Objective To investigate the expression and the distribution of Dickkopf-likel （Dkkll） protein during the development of mouse testis. Methods Testes eDNA samples from BALB/c mice in different postnatal days were hybridized with mouse whole genome affymetrix chip to screen the spermatogenesisrelated genes. The characteristics of the selected genes were analyzed by various bioinformatics tools. The mRNA expression of Dkkll at different stages of testis development and different tissues in mouse were analyzed by RT-PCR. The protein localization of Dkkll in mouse testis was assesed by immunohistoehemistry. Results By analyzing the gene chip signals of mouse testis aged 4 d, 9 d, 18 d, 35 d, 54 d and 6 months, Dkkll was identified with a differential expression in the develop- mental stages of testis. RT-PCR analysis showed that the expression of Dkkll mRNA was firstly detected on 15 d testis tissue and gradually upregulated during the testis developing to the adult stage. The Dkkll protein was predominantly located in spermatocytes and round spermatids in mouse testis. Conclusion The expression of Dkkll is gradually upregulated during the development of mouse testis and corresponds to the mouse spermatogenesis. It may play a critical role in male mammalian spermatogenesis.
