Tardigrades are small aquatic animals less than 1 mm. It can survive even in extreme conditions such as high temperature of 100 degrees to low temperature environment of minus 273 degrees, vacuum space, ultra-high pressure environment, environment under strong radiation.However, the molecular mechanism that underpins these extreme resistances was unclear.A research group at the University of Tokyo, in collaboration with Keio University, has revealed that a new protein derived from bear beetle can protect against radiation damage that is fatal to the DNA of cultured human cells.
The research group determined the genome sequence of the tardigrade, which can survive even when exposed to radiation about 1000 times the median lethal dose of humans, with high accuracy, and revealed that it has about 2 genes. ..One of these proteins was not found in other organisms and was located near the nuclear DNA in the cells of the tardigrade.Even if this protein was introduced into cultured human cells, it was confirmed that it was present near the DNA. Since DNA is damaged by radiation, he decided to investigate radiation resistance.
When the cultured cells into which this protein was introduced were irradiated with X-rays and the amount of DNA cleavage was examined, the amount of cleavage was reduced to about half that of the cells without introduction.Analysis showed that the protein did not repair the injury, but worked to protect the DNA and minimize the injury.This protein was named Dsup (Damage Suppressor) because of its properties of protecting this DNA and reducing damage.Furthermore, it was found that even when the cells were irradiated with X-rays, the proliferative ability was maintained in the Dsup-introduced cells.
A large number of tardigrade-specific genes have been found in this genome analysis.Based on these genetic information, we hope to elucidate the excellent resistance of tardigrades at the molecular level and to develop new technologies that impart various resistance to other animals in the future.
