Biotech Updates

Uniform Accumulation of Recombinant Miraculin in GE tomato Using E8 promoter

March 4, 2011

Miraculin is a taste-modifying protein present in miracle fruit plant, a tropical shrub. It has a unique ability to turn sour into sweet taste, thus it is a potential sweetener for diabetics. Scientist Tadayoshi Hirai of the University of Tsukuba, Japan, used E8 promoter, a tomato fruit-ripening specific promoter, and the CaMV 35S promoter, a constitutive promoter to express the miraculin gene in tomato. Tadayoshi and colleagues compared the accumulation of miraculin accumulation in genetically engineered (GE) tomatoes expressing the miraculin gene driven by the said promoters.

Results showed that there are high levels of miraculin protein in the GE tomato lines with E8 promoter only during red fruit stage. Miraculin protein levels were almost uniform in all fruit tissues. On the other hand, when 35S promoter was used, there was higher miraculin levels in the outer skin of the fruit compared to other tissues. This implies that miraculin accumulation pattern can be controlled by various kinds of promoters. However, during processing of tomatoes, the outer skin is eliminated. Hence, it is better to use E8 promoter to facilitate uniform accumulation of miraculin in GE tomato fruits to be used for processed tomato products.

Transgenic Research Journal subscribers may read the complete research article at