Abstract
Two different types of glutamate synthase, Fd- and NADH-GOGAT, are present in the cyanobacteria Plectonema boryanum. Our previous study suggested that cellular control of Fd-GOGAT level is important for regulation of nitrogen assimilation capacity, under high photosynthesis condition. Here, we examined the promoter activity of the Fd-GOGAT gene by reporter assay. Plasmids with Vibrio harveyi luciferase gene fused with different lengths of 5'-region of Fd-GOGAT gene (2kbp, 500bp, 130bp) were introduced into P. boryanum cells and changes of luciferase activity in response to various external environments (light intensity, carbon and nitrogen sources) were monitored. This reporter assay demonstrated that the balancing between carbon and nitrogen assimilation is an important factor for regulating of Fd-GOGAT gene. This response was significantly affected by the length of promoter region and so determination of cis element is a current aim of further analysis.
