The Cardiff iGEM team of 2017 aimed to produce a high level of gene expression from four promoter constructs in the Nicotiana benthamiana expression system. These constructs were put together using golden gate ligation. Our promoters respond to several different stimuli, are native to Arabidopsis thaliana, and have been characterized previously. We aimed to both quantify their expression levels using luciferase transcriptional units, and use them to create a thyroid stimulating hormone (and thyroid stimulating immunoglobulin) antagonist that could be used to treat Graves' disease. Consequently, we have added several parts to the phytobrick registry. Our antagonist, called TSHantag, has not been previously used as a therapeutic agent, and could be tested in vitro if purified. More details about the project can be found on our project description page.

We also developed a model that is designed to be flexible so that it can be used as a tool for other future iGEM teams or even companies. This was designed so that it can estimate how many plants are needed to create a single dose of any plant-produced therapeutic with a given severity, depending on what plant expression system is used. For our project, we used this to estimate how many plants are required to get a single effective dose of our TSH antagonist. We demonstrated the flexibility by changing one variable extensively, so that it shows different expression vectors and systems. Then, we integrated our research section of our human practices with the model, and estimated how many plants would be required using each expression platform to give a single effective dose to every sufferer of Graves' disease in the US, assuming a mean severity of the disease.

We have expertise using the tobacco expression system and so welcomed collaborations with iGEM teams who wish to test the function of their proteins in plants!