title: In planta expression of HIV-1 p24 protein using an RNA plant virus-based expression vector.
abstract: Plant viruses show significant potential as expression vectors for the production of foreign proteins (e.g., antigens) in plants. The HIV-1 p24 nucleocapsid protein is an important early marker of HIV infection and has been used as an antigen in the development of HIV vaccines. Toward developing a plant-based expression system for the production of p24, we have investigated the use of a (positive)-strand RNA plant virus, tomato bushy stunt virus (TBSV), as an expression vector. The HIV p24 open reading frame (ORF) was introduced into a cloned cDNA copy of the TBSV genome as an in-frame fusion with a 5'-terminal portion of the TBSV coat protein ORF. In vitro-generated RNA transcripts corresponding to the engineered virus vector were infectious when inoculated into plant protoplasts; Northern and Western blot analyses verified the accumulation of a predicted p24-encoding viral subgenomic mRNA and the production of p24 fusion product. Whole-plant infections with the viral vector led to the accumulation of p24 fusion protein in inoculated leaves, which cross-reacted with p24-specific antibodies, thus confirming the maintenance of key antigenic determinants. This study is the first to demonstrate that TBSV can be engineered to express a complete foreign protein of clinical importance. Strategies for optimizing protein yield from this viral vector are discussed.
authors.affiliation: Department of Biology, York University, Toronto, Ontario, Canada.
authors.forename: G
authors.initials: G
authors.lastname: Zhang
authors.forename: C
authors.initials: C
authors.lastname: Leung
authors.forename: L
authors.initials: L
authors.lastname: Murdin
authors.forename: B
authors.initials: B
authors.lastname: Rovinski
authors.forename: K A
authors.initials: KA
authors.lastname: White
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004279:DNA, Viral; D005822:Genetic Vectors; D016655:HIV Core Protein p24 / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics*; D008969:Molecular Sequence Data; D017864:Tombusvirus / Q000235:genetics*
chemical_list: D004279:DNA, Viral; D016655:HIV Core Protein p24