Abstract: Gene expression is one of the most essential activities in life, so exerting the accurate artificial regulation on gene expression is an important method to manipulate protein synthesis and physiological activity. The International Genetically Engineered Machine Competition (iGEM) team from Shanghai Jiao Tong University has exploited three types of innovative genetic regulatory devices based on the concept of synthetic biology since the first participation in 2009, including rare codon switch, membrane scaffold and light-controlled CRISPR interference (CRISPRi) system. By inserting an appropriate number of rare codon right after the start codon of target genes, the precise regulation of gene expression can be achieved so as to manipulate the reaction of a multi-enzyme system in its optimal stoichiometric ratio. Membrane scaffold can anchor target proteins on the cell inner membrane, which shortens the space distance between different proteins, and accelerates the enzymatic reaction rate, while light-controlled CRISPRi system has innovatively combined biological light sensor and emerging CRISPRi technique to achieve the precise regulation of endogenous genes expression on transcriptional level through light signal. These new technologies have favorable applications in improving the fatty acid synthesis and secretion efficiency in Escherichia coli.

Key words: gene expression regulation, fatty acid, rare codon, membrane scaffold, CRISPR interference (CRISPRi)