Team:UCLouvain/OurProject/Overview
Although sunburns seem quite ordinary to get tanned, it’s a real disaster for our skin… Indeed, for several years, our exposure to UV rays has increased and scientists have noticed an upward trend in the risk of developing skin cancers.
Every year in Belgium we count approximately 2.000 new cases of melanoma [1].
Between 2005 and 2015 in Belgium, there has been a 77% increase of new cases of melanoma [2].
According to WHO, there are globally around 2 to 3 million skin cancers each year, and around 132.000 melanoma [3].
One American out of five will develop a skin cancer in his lifetime. We are all affected by this dangerous problem, but some people with specific characteristics are much more concerned.
That’s the reason why we, the 2017 UCLouvain iGEM Team, are participating in the international competition of synthetic biology, iGEM.
Our innovative solution is BactaSun, a bio-badge changing color when exposed to UV rays. Its color gradually switches from white to red. In a nutshell, you are quickly warned when you have to protect your skin.
Actually, we have developed two ways to achieve our goal. Both are using a photocaged amino acid, the ONB-Tyrosine. The cage, the ONB group, is cleaved when exposed to UV rays, which releases the tyrosine amino acid, making it available for protein synthesis (see on the figure below).
Using the iGEM’s biobricks, we have assembled a plasmid containing a gene coding for a RFP. Arabinose activates this gene, thanks to its pBAD promoter.
On the other hand, we knocked out (KO) a gene required for tyrosine synthesis in E. coli, TyrA. A medium containing photocaged tyrosine (ortho-nitrobenzyl tyrosine) is used to grow the bacteria: this special tyrosine is sensitive to UVs, and will be only available for our KO E. coli once uncaged.
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ComS is a small peptide imported into the cytoplasm by the cell. Interacting with ComR, it will form a complex, that acts as a gene activator.
ComS contains some tyrosine. Thanks to a collaboration with Vincent Stroobant of the de Duve Institute, we synthetize ComS using the photocaged tyrosine instead of tyrosine. This new ComS can’t interact with ComR, unless its tyrosine have been uncaged by UVs.
The ComR/ComS complex will simply activate a RFP gene, creating a system responding to UVs as with the first approach.
learn more- [1] CHU de Liège, n.d. Le mélanome [WWW Document]. URL http://www.chu.ulg.ac.be/jcms/c_8187263/le-melanome (accessed 10.24.17).
- [2] Belgian Cancer Registry, n.d. Belgian Cancer Registry — Tableaux sur base annuelle [WWW Document]. URL http://www.kankerregister.org/Statistiques_tableaux%20annuelle (accessed 10.24.17).
- [3] World Health Organization, n.d. WHO | Skin cancers [WWW Document]. WHO. URL http://www.who.int/uv/faq/skincancer/en/ (accessed 10.24.17).
