Objective To analyze the expression characteristics of SRPK2 ( serine /arginine-rich protein specific kinase 2 mRNA and its encoded protein products in mouse testis, and to reveal its molecular role during spermatogenesis. Methods Using semi-quantitative reverse transcription polymerase chain reaction ( RT-PCR) and Western blotting to an-alyze the expression of SRPK2 mRNA and its protein products in several mouse tissues.The stage-specific expression pat-tern of SRPK2 mRNA in mouse testis was examined by real-time quantitative PCR.Immunohistochemical staining was ap-plied to identify the SRPK2 protein distribution in mouse testicular seminiferous tubules and indirect immunofluorescence staining was used to detect the subcellular localization of SRPK2 protein in spermatic cells.Results Semi-quantitative RT-PCR and Western blotting analysis revealed that SRPK2 was highly expressed in mice testis.Real-time quantitative PCR analysis showed that SRPK2 mRNA was expressed abundantly at the stage of 5-and 8-week old mouse testes, suggesting that SRPK2 gene has stage-specific expression patterns during mouse spermatogenesis.Immunohistochemical and indirect immu-nofluorescence staining demonstrated that SRPK2 protein was located around the surface of elongated sperm nucleus. Conclusions SRPK2 is highly expressed in mouse testis and has significant stage-specific expression characteristics with distinct nuclear localization.These results indicate that SRPK2 may participate in precursor mRNA splicing during mouse spermiogenesis.The molecular mechanism of SRPK2 is yet to be further studied.