Spinyhead Croaker Germ Cells Gene Visualizes Primordial Germ Cells in Medaka.

Spinyhead croaker () is an economically important fish suffering from population decline caused by overfishing and habitat destruction. Researches on the development of primordial germ cell (PGC) and reproduction biology were an emergency for the long-term conservation of the involved species. () gene plays an indispensable role in PGC specification, maintenance, and development. In the current study, we report the cloning and expression patterns of in (). RT-PCR analysis revealed that was specifically expressed in both sexual gonads. In the ovary, RNA was uniformly distributed in the oocytes and abundant in oogonia, and gradually decreased with oogenesis. A similar expression pattern was also detected in testis. Dual fluorescent in situ hybridization of and demonstrated that they almost had the same distribution except in oocytes at stage I, in which the RNA aggregated into some particles. Furthermore, 3' UTR was sufficient to guide the Green Fluorescent Protein (GFP) specifically and stably expressed in the PGCs of medaka. These findings offer insight into that is an evolutionarily conserved germline-specific gene and even a potential candidate for PGC manipulation in .