Cloning of Procine Interleukin-18 Mature Gene and Its Expression in Different Prokaryotic Expression Vectors

Porcine interleukin-18 mature protein gene was amplified from porcine spleen cells by RT-PCR.PCR product was cloned into the T vector pGEM-T for sequencing.The result showed that the nucleotide sequence of this gene was 474 bp,which encodes 157 amino acids.It was subcloned into the prokaryotic expressing plasmid vectors pQE30,pET-28a,pGEX6P-1,and transformed into host E.coli strain JM109 or BL21 for expression.The expression of pIL-18 mature protein gene was identified by SDS-PAGE.The result revealed that the expression products were fusion protein with relative molecular mass of 19 000,21 000,45 000,respectively,and the percentage of expression protein in E.coil protein was 17%,28%,27% respectively.