Mode of action

Oocyte

Zona pellucida

Cell biology

Demography

In vitro fertilisation

Ecology

Biology

Human fertilization

Sperm

Acrosome reaction

Evolutionary biology

Genetics

Embryo

Acrosome

Zona pellucida glycoprotein

Fertility

Population

Sociology

Hyperactivation

Andrology

Medicine

Sperm competition

Gamete

Proceedings of the National Academy of Sciences

Significance We show that Bouncer’s homolog in mammals, SPACA4, is required for efficient fertilization in mice. In contrast to fish, in which Bouncer is required for female fertility, SPACA4 is expressed exclusively in the sperm and is required for male fertility. SPACA4 and Bouncer present an intriguing example of homologous proteins that both play key roles in reproduction yet diverged in terms of gene expression pattern and mode of action. Overall, our work identifies SPACA4 as an important sperm protein necessary for zona pellucida penetration during mammalian fertilization. Since human SPACA4 is also expressed exclusively in sperm, we anticipate that our findings in mice will have relevance to human biology.

The conserved fertility factor SPACA4/Bouncer has divergent modes of action in vertebrate fertilization