Expression of Pkd2l2 in testis is implicated in spermatogenesis

Pkd2l2 is a novel member of the polycystic kidney disease (PKD) gene family in mammals. Prominently expressed in testis, this gene is still poorly understood. In this study, reverse transcription polymerase chain reaction (RT-PCR) results showed a time-dependent expression pattern of Pkd2l2 in postnatal mouse testis. Immunohistochemical analysis revealed that Pkd2l2 encoded a protein, polycystin-L2, which was predominantly detectable in the plasma membrane of spermatocytes and round spermatids, as well as in the head and tail of elongating spermatids within seminiferous tubules in mouse testis tissue sections of postnatal day 14 and adult mice. A green fluorescent fusion protein of Pkd2l2 resided in the plasma membrane of HEK 293 and MDCK cells, suggesting that it functions as a plasma membrane protein. Overexpression of Pkd2l2 increased the intracellular calcium concentration of MDCK cells, as detected by flow cytometry. Collectively, these data indicated that Pkd2l2 may be involved in the mid-late stage of spermatogenesis through modulation of the intracellular calcium concentration.