Tardigrades are only 1 mm in size, but are not to be underestimated. They are distributed all over the world.
Tardigrades are adapted to extreme and strongly changing living conditions. They can survive situations, which are deadly for many other creatures, unharmed. For this the tardigrade falls into a dry rigidity (anabiosis or cryptobiosis). This allows them to survive an approximately 20-month stay in liquid air (-200 °C) or 8 hours in liquid helium (-272 °C) without damage. In this rigidity, the tardigrade can spend up to 100 years. The tardigrade can also survive short-term heating to 100 °C, total oxygen starvation, or pressures up to 6000 bar.
In addition, tardigrades can withstand extreme amounts of ionizing radiation. For radioactive gamma radiation, for example, about 5 Gray corresponds to a lethal dose in half of all exposed people. Experiments have shown that this value is 1000 times higher, about 5000 Gray, in tardigrades. The genetic material of the tardigrade is protected by a protein unique to this species, the "damage suppressor protein" DSUP.
Sequence-based analyses propose that the protein associates with nuclear DNA in a non-specific manner, physically shielding DNA from direct radiation and ROS damage. The protein interacts with DNA via the C-terminus. It is highly likely that charge interactions are of particular importance. (https://doi.org/10.1038/s41598-020-70431-1)
Description of our Project
Tardigrades are interesting organisms, which can be found all over the world. They are able to tolerate environmental fluctuations over a long period of time (for example survive several days without oxygen or defy UV radiation). To achieve these properties, tardigrades possess special proteins. One of them is the damage suppressor protein (Dsup), which protects the DNA of the organism from UV radiation induced damage.
The protein protects the DNA by surrounding it like a shield. Due to these characteristics, the protein was used by different scientists, who successfully showed the transfection into Escherichia coli cells and HEK293 cells. With this modification, the cells were able to survive high radiation doses.
The Stuttgart iGEM-Team wants to use these properties within the Tardisun project. By transfecting the protein into eukaryotic cells, we want to improve the life cell imaging method. This method is widely used to observe the localization of proteins in biological processes. In this case, long exposure to light leads to Phototoxicity, which can be avoided, using Dsup. To observe potential changes, we like to perform the life cell imaging method to verify the benefit.
Within the Tardisun project we would like to express and isolate the Dsup protein in Escherichia coli cells. The purified protein should be dispensed into a liquid. In this context, we want to find out if the absorbance properties are independent of the DNA protection function. The developed liquid could be used to protect other surfaces (e.g. skin or other UV sensible surfaces).
Idea of our Project
Our project aims to protect both materials such as plastic and one of the most important organs of humans, the skin, from the damage caused by UV radiation. Why is this important?
High-energy UV radiation damages our skin cells. This can result in cyclobutene pyrimidine dimers, other damages to the DNA directly and in reactive oxygen species (ROS). In addition, gene expression and the immune system are altered. These mutations of the genetic material and cell changes can lead to cell death or in the worst case to the development of a cancer cell. Hence, UV radiation is carcinogenic and can cause many different types of skin cancer . This needs to be prevented, both during summer vacations and at work. Already in Germany, an estimated 2.5 million workers are exposed to an increased risk of skin cancer due to their outdoor work .
Not only our cells but also all other materials exposed to UV radiation will be attacked and damaged. We want to protect plastic polymers and other substances from the sun’s rays with the help of DSUP in order to slow down the degradation. Thereby we want to extend their service life resulting in fewer required replacements. Doing so, less plastic will be produced, and the environment will be protected better .
 M. Ichihashi et all. (2003) UV-induced skin damage ()
 H. Drexler, P. Elsner & J. Schmitt (2015) UV-irradiation-induced skin cancer as a new occupational disease (https://link.springer.com/article/10.1007/s00105-015-3587-z)
 Baljit Singh, Nisha Sharma (2007) Mechanistic implications of plastic degradation (https://www.sciencedirect.com/science/article/pii/S0141391007003539?casa_token=q4AqBStftXQAAAAA:5qiUeBYJbq7xTAI9fyQjPuUjfi1Hn_0CGvPxVr5W9QQBXrW_zN3OgcpXnhajA3KQ1f1iXTYQKf0)