Understanding the molecular basis of primordial germ cell migration

Yellowtail Kingfish (order Perciformes) inhabit tropical and temperate waters of the southern hemisphere. They can be successfully cultured in Australia, and therefore, many fundamental details into the molecular basis of larval development can be easily studied. In particular, the precise molecular mechanism of gonad formation is of interest due to the implications in our understanding of gamete development. To date, there is little understanding of the mechanism of primordial germ cell (PGC) migration leading to gonad formation in any perciform fish. In this study, we have isolated three key genes from the Yellowtail Kingfish that could be involved in PGC migration, namely the stromal cell-derived factor (SDF1), chemokine receptor 4 (CXCR4) and chemokine receptor 7 (CXCR7). Gene expression analyses show that they are produced continuously throughout 1-22 days post hatch and each show distinct localisation in the larval stages investigated. Together, these results provide a platform for further studies into the molecular machinery of PGC migration perciform fish, towards the ultimate development of innovative broodstock surrogates for Southern bluefin tuna.