Molecular Cloning and Expression of Suppressor of Potassium Transport Defect 3 (SKD3) in Rat Testis.

Abstract

Abstract.To analyze the function of heat shock protein (HSP) in spermatogenesis, rat suppressor of potassium transport defect 3 (SKD3) cDNA, a novel member of the HSP family, was cloned in rat testis, and its expression and localization was investigated in rat testis at the mRNA and protein levels. The cDNA and predicted amino acid sequence of rat SKD3 showed approximately 95.6% and 97.0% homology, respectively, with mouse SKD3. All motifs recognized in mouse were conserved in rat. SKD3 mRNA (2.3 kbs) was restricted to the testis among the tissues investigated. SKD3 mRNA was detected by in situ hybridization in spermatogonia, spermatocytes, Leydig cells, and Sertoli cells. Immunoreactive SKD3 from whole rat testis and a Leydig cell line (LC540) was seen at 76 kDa by Western blotting. SKD3 immunoreactive cells were Leydig and Sertoli cells. Although the cellular localizations of SKD3 mRNA and protein were somewhat inconsistent, rat SKD3 cDNA was characterized and various expression patterns of SKD3 mRNA and protein in rat testis were revealed in the present study.