CatSper gene expression in postnatal development of mouse testis and in subfertile men with deficient sperm motility

The search for Ca2+ channels residing in sperm has led to the recent cloning and characterization of a novel gene, named CatSper, which codes for a unique Ca2+ channel expressed exclusively in the testis. It plays an essential role in sperm motility, penetration into the oocyte, and ultimately in male fertility. In this study, we assessed the temporal profile of CatSper gene expression during mouse testis development and performed a semi-quantitative evaluation of expression levels in a group of subfertile men which lack sperm motility.

A small piece of testicular tissue obtained by either multi-site testicular biopsy or orchidectomy was used for semi-quantitative RT-PCR of CatSper and beta2-microglobulin (beta2m, as an internal control) genes.

Our results reveal that: (i) the expression of mouse CatSper is developmentally regulated with a direct correlation between CatSper expression and mouse sexual maturation. CatSper gene expression is first detected at 3 weeks of age and coincides with the appearance of round spermatids in the developing mouse testis. (ii) There is a significant reduction in the level of CatSper gene expression (up to 3.5-fold difference) among patients which lack sperm motility as compared with patients whose infertility cannot be ascribed to a deficiency in motility (used as a control).

The data obtained in this study support a potential role for CatSper in sperm motility and fertility in mouse and human. CatSper is therefore implicated as a potential target to explore the molecular mechanisms of male infertility.