title: Expression of the human hepatitis B virus large surface antigen gene in transgenic tomato plants.
abstract: The original hepatitis B virus (HBV) large surface antigen gene was synthesized. In order to optimize the expression of this gene in tomato plants, the tobacco pathogenesis-related protein S signal peptide was fused to the 5' end of the modified gene and the sequence encoding amino acids S, E, K, D, E, and L was placed at the 3' end. The gene encoding the modified HBV large surface antigen under the control of a fruit-specific promoter was constructed and expressed in transgenic tomato plants. The expression of the antigen from transgenic plants was confirmed by PCR and reverse transcriptase PCR. Enzyme-linked immunoassays using a monoclonal antibody directed against human serum-derived HBsAg revealed that the maximal level of HBsAg was about 0.02% of the soluble protein in transgenic tomato fruit. The amount of HBsAg in mature fruits was found to be 65- to 171-fold larger than in small or medium fruits and leaf tissues. Examination of transgenic plant samples by transmission electron microscopy proved that HBsAg had been expressed and had accumulated. The HBsAg protein was capable of assembling into capsomers and virus-like particles. To our knowledge, this is the first time the HBV large surface antigen has been expressed in plants. This work suggests the possibility of producing a new alternative vaccine for human HBV.
authors.affiliation: Shanghai Key Laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Center, Shanghai Academy of Agricultural Sciences, 2901 Beidi Rd., Shanghai 201106, P. R. China.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Lou
authors.forename: Quan-Hong
authors.initials: QH
authors.lastname: Yao
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhang
authors.forename: Ri-He
authors.initials: RH
authors.lastname: Peng
authors.forename: Ai-Sheng
authors.initials: AS
authors.lastname: Xiong
authors.forename: Hua-Kun
authors.initials: HK
authors.lastname: Wang
mesh_terms: D000284:Administration, Oral; D000595:Amino Acid Sequence; D001483:Base Sequence; D050939:Gene Fusion / Q000276:immunology; D006514:Hepatitis B Surface Antigens / Q000235:genetics / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D006515:Hepatitis B virus / Q000235:genetics / Q000276:immunology*; D006801:Humans; D018551:Solanum lycopersicum / Q000235:genetics* / Q000276:immunology / Q000821:virology*; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified
chemical_list: D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines