Abstract

Tardigrades are widely recognized for their remarkable survival abilities in the face of extreme conditions. The damage suppressor protein (Dsup) is a unique protein in tardigrades presumed responsible for the unusual resistance of tardigrades to various stressors. Dsup has been shown to decrease lethality and improve proliferation of human cells after exposure to ionizing radiation (IR). Recently, it has been shown that it is able to do this by creating a physical barrier surrounding the DNA, which then protects it from IR-related damage. Thus, Dsup may have a role in certain tardigrades’ ability to survive IR, oxidative damage, and UV-C. However, the Dsup protein is not well-conserved even among tardigrades, and previous studies suggest that only the Dsup protein from Ramazzottius varieornatus (Rv) is able to protect the DNA of bacteria from IR, while the Dsup from Hypsibius exemplaris (He) is not. Given this uncertainty, we set out to examine whether both Rv Dsup and He Dsup can protect the DNA of human cells from IR-related damage. We set out to create expression vectors to express both versions of tardigrade Dsup in human cells. We successfully created a human expression vector containing He Dsup, but encountered technical difficulties obtaining the Rv Dsup expression vector. Once we are able to successfully clone Rv Dsup into a vector for human cell expression, we can move forward with expression in human embryonic kidney cells. These cells will then be exposed to the radiomimetic drug bleomycin to assess the effectiveness of both proteins in protecting human cells against IR-related DNA damage. This research will establish if the divergence in the sequence of the Dsup protein truly results in a divergence in the ability to protect human cells from IR-related DNA damage and provide us with interesting insights into the extreme stress tolerance of tardigrades.

Keywords

tardigrade, biology, Dsup, ionizing radiation

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