Efficient production of human zona pellucida-3 in a prokaryotic expression system

The zona pellucida-3 (ZP3) protein plays a pivotal role in oocyte and gamete development. We aimed to produce a recombinant ZP3 peptide using the Escherichia coli secretory system and apply it to a protein chip for detecting anti-ZP3 antibodies. The ZP3 gene was cloned into the pHOA downstream of the phoA promoter and transformed into E. coli YK537. Recombinant ZP3 was secretory expressed by decreasing the inorganic phosphate concentration. Then, rZP3 was purified and coated onto a protein chip, which was used to detect AZP3A in serum samples from 63 infertile patients. The area under the receiver operating characteristic curve was 0.934. The results, in terms of AZP3A detection, of the rZP3-coated protein chip were consistent with those of the ELISA kit. Therefore, our protein chip assay has potential for diagnosis of infertility due to AZP3A, and represents a less costly and simpler assay for clinical and research applications.