MOLECULAR-CLONING, STRUCTURAL-ANALYSIS, AND EXPRESSION OF CARP ZP2 GENE

The cDNAs encoding carp ZP2 homologous to winter flounder and mammalia n ZP2 were cloned. Carp ZP2 contains a tandemly repetitive domain and a nonrepetitive domain. A repeat is composed of 13 amino-acid residues whose consensus sequence is QQTSQQFQPQKPA/V. The length of the repeti tive domain is highly variable, but that of the nonrepetitive domain i s fairly constant among various cDNAs. The termination codons of vario us cDNAs appear at three different positions. Three groups of cDNAs we re therefore categorized. Groups I-III encode a nonrepetitive domain o f 356, 255, and 10 residues, respectively. A carp ZP2 gene correspondi ng to group II cDNA was cloned. It spans 2.4 kb and consists of eight exons and seven introns. Carp ZP2 mRNA was detected only in oocytes bu t not in other tissues. Carp ZP2 is heterogenous in size. The molecula r weight ranges from 40-80 kDa. It is present in vitellogenic but not in previtellogenic oocytes, nor in other tissues. Carp ZP2 content in oocytes increases as vitellogenesis proceeds. (C) 1997 Wiley-Liss, Inc .