CONICET | Buscador de Institutos y Recursos Humanos

Cysteine-Rich Secretory Protein (CRISP) 1, 2, 3 and 4 are mainly expressed in thereproductive tract and have key roles in mammalian fertilization. In spite of this,knockout (KO) mice for each individual protein are fertile whereas double KO(DKO) CRISP1/CRISP4 are subfertile, suggesting the existence of compensatorymechanisms between homologous CRISP family members. Recent results fromour lab revealed that DKO CRISP1/CRISP3 are also subfertile. Based on this, theaim of the present work was to investigate the mechanisms underlying the lowerfertility rates observed in these animals. In order to do this, we first analyzed thepercentage of fertilized eggs recovered from the ampulla of superovulated femalesmated by DKO1/3 or control males. As no significant differences between groups inthese in vivo fertilization rates were observed, the recovered fertilized oocytes fromboth groups were incubated in vitro for additional 5 days to analyze theirsubsequent development. Results showed that the percentage of oocytes frommutant males that reached the blastocyst stage under these conditions wassignificantly lower than that corresponding to controls, suggesting that CRISP1 andCRISP3 may be important for early embryo development. To investigate potentialfunctional deficiencies in mutant sperm that could be responsible for theseobservations, DKO1/3 and control sperm were co-incubated in vitro with eggs(surrounded by both cumulus oophorus and zona pellucida or denuded of thesecoats) and the percentage of fertilized eggs determined. Results revealedsignificantly lower fertilization rates for mutant than for control sperm, confirmingdefects in mutant sperm fertilizing ability. Together, these observations support therole of CRISP1 and CRISP3 for male fertility and fertilization and contribute to abetter understanding of how paternal factors could impact on embryo development.