The Sebastes schlegelii is distributed along the coast of Japan, Korea and China. It is well established that rock fish Sebastes schegelii is dominant for coastal fisheries andwith comparison to other fishes it is likely because of its fast growth and large size hence the cage culture of black rockfish (Sebastes schlegeli) have been set out and gotten into fruitful aquaculture industry since 1990. Now cage farming has become major part of marine fish farming culture. The black rock fish is a viviparous which belongs to family scorpaenidae. The sex determination in mammals is relatively stable and the sex determination and differentiation in fishes vary greatly among species. The mechanisms responsible for the variability are still not clear. Thus sex determination research in fish will provide important insight into the plasticity of the sex determination process in vertebrates besides it is the important role of thyroid hormone receptors in fishes needed not to be ignored but meager information is known about thyroid hormone receptors for growth and developmental impact. In the present work we focused the FTZ-F1 and the cloning of TRα and TRβ in the mature black rockfish from testis and ovary respectively. We also characterize the investigation of their expression pattems in the various tissues of immature and mature fish as well as in fry and juveniles in order to understand the function of these genes. The detailed output of classical genes in black rock fish are being described below. FTZ-F1 is a transcriptional factor regulating the expression of the fushi tarazu gene that belongs to a member of the orphan nuclear receptors. The sex related gene of FTZ-F1 was isolated from testis tissue of black rockfish Sebastes schlegeli by homology cloning. The full-length sequence of S. schlegeli FTZ-FI (ssFTZ-F1) contains a 232 bp 5'UTR, 1449 bp ORF encoding 482 amino acids with an estimated molecular weight of 5.4 KD and a 105 bp 3'UTR Sequence, tissue distribution and phylogenic analysis of the FTZ-F1 showed that the ssFTZ-F1 belonged to FTZ group, with highly conserved regions of Ⅰ,Ⅱ, Ⅲ FTZ-F1 box and AF-2 hexamer. Relatively high expressions were observed at different larva stages detected. In 105 days old juveniles, ssFTZ-F1 expressed in all tissues with high levels in testis, ovary, spleen and brain, while lower levels in other tissues. In mature fish, high expression was observed in testis, ovary, spleen and brain. Trace expression was seen in liver and absolutely no expression was detected all other tissues. The highest expression was always observed in gonads in both the juvenile and the mature fish. Male tissues showed higher expression than their female counterpart (p＜0.05). Thyroid hormones triiodothyronine (T3) and thyroxine (T4) play a vital role for developmental and physiological functions in vertebrates. They are mediated via thyroid hormone receptors (TR). In the present paper we describe the cloning and characterization of two TR genes, thyroid hormone receptor alpha (TRα) and thyroid hormone receptorβ beta (TRβ) from ovary mRNA of a ovoviviparous fish Sebastes schlegelii. Results revealed that main domains and motifs of the two genes were highly conserved. Quantitative real time PCR showed that the mRNA expression levels of both Trαand TRβ were high at 5 dps and slightly lower and constant during 10, 20 and 33 dps. In 105 days old juveniles and three years mature fish, the expression level was higher in gonads, brain, liver and kidney than in other tissues. The highest expression was observed in the gonads. The developmental and tissue expression patterns indicated their involvement in the growth and gonadal development. TRα exhibited higher expression than Trβat all developmental stages and in all detected tissues except female liver, which might indicate the functional differences of these two genes. 展开▼
