Truncated ZP2 does not support sperm binding, and female mice are sterile. (A) Representation of secreted ectodomains of normal mouse ZP2^35–633 and truncated ZP2 lacking ZP2^51–149. Cysteine residues, yellow. Monoclonal antibodies that bind N and C terminal to the postfertilization cleavage site (arrowhead) and zona domains are indicated above. (B) Ovarian histology of moZp2^Trunc and moQuad-Zp2^Trunc transgenic mice in Zp2^Null background as in Fig. 1 C. (C) moQuad^(huZP4) and moQuad-Zp2^Trunc eggs stained with domain-specific monoclonal antibodies as in Fig. 1 D. (D) Immunoblot of eggs (15) from moQuad^(huZP4) (1) and moQuad-Zp2^Trunc (2) mice stained with domain-specific monoclonal antibodies. Molecular masses are indicated on the left. (E) Mouse sperm binding to Zp2^Trunc and moQuad-Zp2^Trunc eggs as in Fig. 1 E.