earticle

영어

Ability to write and synthesize DNA is fundamentally changing the way of research and approach in biotechnology research. However purposeful modification of metabolic pathways, metabolic engineering, is still limited by tuned expression of genes. In this presentation, we will review basic needs of expression systems in the era of synthetic biology and report our work on autoinduction expression systems. Firstly, we developed autoinduction system by using acs promoter. Acetyl-CoA synthetase(Acs) is responsible for the consumption of acetate accumulated during growth phase. Repressed in the presence of glucose and highly expressed at the stationary phase or at the limited growth phase, it suits many aspects of the ideal
expression system in synthetic biology applications. pACE plasmid vectors derived from a pUC containing acs promoter was constructed and tested for the expression of LacZ and GFPuv as reporter proteins. Expression of the reporter proteins was tightly controlled with the carbon source: When glucose was used as a sole carbon source, the expression of LacZ was completely repressed during exponential growth phase and induced only at the stationary phase. When glycerol or organic acids were used, the LacZ was constitutively expressed. The uniform expression of GFPuv in each cell at the stationary phase was confirmed by flow cytometry analysis. This promoter was further evolved to display diverse expression profiles. This acs-based expression would provide a novel autoinduction system, enriching various expression systems available currently in Escherichia coli. A similar expression system is under
development in Bacillus subtilis, which will be discussed in detail during the presentation. (Supported by SynBio Cluster Program, MOKE, Korea)