This is a toolkit where Synthetic biology can make a difference. We are inspired by the undergraduate finalist project ”Noise” and their excellent work.
Lactose intolerance
At the beginning, we learned from previous projects and realized that, when dealing with real-world problems, issues like gene regulation, expression efficiency and system robustness all matter. When creating a great functional prototype, one should pay attention to all the details. And some of the new comers to synthetic biology may find it difficult to deal with these matters. So we thought: why not provide some gene expression toolkits to iGEMers so that they may no longer need to worry about building circuits, but focus on the key problem.
We came up with different versions of gene expression circuits: bacteriophage lambda, kinases reaction pathway, ribo-switch, RNAi and so on. We made efforts on the circuit construction and valid characterization data so users can mainly focus on the input and output which are highly concerned with real-world problems. In this manner, our toolkit can serve as a useful tool to save their time and energy. On the whole, our theme is to offer bricks to help others build their own project.
And this summer we made a little step to our goals. We worked out two versions of gene expression switch----a prokaryote tri-stable version derived from bacteriophage lambda and eukaryote bi-stable version based on ABA-response pathway.
In the tri-stable gene expression switch, users should define two input and related output gene signals. The logic gate below can illustrate the circuit better:
The circuit can rapidly reach its stable state because of the positive feedback design. And users can also adjust its threshold to satisfy different requirements.
And for more application:
We provide a solution to lactose intolerance based on this toolkit.
The input of signals are achieved by two promoters: plac(lactose inducible) and patp2(base inducible). As for the output, we set the gene of interest 1 as iLDH and gene of interest 2 beta-galactosidase. iLDH can transform lactic acid into pyruvate while β-galactosidase can degrade lactose. In this way, the system can provide a promising way for the treatment of lactose intorlance.
In our bi-stable switch, users can define an ON signal and OFF signal to control the expression of the target gene. The most attractive feature of the circuit is switch efficiency, whose mechanism is cascade reaction.
