Mathematical model analyzes light-controlled expression of the CHS promoter in BY-2 cells

The beta-glururonidase (GUS) reporter gene was fused to the 2.0-kb upstream region of Arabidopsis thaliana chalcone synthase (CHS) gene and transferre d into BY-2 cells. CHS promoter expression showed a quick response to light /darkness and its expression level was more than that by the Cauliflower Mo saic Virus (CaMV) 35S promoter [1]. In this study, a kinetic model was deve loped for describing light-enhanced expression of the CHS promoter by tobac co BY-2 cells. This model simulates the behavior of CHS promoter expression by two factors: the specific light absorption rate (light intensity) and t he illumination time. The dependency of GUS synthesis on light intensity is well characterized by using the Monod equation. The dependency on the illu mination time is calculated by using a saturation time constant of illumina tion. The mathematical model demonstrated that the conditioned medium or pa st illumination changed the kinetics of CHS promoter expression. (C) 1999 E lsevier Science S.A. All rights reserved.