The testis-specifically expressed Dpep3 is not essential for male fertility in mice

More than 2300 genes have been reported to be involved in spermatogenesis but the functional roles of most genes in male fertility remain to be elucidated. In this study, we explored the function of dipeptidase 3 (Dpep3), a gene predicted to be testis-specific, in male fertility of mice. We showed that Dpep3 is evolutionarily conserved in human and mouse along with other eutherians. Its mRNA was exclusively detected in testicular tissue and expressed in testes from 7 days postpartum. To further explore its role in male fertility, we generated Dpep3 knockout mice (Dpep3-/-) using the CRISPR/Cas9 technology and found that the male Dpep3-/- mice are fertile despite a significant reduction in sperm count. Histology of testis and progression of meiotic prophase I showed no obvious difference between wild-type and Dpep3-/- mice. All these findings indicate that Dpep3 is not essential for male fertility in mice. These findings will help other researchers to avoid research duplication, save their time and resources to focus on the genes that are indispensable for male fertility.