Expression of biologically active human vascular endothelial growth factor in yeast

Vascular endothelial growth factor (VEGF) is a glycoprotein consisting of two identical polypeptide chains linked by a disulfide bond. The unique biological activities of VEGF include its potent mitogenic and permeability inducing properties specific for the vascular endothelium. VEGF is implicated in tumor angiogenesis, wound healing, and the stimulation of collateral vessel formation at the site of arterial occlusion. Therefore, in order to produce large quantities of biologically active VEGF, a splice variant (VEGF₁₆₅) was cloned and expressed in a yeast expression system. The coding region of VEGF₁₆₅ was isolated from U937 cells by RT-PCR, sequenced and then cloned into the yeast expression vector pHILS1. VEGF₁₆₅ was secreted into the medium as a dimer. Recombinant VEGF reacted to antibodies raised against the N-terminal and C-terminal synthetic polypeptides of human VEGF. As much as 35-40 mg/L of purified VEGF could be obtained from the yeast expression system. The recombinant protein was biologically active in inducing vascular endothelial cell proliferation in vitro and permeability changes in vivo.