Reduction of Autophagy for the Enhanced Production of hCTLA4Ig in Transgenic Rice Cell Cultures

초록

Transgenic plant cell cultures are an attractive expression system for the production of industrial and pharmaceutical proteins because of their advantages in safety and low production cost. Human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4Ig) was produced and secreted when sugar was depleted in culture medium by transgenic plant cell lines (Oryza sativa L.) using RAmy3D promoter. Therefore, cell death by sugar starvation during production phase is inevitable and the main obstacle to overcome. Autophagy is a degradative process used in eukaryotic cells for the maintenance by degrading long-lived proteins and organelles. Many researchers reported that the activation and inhibition of autophagy by chemical agents such as rapamycin and 3-methyladenine (3-MA) are possible, respectively. In this study, we investigated the effects of rapamycin on cell growth and protein production by transgenic rice cells under autophagy condition due to sugar starvation. In addition, by using an autophagy marker (monodansylcadaverine) and an autophagy inhibitor such as 3-methyladenine (3-MA), occurrence and reduction of autophagy could be confirmed during the sugar-starved production phase. In conclusion, the production of hCTLA4Ig could be enhanced by the additions of 3-MA by inhibiting autophagy in transgenic rice cell cultures.