Researchers at the  University of Copenhagen, Denmark, have identified a mechanism that  prevents natural DNA errors in our cells. These errors can lead to permanent  damage to our genetic code and potentially diseases such as cancer.
Cassie Sims
Mutations occurring in human DNA can lead to fatal diseases  like cancer. It is well documented that DNA-damaging processes, such as smoking  tobacco or being exposed to high levels of ultraviolet (UV) light through  sunburn, can lead to increased risk of developing certain forms of cancer. 
Unfortunately, sometimes DNA damage can be spontaneous and  occur as part of normal cellular processes such as DNA replication. Scientists  have been interested in how this occurs and associated risk factors for many  years.
In adult humans 250 bn cells divide and replenish each day. Damage to DNA occurs regularly during this process, but the most harmful is that which can be inherited – passed on from mother cells to newly born daughter cells. If the mother cell cannot fix the DNA it is vital that the daughter cell can, to ensure the damage isn’t passed on further.
Scientists at the University of Copenhagen have labelled a specific part of a cell that plays a vital role in DNA replication to monitor the processes occurring. This has made it possible, for the first time, to observe the fate of inherited DNA damage from mother to daughter cells. Tracking living cells under a microscope for up to days at a time is a challenging task.
The researchers found that the cell made attempts to repair  the inherited damaged DNA using a ‘repair toolkit’. The key molecular part of  this toolkit is an enzyme called RAD52, which now qualifies as a tumour-suppressing protein and can guard our DNA against potential cancer-causing  mutations.
It is hoped that this new knowledge may help improve cancer  therapy. Understanding the timing and mechanisms of DNA repair could lead to  the development of new drugs and minimisation of treatment side effects.
‘Our work reveals unexpected ways in which cells deal with inherited DNA damage. With the identification of the key proteins driving this process, we have laid the foundation for investigations into potential therapeutic applications,’ says Julian Spies, postdoc at the Novo Nordisk Foundation Centre for Protein Research at the university.
DOI: 10.