Biology Department, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Biology Department, The University of North Carolina at Asheville, Asheville, NC 28804, USA.
Biology Department, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Curr Biol. 2024 May 6;34(9):1819-1830.e6. doi: 10.1016/j.cub.2024.03.019. Epub 2024 Apr 12.
Tardigrades can survive remarkable doses of ionizing radiation, up to about 1,000 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 the damage is repaired. We show that this species 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 in vivo for tardigrade radiation tolerance. We hypothesize that the tardigrades' ability to sense ionizing radiation and massively upregulate specific DNA repair pathway genes may represent an evolved solution for maintaining DNA integrity.
缓步动物能够承受惊人剂量的电离辐射，其承受量约为人类致死剂量的 1000 倍。至于它们是如何做到这一点的，目前还不完全清楚。我们发现，缓步动物 Hypsibius exemplaris 在伽马辐射下会遭受 DNA 损伤，但这种损伤可以得到修复。我们表明，这种物种对电离辐射有特定且强大的反应：辐射会迅速上调许多 DNA 修复基因。这种上调令人惊讶地极端——使一些 DNA 修复转录本成为动物中最丰富的转录本之一。通过在细菌中表达缓步动物基因，我们验证了一些修复基因的表达增加足以提高辐射耐受性。我们表明，至少有一种这样的基因对于缓步动物的辐射耐受性很重要。我们假设，缓步动物感知电离辐射并大量上调特定的 DNA 修复途径基因的能力，可能代表了维持 DNA 完整性的一种进化解决方案。
