The zona pellucida is an extracellular matrix that surrounds the oocyte and early embryo. It is composed primarily of three or four glycoproteins with various functions during fertilization and preimplantation development. The protein encoded by this gene ensures the structural integrity of the zona pellucida. Mutations in this gene are a cause of oocyte maturation defect and infertility. [provided by RefSeq, May 2014].