Construction of expression vector of growth hormone cDNA from Hypophthalmichthys molitrix and its expression in Escherichia coli

Total RNA was isolated from silver carp ( Hypophthalmichthys molitrix ) pituitaries. The cDNA fragment of 1. 2 kb encoding growth hormone ( GH) was amplified by reverse transcription polymerase chain reaction (RT- PCR) using total RNA as template. The amplified cDNA was inserted at the EcoRI site in vector pBluescipt KSII + and resulted in plasmid pBS - scGHcDNA. GH cDNA fragment of 1 kb w ithout signal peptide sequence was amplified using pBS - scGHcDNA as template and introduced to expression vector pRSET5b, generating scGH expression plasmid pRSET5b - scGH. The bacteria BL21 ( DE3) plys were transfected with pRSET5b- scGH. The expression of scGH peptide of 22kD in the transfected BL21( DE3) plys was detected by PAGE. Western blotting demonstrated that the recombinant scGH could specially react with monoclonal antibody to grass carp ( Ctenopharyngodon idellus ) GH.