Cloning and optimized expression of human angiogenin in E-coli

Angiogenin(ANG) is an important factor of angiogenesis during different stage of tumor development and exists widely in various tumors. To study the biological function and find the antagonistic drugs of angiogenin, the angiogenin was allowed to be expressed by E. coli. By the aid of computer, the sequence around the start codon of angiogenin gene was modified according to local secondary structure. The modified human ang gene was amplified by reverse-transcription polymerase chain reaction from the human lung cancer cell line A549. and inserted into the prokaryotic expression vector pLDH99. After screening, high expression recombinants were obtained, and the expression level of the hANG was about 30% of total bacteria protein by SDS-PAGE. Biological assays indicated that the rhANG could induce new blood vessel formation in CAM in vitro. Our data showed that the recombinant hANG was active and the optimized expression of ang gene was practicable.