrein 27 (Klk27) [4], reproductive homeobox 5 (Rhox5) [5], epididymal peptidase inhibitor (Eppin) [6], and cytochr