This invention is a control element for a genetic circuit which allows regulation with tradeoffs and the calculation of the ratio of two input signals.
Synthetic biology relies on regulation of gene expression which is difficult for complex functions. This invention is a control element for genetic circuits for predictable programming of biology.
This technology is based on T7 RNA polymerase which initiates transcription with high specificity allowing for orthogonal regulation. This polymerase, which is transferable between cell types, has a conserved core and a variable promoter recognition region which controls specificity. This invention is a recombinant T7 RNA polymerase consisting of two separately expressed protein fragments, which were created by bisecting the protein at a library of random sites to identify locations where function is retained. The inventors have created a system of one conserved fragment, and up to four variable ones, in which the variable proteins can bind the conserved protein and make it functionally target a promoter DNA sequence and initiate transcription. Therefore, this invention may be used to implement a type of trade-off logic where expression of one pathway decreases as another increases, or as a ratio calculator that allows the measurement of the ratio between two input signals and returns a single protein expression level as a result.
Conserved protein amount sets the maximum
transcriptional output from the system
Variable proteins allocate transcriptional potential
polymerases are widely used; invention can be used with many existing systems and