Alternative Carbon Sources for Enhanced Production of Acid α-glucosidase under Sugar Starvation in Rice Cell Cultures

초록

Pompe disease is known to be caused by the deficiency of the acid α-glucosidase (GAA). GAA could be produced by rice cell culture systems, which have several advantages such as safety as well as proper posttranslational modification. RAmy3D promoter that is hexokinase-dependent and induced by surgar starvation is used to overcome low protein productivity in rice cell cultures. Since sugar starvation induces cell death and proteolysis, alternative carbon sources which are not recognized by hexokinase can be added for the delay of cell death and enhancing target recombinant protein production.In this study, alternative carbon sources such as fructose, mannitol, and sorbitol were added into culture medium under sugar starvation condition. In sugar-free medium, most of the cells died at day 9. When sorbitol was added, cell viability could be maintained for longer time up to 18 days depending on the concentration. Also, GAA production was increased by the delay of cell death. However, fructose and mannitol did not show any significant effects. In addition, sugar uptake analysis showed that rice cells could utilized both sorbitol and fructose.In conclusion, sorbitol is thought to be a potential alternative carbon source under sugar starvation.