Expression and genomic organization of zonadhesin-like genes in three species of fish give insight into the evolutionary history of a mosaic protein
Date
2005-11-22
Authors
Hunt, Peter N D
Wilson, Michael D
Von Schalburg, Kristian R
Davidson, William S
Koop, Ben F
Journal Title
Journal ISSN
Volume Title
Publisher
BioMed Central
Abstract
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.
Description
BioMed Central
Keywords
Citation
Hunt et al. Expression and genomic organization of zonadhesin-like genes in three species of fish give insight into the evolutionary history of a mosaic protein. BMC Genomics 2005, 6 :16