Molecular cloning of cDNAs encoding pituitary glycoprotein hormone α, FSH β and LH β subunits in ayu, Plecoglossus altivelis

Abstract

Complementary DNAs (cDNAs) encoding follicle-stimulating hormone (FSH) β, luteinizing hormone (LH) β and glycoprotein hormone (GPH) α subunits were isolated and characterized from ayu pituitary using a PCR technique. The FSH β, LH β and GPH α subunit cDNAs were found to be 556, 588 and 621 base pair (bp) long, encoding 384, 432 and 357bp long open reading frames, respectively. The deduced amino acid sequences of the putative mature forms of ayu GPH α and LH β subunits were on average 63% homologous with those of other teleosts, whereas ayu FSH β subunit was on average 42% homologous. These results show that ayu has two different types of gonadotropins (FSH and LH), as in other teleosts. FSH β subunit mRNA was mainly detected during early vitellogenesis and spermatogenesis. In contrast, LH β subunit mRNA was detected during the late phase of gonadal development, suggesting that the primary function of FSH may be to initiate gametogenesis, while LH may have a role in the development of gametes.