This gene appears to have resulted from a fusion of DNA sequences derived from 2 distinct loci, specifically through the duplication of two internal exons from the POM121 gene and four 3' exons from the ZP3 gene. The 5' end of this gene is similar to the 5` coding region of the POM121 gene which encodes an integral nuclear pore membrane protein. However, the protein encoded by this gene lacks the nuclear pore localization motif. The 3' end of this gene is similar to the last 4 exons of the zona pellucida glycoprotein 3 (ZP3) gene and the encoded protein retains one zona pellucida domain. Multiple protein isoforms are encoded by transcript variants of this gene.