Researchers have uncovered the way that cells detect DNA damage, an emergency response that is key to preventing tumours developing.
The alarm does not detect damage to DNA directly, but instead responds to molecules of RNA, the molecular cousin to DNA, getting damaged and colliding with each other.
The process was tested in mice that had been sunburned, where UV light had damaged RNA and caused it to collide with ribosomes, the cell’s protein factories.
A protein called ZAK detects the collisions and raises an alarm that triggers an inflammatory response, causing the cells to swell and redden in a process familiar to anyone who has got sunburnt.
When mice were genetically modified to lack ZAK, they did not recognise the RNA collisions, and took far longer to show the symptoms of sunburn.
This shows, counter-intuitively, that RNA, not DNA, acts as the cellular alarm for genetic damage.
