The conserved fertility factor SPACA4/Bouncer has divergent modes of action in vertebrate fertilization
Yoshitaka Fujihara, Sarah Herberg, Andreas Blaha, Karin Panser, Kiyonori Kobayashi, Tamara Larasati, Maria Novatchkova, Hans‐Christian Theussl, Olga Olszanska, Masahito Ikawa, Andrea Pauli
Abstract
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.