Expression of Protein Complex Comprising the Human Prorenin and (Pro)Renin Receptor in Silkworm Larvae Using Bombyx mori Nucleopolyhedrovirus (BmNPV) Bacmids for Improving Biological Function

Abstract

Three forms of recombinant protein complexes comprising the human prorenin (hPro) and (pro)renin receptor (hPRR) (hPRR/prorenin) were successfully expressed in the silkworm larvae using Bombyx mori nucleopolyhedrovirus (BmNPV) bacmids. They were localized in the fat body cells and formed a prorenin-bound hPRR complex. The expressed levels of hPro and hPRR were similar judging from Western blotting. The hPRR/prorenin complex containing 40 mug of hPRR (yield, 43%) and 30 mug of hPro (yield, 34%) was purified from 15 silkworm larvae by a series of purification using anti-FLAG and Strep-Tactin affinity chromatography. The renin activity of the purified hPRR/prorenin complex was 3.8-fold that of the mixture of hPRR and hPro expressed individually in vitro judging from the renin assay. These results show that the unstable transmembrane protein, hPRR, was coexpressed stably with ligand, hPro, and formed a stable protein, hPRR/prorenin complex that showed a high catalytic active form.