Cloning, characterization and expression of estrogen receptor beta in the male half-smooth tongue sole, Cynoglossus semilaevis

摘要

A full-length sequence encoding the estrogen receptor beta was isolated from half-smooth tongue sole, Cynoglossus semilaevis (hstsER beta) using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends procedures. The hstsER beta cDNA clone was found to contain 1,791 nucleotides including an open reading frame that encodes 578 amino acids. The deduced hstsER beta protein consisted of six nuclear receptor-characteristic domains. Based on a phylogenetic analysis, the hstsER beta C and E domains are highly conserved compared to other fishes. The potential phosphorylation sites for PKC, CK-2 and PTK are also found in this protein. Highest amino acid identities were found for hstsER beta with common carp (Cyprinus carpio) ER beta (76 %) and Japanese flounder (Paralichthys olivaceus) ER beta (76 %). Tissue expression analysis confirmed that the hstsER beta was widely distributed and predominantly expressed in testis, brain and liver. Seasonal changes in the testis, brain and liver expression profiles of hstsER beta were examined by RT-PCR; the present results suggest that level of hstsER beta in brain increased to the highest then decreases with gonadal growth; whereas in the testis and liver, the hstsER beta mRNA level dropped to lowest then slightly increased.