Characterization of DNA damage suppression from the tardigrade ( Ramazzottius varieornatus ) gene Dsup in E. coli through ultraviolet radiation and hydrogen peroxide exposure

Tardigrades (genus Ramazzottius) , also known as water bears, are microscopic aquatic multicellular organisms that can be found in just about any environment. The creatures are known to be extremotolerant, which is an oddity since most extremotolerant organisms are single‐celled bacteria or archaea. With well over 1000 different species, these stoic creatures can withstand dehydration, freezing, high pressures, and even the vacuum of outer space (Hashimoto 2017). Interestingly, while most mammals would find roughly 5–10 grays of ionizing radiation fatal, and some prokaryotes such as E. coli could survive roughly 50 grays, tardigrades can survive up to 5,000 grays of radiation. What allows tardigrades to survive radiation that would be fatal to most other organisms? In this research, we have chosen to focus on the Ramazzottius varieornatus Damage suppressor gene (Dsup). The gene produces proteins that contribute to an organism's tolerance to harsh environmental stresses by suppressing both single strand and double strand breaks in DNA and therefore improving overall radiotolerance (Hashimoto 2017). What makes the gene even more intriguing, however, is that it has been cultured in human and animal cells and found to improve radiotolerance and viability of irradiated cells. With the information known, there holds some potential for having this gene produce a practical method for fixing DNA breaks and preventing mutation from ionizing radiation (i.e. UV rays from the sun). To confirm the original findings as seem in Hashimoto et al . (2017) as well as refine them for the context of our laboratory, we transformed E. coli with a plasmid containing Dsup and subjected the resulting transformants to either ultraviolet light or hydrogen peroxide with the goal of challenging the DNA repair machinery as well as the ability of Dsup to prevent DNA breaks. DNA damage was assessed through the comet assay, a single‐cell gel electrophoresis technique for the detection of damage through silver nitrate staining. Overall, E. coli cells with the Dsup plasmid showed significantly lower levels of DNA damage when insulted with ultraviolet radiation. Ongoing research is assessing the effectiveness of Dsup in response to hydrogen peroxide damage. Going forward, we are working towards site‐directed mutagenesis experiments with the goal of better characterizing Dsup's role in suppressing DNA damage. Support or Funding Information Hampden‐Sydney College Office of Undergraduate Research This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .