Abstract
The SRY (sex-determining region on the Y chromosome) is essential for male development; however, the molecular mechanism by which the SAY induces testis development is still unclear. To elucidate the mechanism of testis development, we identified SAY-interacting proteins using a yeast two-hybrid system. We found two ribosomal proteins, RPS7 (ribosomal protein S7) and RPL13a (ribosomal protein L13a) that interact with the HMG (high-mobility group) box domain of SAY. Furthermore, we confirmed the intracellular distributions of RPS7, RPL13a and SAY and found that the three proteins were co-expressed in COS1 cells. SAY, RPS7 and RPL13a were co-localized in nuclear speckles. These findings suggest that SAY plays an important role in activities associated with nuclear speckles via an unknown mechanism.