Expression and genomic organization of zonadhesin-like genes in three species of fish give insight into the evolutionary history of a mosaic protein

• Published in: BMC Genomics
• Main Authors: Hunt, Peter N D, Wilson, Michael D, Von Schalburg, Kristian R, Davidson, William S, Koop, Ben F
• Format: Article in Journal/Newspaper
• Language: English
• Published: BioMed Central 2005
• Subjects: Canada; Atlantic salmon; Salmo salar
• Online Access: http://hdl.handle.net/1828/5490; http://www.biomedcentral.com/1471-2164/6/165; https://doi.org/10.1186/1471-2164-6-165

BioMed Central Background: The mosaic sperm protein zonadhesin (ZAN) has been characterized in mammals and is implicated in species-specific egg-sperm binding interactions. The genomic structure and testes-specific expression of zonadhesin is known for many mammalian species. All zonadhesin genes characterized to date consist of meprin A5 antigen receptor tyrosine phosphatase mu (MAM) domains, mucin tandem repeats, and von Willebrand (VWD) adhesion domains. Here we investigate the genomic structure and expression of zonadhesin-like genes in three species of fish. Results: The cDNA and corresponding genomic locus of a zonadhesin-like gene (zlg) in Atlantic salmon (Salmo salar) were sequenced. Zlg is similar in adhesion domain content to mammalian zonadhesin; however, the domain order is altered. Analysis of puffer fish (Takifugu rubripes) and zebrafish (Danio rerio) sequence data identified zonadhesin (zan) genes that share the same domain order, content, and a conserved syntenic relationship with mammalian zonadhesin. A zonadhesinlike gene in D. rerio was also identified. Unlike mammalian zonadhesin, D. rerio zan and S. salar zlg were expressed in the gut and not in the testes. Conclusion: We characterized likely orthologs of zonadhesin in both T. rubripes and D. rerio and uncovered zonadhesin-like genes in S. salar and D. rerio. Each of these genes contains MAM, mucin, and VWD domains. While these domains are associated with several proteins that show prominent gut expression, their combination is unique to zonadhesin and zonadhesin-like genes in vertebrates. The expression patterns of fish zonadhesin and zonadhesin-like genes suggest that the reproductive role of zonadhesin evolved later in the mammalian lineage. This research was supported by the Natural Sciences and Engineering Research Council of Canada (BFK), the Canadian Institutes of Health Research (BFK), and the University of Victoria/ Michael Smith Foundation for Health Research (PNDH, MDW). Faculty Reviewed