Tuesday, July 13, 2010

DNA 'molecular scissors' discovered

2010-07-12

Scientists at the University of Dundee have discovered a protein that acts as a 'molecular scissors' to repair damaged DNA in our cells, a finding which could have major implications for cancer treatments.

Dr John Rouse and colleagues in the Medical Research Council (MRC) Protein Phosphorylation Unit, which is based in the College of Life Sciences at Dundee, discovered a protein, known as FAN1, which is present in each cell and plays a vital role in maintaining healthy DNA and thus prevents mutations which can lead to cancers.

'The DNA in our cells is like an instruction manual for the proper working of each cell,' said Dr Rouse, a Programme Leader in the Medical Research Council Protein Phosphorylation Unit in the College of Life Sciences.

'A major problem is that DNA becomes damaged regularly. 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.

'However, cells are very good at recognising when DNA has become damaged and they are good at finding DNA damage and repairing it. For example, cells can quickly detect breakages in DNA and quickly fix these breaks. Many different factors help this process but we still haven't identified all of them or exactly how this process works.

'With our findings we have unlocked a major part of the puzzle. We discovered a new protein, FAN1, which is essential for the repair of DNA breaks and other types of DNA damage.

'During repair of DNA damage, DNA 'flaps' are produced that must be trimmed for repair to be completed. These leftover pieces of DNA get in the way during DNA repair and that is why they have to be removed. FAN1 carries out this task, and in this sense it acts like a 'molecular scissors'.

'Our study shows that superfluous pieces of DNA are cut by FAN1. 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.

Physorg

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