earticle

영어

Human cytotoxic T lymphocyte-associated antigen4-immunoglobulin (hCTLA4Ig), an immunosuppressive agent, was expressed in transgenic rice cells using RAmy3D promoter and RAmy1A signal peptide for the inducible production and secretion in to culture media by sugar depletion. When producing proteins by using transgenic plant cells, the biggest problem is low productivity. Since our system inducibly produces target proteins after the starvation of sugar, the production is possible only when there is no energy source. For this reason, the viability of the cells is reduced after induction.
Therefore, this possibility of improving productivity by adding alternative energy source was investigated in this study. To improve the productivity of hCTLA4Ig, pyruvic acid and sodium pyruvate were added in transgenic rice cell cultures. When 87 and 174 mM pyruvic acid were added during the production phase, the viability of cells has been similar to that of control.
However no hCTLA4Ig was produced. It has been shown that pyruvic acid was not an effective energy source in this system. Both concentrations (87 , 174 mM) of sodium pyruvate were also added to determine the optimal level.
When 87 mM sodium pyruvate was added in suger-free media, the rate of cell death become lower and the production of hCTLA4Ig was increased. When sodium pyruvate were not added, viability was almost zero at day 6.
However, by adding sodium pyruvate, 18% of viability could be kept until the tenth day. In addition, the production of hCTLA4Ig could be enhanced.