Dsup
From Wikipedia, the free encyclopedia
Dsup (contraction of damage suppressor) is a DNA-associating protein, unique to the tardigrade,[1] that suppresses the occurrence of DNA breaks by radiation.[2][3][4][5] When human HEK293 cells were engineered with Dsup proteins, they showed approximately 40% more tolerance against X-ray radiation.[5]
Damage suppressor protein | |||||||
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Identifiers | |||||||
Organism | Ramazzottius varieornatus (tardigrade) | ||||||
Symbol | Dsup | ||||||
UniProt | P0DOW4 | ||||||
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Tardigrades can withstand 1,000 times more radiation than other animals,[6] median lethal doses of 5,000 Gy (of gamma rays) and 6,200 Gy (of heavy ions) in hydrated animals (5 to 10 Gy could be fatal to a human).[6] The only explanation found in earlier experiments for this ability was that their lowered water state provides fewer reactants for ionizing radiation.[6] However, subsequent research found that tardigrades, when hydrated, still remain highly resistant to shortwave UV radiation in comparison to other animals, and that one factor for this is their ability to efficiently repair damage to their DNA resulting from that exposure.[7] A landmark study on Dsup protein showed that it can bind nucleosomes in the cell and protect DNA.[8]
The Dsup protein has been tested on other animal cells. Using a culture of human cells that express the Dsup protein, it was found that after X-ray exposure the cells had fewer DNA breaks than control cells.[3]
After hydrogen peroxide treatment Dsup+ cells mainly activate the detoxification systems and the antioxidant enzymes that limit oxidative stress and eliminate oxidative free radicals, while DNA repair mechanisms are only marginally activated.[9] Thus, upon induction of oxidative stress Dsup protein appears to mainly protect DNA directly.[9]
Dsup protein has been found to be neurotoxic and promote neurodegeneration when expressed in cultured neurons by increasing DNA damage through the formation of double strand breaks.[10]