Poster: Molecular & Cellular Plant-Microbe Interactions: Biotechnology
Displaying foreign proteins and peptides on the surface of Pepino mosaic virus virions
C. LI (1), S. Shi (1), N. Yu (1), Z. Xiong (1) (1) University of Arizona, U.S.A.
Pepino mosaic virus (PepMV), a member of Potexvirus genus, infects tomatoes and causes only mild symptoms under high intensity light conditions. However, its infection is highly productive and yields a large amount of virions in tomatoes. The flexuous PepMV virions (510 nm x ~13 nm in dimensions) are made of 1290 identical copies of a 25 kDa capsid protein (CP) with exposed N-terminus at the virion surface. Therefore, PepMV virions are ideal nanoparticles to display useful antigens and antibodies fused at the N-terminus of the CP. Using a highly infectious cDNA clone as the backbone, we have developed a virus-based expression system that is capable of displaying foreign proteins and peptides on the surface of PepMV virions. Two unique restrictions sites have been engineered immediately downstream the AUG translation initiation codon of PepMV CP to allow convenient and directional cloning of any foreign proteins and peptides into the expression vector. Several 2A self-cleavage peptides from picornaviruses have also been inserted between the restriction sites and PepMV CP to modulate variable ratios of CP fusion proteins and mature CP. m7G-capped in vitro transcripts synthesized from the vectors are highly infectious, yielding high level expressions of foreign proteins and peptides in inoculated plants. The PepMV-based protein display system is expected to have a wide range of applications in pharmaceuticals and diagnosis.