[Cloning of VEGF receptor KDR and its expression in insect cells]

The cDNA fragment of the first 3 loops of VEGF receptor, KDR, was cloned by PCR and inserted into a baculovirus expression plasmid pFASTBACI. The competent E. coli DH10BAC cell, which contain another plasmid with baculovirus genome in it, was transformed with pFASTBACI-KDRn3. Homologous recombination in the prokaryotic cells resulted in a recombinant plasmid containing KDRn3 in baculovirus genome. Transfection of the insect cell SF-9 with above plasmid generated a recombinant baculorvirus contain target gene fragment. SDS-PAGE and Western blot analysis of the supernatant of the infected SF-9 cell showed that KDRn3 was secreted in the medium. The recombinant protein was verified with Western blot and tested for their binding activity with VEGF. Its anti-angiogenic activity was assayed on chorionic allantoic membrane(CAM) of fertilized egg. The results showed that the recombinant protein could inhibit new vessel formation on CAM of fertilized eggs.