Abstract: Objective To construct the prokaryotic expression vector for mouse chromogranin B gene.Methods Reverse transcriptase-polymerase chain reaction(RT-PCR) was performed on the total RNA extracted from the mouse brain to obtain the cDNA of chromogranin B.The cDNA fragment of CgB was inserted into pMD-T vector.DNA sequencing was performed before the amplified products were cloned into the prokaryotic expression vector pGEX identified by endonuclease digestion.The amplified products were confirmed as the cDNA of chromogranin B by DNA sequencing.The chromogranin B fusion protein expressed in E.coli was identified by Western Blot.Results There was only one obvious band at the position of relative molecular weight 140,and it was equivalent to the expected value.Conclusion The recombinant fusion expression vector pGEX is constructed,and chromogranin B fusion protein gene is expressed in E.coli successfully.

Key words: RT-PCR, chromogranin B, gene expression