Reduction of 13 kD prolamins increases recombinant protein yield and recovery rate in rice endosperm

RNA silencing inducible sequence (RSIS) causes post-transcriptional gene silencing (PTGS) of 5' or 3' flanking sequence-containing genes by inhibiting proper transcriptional termination. Exploiting this nature, 13 kD Pro-less, in which major seed storage protein (SSP) 13 kD prolamins are reduced, has been generated. In 13 kD Pro-less, other SSPs, such as glutelins, are increased as a compensation effect to maintain amino acid pool. 7Crp is the seven-linked epitope peptide derived from major cedar pollen allergens Cry j 1 and Cry j 2. When 7Crp is expressed in 13 kD Pro-less endosperm, accumulation level of 7Crp increased. Furthermore, recovery rate of 7Crp without reducing reagent increased. These findings indicate that 13 kD Pro-less endosperm provides a good production platform for recombinant proteins.