Molecular characterization and expression pattern of inhibin α and ßb in Chinese tongue sole (Cynoglossus semilaevis).

Inhibin plays important roles in vertebrate reproduction and development. In this study, we have cloned two genes encoding inhibin subunits, inhα and ihnßb, in Chinese tongue sole. inhα consists of 1032 bp, encoding a 343 amino-acid protein. inhßb is composed of 1275 bp, encoding a 424 amino-acid protein. Phylogenetic tree analysis indicated that INHα and INHßB were independently evolved. qPCR showed that inhα expression of in male testis was higher than that in ovary and pseudomale testis, while the expression of inhßb in ovary was higher than that in male and pseudomale testis. During gonadal developmental stages, inhα expression reached highest at 120 days post hatching (dph) both in ovary and testis, then showed decline in ovary but it was first decreased and then increased in the testis. Similarly, inhßb expression in ovary was low at 50-80 dph. At 120 dph, its expression was significantly increased to the peak level, and then gradually decreased. inhßb expression in testis maintained at a low level. During the embryonic developmental stages, inhα displayed the highest expression at 32-cell stage, whereas inhßb reached the highest expression at blastula stages. In situ hybridization data showed that both of inhα and inhßb were detected in oocytes of all stages. In male testis, inhα and inhßb was localized in spermatogonia, spermatocytes, spermatozoa, sertoli and leydig cells. In pseudomale testis, inhα showed the similar pattern in male testis, while the inhßb was detected in spermatocytes and spermatozoa. These data suggested that inhα may participate the spermatogenesis and oogenesis of Chinese tongue sole, while inhßb might predominantly function in oogenesis.