Male infertility has become an increasingly common health concern in recent years. Apart from environmental factors, nutrition, lifestyle, and sexually transmitted diseases, genetic defects are important causes of male infertility. Many genes have been demonstrated to be associated with male infertility. However, the roles of some functional genes in infertility, especially those that are specifically expressed in the reproductive system, remain to be elucidated. Here, we demonstrated that the testis-specific gene coiled-coil domain-containing 87 (Ccdc87) is critical for male fertility. Reverse-transcriptase polymerase chain reaction and western blot analyses revealed that the Ccdc87 mRNA and protein were only expressed in mouse testis. Ccdc87 expression first appeared at postnatal day 14 and remained at a relatively high level until adulthood. Male mice lacking Ccdc87 gene (Ccdc87^−/−) were found to be subfertile. Approximately 20% of Ccdc87-null sperm from the testis and epididymis displayed severe abnormity of acrosome and cell nucleus. Sperm isolated from the cauda epididymides of Ccdc87^−/− mice exhibited decreased initial motility but did not show any change in capacitation. Additionally, Ccdc87 disruption led to the impotency of sperm spontaneous and progesterone-induced acrosome reaction. Moreover, in vitro fertilization assays indicated that the fertilizing capacity of Ccdc87^−/− sperm was significantly reduced. Taken together, these findings provide a new clue to understand the genetic causes of male infertility.

Summary Sentence

A testis-specific protein, coiled-coil domain-containing 87 (CCDC87), plays critical roles in male fertility as a participant to regulate sperm morphology and acrosome reaction.