According to R. Scott Williams, Ph.D., the proteins that repair DNA are like the molecular sentinels that home in on damaged DNA and protect cells from environmental damage. He said oftentimes these same proteins are mutated in heritable neurodegenerative diseases and syndromes that predispose a person to cancer. ..

...determined how a protein known as aprataxin functions in yeast. Aprataxin participates in the repair of damaged DNA in humans, and mutations in the gene that encodes aprataxin (APTX) cause hereditary neurological disorders. Until recently, scientists didn’t understand how aprataxin protected DNA or how the gene mutations shut down the protein.

.. final critical step in repairing damaged DNA is called ligation, which involves chemically joining broken strands of DNA together. Like many biological processes, ligation can fail when DNA ligases attempt to link normal DNA strands with strands that have been modified as a result of environmental DNA damage. Such failure results in the production of additional DNA damage called DNA adenylates. Aprataxin acts as a DNA ligase proofreader by repairing DNA adenylates, but mistakes in the protein can have deleterious effects in humans...

http://www.niehs.nih.gov/news/newsle...aphy/index.cfm

(WOW!!! Madelyn)