DNA repair 'scissors' discovered
Researchers say they have unlocked a "major part" in the puzzle of understanding how DNA repairs itself.
A team from the University of Dundee said they believed the finding could have implications for the future treatment of cancer.
They have discovered a protein, known as FAN1, which plays a vital role in maintaining healthy DNA.
Researchers described the protein as "molecular scissors" which repair damaged DNA in human cells.
This could help to prevent mutations which eventually lead to cancer.
Dr John Rouse, who is heading the team behind the discovery, said a major problem with DNA is that it is regularly damaged.
He said: "If DNA damage is not fixed quickly then these instructions are changed and the result is mutations - undesirable changes in DNA - that can cause the cell to become abnormal.
"This is essentially what causes cancer."
Scientists have still to identify all the different factors contributing to DNA repair.
However, Dr Rouse said: "With our findings we have unlocked a major part of the puzzle."
The team found that during the natural DNA repair process, DNA 'flaps' are produced that need to be trimmed if the repair is to be completed.
These leftover pieces of DNA can get in the way during the repair process so must be removed.
FAN1 carries out this task, acting as "molecular scissors", said Dr Rouse.
"Our study shows that superfluous pieces of DNA are cut by FAN1," he said.
"Cells that do not have FAN1 are unable to repair DNA breaks and their DNA becomes irreversibly damaged and cells die. This underlines the fundamental importance of FAN1."
He added: "Now that we have identified FAN1 and the role it plays in repairing DNA we can start to develop drugs that inhibit it.
"This may have a significant effect in cancer, primarily in helping to greatly enhance the efficacy of drugs used in chemotherapy treatments."
The research is published in the latest edition of the journal Cell.
The work was funded by the Medical Research Council.