ATR blocks telomerase from converting DNA breaks into telomeres. (https://pubmed.ncbi.nlm.nih.gov/38359122/)

These scientists wanted to understand how a specific enzyme called telomerase can cause problems when DNA in our cells gets broken. They found that when certain breaks happen in our DNA, telomerase can add extra DNA sequences to try to fix the break. This can sometimes lead to mistakes in the DNA, like adding extra telomeres or deleting parts of the DNA.

To study this, the scientists created a way to see how telomerase behaves when DNA breaks occur in human cells. They used tools called Cas9 and I-SceI to create these breaks in the DNA. They found that telomerase can add extra DNA sequences to the broken parts, which can be harmful to the cell's genetic material.

However, they also discovered that our cells have a way to protect themselves from these mistakes. A protein called ATR kinase can stop telomerase from adding extra DNA when the breaks are being repaired. This helps prevent any harmful changes to the DNA.

Overall, the scientists learned that while telomerase can sometimes cause problems in normal cells, it might actually help cancer cells survive and grow. This study helps us understand more about how our cells work and how certain processes can impact our health.

Kinzig CG., Zakusilo G., Takai KK., Myler LR., de Lange T. ATR blocks telomerase from converting DNA breaks into telomeres. Science. 2024 Feb 16;383(6684):763-770. doi: 10.1126/science.adg3224. Epub 2024 Feb 15.