The authors of the new work have found a new explanation for why people in space begin to age quickly. The point is that DNA replication under microgravity conditions is more error-prone.
The researchers decided to find out if enzymes can accurately copy cellular DNA under microgravity conditions. The experiment was carried out in an airplane flying in a parabolic pattern: this way you can get conditions close to weightlessness.
DNA polymerases are essential enzymes for copying and repairing DNA. Even under ideal conditions, they make mistakes. Under microgravity conditions, DNA polymerases become more error prone. – Aaron Rosenstein, University of Toronto Fellow
Previously, researchers found that when DNA is exposed to cosmic rays and solar particles, it can actively mutate. Changes in individual nucleotides, cross-links, inversions and deletions caused by cosmic radiation increase the risk of developing cancer, genetic abnormalities in a growing fetus, and also contribute to tissue degradation and the development of cataracts.
But it was unknown whether weightlessness affects human DNA replication. If the copies of DNA polymerase are less accurate, then mutagenicity increases with each new copy. This leads to a higher incidence of cancer. In 2020, researchers at the University of Rome, Tor Vergata, discovered that cosmic radiation destroys cells and contributes to the diseases commonly associated with aging.
The authors of the new work were the first to find out that under zero gravity, the error rate in DNA polymerases is higher in E. coli bacteria. During their work, they observed one cycle of replication of a DNA fragment under microgravity conditions.
