title: An E8 promoter-HSP terminator cassette promotes the high-level accumulation of recombinant protein predominantly in transgenic tomato fruits: a case study of miraculin.
abstract: The E8 promoter-HSP terminator expression cassette is a powerful tool for increasing the accumulation of recombinant protein in a ripening tomato fruit. Strong, tissue-specific transgene expression is a desirable feature in transgenic plants to allow the production of variable recombinant proteins. The expression vector is a key tool to control the expression level and site of transgene and recombinant protein expression in transgenic plants. The combination of the E8 promoter, a fruit-ripening specific promoter, and a heat shock protein (HSP) terminator, derived from heat shock protein 18.2 of Arabidopsis thaliana, produces the strong and fruit-specific accumulation of recombinant miraculin in transgenic tomato. Miraculin gene expression was driven by an E8 promoter and HSP terminator cassette (E8-MIR-HSP) in transgenic tomato plants, and the miraculin concentration was the highest in the ripening fruits, representing 30-630 μg miraculin of the gram fresh weight. The highest level of miraculin concentration among the transgenic tomato plant lines containing the E8-MIR-HSP cassette was approximately four times higher than those observed in a previous study using a constitutive 35S promoter and NOS terminator cassette (Hiwasa-Tanase et al. in Plant Cell Rep 30:113-124, 2011). These results demonstrate that the combination of the E8 promoter and HSP terminator cassette is a useful tool to increase markedly the accumulation of recombinant proteins in a ripening fruit-specific manner.
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki, 305-8572, Japan.
authors.forename: Natsuko
authors.initials: N
authors.lastname: Kurokawa
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Hirai
authors.forename: Mariko
authors.initials: M
authors.lastname: Takayama
authors.forename: Kyoko
authors.initials: K
authors.lastname: Hiwasa-Tanase
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ezura
mesh_terms: D017360:Arabidopsis; D029681:Arabidopsis Proteins / Q000235:genetics; D005638:Fruit / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D006023:Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D006360:Heat-Shock Proteins / Q000235:genetics; D018551:Solanum lycopersicum / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000235:genetics; D013728:Terminator Regions, Genetic
chemical_list: D029681:Arabidopsis Proteins; D006023:Glycoproteins; C446287:HSP18.2 protein, Arabidopsis; D006360:Heat-Shock Proteins; D011994:Recombinant Proteins; C008533:miraculin protein, Synsepalum dulcificum