Project description:Tardigrades can survive remarkable doses of ionizing radiation, up to about 1000 times the lethal dose for humans. How they do so is incompletely understood. We found that the tardigrade Hypsibius exemplaris suffers DNA damage upon gamma irradiation, but damage is repaired. We show that tardigrades have a specific and robust response to ionizing radiation: irradiation induces a rapid and dramatic upregulation of many DNA repair genes. By expressing tardigrade genes in bacteria, we validate that increased expression of some repair genes can suffice to increase radiation tolerance. We show that at least one such gene is necessary for tardigrade radiation tolerance. Tardigrades’ ability to sense ionizing radiation and massively upregulate specific DNA repair pathway genes may represent an evolved solution for maintaining DNA integrity.
Project description:Tardigrades can survive remarkable doses of ionizing radiation, up to about 1000 times the lethal dose for humans. How they do so is incompletely understood. We found that the tardigrade Hypsibius exemplaris suffers DNA damage upon gamma irradiation, but damage is repaired. We show that this tardigrade has a specific and robust response to ionizing radiation: irradiation induces a rapid upregulation of many DNA repair genes. This upregulation is unexpectedly extreme, making some DNA repair transcripts among the most abundant transcripts in the animal. By expressing tardigrade genes in bacteria, we validate that increased expression of some repair genes can suffice to increase radiation tolerance. We show that at least one such gene is important for tardigrade radiation tolerance. We hypothesize that tardigrades’ ability to sense ionizing radiation and massively upregulate specific DNA repair pathway genes may represent an evolved solution for maintaining DNA integrity.
Project description:Recent studies have shown that proteins unique to tardigrades are involved in the remarkable ability of these small animals to withstand desiccation and ionizing radiation (IR). For resistance to IR, only one tardigrade unique protein has been identified so far: Dsup, for DNA damage suppressor, found in R. varieornatus and H. exemplaris. Rv-Dsup protects from DNA damage by X-rays in human cells, suggesting that DNA protection is important for resistance to IR. Here, we chose to investigate the role of DNA repair and search for novel tardigrade unique genes involved in resistance to IR. For this, we performed an unbiased proteome analysis of H. exemplaris either untreated, or at 4h post-irradiation, 24h post-irradiation and after Bleomycin treatment.
