Annual killifish: an approach to the choriogenins of Austrolebias charrua egg envelope

Annual killifish are freshwater teleosts that have a short lifespan and inhabit shallow temporal ponds in regions of the Americas and Africa. During the dry season, adults die while embryos survive by being buried in the bottom mud and hatching during the next rainy season. Juveniles reach sexual maturity within few weeks. Hence, species survival is entirely embryo-dependent, and killifish exhibit a set of unique developmental features. Epiboly is temporarily and spatially detached from axis formation (dispersion-reaggregation phase) and embryos undergo reversible arrests or diapauses. Furthermore, the egg envelope is a notably strong structure and protects the embryos during the long development that they undergo. The present study reports the identification and characterization of two egg envelope proteins and the involved genes, achzpL and achzpH, both expressed in the liver under hormone regulation. This study’s results help to elucidate the function of the embryo egg envelope. Moreover, the oestrogen-regulated liver expression of these genes allows us to suggest components of the annual killifish egg envelope as possible biomarkers to monitor water contamination.