Mice homozygous for an insertional mutation in the Zp3 gene lack a zona pellucida and are infertile

Abstract

Mammalian oocytes synthesize and secrete a zona pellucida that surrounds the growing oocytes, ovulated eggs and preimplantation embryos. The extracellular zona matrix is composed of three glycoproteins (ZP1, ZP2, ZP3) that are involved in folliculogenesis, species-specific fertilization, and passage of the early embryo down the oviduct. We have established a mouse line in which Zp3 has been inactivated by homologous recombination with an insertional mutation. Neither Zp3 transcripts nor ZP3 protein was detected in female mice homozygous for the mutation (Zp3(-/-)), whereas both ZP1 and ZP2 were present in mutant oocytes. Homozygous mutant Zp3(-/-) mice had follicles with germinal-vesicle-int..