Fig. 1.

ZP domain genes identified from a pink abalone (H. corrugata) ovary EST library. RACE was used to extend ESTs predicted to have homology to ZP domain proteins, identifying nine ovary-expressed genes in addition to VERL. Phylogenetic analysis of the ZP domain from these genes (≈768 nucleotides) employing likelihood was performed under the general time reversible model with four rate categories by using PAUP (38). Terminal branches in the tree are labeled with a proposed gene name specifying whether the protein is found within solubilized VE material (VERL, VEZP2 to VEZP9) or not (ZPA), and bootstrap support based on 100 bootstrap replicates is shown for nodes with ≥50% support. Protein domains previously characterized for VERL (48) or computationally predicted via SMART (www.embl-heidelberg.de) for recently identified ZP genes are shown, including signal peptides (SP), internal repeats, and ZP, as well as transmembrane domains (TMD).