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Team:NRP-UEA-Norwich/Quanticare
From 2012.igem.org
As part of our human practices we have produced a film in conjunction with our artist [http://www.amycongdon.com/#!mainPage Amy Congdon] which explores a futuristic world where synthetic biology is an aspect of everyday life. As we explored the idea of synthetic biology in the future we developed the idea of "Quanticare", a company created on the back of synthetic biology's rise to prominence. As the project within the labs continued and the idea of the Comparator Circuit and the Flexible Bacterial/Mammalian Hybrid Promoter came about we looked at how this new idea of cellular computing could be used within the Quanticare concept, leading to the idea of the living tattoo, Cura.
We wanted to produce something that would spark the imagination of the wider public and truly show the future power and potential of synthetic biology, and we believe that Cura and Quanticare have achieved those aims. With Cura we have developed an original idea of a tattoo not drawn with ink, but instead drawn with immortalised mammalian cells containing different BioBricks. The concept involves each shape of the tattoo containing cells with specific BioBricks that sense a particular chemical within the body, and report on any particular changes on that chemical's levels.
The comparator circuit project involves multiple promoters that are sensitive to similar chemicals, a different reporter/effector enzyme for each promoter, and a range of specially designed DNA leaders that go between the promoter and reporter of each gene system. The idea involves the specially designed DNA leaders being complementary to one another and resulting in DNA annealing which covers the ribosome binding site; this means that mRNAs transcribed following activation of the promoters will cancel one another out and fail to be translated. If there is an imbalance of substrates one set of mRNAs would be produced in excess of the others and would not anneal to one another, therefore resulting in translation and expression of the associated protein. This is demonstrated in Figure 1. where two sets of mRNA have been produced, one with an RFP reporter and one with a CFP reporter; due to an imbalance in substrates four lots of the RFP-associated mRNA have been produced, while only two lots of the CFP-associated mRNAs have been produced. As the image shows the two CFP-associated mRNAs have annealed with two of the RFP-associated mRNAs, blocking the RBS and preventing translation, however due to the imbalance there are two RFP-associated mRNAs left to be translated and thus RFP would be expressed in this situation.
Similar comparator circuit set-ups would be used in the Cura tattoo. For instance in the case of Type I Diabetes one promoter would sense blood sugar while another would sense insulin; if the blood sugar outweighed the insulin, more of the mRNA with the blood sugar promoter would be produced and thus an effector enzyme for the production of insulin could be included in this mRNA in order to increase insulin production. If insulin production becomes too high the imbalance would shift so more of the mRNA with the insulin-sensing promoter was produced, and an effector enzyme to break down excess insulin could be translated from this mRNA strand in order to normalise insulin levels. A system such as this, as well as others (which simply report changes through fluorescent proteins), are explored in Figure 2.
