Research Of High Expression Of Recombinant Human Morphogenetic Protein-4 In Escherichia Coli

Objective To obtain recombinant human bone morphogenetic protein-4 (rhBMP-4) in E.coli for application in scientific and pharmaceutical research.Methods Firstly, to get rhBMP-4 DNA sequence with lower GC content and codons preference by PCR amplication of using five pairs of modified primers without any change in amino acid. Secondly, the rhBMP-4 DNA was cloned into pET-3c vector and the reconstructed vector pET-3c/rhBMP-4 transformed into host strain BL21(DE) plysS,. The engineering recombinant Ecoli was named as GSH and induced by 1.0 mmol/L IPTG . Thirdly , GSH growth-condition was optimized and rhBMP-4 expressed level was improved . Then , inclusion body of recombinant protein were collected , purificated and renaturated . Finally,the biological activity of renaturated protein were checked by reversed phase HPLC C₈ column, western blotting, C2C12 differentiation in vitro and mouse ectopic bone formation in vivo.Results rhBMP-4 could be expressed up to 39.6% of the total bacterial protein in engineering GSH line. But mostly recombinant protein was inactive inclusion body. After renaturation, the rhBMP-4 shows good bioactivities in vitro and in vivo test.Conclusion rhBMP-4 was expressed in E.coli expression system successfully. The strategy of codon modified in DNA level could be as an universal method to achieve heterologous gene high expression in E.coli.