Cryo-EM structures of RAD51 assembled on nucleosomes containing a DSB site. (https://pubmed.ncbi.nlm.nih.gov/38509361/)

These scientists wanted to understand how a protein called RAD51 helps to repair breaks in our DNA. They used a special technique called cryo-electron microscopy to take very detailed pictures of RAD51 when it is attached to a structure in our cells called a nucleosome.

They found that RAD51 can take on two different shapes when it is attached to the nucleosome - one looks like a ring and the other looks like a filament. In the ring shape, RAD51's parts on the outside of the ring directly interact with the DNA in the nucleosome where the break is located. In the filament shape, RAD51 helps to pull apart the DNA in the nucleosome to expose the damaged area.

The scientists also discovered that certain changes in RAD51 can make it harder for the protein to attach to the nucleosome, which can then affect how well it can repair the DNA. They tested this by making similar changes in a similar protein in yeast cells and found that those cells had trouble repairing their DNA properly.

Overall, this study helped the scientists understand better how RAD51 works with nucleosomes to find and fix breaks in our DNA, which is important for keeping our cells healthy.

Shioi T., Hatazawa S., Oya E., Hosoya N., Kobayashi W., Ogasawara M., Kobayashi T., Takizawa Y., Kurumizaka H. Cryo-EM structures of RAD51 assembled on nucleosomes containing a DSB site. Nature. 2024 Apr;628(8006):212-220. doi: 10.1038/s41586-024-07196-4. Epub 2024 Mar 20.